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   2137篇
  免费   72篇
  国内免费   17篇
财政金融   124篇
工业经济   66篇
计划管理   256篇
经济学   703篇
综合类   227篇
运输经济   9篇
旅游经济   19篇
贸易经济   191篇
农业经济   414篇
经济概况   217篇
  2024年   3篇
  2023年   25篇
  2022年   19篇
  2021年   37篇
  2020年   93篇
  2019年   34篇
  2018年   47篇
  2017年   80篇
  2016年   89篇
  2015年   50篇
  2014年   118篇
  2013年   189篇
  2012年   140篇
  2011年   170篇
  2010年   158篇
  2009年   156篇
  2008年   146篇
  2007年   116篇
  2006年   128篇
  2005年   100篇
  2004年   57篇
  2003年   61篇
  2002年   44篇
  2001年   51篇
  2000年   30篇
  1999年   26篇
  1998年   23篇
  1997年   13篇
  1996年   11篇
  1995年   3篇
  1994年   6篇
  1993年   3篇
排序方式: 共有2226条查询结果,搜索用时 31 毫秒
51.
In recent years, numerous articles have addressed management strategies aimed at assisting forests to adapt to climate change. However, these seldom take into account the practical and economic implications of implementing these strategies, notably, supply of forest plants and seed. Using semi-structured interviews with practitioners involved in the plant and seed supply chain in Great Britain, we highlight a series of practical and economic bottlenecks commonly encountered in the supply of locally sourced seed and domestically produced planting stock for native woodland and hedging markets. We find that adoption of alternative seed sourcing strategies, designed specifically to account for directional climate warming, is likely to exacerbate existing problems by adding further complexity to decisions nurseries make about tree species and seed origins to produce. The lack of long-term market predictability brought about by the current configuration of forestry grants and regulations and, in particular, the administrative systems for processing grant applications is identified as a major impediment to having a sustainable and competitive supply of home-grown and currently adapted planting stock. Finally, the time and effort it takes to supply healthy plants for native woodland creation projects deserves much wider recognition throughout the industry and will be crucial if planting objectives are to be met sustainably.  相似文献   
52.
This paper aims to provide a deeper understanding of transition drivers by reviewing four major strands of inquiry in transition studies: Multi Level Perspective (MLP); Strategic Niche Management (SNM); Transition Management (TM); Technological Innovation Systems (TIS). To the best of our knowledge, none of these contributions have so far provided a clear-cut classification of main drivers of transitions, as evidenced by the difficulty of practitioners in reaching goals as entrepreneurs, or policy makers in supporting economic growth. We believe that these theoretical streams share views relating the origin and drivers of transitions and that the analysis of the multi-level developments and systemic sub-processes by using the Integrative Propositional Analysis (IPA) allows for a more comprehensive identification of transition drivers. By mapping causal relationships within each perspective and by developing an integrative framework that takes in due account of overlaps between theories, we derived a new conceptual structure for the identification of transitions’ drivers.  相似文献   
53.
The growth of an even-aged stand usually follows a S-shaped pattern, implying that the growth function is convex when stand age is low and concave when stand age is high. Given such a growth function, the Faustmann model could in theory have multiple optima and hence an interior local minimum solution. To ensure that the rotation age at which the first derivative of the land expectation value equals zero is a maximum, it is often assumed that the growth function is concave in stand age. Yet there is no convincing argument for excluding the possibility of conducting the final harvest before the growth function changes to concave. We argue that under normal circumstances the Faustmann model does not have any interior minimum. It is neither necessary nor proper to assume that the growth function is concave in the vicinity of the optimal rotation age. When the interest rate is high, the optimal rotation may lie in the interval on which the growth function is convex, i.e. before volume or value growth culminates.  相似文献   
54.
This paper analyses the reliability and consistency of subjective well‐being measures, using the Life in Transition Survey. Drawing on two life satisfaction questions with alternative scales, our results do not reveal substantial biases in accounts of life satisfaction due to framing. Subjective individual assessments of household relative income position, on the other hand, do not appear to be reliable predictors of objective poverty or wealth. We find that subjective relative income position is only weakly correlated with objective welfare measures. There are differences in evaluations of the household's relative standing across different household members, and these differences are correlated with respondent characteristics.  相似文献   
55.
针对多层微波集成电路设计的微带线层间互连问题,介绍了垂直通孔互连、垂直带条互连和层耦合过渡互连三种高性能的互连方法,并且采用三维电磁仿真软件HFSS对这三种互连结构进行了建模和仿真。仿真结果表明,垂直通孔互连和垂直带条互连在0.1~25 GHz的频宽范围内,回波损耗S11<-20 dB,插入损耗S21>-1 dB,互连性能优良,而层耦合过渡互连在20~68 GHz内回波损耗S11 <-20 dB,插入损耗S21>-1 dB,具有在毫米波频段实现互连的潜力。  相似文献   
56.
It is widely accepted that disparities in education contribute to the poor labour market outcomes experienced by ethnic minority groups and consequently to their poverty. In this article, I analyse differential educational benefits in Bulgaria and compare returns to education for the Roma minority with the majority population and the Turkish minority. I show that both ethnic minority groups have lower education levels and employment rates than the majority population and that they also have lower returns to education. This result could be related to minorities' lower education quality as well as to discrimination in the labour market. Integration policies should thus aim to improve employability and labour market competence of vulnerable groups starting from school.  相似文献   
57.
The westernization of Asian countries has led to the rapid expansion of Western-style fast-food restaurants, which are believed to be fueling an unprecedented rise in body mass in these countries. This study tests this belief using longitudinal data from China. Exploiting the opening of a Western-style fast-food restaurant in a particular community, we conduct a transition analysis to make a more convincing causal interpretation than the standard cross-sectional or fixed-effects approach. Considering several measures of fatness, we find no robust evidence of Western fast food having a substantial effect overall, but there is some indication of effect heterogeneity.  相似文献   
58.
The lack of effective farmer demand is a major factor that restricts the development of China's forest insurance. To solve this problem, this study uses a Logit model to conduct an empirical analysis of relevant factors in the farmers’ demand for forest insurance, based on field survey data of Lin’an County, Zhejiang Province. The results show that the farmers’ understanding of forest insurance, the proportion of forestry revenues in the total household income, forest size, forest disaster frequency, forest insurance liability, insurance amount setup, and the farmers’ satisfaction regarding the premium subsidy policy, are the main factors that affect the farmers’ demand for forest insurance. Therefore, we propose to expand forest insurance promotion, raise the farmers’ income, rationally design insurance products, and optimize the forest premium subsidy policy to enhance the farmers’ willingness to participate in forest insurance.  相似文献   
59.
Through travel diaries and interviews with newly retired urban residents in Sweden our aim was to explore (1) mobility patterns in the transition to retirement, (2) the influence of space–time restrictions and resources on mobility and (3) the meaning and embodied experience of mobility. This time-geographic study contributes with knowledge on how mobility is influenced by individual, social and geographical contexts. Illustrated by four cases, our result show that retirement changes the preconditions for mobility and creates new space–time restrictions. To spend more time on projects that were previously carried out outside working time, such as caring for grandchildren, volunteer work and household responsibilities, influenced the informants’ demands for mobility and choice of transport mode. However, the informants have resources that can be seen as strategies to overcome space–time restrictions. Most of the informants found it important to structure the day, to some it was vital to have something to do during the day while others enjoyed the possibility to take each day as it comes. Everyday mobility was a way of forming a structure by getting out of the house, either just for a walk or for making errands. The informants’ embodied experiences of mobility influenced their choice to walk and cycle for transport for the reasons of comfort, get fresh air, or simply to get out of the house. The daily mobility pattern that was established was a result of individual preferences and resources as well as negotiations with family members. We conclude that the transition to retirement is a period when new mobility patterns are considered, evaluated and practiced.  相似文献   
60.
Land Use and Land Cover (LULC) changes have profound impacts on the functioning of (agro)ecosystems and have potential to mitigate global climate change. However, we still lack interdisciplinary methods to project future LULC scenarios at spatial scales that are relevant for local decision making and future environmental assessments. Here we apply an interdisciplinary approach to develop spatially explicit projections of LULC at a resolution of 30 × 30 m informed by historic relationships between LULC and their key drivers, within the context of the four qualitative scenarios of global shared socioeconomic pathways. We apply this methodology to a case study in the Zona da Mata, Brazil, which has a history of major LULC changes. The analysis of LULC changes from 1986 to 2015 indicates that pasture area decreased from 76 to 58 % of total area, while forest areas increased from 18 to 24 %, and coffee from 3 to 11 %. Environmental protection legislation, rural credit for smallholder farmers, and demand for agricultural and raw products were identified as main drivers of LULC changes. Projected LULC for 2045 strongly depends on the global socioeconomic pathway scenarios, and forest and coffee areas may increase substantially under strong government measures in the environmentally conscious Green Road scenario or decrease in the high consumption Rocky Road scenario. Our study shows that under the set of drivers during the past three decades reforestation can go hand in hand with increase of agricultural production, but that major and contrasting changes in LULC can be expected depending on the socioeconomic pathway that will be followed in the future. To guide this process, LULC scenarios at the local scale can inform the planning of local and regional development and forest conservation.  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