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   15048篇
  免费   440篇
财政金融   3105篇
工业经济   1113篇
计划管理   2456篇
经济学   3339篇
综合类   156篇
运输经济   112篇
旅游经济   233篇
贸易经济   2476篇
农业经济   651篇
经济概况   1818篇
信息产业经济   2篇
邮电经济   27篇
  2023年   83篇
  2021年   102篇
  2020年   217篇
  2019年   278篇
  2018年   369篇
  2017年   387篇
  2016年   354篇
  2015年   235篇
  2014年   388篇
  2013年   1739篇
  2012年   439篇
  2011年   505篇
  2010年   471篇
  2009年   483篇
  2008年   442篇
  2007年   388篇
  2006年   361篇
  2005年   279篇
  2004年   285篇
  2003年   291篇
  2002年   297篇
  2001年   297篇
  2000年   309篇
  1999年   309篇
  1998年   315篇
  1997年   278篇
  1996年   234篇
  1995年   224篇
  1994年   241篇
  1993年   244篇
  1992年   273篇
  1991年   261篇
  1990年   202篇
  1989年   185篇
  1988年   168篇
  1987年   164篇
  1986年   168篇
  1985年   241篇
  1984年   259篇
  1983年   255篇
  1982年   215篇
  1981年   198篇
  1980年   173篇
  1979年   171篇
  1978年   161篇
  1977年   138篇
  1976年   128篇
  1975年   141篇
  1974年   104篇
  1973年   101篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
This paper presents an approach to assessing the efficacy of public spending on research and development in state programs. At present, there is a need to develop a unified approach to the analysis and evaluation of the efficacy of such spending from the perspective of participants in state programs (federal executive bodies). The proposed approach does not allow evaluating the efficacy of public spending on the development of research areas assigned to the authors.  相似文献   
2.
3.
Review of Quantitative Finance and Accounting - We examine how changes in dividend policy in 2008 as the financial crisis was unfolding influenced firm risk-adjusted returns in the following years....  相似文献   
4.
Most development projects encounter a highly uncertain entitlement process that is largely uncontrollable by developers. In this study, entitlement is modeled as a separate stage within a compound real option, where developers begin with minimal control (maximum risk) and each successful stage increases control (decreases risk). We solve the model analytically, provide three‐dimensional numerical comparisons, and empirically test the model's predictions using hand collected rezoning petitions. Our main result refines the classic development option model: developers first invest early (secure entitlements) in order to obtain the option to subsequently delay investment (construct the optimal building at the optimal time).  相似文献   
5.
During patent litigation, pay‐for‐delay (P4D) deals involve a payment from a patent holder of a branded drug to a generic drug manufacturer to delay entry and withdraw the patent challenge. In return for staying out of the market, the generic firm receives a payment, and/or an authorized licensed entry at a later date, but before the patent expiration. We examine why such deals are stable when there are multiple potential entrants. We combine the first‐mover advantage for the first generic with the ability of the branded manufacturer to launch an authorized generic (AG) to show when P4D deals are an equilibrium outcome. We further show that limiting a branded firm's ability to launch an AG before entry by a successful challenger will deter such deals. However, removing exclusivity period for the first generic challenger will not.  相似文献   
6.
We analyse the effect of a large scale infrastructure investment, namely the construction of the Oresund bridge, on the local and supra-regional economy. We employ the synthetic control method to construct counterfactual regions that mimic the trajectory of Malmo and Southern Sweden without treatment. Our results point to a positive effect. However, placebo tests in space and time only reveal statistical significance at a larger regional level. The results suggest that spillover effects are eminent.  相似文献   
7.
This study back-tests a marginal cost of production model proposed to value the digital currency Bitcoin. Results from both conventional regression and vector autoregression (VAR) models show that the marginal cost of production plays an important role in explaining Bitcoin prices, challenging recent allegations that Bitcoins are essentially worthless. Even with markets pricing Bitcoin in the thousands of dollars each, the valuation model seems robust. The data show that a price bubble that began in the Fall of 2017 resolved itself in early 2018, converging with the marginal cost model. This suggests that while bubbles may appear in the Bitcoin market, prices will tend to this bound and not collapse to zero.  相似文献   
8.
This article explores the adoption of new technology in organisations that provide senior citizen care. Inspired by Niklas Luhmann’s systems theory, we study how technology reduces complexity by identifying client needs and ensuring predictability in service delivery. However, how technologies are adopted in practice is not determined by technology since it is also structured by care-workers' continuous decision-making. Against this backdrop, we explore how technologies alter the conditions for decision-making in two settings of elderly care, and we describe how care workers seek to adapt technologies to their practical needs as well as conception of care ethics. Developing a systems theory approach, the article eschews a priori assumptions of technological constraint on care-workers’ professional autonomy, offering a more open-ended exploration of diversified strategies for coping with new technology. Our case studies show that employees develop diversified strategies for technology adoption, including both non-usage, heated resistance, excessive embrace, and creative adaption.  相似文献   
9.
10.
We propose parametric copulas that capture serial dependence in stationary heteroskedastic time series. We suggest copulas for first‐order Markov series, and then extend them to higher orders and multivariate series. We derive the copula of a volatility proxy, based on which we propose new measures of volatility dependence, including co‐movement and spillover in multivariate series. In general, these depend upon the marginal distributions of the series. Using exchange rate returns, we show that the resulting copula models can capture their marginal distributions more accurately than univariate and multivariate generalized autoregressive conditional heteroskedasticity models, and produce more accurate value‐at‐risk forecasts.  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