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   5330篇
  免费   1246篇
财政金融   985篇
工业经济   473篇
计划管理   1247篇
经济学   1317篇
综合类   13篇
运输经济   118篇
旅游经济   59篇
贸易经济   1415篇
农业经济   327篇
经济概况   622篇
  2023年   7篇
  2022年   9篇
  2021年   94篇
  2020年   191篇
  2019年   516篇
  2018年   258篇
  2017年   401篇
  2016年   387篇
  2015年   407篇
  2014年   412篇
  2013年   676篇
  2012年   425篇
  2011年   389篇
  2010年   357篇
  2009年   251篇
  2008年   264篇
  2007年   203篇
  2006年   182篇
  2005年   157篇
  2004年   147篇
  2003年   134篇
  2002年   126篇
  2001年   119篇
  2000年   84篇
  1999年   39篇
  1998年   30篇
  1997年   17篇
  1996年   19篇
  1995年   16篇
  1994年   17篇
  1993年   17篇
  1992年   15篇
  1991年   14篇
  1990年   7篇
  1989年   7篇
  1988年   9篇
  1987年   10篇
  1986年   6篇
  1985年   12篇
  1984年   10篇
  1983年   13篇
  1982年   15篇
  1981年   17篇
  1980年   12篇
  1979年   16篇
  1978年   10篇
  1977年   7篇
  1974年   5篇
  1972年   4篇
  1968年   4篇
排序方式: 共有6576条查询结果,搜索用时 46 毫秒
61.
We propose two novel approaches for feature selection and ranking tasks based on simulated annealing (SA) and Walsh analysis, which use a support vector machine as an underlying classifier. These approaches are inspired by one of the key problems in the insurance sector: predicting the insolvency of a non‐life insurance company. This prediction is based on accounting ratios, which measure the health of the companies. The approaches proposed provide a set of ratios (the SA approach) and a ranking of the ratios (the Walsh analysis ranking) that would allow a decision about the financial state of each company studied. The proposed feature selection methods are applied to the prediction the insolvency of several Spanish non‐life insurance companies, yielding state‐of‐the‐art results in the tests performed. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
62.
A feature transformation method based on domain knowledge for arti?cial neural networks (ANNs) is proposed. The method of feature transformation based on domain knowledge converts continuous values into discrete values in accordance with the knowledge of experts in speci?c application domains. This approach effectively ?lters data, trains the classi?er, and extracts the rules from the classi?er. In addition, it reduces the dimensionality of the feature space, which not only decreases the cost and time in the operation but also enhances the generalizability of the classi?er. The experimental results of the proposed approach will be compared and tested statistically with the results of the linear transformation method. The results show that the method of feature transformation based on domain knowledge outperforms the linear transformation in modelling of ANNs. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   
63.
The Cuban economy has experienced a significant increase in foreign direct investment over the past decade due to the end of the Soviet Union and the establishment of more liberal trade policies. Although the U.S. embargo of trade with Cuba still exists, there has been movement lately that suggests the end of the four‐decades‐old policy. The purpose of this article is to analyze the current Cuban business environment and to identify potential entrepreneurial opportunities in the service sector. Major trade partners are also reviewed and managerial implications discussed. © 2006 Wiley Periodicals, Inc.  相似文献   
64.
This research proposes an approach to measure hospital performance based on a generalization of Banker and Morey (1986) and Førsund (1996). This approach considers quasi-fixed inputs explicitly, calculates their implicit cost, and quantifies returns to scale. The performance measure is decomposed into allocative and technical inefficiencies. Based on a very complete data set of Québec hospitals, we find that significant inefficiencies of up to 17% ($700 CAN million) could have been saved through improved performance. Postestimation analyses that include qualitative measures of care suggest that differences in performance are attributable to differences in management or unobservable quality of care rather than patient case mix.  相似文献   
65.
Consider the standard linear model Y=X θ + ε. If the parameter of interest is a full rank subsystem K′θ of mean parameters, the associated information matrix can be defined via an extremal representation. For rank deficient subsystems, Pukelsheim (1993) introduced the notion of generalized information matrices that inherit many properties of the information matrices. However, this notion is not a direct extension of the full rank case in the sense that the definition of the generalized information matrix applied to full rank subsystems does not lead to the usual information matrix. In this paper, we propose a definition of the information matrix via an extremal representation that encompasses the full rank and the non-full rank cases. We also study its properties and show its links with the generalized information matrices.  相似文献   
66.
E-commerce not only has tremendous potential for growth but also poses unique challenges for both incumbents and new entrants. By examining drivers of firm performance in e-commerce from a capabilities perspective, the authors conceptualize three firm capabilities that are critical for superior firm performance in e-commerce: information technology capability, strategic flexibility, and trust-building capability. The extent and nature of market orientation is conceptualized as a platform for leveraging e-commerce capabilities. The authors test the effects of e-commerce capabilities on performance (e.g., relative profits, sales, return on investment) using data from 122 e-brokerage service providers. The results indicate that information technology capability and strategic flexibility affect performance given the right market orientation. Amit Saini (asaini2@unl.edu) is an assistant professor of marketing at University of Nebraska-Lincoln. He conducts research in the area of marketing strategy, technology-marketing interface, e-commerce strategy, and customer relationship management. He has presented papers at major conferences, and his research appears in theJournal of the Academy of Marketing Science and American Marketing Association—Marketing Educator’s Conference Proceedings. His industry experience includes sales management and quantitative market research. Jean L. Johnson (Johnsonjl@wsu.edu) is a professor of marketing at Washington State University. Her research includes partnering capabilities development in, and management of, interfirm relationships and management of international strategic alliances. Her research appears in journals such as theJournal of Marketing, the Journal of International Business Studies, theJournal of the Academy of Marketing Science, and theInternational Journal of Research in Marketing. She serves on the editorial boards of theJournal of Marketing, theJournal of the Academy of Marketing Science, the Journal of Retailing, theJournal of Business and Industrial Marketing, and reviews for others. She spent several years in the advertising industry and has lived, taught, and conducted research in France and Japan. She has been selected to cochair the 2006 winter American Marketing Association (AMA) conference.  相似文献   
67.
Bauwens  Luc  Giot  Pierre 《Empirical Economics》2003,28(4):709-731
This paper proposes an asymmetric autoregressive conditional duration (ACD) model, which extends the ACD model of Engle and Russell (1998). The asymmetry consists of letting the duration process depend on the state of the price process. If the price has increased, the parameters of the ACD model can differ from what they are if the price has decreased. The model is applied to the bid-ask quotes of two stocks traded on the NYSE and the evidence in favour of asymmetry is strong. Information effects (Easley and O'Hara 1992) are also empirically relevant. As the model is a transition model for the price process, it delivers `market forecasts' of where prices are heading. A trading strategy based on the model is implemented using tick-by-tick data.While remaining responsible for any error in this paper, the authors would like to thank R. Anderson, G. Le Fol, C. Gouriéroux, J. Jasiak, W. Pohlmeier, A. Roell, O. Scaillet, S. Wei and three anonymous referees for useful remarks and suggestions on previous versions. The authors would also like to thank A. Ruttiens from KBC-CBC for useful discussions on practical issues related to trading. Support of the European Commission Human Capital and Mobility Program through the network `Econometric inference using simulation methods' is gratefully acknowledged. This paper presents research results of the Belgian Program on Interuniversity Poles of Attraction initiated by the Belgian State, Prime Minister's Office, Science Policy Programming. The scientific responsibility is assumed by the authors.  相似文献   
68.
69.
We propose an optimal filter to transform the Conference Board Composite Leading Index (CLI) into recession probabilities in the US economy. We also analyse the CLI's accuracy at anticipating US output growth. We compare the predictive performance of linear, VAR extensions of smooth transition regression and switching regimes, probit, non‐parametric models and conclude that a combination of the switching regimes and non‐parametric forecasts is the best strategy at predicting both the NBER business cycle schedule and GDP growth. This confirms the usefulness of CLI, even in a real‐time analysis. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
70.
This paper analyses the political support for a social insurance that includes elements of redistribution when there exists an imperfect private insurance alternative. Individuals differ both in their income and risk. The social insurance is compulsory and charges an income-related contribution with pooling of risks. The private insurance is voluntary and charges a contribution based on individual risks. However due to the adverse selection problem, private insurance companies provide only partial insurance. Adopting a non-expected utility model, we show that there is a general majority support for social insurance and that this support is increasing with risk aversion. We also show that a mixed insurance is politically impossible, regardless of the degree of redistribution of social insurance and the joint distribution of risk and income in the population. Lastly, we analyse how the political support for social insurance is affected by any change in its redistributive component and the possibility of using genetic tests.  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