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   31440篇
  免费   799篇
  国内免费   1篇
财政金融   6192篇
工业经济   2296篇
计划管理   4778篇
经济学   6912篇
综合类   462篇
运输经济   260篇
旅游经济   584篇
贸易经济   5194篇
农业经济   1470篇
经济概况   3967篇
信息产业经济   5篇
邮电经济   120篇
  2023年   161篇
  2021年   207篇
  2020年   353篇
  2019年   588篇
  2018年   693篇
  2017年   726篇
  2016年   711篇
  2015年   447篇
  2014年   779篇
  2013年   3325篇
  2012年   985篇
  2011年   1114篇
  2010年   950篇
  2009年   1074篇
  2008年   1014篇
  2007年   873篇
  2006年   789篇
  2005年   741篇
  2004年   714篇
  2003年   681篇
  2002年   722篇
  2001年   623篇
  2000年   612篇
  1999年   601篇
  1998年   532篇
  1997年   558篇
  1996年   527篇
  1995年   464篇
  1994年   484篇
  1993年   500篇
  1992年   502篇
  1991年   485篇
  1990年   386篇
  1989年   366篇
  1988年   352篇
  1987年   359篇
  1986年   369篇
  1985年   565篇
  1984年   515篇
  1983年   472篇
  1982年   457篇
  1981年   403篇
  1980年   453篇
  1979年   381篇
  1978年   322篇
  1977年   311篇
  1976年   245篇
  1975年   258篇
  1974年   217篇
  1973年   205篇
排序方式: 共有10000条查询结果,搜索用时 546 毫秒
191.
192.
This paper investigates whether governments can change market structures through interventions. We study the effects of four political events over the life cycle of the market for daily newspapers in the Netherlands. We find that policy measures meant to lower entry barriers in an expanding industry created new entry and increased survival chances for potential entrants and incumbent newspapers. Exit barrier enhancing policies to reduce concentration tendencies have not been successful.  相似文献   
193.
Lejeune  Miguel A. 《NETNOMICS》2002,4(2):145-162
Denial of Service (DoS) attacks consist of overwhelming a server, a network or a Web site in order to paralyze its normal activity. The additional parameter in Distributed Denial of Service (DdoS) attacks is the distributing strategy. It means that DDoS attacks do not come from a single computer but stem from all accessible channels and servers. Consequences are multiple, ranging from system errors, temporary inability to access the Web site for normal users to challenging the actual reliability of the Internet. Despite this, Internet users show carelessness. The explanation lies in the specificities of DDoS attacks. We explore possibilities to raise users' awareness about the actual amplitude of problems caused by DDoS attacks. We suggest a careful examination of Internet pricing mechanisms and switching from flat to usage-constraining pricing schemes.  相似文献   
194.
The use of transferable discharge permits as a water pollution control policy is rapidly increasing in the United States. Drawing on evidence from existing water quality trading programs, this paper provides a taxonomy of the forms that such markets take. Four main structures are identified: exchanges, bilateral negotiations, clearinghouses, and sole-source offsets. Each of these structures has its own strengths and weaknesses; none is optimal for all scenarios. Since market structure is largely determined by a program's rules, policy makers should be aware of the differences between these structures and the conditions under which each comes to be.  相似文献   
195.
Until the stock market bubble burst in 2000–2002, most CFOs viewed their defined benefit pension plans as profit centers and relatively risk‐free sources of income. Since neither pension assets nor liabilities were reported on corporate balance sheets, and expected returns on pension stocks could be substituted for actual returns when reporting net income, the risks associated with DB plans were masked by GAAP accounting and thus assumed to have no bearing on corporate capital structure. But when stock prices and corporate profits fell together, the risks associated with conventional stock‐heavy pension plans showed up first in reduced pension surpluses (or, in many cases, deficits) and then later in higher required cash contributions and lower reported earnings. As a consequence, today's investors (and rating agencies) are viewing pension and other legacy liabilities as corporate debt, and demands for transparency and increased funding have triggered accounting changes and proposed legislative reforms that will further unmask the economics. This article aims to provide both private‐sector and public‐sector CFOs with suggestions for reducing and controlling the cost of providing for the retirement of their employees. Profitable, tax‐paying companies with DB plans should consider (1) funding any unfunded liabilities (if necessary, by issuing debt) and (2) reducing pension equity and interest rate exposures by shifting some (if not all) pension assets into bonds and defeasing the pension liability (achieving a tax arbitrage in the process). And in cases where the expected costs of maintaining DB plans outweigh the benefits, companies should consider freezing or terminating their plans and switching to a defined contribution (DC) or some form of hybrid plan. The authors also propose similar changes for public pension plans, where underfunding and mismatch problems are greater, less transparent, and in some ways less tractable than those of corporate DB plans.  相似文献   
196.
Summary. This research studies the role of multivariate distribution structures on random asset returns in determining the optimal allocation vector for an expected utility maximizer. All our conclusions pertain for the set of risk averters. By carefully disturbing symmetry in the distribution of the, possibly covarying, returns, we ascertain the ordinal structure of the optimized allocation vector. Rank order of allocations is also established when a permutation symmetric random vector is mapped into the returns vector through location and scale shifts. It is shown that increased dispersion in the vectors of location and scale parameters benefit, ex-ante, investors as does a decrease in the rank correlation coefficient between the location and scale parameter vectors. Revealed preference comparative static results are identified for the location and scale vectors of asset returns. For most issues addressed, we arrive at much stronger inferences when a safe asset is available. Received: August 8, 2000; revised version: January 8, 2001  相似文献   
197.
The debate around the ‘Global City Hypothesis’ (GCH), and particularly the research agenda of the ‘Globalization and World Cities’ network, have been preoccupied recently with the business and technological dimensions of so–called ‘global cities’. This article seeks to recover the role of immigration in large urban economies. Using mainly observations from European metropolises, I argue first that the GCH requires significant revision insofar as it can be used as a tool for addressing issues of inequality, and I offer five propositions for a renewal of the existing contours of the GCH. Second, beyond these revisions, I suggest a complete reformulation of the debate by linking it with ideas emanating from the literature on transnationalism. Le débat sur ‘l’Hypothèse de la ville globale’, et notamment sur le programme de recherche du réseau ‘Mondialisation et Villes mondiales’, s’est récemment soucié des dimensions économiques et technologiques des dites ‘villes planétaires’. Cet article tente de révéler le rôle de l’immigration dans les grandes économies urbaines. A partir d’observations de métropoles européennes principalement, il affirme d’abord que, dans la mesure où cette hypothèse peut servir d’outil pour aborder les questions d’inégalité, elle requiert une importante révision; sont donc exposées cinq propositions pour en renouveler les profils existents. Il suggère ensuite une reformulation complète du débat en l’associant à des idées émanant de travaux sur le transnationalisme.  相似文献   
198.
Recently, much of the research into the relation between market values and accounting numbers has used, or at least made reference to, the residual income model (RIM). Two basic types of empirical research have developed. The “historical” type explores the relation between market values and reported accounting numbers, often using the linear dynamics in Ohlson 1995 and Feltham and Ohlson 1995 and 1996. The “forecast” type explores the relation between market value and the present value of the book value of equity, a truncated sequence of residual income forecasts, and an estimate of the terminal value at the truncation date. The analysis in this paper integrates these two approaches. We expand the Feltham and Ohlson 1996 model by including one‐ and two‐period‐ahead residual income forecasts to infer “other” information regarding future revenues from past investments and future growth opportunities. This approach results in a model in which the difference between market value and book value of equity is a function of current residual income, one‐ and two‐period‐ahead residual income, current capital investment, and start‐of‐period operating assets. The existence of both persistence in revenues from current and prior investments and growth in future positive net present value investment opportunities leads us to hypothesize a negative coefficient on the one‐period‐ahead residual income forecast and a positive coefficient on the two‐period‐ahead residual income forecast. Our empirical results strongly support our hypotheses with respect to the forecast coefficients.  相似文献   
199.
200.
This paper gives a tree-based method for pricing American options in models where the stock price follows a general exponential Lévy process. A multinomial model for approximating the stock price process, which can be viewed as generalizing the binomial model of Cox, Ross, and Rubinstein (1979) for geometric Brownian motion, is developed. Under mild conditions, it is proved that the stock price process and the prices of American-type options on the stock, calculated from the multinomial model, converge to the corresponding prices under the continuous time Lévy process model. Explicit illustrations are given for the variance gamma model and the normal inverse Gaussian process when the option is an American put, but the procedure is applicable to a much wider class of derivatives including some path-dependent options. Our approach overcomes some practical difficulties that have previously been encountered when the Lévy process has infinite activity.  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