全文获取类型
收费全文 | 4606篇 |
免费 | 123篇 |
国内免费 | 11篇 |
专业分类
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 |
出版年
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 15 毫秒
61.
Over the last two decades, extensive literature has examined the socioeconomic and environmental impacts of China's Sloping Land Conversion Program (SLCP), a program that was launched in late 1990s to mitigate the environmental effects of agricultural production and reduce rural poverty. However, little empirical evidence exists with regard to the impact of SLCP on rural households' sensitivity to nature-induced changes and environmental challenges. In this study, household-level data covering the period 1995–2010 from five Chinese provinces were used to examine the effect of SLCP on farmers' sensitivity to climate change. The empirical results show that participation in SLCP significantly reduced farmers' sensitivity to climate change by reducing their dependency on land and natural resources for income, and by diversifying their livelihood options. Spatially, the results reveal that the effect of SLCP on farmers' sensitivity vary across regions. Specifically, SLCP was found to have a ‘rate effect’ on farmers in the Northern regions and a ‘level effect’ on farmers in the Southern regions. Likewise, we found that the effect of SLCP differs considerably across income groups, with the effect on low- and middle-income groups being most significant. The results indicate that subsidy is the main pathway through which SLCP reduces farmers' sensitivity to climate change. In contrast, we found inclusive evidence about the indirect effect of SLCP farmers' sensitivity through the promotion of non-agricultural employment. These results carry major implications with regard to the effectiveness of ecological conservation programs and their mitigation potential through building farmers' resilience in China and ecologically fragile environments. 相似文献
62.
To mainstream sustainability, we need to understand the value gained from sustainability by users. We apply a user-centred design methodology to develop an agile, iterative, incremental and reflexive process to understand the sustainability value proposition for Lufthansa City Center travel agents. We analyse the failure of sustainability communications within the online platforms used by these agents and explore why the agents factor out sustainability information during the customer sales process. We identify how agents and customers understand sustainability, and we explore opportunities to co-create sustainability value. Furthermore, we prototype, and then test, methods of empowering travel agents to communicate sustainability to their customers as a value-adding proposition. 相似文献
63.
Most small-scale social economies are characterised by their deficiency, lack, and/or difficulty in matching natural data. Against this backdrop, this paper builds a relatively uniform theoretical framework and designs a more economical and objective method for demarcating ecological conservation redlines (ECR) based on sensitivity assessment of ecosystem services. The results show that the sensitivity assessment model designed in this study can identify sensitive zones effectively, and that the ECR in Hubei Province are well within the sensitive zones so identified. The delimited areas based on the sensitive assessment of ecosystem services have great similarities (95%) with the actual ECR areas in Hubei Province. The most ecologically important functional zones (EIFZ) can also be identified using the regional ecological sensitivity coefficient. When the threshold of EIFZ is set higher, the probability that it falls within the ecologically sensitive areas is greater and the ECR delimited by the method proposed in this study will be more reliable. Theoretically, the delimitation of ECR can be inserted at any evaluation level with a grid resolution higher than that of the land use data, which can be used as a supplement to the ECR delimitation method in ecology or geography. 相似文献
64.
Researchers have spent substantial effort to identify factors influencing pesticide use intensity. However, few studies have compared the relative importance of these factors. This study examines four categories of factors that potentially influence farmers’ pesticide use decisions by evaluating incentivized experiment data, farm survey data, and remote sensing data in China. Our results suggest that land diversification has the largest effect on farmers’ pesticide use. Compared with the most rice-intensive landscape type, less rice-intensive systems cause farmers to spray less on middle rice. Heavy pesticide use intensity is associated with land fragmentation as small-scale farms still dominate crop production. Farmers’ integrated pest management knowledge has significant effects on pesticide use. We also find that loss and ambiguity preferences, rather than risk preferences, are more likely to affect pesticide use intensity. 相似文献
65.
基于结构方程模型的集聚农户共生认知及影响因素分析:以重庆市为例 总被引:2,自引:0,他引:2
研究目的:探讨对集聚农户共生、集聚区土地利用率提高的影响因素,为提升农户共生的认知水平、优化农户共生关系及促进资源的节约集约利用提供有效路径及理论指导。研究方法:参与式农户调查,结构方程模型。研究结果:(1)户主自身特征、农户家庭特征、集聚共生效益特征及外部环境与政策特征这4类外源潜变量对农户共生认知产生重要影响且影响程度大小不同,其中,集聚共生效益特征的影响最为显著,外部环境与政策特征、户主自身特征和农户家庭特征的影响依次减弱;(2)是否为干部、对原集聚模式的满意度、是否促进农户生产生活条件和政府对集聚区的补贴力度分别对这4类外源潜变量具有较好的解释能力。研究结论:显化农户共生效益、增强"精英"农户及村干部的正向引导、提升农户成员受教育水平、培养农户"共生共荣"理念等是深化农户共生关系,促进和谐乡村人居环境建设的重要路径。 相似文献
66.
Land fragmentation has been identified to greatly undermine crop production in many countries. In the case of Ghana’s customary tenure system, household farmlands are relatively small and are highly fragmented. Recent agricultural drives, however, have focused on farm level interventions that are ad hoc with short-term benefits. A sustainable long-term application of land consolidation which reorganises farmlands may improve yields, reduce the cost of production and improve the incomes of farmers. The successful implementation of land consolidation depends greatly on the suitability of local conditions with respect to land tenure and land use. However, in Ghana’s customary lands, the alignment between the requirements for land consolidation and existing conditions remains unexplored. This study investigated the feasibility of land consolidation within the customary tenure by juxtaposing the local conditions of the study areas with the baseline conditions for land consolidation outlined in literature. Using both qualitative and spatial data, the study revealed some traits of convergence and divergence with respect to the baseline conditions in the study areas. For example, conditions such as the existence of land fragmentation, suitable topography and soil distribution were fully met. Conditions such as the existence of a land bank, technical expertise, and infrastructure and supportive legal frameworks were partially met. The remaining conditions such as the willingness to participate, availability of a land information system and favorable land ownership structure were non-existent. The circumstances surrounding these unmet conditions are deeply embedded in customs and traditions that hardly yield to change. Since these conditions are fundamental for land consolidation, their absence negates the feasibility of land consolidation under the current tenure system of the study areas. 相似文献
67.
68.
Shortfalls in global food production, coupled with the growing visibility of climate change's disruptive effects, have underlined for many observers the importance of devoting rural lands to their ‘optimal’ use, where they can make maximal contributions to the global imperatives of feeding the human population and maintaining vital environmental services. In this context observers have endorsed rural land use planning as a way to insure that, at least in theory, lands get devoted to their best uses. In practice, land use planning in the developing world has resembled ‘organized anarchy’. Small landholders with insecure land tenure, overseas investors seeking large land deals, NGOs representing indigenous peoples, government officials, and staff from international environmental NGOs and multilateral organizations have come together in strategic action fields to struggle over and sometimes negotiate land use plans for contested landscapes. These plans represent a strategic, spatially explicit response to the climate change–biodiversity–food security crisis. 相似文献
69.
The conservation and management of protected areas in urban settings has become increasingly challenging with dynamics over land use change in adjacent urban areas being highly relevant to, but at times conflicting with, the protected area. This study seeks to better understand the implications of land use change processes to urban protected area management through the case study of the Las Piñas – Parañaque Critical Habitat and Ecotourism Area (LPPCHEA) in Metro Manila, Philippines. Factors and processes influencing land use change and protected area management and the impact of stakeholders’ perceptions on protected area were analyzed. The urban protected area in itself has limited influence on its surrounding urban areas, as land use change in these areas is shaped more by social, economic and policy/institutional factors occurring within the context of urban-regional development. The study also found that land use conflict is evident in an urban protected area due to the competing ecosystem services derived by various stakeholders. This discord is deepened by the lack of coordination between land use planning and protected area management. Integrating protected area management with land use planning through legally binding instruments, specific timeframes and clear internal procedures can help resolve land use conflict for an urban protected area at the strategic or policy level. 相似文献
70.
Land use transitions are rated among the leading sources of greenhouse gas emissions in the tropics. They significantly challenge the functioning of ecosystems and affect multi-temporal stability of greenhouse gases such as N2O and soil properties. Studies on dynamics in nitrogen balances are essential in understanding greenhouse gas emissions such as N2O and to manage their impacts on productivity. In this study, multi-temporal Landsat images (1975, 1995 and 2012) were classified to determine land use transitions and potential drivers. The classified images were categorized into degraded and non-degraded lands and eighty sampling plots generated within the entire study area. Soil samples were then collected at 0–15, 15–30 and 30–60 cm depths on each plot and soil nitrogen determined. A regression analysis was developed to determine the influence of forest and grassland degradation on soil nitrogen. Results indicated a significant change in major land use and land cover types. Specifically, there was a decrease in areas covered by forests, woodland and grassland, however, area covered by less dense forest increased. Results also indicated variability in mean nitrogen content between degraded and non-degraded areas and depths. Furthermore, levels of degradation influence nitrogen content up to a soil depth of 30 cm. The present study is relevant in the detailed assessment of the extent of damage and threats posed to biodiversity hotspots in sub-Saharan Africa. These results are transferable to other parts of the world characterized by dynamic ecological transformation. 相似文献