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   24390篇
  免费   621篇
  国内免费   14篇
财政金融   4457篇
工业经济   1850篇
计划管理   3991篇
经济学   5321篇
综合类   410篇
运输经济   174篇
旅游经济   467篇
贸易经济   4289篇
农业经济   1102篇
经济概况   2931篇
邮电经济   33篇
  2021年   160篇
  2020年   280篇
  2019年   419篇
  2018年   541篇
  2017年   597篇
  2016年   561篇
  2015年   371篇
  2014年   551篇
  2013年   2475篇
  2012年   710篇
  2011年   770篇
  2010年   664篇
  2009年   721篇
  2008年   753篇
  2007年   657篇
  2006年   591篇
  2005年   615篇
  2004年   550篇
  2003年   535篇
  2002年   481篇
  2001年   462篇
  2000年   457篇
  1999年   443篇
  1998年   437篇
  1997年   441篇
  1996年   429篇
  1995年   369篇
  1994年   362篇
  1993年   396篇
  1992年   402篇
  1991年   393篇
  1990年   328篇
  1989年   299篇
  1988年   252篇
  1987年   295篇
  1986年   299篇
  1985年   423篇
  1984年   412篇
  1983年   421篇
  1982年   375篇
  1981年   364篇
  1980年   353篇
  1979年   347篇
  1978年   256篇
  1977年   265篇
  1976年   233篇
  1975年   211篇
  1974年   195篇
  1973年   171篇
  1972年   126篇
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
61.
62.
We provide a framework in which we link the valuation and assetallocation policies of defined benefits plans with the lifetimemarginal productivity schedule of the worker and the pensionplan formula. In turn, we examine the retirement policies thatare implied by the primitives of the model and the value ofpension obligations. Our model provides an explicit valuationformula for a stylized defined benefits plan. The optimal assetallocation policies consist of the replicating portfolio independentof the pension liabilities. We show that the worker with retirewhen the ratio of pension benefits to current wages reachesa critical value which depends on the parameters of the pensionplan and the discount rate. Using numerical techniques we analyzethe feedback effect of retirement policies on the valuationof plans and on the asset allocation decisions.  相似文献   
63.
64.
65.
This report looks at evaluation studies of a number of cooperative academic-industrfy research programmes in Europe, and suggests that indirect economic benefits should be taken into account as well as motives and goals of participating firms.  相似文献   
66.
The economics of land transfer and title insurance   总被引:3,自引:0,他引:3  
In the presence of uncertainty over the title of land (due to fraud or error), a legal system can protect either the current (innocent) owner, or a previous owner who claims title. The predominant system in the United States generally awards title to the latter in the event of legitimate claim. Thus, current owners frequently purchase title insurance to provide indemnification in the event of a loss. In contrast, the Torrens system awards title to the current owner, but provides for indemnification of any legitimate claimants. We evaluate these two systems and argue that if transaction costs are low, both promote efficient assignment of title (according to the Coase Theorem), but if transaction costs are high, the Torrens system is more likely to award title to the party that values it the most (namely, the current possessor).  相似文献   
67.
Medic (Medicago spp.) pastures are widely grown in rotation with dryland cereal crops in Mediterranean climate zones of Australia. Attempts since the 1960's to introduce this system to Mediterranean west Asia and north Africa (the native region of medic) have not lead to significant adoption; farmers in the region recognize medic, but as a weed and natural pasture plant. This first detailed economic evaluation of the rotational medic system was conducted using a whole-farm linear programming model based on the agricultural system of north-west Syria. The model represents in detail impacts of rotation on yields, labor requirements of alternative farm activities, availability of family and hired labor, subsistence income requirements, livestock feed sources and uses at different times and a choice of sheep stocking rates. Biological data for the analysis are based on a large six-year cropping and grazing experiment near Aleppo on terra-rossa soil with rainfall mainly in winter and averaging about 330 mm annually. The trial compared a dryland medic-wheat system and traditional two-year rotations of wheat with: fallow, watermelon, lentil and vetch. Results indicate that, given current prices and yields from the trial, medic is less profitable than traditional rotations. The model was used to investigate situations in which medic would be economically preferred. Selection of a medic rotation by the model was found to be particularly sensitive to the area of the farm and the price of labor. On small farms, labor availability per hectare is high, favouring the production of labor intensive crops such as lentil and watermelon. On larger farms, labor costs of these enterprises are substantial, increasing the relative profitability of medic, especially if labor prices increase. Interestingly, the relative desirability of medic is more sensitive to its impact on subsequent wheat crops than to the level of pasture production. We also found that modest increases in the prices of sheep products (especially milk) have a major impact on the economic performance of medic. These insights will allow improved focusing and targeting of future research and extension activities.  相似文献   
68.
A conceptual framework of anonymity in Group Support Systems   总被引:2,自引:2,他引:0  
As the development and use of automated systems for collaborative work grows, the need for a better understanding of these systems becomes more important. Our focus is on one type of system, a Group Support System (GSS) and, in particular, on one important aspect of a GSS—anonymity. A conceptual framework for the study of anonymity in a GSS is presented, which describes the general classes of variables and their relationships. These variables include the factors that influence anonymity in a GSS, types of anonymity, and the effects of anonymity on a message sender, receiver, group process, and outcome. Each of these variables is discussed with working propositions presented for important group process and outcome measures. The objectives of this article are to highlight the importance and complexity of anonymity, to act as a guide for empirical investigations of anonymity, and to influence future GSS development and use.  相似文献   
69.
Our paper provides a brief review and summary of issues and advances in the use of latent structure and other finite mixture models in the analysis of choice data. Focus is directed to three primary areas: (1) estimation and computational issues, (2) specification and interpretation issues, and (3) future research issues. We comment on what latent structure models have promised, what has been, to date, delivered, and what we should look forward to in the future.  相似文献   
70.
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