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   3829篇
  免费   94篇
财政金融   713篇
工业经济   293篇
计划管理   592篇
经济学   915篇
综合类   95篇
运输经济   32篇
旅游经济   41篇
贸易经济   607篇
农业经济   231篇
经济概况   398篇
邮电经济   6篇
  2021年   24篇
  2020年   52篇
  2019年   64篇
  2018年   95篇
  2017年   109篇
  2016年   88篇
  2015年   47篇
  2014年   104篇
  2013年   408篇
  2012年   113篇
  2011年   145篇
  2010年   128篇
  2009年   129篇
  2008年   137篇
  2007年   117篇
  2006年   103篇
  2005年   80篇
  2004年   90篇
  2003年   80篇
  2002年   79篇
  2001年   80篇
  2000年   81篇
  1999年   58篇
  1998年   74篇
  1997年   52篇
  1996年   56篇
  1995年   50篇
  1994年   54篇
  1993年   48篇
  1992年   64篇
  1991年   51篇
  1990年   44篇
  1989年   39篇
  1988年   46篇
  1987年   38篇
  1986年   31篇
  1985年   63篇
  1984年   62篇
  1983年   73篇
  1982年   57篇
  1981年   65篇
  1980年   52篇
  1979年   54篇
  1978年   53篇
  1977年   29篇
  1976年   34篇
  1975年   26篇
  1974年   28篇
  1973年   34篇
  1972年   20篇
排序方式: 共有3923条查询结果,搜索用时 15 毫秒
51.
We compare different contingent valuation question formats with each other and with observed behaviour for a non-monetary estimation task, the expected number of kilometers travelled by automobile. Open-ended questions, open-ended follow-up questions, dichotomous choice (DC) questions, and double-bound DC questions are included. The single and double-bound DC questions result in an estimated mean about twice as high as the actual value and the open-ended mean. The DC question overestimation seems to be due to an anchoring effect leading to yea-saying behaviour. Our results about the difference between DC questions and open-ended questions is consistent with the pattern observed in contingent valuations studies of the willingness to pay. Our results indicates that DC questions seem to be associated with a general overestimation problem that is present even for simple non-monetary estimation tasks.  相似文献   
52.
We analyze how the market processes a signaling event by studying a sample of self-tender offers, events often viewed as signals of firm value. By examining changes in the degree of informed trading, we find asymmetric information costs fall at announcement, remain low throughout the event, and increase at offer expiration. By one month following expiration, informed trading returns to a level not significantly different from that prior to the offer. Higher risk firms have significantly larger declines in information asymmetry during the offer. Increases in information asymmetry persist one month following expiration for firms with lower pre-offer informed trading. (JEL G14, G32)  相似文献   
53.
Using a small empirical model of inflation, output, and money estimated on U.S. data, we compare the relative performance of monetary targeting and inflation targeting. The results show monetary targeting to be quite inefficient, yielding both higher inflation and output variability. This is true even with a nonstochastic money demand formulation. Our results are also robust to using a P∗ model of inflation. Therefore, in these popular frameworks, there is no support for the prominent role given to money growth in the Eurosystem's monetary policy strategy.  相似文献   
54.
Background: Validation of overall survival (OS) extrapolations of immune-checkpoint inhibitors (ICIs) during the National Institute for Health and Care Excellence (NICE) Single Technology Assessment (STA) process is limited due to data still maturing at the time of submission. Inaccurate extrapolation may lead to inappropriate decision-making. The availability of more mature trial data facilitates a retrospective analysis of the plausibility and validity of initial extrapolations. This study compares these extrapolations to subsequently available longer-term data.

Methods: A systematic search of completed NICE appraisals of ICIs from March 2000 to December 2017 was performed. A targeted search was also undertaken to procure published OS data from the pivotal clinical trials for each identified STA made available post-submission to NICE. Initial Kaplan-Meier curves and associated extrapolations from NICE documentation were extracted to compare the accuracy of OS projections versus the most mature data.

Results: The review identified 11 STAs, of which 10 provided OS data upon submission to NICE. The extrapolations undertaken considered parametric or piecewise survival models. Additional data cut-offs provided a mean of 18 months of OS beyond the end of the original data. Initial extrapolations typically under-estimated OS from the most mature data cut-off by 0.4–2.7%, depending on the choice of assessment method and use of the manufacturer- or ERG-preferred extrapolation.

Conclusion: Long-term extrapolation of OS is required for NICE STAs based on initial immature OS data. The results of this study demonstrate that the initial OS extrapolations employed by manufacturers and ERGs generally predicted OS reasonably well when compared to more mature data (when available), although on average they appeared to underestimate OS. This review and validation shows that, while the choice of OS extrapolation is uncertain, the methods adopted are generally aligned with later-published follow-up data and appear appropriate for informing HTA decisions.  相似文献   

55.
In many preferential trade agreements (PTAs), countries exchange not only reductions in trade barriers but also cooperation in non-trade issues such as labour and environmental standards, intellectual property, etc. We provide a model of PTAs motivated by cooperation in non-trade issues and analyse its implications for global free trade and welfare. We find that such PTAs increase the cost of multilateral tariff reductions and thus cause a stumbling block to global free trade. This occurs because multilateral tariff reductions decrease the threat that can be used in PTAs and thus the surplus that can be extracted from them. By explicitly modelling the interaction between preferential and multilateral negotiations, we derive a testable prediction and provide novel econometric evidence that supports the model's key prediction. The welfare analysis shows that the current World Trade Organization rules allowing this type of PTAs may be optimal for economically large countries, thus the model can predict the rules we observe. We also analyse alternative rules that constitute a Pareto improvement.  相似文献   
56.
This is the first paper to consider a mixed oligopoly in which a public Stackelberg leader competes with both domestic and foreign private firms. The welfare maximising leader is shown to always produce less than under previous Cournot conjectures. Introducing leadership also alters previous public pricing rules resulting in prices that may be either greater than or less than marginal cost depending on the relative number of domestic firms. Furthermore, entry of a foreign firm will increase welfare only when the relative number of domestic firms is small, but that share is shown to be larger than has been indicated without leadership. Unlike previous models, the influence on public profit of a foreign acquisition is ambiguous and is related to the relative number of domestic firms. Finally, the consequences of privatisation are shown, for the first time, to depend on the relative number of domestic firms.  相似文献   
57.
Conventional wisdom holds that when a firm gets into trouble due to lagging sales and rising costs, cutting the size of the organization to reduce fat and waste is a normal and effective response. In this study, evidence was found to suggest that just the opposite might be true. The financial performance of Fortune 100 companies was tracked over a five-year period—two years prior to the announced layoff, the year of the layoff announcement, and two years following it. Contrary to expectations, the results indicate that financial performance worsened, rather than improved, following announced layoffs. Strategic and human resource implications for the management of corporate downsizing are provided.  相似文献   
58.
Errors of measurement have long been recognized as a chronic problem in statistical analysis. Although there is a vast statistical literature of multiple regression models estimating the air pollution-mortality relationship, this problem has been largely ignored. It is well known that pollution measures contain error, but the consequences of this error for regression estimates is not known. We use Lave and Seskin's air pollution model to demonstrate the consequences of random measurement error. We assume a range of 0% to 50% of the variance of the pollution measures is due to error. We find large differences in the estimated effects on mortality of the pollution variables as well as the other explanatory variables once this measurement error is taken into account. These results cast doubt on the usual regression estimates of the mortality effects of air pollution. More generally our results demonstrate the consequences of random measurement error in the explanatory variable of a multiple regression analysis and the misleading conclusions that may result in policy research if this error is ignored.  相似文献   
59.
Abstract . Today's conventional economics typically ignores the impact of alternative forms of work organization upon the welfare of the worker. In effect, its methodology is concerned with the welfare of the individual as a consumer, but not with the welfare of the individual as a worker. Hence, welfare conclusions of economics are subject to challenge on grounds of being incomplete. Whether the worker is alienated or achieves self-fulfillment, etc., stands in no necessary relationship to either the formal lines of enterprise ownership, political ideology or form of economic system. Questions of authority and power in work organizations and the workplace conditions affecting the worker on the job transcend them.  相似文献   
60.
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