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   1089篇
  免费   34篇
财政金融   329篇
工业经济   92篇
计划管理   177篇
经济学   187篇
综合类   10篇
运输经济   3篇
旅游经济   15篇
贸易经济   155篇
农业经济   69篇
经济概况   86篇
  2023年   7篇
  2022年   6篇
  2021年   6篇
  2020年   17篇
  2019年   31篇
  2018年   32篇
  2017年   23篇
  2016年   29篇
  2015年   10篇
  2014年   34篇
  2013年   100篇
  2012年   30篇
  2011年   46篇
  2010年   35篇
  2009年   42篇
  2008年   45篇
  2007年   45篇
  2006年   44篇
  2005年   29篇
  2004年   31篇
  2003年   28篇
  2002年   29篇
  2001年   30篇
  2000年   29篇
  1999年   25篇
  1998年   25篇
  1997年   25篇
  1996年   20篇
  1995年   24篇
  1994年   18篇
  1993年   11篇
  1992年   15篇
  1991年   16篇
  1990年   15篇
  1989年   8篇
  1988年   12篇
  1987年   6篇
  1986年   8篇
  1985年   16篇
  1984年   14篇
  1983年   14篇
  1982年   15篇
  1981年   12篇
  1980年   9篇
  1979年   5篇
  1977年   5篇
  1976年   14篇
  1974年   6篇
  1973年   5篇
  1972年   4篇
排序方式: 共有1123条查询结果,搜索用时 15 毫秒
51.
Agriculture–nutrition linkages (ANLs) have been increasingly investigated in the literature. However, nutritional returns and costs of household agricultural production practices (APPs) in semisubsistence settings are poorly understood. We fill these knowledge gaps using pooled cross-section data sets in Tajikistan, where semisubsistence farming and undernutrition coexist despite relatively good agricultural infrastructure and education systems. Agricultural diversification, yield enhancement, production expansion are positively associated with various nutritional outcomes, particularly in areas with poor food market access. Decomposition exercises suggest that nutritional returns and costs of these APPs vary across households, and the adoption of APPs is driven by the expected nutritional returns. In Tajikistan, improving nutrition through household ANLs requires growing the smallholder agricultural sector in multiple dimensions, including diversification, intensification, and expansion, while also understanding better the pathways of ANLs and addressing bottlenecks at appropriate stages of such pathways.  相似文献   
52.
In this paper we look at the manner in which ideas coming from complexity science change our understanding of the cognitive powers of agents that is really necessary to explain the evolution of markets and of firms. The general ideas behind complex systems dynamics and evolution are presented and then two examples are treated in detail. The first in an evolutionary model of a market in which some new product is developed by competing firms and their “task” is to find a strategy in terms of quality and price that will be sustainable. This essentially requires agents/firms to discover mutually compatible strategies, and to create thereby sustainable market niches. The second example considers the internal structure of firms, in terms of their constituent working practices and skills. It demonstrates that it is precisely their ignorance of the consequences of adopting any particular practice that generates diversity in the emergent capabilities of firms, exploring the dimension of potential demand and therefore leading to a successful and sustainable business sector. The work supports the notion that the cognitive abilities that are involved are not about deduction and logic, as a traditional view of rationality might suggest, but are about the development and contraction of interpretive frameworks, which will be different for each player. The paper links these examples to a general recognition of the idea that complex, multi-agent systems evolve through successive “structural attractors”—multi-dimensional dynamical systems—with temporary structural stability. Because real systems contain both the structure and deviations from it, then there is a constant probing of structural stability and the possibility of qualitative change to a new structural attractor. This resembles the ideas in biological evolution related to “punctuated equilibria,” but it also links this to the idea of emergent and evolving networks of interaction, never of course near thermodynamic equilibrium.   相似文献   
53.
54.
This article evaluates irrigated agriculture sector response and resultant economic impacts of climate change for a part of the Murray Darling Basin in Australia. A water balance model is used to predict reduced basin inflows for mild, moderate and severe climate change scenarios involving 1, 2 and 4°C warming, and predict 13, 38 and 63% reduced inflows. Impact on irrigated agricultural production and profitability are estimated with a mathematical programming model using a two‐stage approach that simultaneously estimates short and long‐run adjustments. The model accounts for a range of adaptive responses including: deficit irrigation, temporarily following of some areas, permanently reducing the irrigated area and changing the mix of crops. The results suggest that relatively low cost adaptation strategies are available for a moderate reduction in water availability and thus costs of such a reduction are likely to be relatively small. In more severe climate change scenarios greater costs are estimated. Adaptations predicted include a reduction in total area irrigated and investments in efficient irrigation. A shift away from perennial to annual crops is also predicted as the latter can be managed more profitably when water allocations in some years are very low.  相似文献   
55.
Community Supported Agriculture (CSA) programmes have recently received attention for their potential to influence food lifestyle behaviours and health outcomes, though studies have mostly drawn from small samples (n?t-tests assess if paired means are statistically different, and multiple regressions of paired differences on socioeconomic factors, self-reported health, and years of CSA enrolment estimate the effect of respondent characteristics on behaviour change. The results strongly suggest that CSAs have the potential to positively impact shareholders’ food lifestyle behaviours and health outcomes, and that those reporting ‘poor health’ prior to CSA enrolment exhibited the most change overall. These results should be taken as an initial, yet promising, analysis of the impact of CSA participation on shareholder food lifestyle behaviours and health outcomes.  相似文献   
56.
This study measures the economic impact of the first phase of the Cocoa Livelihood Program (CLP‐I), a current World Cocoa Foundation (WCF) project, sponsored by the Bill and Melinda Gates Foundation and aimed at improving the livelihood of over 200,000 small cocoa producers in sub‐Saharan Africa via training, crop diversification, and farmer‐based organizations. Using data collected from 2,048 pre‐ and post‐CLP‐I interviews of cocoa producers in Ghana, Cote d'Ivoire, Nigeria, and Cameroon, the results show that yield enhancements attributable to CLP‐I are 32%, 34%, 50%, and 62% in Ghana, Côte d'Ivoire, Nigeria, and Cameroon, respectively. Using a total program cost of $151–$200 per beneficiary and estimated annual benefits of $109–$322 per beneficiary over 25 years, the benefit‐cost ratios are estimated to range from $18 to $62 for every dollar spent on human capital development. These results suggest the WCF should endeavor to increase the number of farmers who receive all, not some, of the components of the program. This would not only help ensure that each producer obtains as much human capital as possible from each of the training programs but increases the probability of reaching the CLP goal of doubling the income of cocoa‐growing households.  相似文献   
57.
Childhood drowning remains a serious public health problem worldwide. The Australian Water Safety Council has set as one of its highest priorities the reduction of drowning deaths in children aged 0–14 years. However, concerns have recently been raised that many students completing primary school still lack the ability to recognize potential aquatic risks, cope with emergencies or assist someone else in danger. In this study, 107 primary school children aged 11–12 completed a one day training programme led by surf lifesaving instructors. Pre, post and eight week follow-up measures showed statistically significant improvements in recognition of the red ‘beach closed’ flag, aquatic safety signs, how to identify a rip current and choosing the safest place to swim at a beach that included a rip current in the picture. Following training students were more willing to provide first aid assistance to family members and friends in an emergency situation. Findings reinforce the value of school-based training that provides a general foundation for aquatic safety, with the caveat that current programmes must be evaluated to ensure their content has a robust prevention focus.  相似文献   
58.
This paper considers whether the National Economic Association and its journal the Review of Black Political Economy have enhanced the scholarly status of black economists. A bibliometric analysis reveals that while the typical black economist has never published in the Review of Black Political Economy, the share of black economists publishing in the Review of Black Economy approximates the share of all articles published on the economic and political economy of race by black economists, and the share of articles published in the Review of Black Political Economy by black economists appears higher than typical journals in economics—particularly for black economists employed at Historically Black Colleges and Universities. We also find that similar to other economics journals non-black economists dominate the share of published articles, and publications in the Review of Black Political Economy appear to be consistent with Lotka’s Law of scientific productivity suggesting that the journal is a standard outlet for research no different from any other science journal. Our results imply a plausible counterfactual that if the National Economic Association and Review of Black Political Economy did not exist, the scholarly status of blacks in the economics profession would have been lower than currently observed.  相似文献   
59.
A farm-level deterministic and stochastic nonparametric tests of profit maximization and cost minimization behaviour for a sample of 112 Kansas farms was completed from 1996 to 2013. Allowing for monotonic non-regressive technological change and using a 10% significance level, 73 farms violated the profit-maximization hypothesis and 58 farms violated the cost minimization hypothesis. More profit maximization violations existed relative to cost minimization violations. However, comparing these results with results for 289 Kansas farms using data from 1973 to 1990, farms have significantly reduced profit maximizing violations. Cost minimizing behaviour has not changed substantially.  相似文献   
60.
We discuss a mixed methodology for analyzing pile sorting data. We created a list of 14 barriers to colon cancer screening and recruited 18, 13, and 14 participants from three American Indian (AI) communities to perform pile sorting. Quantitative data were analyzed by cluster analysis and multidimensional scaling. Differences across sites were compared using permutation bootstrapping. Qualitative data collected during sorting were compiled by AI staff members who determined names for the clusters found in quantitative analysis. Results showed five clusters of barriers in each site although barriers in the clusters varied slightly across sites. Simulation demonstrated type I error rates around the nominal 0.05 level whereas power depended on the numbers of clusters, and between and within cluster variability.  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