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   32253篇
  免费   344篇
  国内免费   13篇
财政金融   5349篇
工业经济   1918篇
计划管理   5029篇
经济学   7179篇
综合类   767篇
运输经济   100篇
旅游经济   305篇
贸易经济   7284篇
农业经济   816篇
经济概况   3232篇
信息产业经济   45篇
邮电经济   586篇
  2021年   96篇
  2020年   162篇
  2019年   247篇
  2018年   2636篇
  2017年   2426篇
  2016年   1578篇
  2015年   323篇
  2014年   485篇
  2013年   1526篇
  2012年   856篇
  2011年   2392篇
  2010年   2207篇
  2009年   1944篇
  2008年   1983篇
  2007年   2323篇
  2006年   458篇
  2005年   759篇
  2004年   819篇
  2003年   938篇
  2002年   579篇
  2001年   385篇
  2000年   360篇
  1999年   280篇
  1998年   301篇
  1997年   290篇
  1996年   306篇
  1995年   263篇
  1994年   256篇
  1993年   275篇
  1992年   260篇
  1991年   258篇
  1990年   232篇
  1989年   199篇
  1988年   167篇
  1987年   200篇
  1986年   214篇
  1985年   295篇
  1984年   315篇
  1983年   292篇
  1982年   262篇
  1981年   254篇
  1980年   222篇
  1979年   227篇
  1978年   167篇
  1977年   180篇
  1976年   144篇
  1975年   127篇
  1974年   119篇
  1973年   104篇
  1972年   77篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
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   
33.
In this paper the efficiency of the UK stock market is examined using the FT Ordinary share price and dividend indices for the period January 1947 to June 1987. In particular, we examine the validity of the present value model of stock prices using a vector error correction model (VECM). Amongst the findings reported in the paper are that stock prices and dividends are cointegrated and the cross-equation restrictions imposed on the VECM are strongly rejected.  相似文献   
34.
Across nations or regions, the debate on optimum exchange rate cum monetary policies is not yet resolved on three levels. First is the optimum domain of fixed exchange rates versus keeping them flexible. Second is the subordinate debate on whether one needs full monetary union (as in continental Europe) to secure an optimum currency area's internal domain; or, whether virtually fixed exchange rates — where national currencies remain in circulation — can be sufficient. Third is whether a regional grouping of economies with close trade ties (as in East Asia) gain by collectively pegging to an outside currency such as the US dollar. Using an axiomatic approach, which limits the set of cross‐country financial claims to what is feasible, I analyse how best to both share and reduce macroeconomic risks on these three levels. JEL classification: F31, F36.  相似文献   
35.
This research extends the literature on nonfinancial performance measures (NFPMs) by assessing (1) the information content of a broader set of NFPMs and (2) whether NFPMs provide information not provided by financial performance measures (FPMs) from all previously identified FPM categories, rather than just earnings and book value. Specifically, exploratory and confirmatory factor analysis results presented in this paper demonstrate that nineteen NFPMs of major airlines capture seven underlying constructs not captured by eighteen common FPMs. Additionally, this research develops reliable composite measures of the identified performance measure constructs, which prior research argues are superior to individual performance measures.  相似文献   
36.
Summary. Combining a strategy model, an inference procedure and a new experimental design, we map sequences of observed actions in repeated games to unobserved strategies that reflect decision-makers’ plans. We demonstrate the method by studying two institutional settings with distinct theoretical predictions. We find that almost all strategies inferred are best responses to one of the inferred strategies of other players, and in one of the settings almost all of the inferred strategies, which include triggers to punish non-cooperators, are consistent with equilibrium strategies. By developing a method to infer unobserved repeated-game strategies from actions, we take a step toward making game theory a more applied tool, bridging a gap between theory and observed behavior.Received: 23 December 2002, Revised: 19 April 2005, JEL Classification Numbers: C72, C80, C90.The authors are indebted for discussions with Ray Battalio, David Cooper, Robin Dubin, John Duffy, Ellen Garbarino, Susan Helper, Margaret Meyer, John Miller, Jim Rebitzer, Mari Rege, Al Roth, and John Van Huyck. The authors also benefited from discussants at economic department seminars at Case Western Reserve, McMaster and McGill University, University of Pittsburgh, SUNY-Stony Brook, and Texas A&M, and participants at the 2002 European Winter Meeting of the Econometric Society. We are grateful for the financial support provided by the Department of Economics at the University of Pittsburgh and Case Western Reserve University.  相似文献   
37.
Editorial     
  相似文献   
38.
At present, our society and its social security system are not prepared to cope with the challenges resulting from the continuous increase of life expectancy. The traditional concept of disease has to be modified for serving the special needs of the elderly. The optimistic compression of disease theory is an intriguing model, but lacks prove by available data. The anti-aging boom diverts the focus from the social and financial burden that will be unevitably caused by long-term care in the future. If there will not be an — up to now unforeseeable — breakthrough in research, particularly dementia will have an enormous impact on social cost which is often underestimated.  相似文献   
39.
The evolution of society and economic pressure has provided the impetus for operating on a 24-hr basis in many industries. This has occurred with relatively little attention toward sleep deprivation and related problems facing shift workers and the organizations employing them. This paper first documents the move toward shift work and some sleep problems associated with it. We then describe sleep disorders that impact job performance. Next, we describe alternative schedules and give suggestions for shift work implementation. Finally, we offer some normative advice regarding the treatment of shift employees.  相似文献   
40.
Efficient Liability Rules: Complete Characterization   总被引:5,自引:0,他引:5  
Received May, 18, 2000; revised version received March, 19, 2001  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