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   29755篇
  免费   676篇
财政金融   5411篇
工业经济   2235篇
计划管理   5065篇
经济学   6708篇
综合类   315篇
运输经济   187篇
旅游经济   494篇
贸易经济   4571篇
农业经济   1450篇
经济概况   3922篇
邮电经济   73篇
  2021年   171篇
  2020年   281篇
  2019年   387篇
  2018年   548篇
  2017年   546篇
  2016年   511篇
  2015年   381篇
  2014年   584篇
  2013年   2880篇
  2012年   793篇
  2011年   866篇
  2010年   684篇
  2009年   825篇
  2008年   867篇
  2007年   782篇
  2006年   726篇
  2005年   683篇
  2004年   671篇
  2003年   660篇
  2002年   612篇
  2001年   622篇
  2000年   613篇
  1999年   530篇
  1998年   546篇
  1997年   515篇
  1996年   509篇
  1995年   462篇
  1994年   509篇
  1993年   522篇
  1992年   490篇
  1991年   512篇
  1990年   461篇
  1989年   395篇
  1988年   397篇
  1987年   390篇
  1986年   401篇
  1985年   589篇
  1984年   550篇
  1983年   547篇
  1982年   539篇
  1981年   454篇
  1980年   440篇
  1979年   454篇
  1978年   388篇
  1977年   350篇
  1976年   276篇
  1975年   270篇
  1974年   252篇
  1973年   242篇
  1972年   201篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
In late 1994, GTE, one of the largest telecommunications firms in the world, entered an auction for the rights to provide personal communications services (PCS) using the electromagnetic spectrum. The administering agency, the Federal Communications Commission, adopted a novel multiple-round format for the PCS auction. The format presented GTE with a complex bidding problem. This article describes how the GTE bidding team answered the following question: Given its budget and valuations and the information available about rival bidders, how should GTE bid to achieve the best attainable outcome?  相似文献   
162.
An optimal advertising rule is derived for a good sold in an open market (beef) when a related substitute good (chicken) is production rationed and whose imports are subject to trade restrictions. Such a rule is developed using a multi-market equilibrium displacement model that reflects demand interrelatedness, open trade of the advertised good (beef), with rationed production and restricted trade of the related good (chicken). The optimal rule nests earlier optimal advertising rules under a variety of conditions. Results underscore the importance of accounting for cross-product advertising effects. When these effects are present (absent), the optimal generic beef advertising intensity in Canada is shown to fall (rise) with elimination of supply management in Canada's chicken sector.
L'auteur dérive une règie sur l'optimisation de la publicité pour un produit vendu sur un marché libre (bœuf) en présence d'un produit de substitution rationné dont on restreint les importations. Pour parvenir à une telle règie, l'auteur a utilisé un modèle de déplacement du point d'équilibre sur un marché multiple illustrant les liens entre la demande des produits concernés, le libre-échange du produit faisant l'objet de la publicité (bœuf) et la restriction de la production et des importations du produit apparenté (poulet). La règie d'optimisation englobe les règles antérieures sur l'optimisation de la publicité dans diverses situations. Les résultats soulignent qu'il est important de prendre en compte les retombées de la publicité sur les autres produits. Au Canada, en présence (absence) de telles retombées, le degré optimal de publicité générique sur le bœuf diminue (augmente) avec l'abolition de la gestion de l'offre de poulet.  相似文献   
163.
We extend the research on postinjury employment by estimating productivity losses for workers with permanent partial disabilities (PPDs) in the first three years after injury. Our method distinguishes between productivity losses attributed to spells of work absence versus reduced earnings during spells of employment. The method is applied to data for 800 Ontario workers with PPDs. The results document large productivity losses persisting at least three years after injury, with different loss patterns for workers returning to stable versus unstable employment. Human capital investments or job accommodations can reduce productivity losses, but the significant determinants of losses differ for the stable versus unstable employment groups.  相似文献   
164.
An interest charge is made up of an award for waiting known as the real rate of interest, a premium for risk and compensation for transaction costs. Where inflation exists the lender seeks further compensation. In order to understand the composition and evolution of different versions of the usury prohibition it is necessary to ask which components of an interest charge are prohibited by each version. The Judaic prohibition has two aspects which are of particular interest to business historians and students of usury. First, the general rule is that a reward for waiting is prohibited. This focuses on the time-based part of interest charge. Second, interest is prohibited because it amounts to placing a stumbling block before the blind. This focuses on the typical gullibility of the borrower confronted by a more expert, better funded lender. Economics confirms and enriches our understanding of these important aspects of the prohibition. They achieve this by increasing our understanding of two facts: first, that the borrower is a gullible individual subject to irrational and inconsistent behaviour; and, second, that this behaviour relates to the waiting aspect of interest which is proscribed in the prohibition. How far these insights apply to other civilisations' prohibition, particularly those which derive from the Judaic prohibition, merits further study; so also do the ethical lessons of the Mosaic rules for a globalised society based on capitalism.  相似文献   
165.
Does Hedging Affect Firm Value? Evidence from the US Airline Industry   总被引:1,自引:0,他引:1  
Does hedging add value to the firm, and if so, is the source of the added value consistent with hedging theory? We investigate jet fuel hedging behavior of firms in the US airline industry during 1992–2003 to examine whether such hedging is a source of value for these companies. We illustrate that the investment and financing climate in the airline industry conforms well to the theoretical framework of Froot, Scharfstein, and Stein (1993). In general, airline industry investment opportunities correlate positively with jet fuel costs, while higher fuel costs are consistent with lower cash flow. Given that jet fuel costs are hedgeable, airlines with a desire for expansion may find value in hedging future purchases of jet fuel. Our results show that jet fuel hedging is positively related to airline firm value. The coefficients on the hedging variables in our regression analysis suggest that the “hedging premium” is greater than the 5% documented in Allayannis and Weston (2001), and might be as large as 10%. We find that the positive relation between hedging and value increases in capital investment, and that most of the hedging premium is attributable to the interaction of hedging with investment. This result is consistent with the assertion that the principal benefit of jet fuel hedging by airlines comes from reduction of underinvestment costs.  相似文献   
166.
167.
Evaluating FOMC forecasts   总被引:1,自引:0,他引:1  
Monetary policy outcomes have improved since the early 1980s. One factor contributing to the improvement is that Federal Reserve policymakers began reporting economic forecasts to Congress in 1979. These forecasts indicate what the Federal Open Market Committee (FOMC) members think will be the likely consequence of their policies. We evaluate the accuracy of the FOMC forecasts relative to private sector forecasts, the forecasts of the Research Staff at the Board of Governors, and a naïve alternative. We find that the FOMC output forecasts were better than the naïve model and at least as good as those of the private sector and the Fed staff. The FOMC inflation forecasts were more accurate than the private sector forecasts and the naïve model; for the period ending in 1996, however, they were not as accurate as Fed staff inflation forecasts.  相似文献   
168.
Predicting the geo-temporal variations of crime and disorder   总被引:2,自引:0,他引:2  
Traditional police boundaries—precincts, patrol districts, etc.—often fail to reflect the true distribution of criminal activity and thus do little to assist in the optimal allocation of police resources. This paper introduces methods for crime incident forecasting by focusing upon geographical areas of concern that transcend traditional policing boundaries. The computerised procedure utilises a geographical crime incidence-scanning algorithm to identify clusters with relatively high levels of crime (hot spots). These clusters provide sufficient data for training artificial neural networks (ANNs) capable of modelling trends within them. The approach to ANN specification and estimation is enhanced by application of a novel and noteworthy approach, the Gamma test (GT).  相似文献   
169.
170.
Generally valid scientific explanations of observable social phenomena are still hardly available. By applying philosophical insights generated by Quine and derived from semiotics to social research methodology three kinds of context dependencies accompanying theory formation within social science are identified. The third context dependency is mostly not attended in theory formation about social phenomena thereby producing a ``connotation fallacy', which leaves almost all social theories undetermined and fallible. These context dependencies should be taken into account in the research design and be tested for using statistical criteria comprising a new methodology presented in this article.  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