首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   4606篇
  免费   123篇
  国内免费   11篇
财政金融   136篇
工业经济   83篇
计划管理   549篇
经济学   643篇
综合类   240篇
运输经济   52篇
旅游经济   67篇
贸易经济   198篇
农业经济   2473篇
经济概况   299篇
  2024年   17篇
  2023年   70篇
  2022年   75篇
  2021年   101篇
  2020年   351篇
  2019年   106篇
  2018年   111篇
  2017年   242篇
  2016年   207篇
  2015年   158篇
  2014年   309篇
  2013年   305篇
  2012年   305篇
  2011年   401篇
  2010年   318篇
  2009年   292篇
  2008年   209篇
  2007年   250篇
  2006年   245篇
  2005年   181篇
  2004年   137篇
  2003年   107篇
  2002年   65篇
  2001年   46篇
  2000年   30篇
  1999年   23篇
  1998年   14篇
  1997年   11篇
  1996年   3篇
  1995年   8篇
  1994年   4篇
  1993年   7篇
  1992年   5篇
  1991年   5篇
  1990年   1篇
  1988年   2篇
  1986年   1篇
  1985年   8篇
  1984年   6篇
  1982年   2篇
  1981年   1篇
  1977年   1篇
排序方式: 共有4740条查询结果,搜索用时 31 毫秒
51.
Standard New Keynesian models have often neglected temporary sales. In this study, we ask whether this treatment is appropriate. We use Japanese scanner data covering the last two decades and find a negative correlation between the frequency of sales and hours worked. We then construct a model that takes households' decisions regarding their allocation of time for work, leisure, and bargain hunting into account. We show that the decline in hours worked explains the rise in the frequency of sales. The real effect of monetary policy shocks weakens by around 40% due to temporary sales, but monetary policy still matters.  相似文献   
52.
Natural vegetation enhances the value of agricultural landscapes for people and wildlife. However, the role of anthropogenic versus topographic factors in driving the extent of natural vegetation cover within agricultural lands at large spatial scales remains unexplored. I assessed the influence of anthropogenic and topographic variables on the extent of agricultural mosaics with high natural vegetation cover in the country of Turkey where a large extent of natural and semi-natural vegetation is maintained by traditional agriculture. GIS layers depicting human land use, elevation, slope, roads and population data were obtained and summarized at two spatial scales, within provinces and for 100 km2 grid cells covering the country’s entire agricultural land area. Average farm size was also obtained at province level. Hierarchical Partitioning was conducted to determine the independent effect of anthropogenic and topographic variables on the variation in agriculture with high natural vegetation. Slope had the largest independent effect on the variation in the proportion of agricultural mosaic with high natural vegetation cover. The extent of agricultural and settlement area also explained much of the variation in natural vegetation across both grid cells and provinces. The proportion of natural vegetation increased as human population and road density decreased across grid cells and as average farm size decreased across provinces. These results suggest that while topography is the primary driver of natural vegetation cover within agricultural mosaics in Turkey, the pressures associated with urban development and agricultural industrialization may also influence the cultural and wildlife value of agricultural landscapes.  相似文献   
53.
This special issue integrates eleven papers focussing on indicators able to convey the multiple expectations that society has concerning agricultural land. As scale issues have been so far overlooked within this research topic, a particular focus of this themed issue is to highlight the need for reconciling assessments across scales. The shared purpose of the contributions is to examine how the multiple societal expectations concerning agrarian landscapes might be incorporated into land use policy at different governance levels.A core set of these papers were presented in the symposium “Linking social indicators across scales”, to the European Congress of the International Association of Landscape Ecology (IALE) in September 2013 in Manchester, UK. This symposium was organized to create the time and space for a discussion on the issues of scale when capturing societal preferences concerning agrarian landscapes. While the landscape scale was specifically addressed by four papers, seven papers examined broader geographic units in addition to up-scaling and downscaling issues.  相似文献   
54.
Land exploitation, as an important strategy to mitigate farmland loss and stabilize grain production, has been adopted to compensate farmland loss due to rapid urbanization in China. Bounded by the limited capacity and obvious spatial variations of national farmland reserves, it is essential to arrange land exploitation activities timely and reasonably. In this study, we propose an indicator for the status of regional land exploitation, the Exploitation Degree, to facilitate an overview of land exploitation programs in China at both provincial and prefectural levels based on project data from 2006 to 2012. To further our understanding of the regional features of land exploitation activities, we employ the Lasso model to identify and quantitatively assess influencing factors on land exploitation. Our study shows that: (1) contemporary land exploitation practices in China are significantly inconsistent across exploitable farmland reserves. Some areas are greatly over-exploited and such irrational land exploitation has been persistent; (2) related national land plans designed to guide land exploitation efforts centered on resource-rich regions and critical areas do not function as intended. Therefore, we suggest that China⿿s land exploitation policy shall be improved by reconsidering the orientation of land exploitation policy, coordinating land exploitation activities with productivity improvements and eco-system protection, and enhancing the power and scope of the plans in controlling and guiding land resource management.  相似文献   
55.
This paper focuses on the estimation of direct damages caused by three flood scenarios with different return periods in the section Făgetul de Sus – Ghimeş – Palanca Pass of Trotuș River, with the aim of highlighting the need of improved land use plans. The damage for three land use classes (residential building, infrastructure and agriculture) were estimated using the damage curves developed by the European Joint Research Centre (JRC) as well as site specific maximum damage values. The data were processed with the help of the ArcMap 10.2 software and FloodRisk tool from QGIS software. Furthermore, the flood risk was assessed using the damage – probability curves, which associates the damage with the corresponding frequency of occurrence. This method was identified and adapted to the characteristics of the study area in order to develop a methodology of flood risk assessment that is answering the question: does the lack of land use plans increase the vulnerability and the flood damage? The results showed that the greatest damages are registered for the residential building land use class for a flood probability of 0.001. In this case the damages reach up to 60% on the scale range of deterioration factor, the total damage value being 2 million euros. For the same hazard probability the total registered damage value for roads is 7500 euro, for railways is around 12,000 euro, while for agriculture is around 84,000 euro. These results highlight the need of protection measures and land use plans development and implementation. Regarding the protection measures we consider that the egalitarianism would be the concept that should be applied in the study area and also an improved cooperation between government, specialized agencies and local authorities at local level would lead to a more efficient flood risk management process. The proposed methodology can be applied for micro-scale analysis, providing quantitative results regarding the flood damage and flood risk assessment. It includes a detailed vulnerability analysis of the elements-at-risk with the aim of developing a more comprehensive approach of flood risk assessment.  相似文献   
56.
The spread of free trade agreements (FTAs) in Southeast Asia has ignited a debate about their impact on enterprises including the business costs from the Asian ‘noodle bowl’ effect. This paper undertakes a comparative and firm-level analysis of the determinants of FTA use in Indonesia, Malaysia and the Philippines. The likelihood of firms using important ASEAN+1 FTAs (e.g. the ASEAN-China FTA, the ASEAN-Japan FTA and ASEAN-Korea FTA) is positively associated with acquiring knowledge about FTAs, building technological capabilities, and membership in industrial clusters. Non-use of FTAs is explained by a lack of information about FTAs and the absence of FTAs with major trading partners. Key policy implications are the need to improve business support for FTAs, to conclude FTAs with major trading partners, and to create a database on FTA preference use.  相似文献   
57.
A right of commoners to pastures existed since the Early Middle Ages in Anglo-Saxon England and the European mainland, including Tyrol in Austria. Lowland commons institutions were largely dissolved by the 19th century; however, in the European Alps contiguous commons remain alive. Some two thousand alpine commons institutions are registered in the Tyrolean parcel cadaster and land registry. A specific study of West-Tyrolean commons (known as Agrargemeinschaft or AGMs), framed by Ostrom's design principles is presented. General lessons for land policy and land administration are extracted. An interview period was split between the Inn valley and the Ötztal. Roughly half are considered independent: others are regulated by the Tyrolean Agricultural Authority. Some AGMs hold the full bundle of land rights: others only hold pastoral and forestry rights. AGMs consisted either of a single cadastral parcel or several contiguous parcels. In the Inn valley villages the pastoral commons were owned by the municipalities, while in the researched Ötztal, AGMs are frequently the full owners of the commons. AGM membership ranges between 5 and 60 farm households. The number of livestock units pastured was in most cases stipulated in approved regulations. Alpine commons larger than 200 ha are also hunting-zones: revenue is collected from the lease of hunting rights. Most of the alpine commons are designated and used as ski-zones. Upper portions of two alpine commons in the Ötztal are state protected natural areas. The number of farms with pastoral rights is declining at District and State level. Key lessons for land policy and land administration include: Ostrom's design principles being a precondition rather than a panacea; commons institutions requiring one clear ownership party; both public and collective ownership producing success; publically owned commons requiring a local representative; small membership numbers being preferable; small shareholdings not being preferable; decentralized governance being beneficial; internal democratic elections being beneficial; internal boundary records being superfluous; explicit sanctions being superfluous; mixed economies being acceptable; and geography being a significant influence on the longevity of pastoral commons.  相似文献   
58.
The growing demand for a wide range of private and public goods and services from a finite land resource is increasingly challenging for planners at local, regional, national and international scales. The Scottish Government's development of a Land Use Strategy has given salience to resolving conflicts and enhancing synergies in land use. In Scotland, the poorest quality farmland is often designated for nature and landscape conservation and the highest quality farmland often protected for food production. This means that many of the competitive pressures on land are experienced in what we term the ‘squeezed middle’. The paper identifies the multiple (and not exclusively economic) drivers of land use choices and, through an ecosystem services lens, explores three particular areas of land use conflict. These are (i) the continued high level of public support for farming, which has done little to address the problem of low farm incomes; (ii) the pressure to increase woodland planting on farm (and other) land; and (iii) conflicts associated with intensive game management, especially on sporting estates. Using the Scottish situation as an example, the heterogeneity of land use pressures means that there is a danger of the principles of the Land Use Strategy becoming lost in translation from national policy to practical land use decision-making. The appropriate scale for delivery of integrated ecosystem services may therefore be more local than current pilot projects, and may require more active participation of land managers. It may also require policy instruments that are more flexible in adapting to the local context, including payments for ecosystem services.  相似文献   
59.
One of the main issues with the concept of ecosystem services is its absence on the ground in concrete operational decision-making contexts; that is, an implementation gap. In this study, we investigated if this gap could be overcome through the use of open-source data and free tools, and the adoption of a short-term participatory process. We tested these methods in the context of a project in the urban metropolitan area of Bordeaux (Communauté urbaine de Bordeaux: CUB) in France. The ecosystem services were defined using a participatory approach involving local stakeholders, and then selected scenarios were simulated to test the impact of various development or conservation plans. The study addressed three main questions: (1) Is it possible to adopt a simple methodological approach that overcomes the implementation gap through the development of a user-friendly and inclusive method? (2) What is the added value of a participatory approach? (3) With regards to four scenarios in this territory, what are the ES trends in the selected biophysical and monetary indicators, and will knowledge of these trends help planners to shape a sustainable trajectory for the territory?  相似文献   
60.
In the past few decades, urbanisation has become a major phenomenon in European cities, thus representing one of the key human land cover changes with socio-economic and environmental impacts. In the Lisbon metropolitan region it is estimated that 17% of natural and farmland have been transformed into artificial areas. Since the end of 1990s, specific EU guidelines have been issued to contain urban sprawl and preserve agricultural land. Spatial planning in Portugal obviously is integrating these assumptions into the statutory land-use master plans. But what is the performance of this land use planning system regarding land cover evolution itself? Based on the Lisbon metropolitan region (LMR), one of the major areas of urban growth in Portugal, we examine spatio-temporal land cover patterns between 1990 and 2007 by integrating cross-matrix analysis, spatial metrics, and gradient analysis. Additionally, we overlay these land cover dynamics with municipal master plans that regulate land development in order to assess the compliance levels of this land-use regulatory system. Results indicate that: artificial areas are growing by coalescence and/or by scattered development along an urban–rural gradient; agricultural land is reducing and fragmentation is increasing to enlarge peri-urban spaces; there are high levels of conversion of agricultural land into urban land in protected areas, thus showing a lack of compliance to the land use regulatory system visible in the existing gaps between the original land-use assignments of the master plan and the actual developments.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号