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   34119篇
  免费   155篇
  国内免费   3篇
财政金融   5654篇
工业经济   2071篇
计划管理   5758篇
经济学   7487篇
综合类   756篇
运输经济   143篇
旅游经济   366篇
贸易经济   7480篇
农业经济   936篇
经济概况   2982篇
信息产业经济   45篇
邮电经济   599篇
  2024年   78篇
  2021年   132篇
  2020年   233篇
  2019年   341篇
  2018年   2610篇
  2017年   2399篇
  2016年   1579篇
  2015年   379篇
  2014年   550篇
  2013年   1780篇
  2012年   925篇
  2011年   2424篇
  2010年   2241篇
  2009年   2030篇
  2008年   2041篇
  2007年   2325篇
  2006年   519篇
  2005年   816篇
  2004年   812篇
  2003年   921篇
  2002年   612篇
  2001年   407篇
  2000年   381篇
  1999年   314篇
  1998年   345篇
  1997年   337篇
  1996年   339篇
  1995年   290篇
  1994年   292篇
  1993年   307篇
  1992年   299篇
  1991年   277篇
  1990年   257篇
  1989年   232篇
  1988年   177篇
  1987年   203篇
  1986年   228篇
  1985年   318篇
  1984年   320篇
  1983年   316篇
  1982年   280篇
  1981年   270篇
  1980年   222篇
  1979年   240篇
  1978年   175篇
  1977年   190篇
  1976年   158篇
  1975年   129篇
  1974年   119篇
  1973年   108篇
排序方式: 共有10000条查询结果,搜索用时 21 毫秒
991.
Applying econometric analysis to a model recently used by Parish, this article examines the short-run implications for consumers and producers of the pricing decisions of the Western Australian Egg Board over the period 1953-54 to 1962-63.  相似文献   
992.
Alternative Firm Strategies for Signaling Quality in the Food System   总被引:1,自引:0,他引:1  
Dynamics in the global food system, coupled with rapid advance in agricultural biotechnology, have resulted in additional demands for capturing information and sharing information vertically within the supply chain. Food safety and quality characteristics are a cornerstone of this information demand. Events such as foot-and-mouth disease (FMD) and bovine spongiform encephalopathy (BSE), genetic engineering and animal welfare concerns have laid the foundation for additional information need.
Managers of private firms within the food supply chain must decide how to respond to the situation. A crucial component of the problem is what and how to provide information to downstream customers as well as stipulate what and how information is received from upstream suppliers. Alternative signaling mechanisms abound. The choice among these alternative signals, or combination of alternatives, has both short- and long-run implications for the reputation of the firm, its products or services, and the efficiency with which it conducts its business. The signaling problem in the supply chain is bidirectional and has three critical dimensions: information asymmetry, incentive asymmetry, and arduous measurability. From a broad perspective, the choice set for signaling includes: strategies that rely on third-party protocols and procedures; differentiation through branding and reputation; indemnification strategies such as insurance, warranties, and bonding; and coordination strategies such as strategic alliances and vertical integration (intemalization). Each mechanism for signaling differentially influences the three dimensions of the signaling problem. No globally optimal strategy solution exists. Differentiation through branding and reputation mitigate the signaling problem relatively well compared with the other alternatives.  相似文献   
993.
The European Union spent about two billion ECU per year on subsidies for the olive oil sector, of which Spain received about 35%. For the rainfed areas in southern Spain the olive oil sector is crucial, and so are these subsidies. The European Commission has formulated two options to change the subsidy system, but these do not take the production systems and environmental aspects into account. Many olive plantations are affected by soil erosion. This paper analyses the olive tree production systems in southern Spain, the subsidy systems and the soil erosion problems. It then raises the question whether the subsidies could not be provided in a different way, in order to make olive tree cultivation more sustainable by reducing soil erosion and flood hazard.  相似文献   
994.
This paper estimates technical efficiency (TE) measures using four alternative production frontier models, and evaluates the sensitivity of the results to the choice of methodology. The Cobb-Douglas functional form along with data for 1982 and 1983 from 404 dairy farms located throughout six northeastern states in the US are used in the estimation. A general conclusion is that, broadly speaking, frontier function models are neutrally upwardly scaled versions of the OLS or average model. A second conclusion is that different models yield markedly different efficiency levels across firms. However, the correlation between the indexes from the various methods is high, which implies that the ordinal ranking of firms according to their measured level of technical efficiency appears to be independent of the method used for a given year. By comparison, the correlation between efficiency indexes for the same method across time, although positive, is much lower than the previous set of correlations. Correlation analysis of efficiency versus farm size and of efficiency versus returns over variable costs, based on the alternative models, yielded consistent results.  相似文献   
995.
The United States (US) exports more than US$6 billion in agricultural commodities to the European Union(EU) each year, but one issue carries the potential to diminish this trade: use of biotechnology in food production. The EU has adopted more stringent policies towards biotechnology than the US. Understanding differences in European and American policies towards genetically modified (GM) foods requires a greater understanding of consumers’ attitudes and preferences. This paper reports results from the first large‐scale, cross‐Atlantic study to analyse consumer demand for genetically modified food in a non‐hypothetical market environment. We strongly reject the frequent if convenient assumption in trade theory that consumer preferences are identical across countries: the median level of compensation demanded by English and French consumers to consume a GM food is found to be more than twice that in any of the US locations. Results have important implications for trade theory, which typically focuses on differences in specialization, comparative advantage and factor endowments across countries, and for on‐going trade disputes at the World Trade Organization.  相似文献   
996.
Alternative land management practices, including agroforestry, help to maintain levels of soil organic matter (SOM) and can facilitate soil carbon (C) sequestration for mitigating atmospheric CO2 emissions. This study quantified C inputs and determined the changes of the soil C pool in a 19-year-old Gliricidia sepium alley cropping system, studied at two fertiliser levels (tree prunings only [? N], and tree prunings plus chicken manure [+ N]), and was compared to a sole crop system. Carbon input from tree prunings ranged from 455 to 457 g C m? 2 y? 1, whereas C inputs from crop residues were similar between alley- and sole crops ranging from 121 to 159 g C m? 2y? 1. The soil organic C (SOC) pool in the alley crop was 16–23% higher than the sole crop. In the 19th year of alley farming, SOC was significantly higher (p < 0.05) in the alley crop (3.2%) compared to the sole crop (2.4%), and was also greater compared to that at the time of establishment of the agroforestry system (2.8%). Gross SOC turnover to a 20-cm depth ranged from 12 to 14 years in the + N and ?N alley crops compared to 49 and 50 years in the + N and ?N treatments for the sole crops. Residue stabilisation efficiency in the alley crops was 39% and 55% in + N and ?N treatments respectively.  相似文献   
997.
We identify the impact of emergency food aid programs after the 2002 drought in rural Ethiopia on future welfare. Based on a difference-in-differences matching estimator, participation in food-for-work increases growth in total consumption and food consumption eighteen months after the drought. Separately, receiving free food raises growth in food consumption, but, surprisingly, negatively impacts food security. Food-for-work benefited households in the middle and upper tail of the consumption distribution, while the better-targeted free food program benefited the poorest. Evidence suggests these impacts demonstrate accumulated and persistent effects of food aid received in the first twelve months after the drought.  相似文献   
998.
Why Farmers Quit: A County-Level Analysis   总被引:1,自引:0,他引:1  
We identify the effects of alternative explanatory variables on the propensity of U.S. farmers to cease farming, with a particular emphasis on understanding the roles of off-farm employment and federal farm program payments. Conventional ordinary least squares analysis using all counties suggests that off-farm employment has no statistical effect on the (net) number of farmers quitting between 1987 and 1997, ceteris paribus . A more refined analysis, which separates counties losing farmers from those that gained farmers, reveals subtle and less clear-cut effects of off-farm employment (and federal program payments) on farm exits.  相似文献   
999.
Recent work by agricultural economists has failed to adequately identify why consumers desire country-of-origin labeling, a key piece of information needed to determine whether a market-failure exists. This paper brings to the attention of agricultural economists a sizable body of literature on country-of-origin effects from the marketing and business disciplines. Based on this literature, we draw a distinction between several consumer motivations for origin labels and we identify which of these is cause for public policy. We propose several research questions that require answers if the consequences of country-of-origin labeling policy are to be fully understood.  相似文献   
1000.
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