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   31416篇
  免费   761篇
  国内免费   2篇
财政金融   5720篇
工业经济   2138篇
计划管理   5435篇
经济学   7115篇
综合类   325篇
运输经济   193篇
旅游经济   501篇
贸易经济   5130篇
农业经济   1443篇
经济概况   4002篇
邮电经济   177篇
  2021年   197篇
  2020年   317篇
  2019年   420篇
  2018年   662篇
  2017年   661篇
  2016年   649篇
  2015年   476篇
  2014年   688篇
  2013年   3115篇
  2012年   945篇
  2011年   956篇
  2010年   798篇
  2009年   907篇
  2008年   956篇
  2007年   832篇
  2006年   802篇
  2005年   759篇
  2004年   705篇
  2003年   689篇
  2002年   646篇
  2001年   665篇
  2000年   636篇
  1999年   543篇
  1998年   553篇
  1997年   510篇
  1996年   483篇
  1995年   466篇
  1994年   495篇
  1993年   516篇
  1992年   473篇
  1991年   489篇
  1990年   460篇
  1989年   377篇
  1988年   379篇
  1987年   384篇
  1986年   397篇
  1985年   573篇
  1984年   540篇
  1983年   543篇
  1982年   519篇
  1981年   459篇
  1980年   439篇
  1979年   451篇
  1978年   395篇
  1977年   346篇
  1976年   282篇
  1975年   280篇
  1974年   252篇
  1973年   246篇
  1972年   203篇
排序方式: 共有10000条查询结果,搜索用时 406 毫秒
1.
We propose a new framework exploiting realized measures of volatility to estimate and forecast extreme quantiles. Our realized extreme quantile (REQ) combines quantile regression with extreme value theory and uses a measurement equation that relates the realized measure to the latent conditional quantile. Model estimation is performed by quasi maximum likelihood, and a simulation experiment validates this estimator in finite samples. An extensive empirical analysis shows that high‐frequency measures are particularly informative of the dynamic quantiles. Finally, an out‐of‐sample forecast analysis of quantile‐based risk measures confirms the merit of the REQ.  相似文献   
2.
Differences in accrued gains and investors’ tax-sensitivity induce variation in a capital gains lock-in effect across mutual funds even for the same stock at the same time. Exploiting this variation, we show this effect influences funds’ governance decisions: higher capital gains decrease the likelihood a fund exits prior to contentious votes and increase the likelihood a fund votes against management. Consistent with tax motivation, these findings are concentrated among funds with tax-sensitive investors. Further, high aggregate capital gains across funds holding a stock predict a higher likelihood management loses a vote and a lower likelihood a contentious vote is proposed.  相似文献   
3.
Growing urbanisation in South Africa is reflected in burgeoning Working class and informal township settlements on the fringes of its major towns and cities. Paired with this is an increasing reliance on cash as the primary means of economic transaction, which has in turn stimulated the growth of micro-enterprise business activities within the township context. This article discusses the findings of an eight-township small-area census which occurred between 2010 and 2013 in Cape Town, Johannesburg, Ekurhuleni and Durban townships representing 250 000 residents. The researchers were able to establish the scope and scale of informal food and drink retailing in these localities. Of the 10 049 micro-enterprises located in the study, some 3966 (or 39% of the total) trade in food. These include enterprises in primary production, fresh produce retailing, grocery retailing from house and spaza shops, and informal foodservice enterprises. Food is the basis for much township informal business and plays an important role in making food increasingly affordable and locally accessible, and in creating cash employment. The article builds on the knowledge base of the township informal economy role in bolstering food security needs for the marginalised.  相似文献   
4.
Without guaranteed compensation, granted by the German Renewable Energy Sources Act (Erneuerbare Energien Gesetz/EEG), biogas plants compete with all other plant types on the market for electrical energy. However, exchange-based electricity products do not currently permit an economically viable operation of biogas plants owing to their cost situation.  相似文献   
5.
6.
Societal pressures for greater sustainability can encourage firms to target part of their innovation activities at ecological initiatives (i.e., eco-innovation). Yet, depending on their value function, firms can respond differently to such pressures and exhibit variance in their eco-innovation activities. In this paper, we investigate the idea that a firm’s ownership structure may play a significant role in determining its engagement in eco-innovation. Specifically, we propose that ownership by family blockholders increases the value attached to the company’s reputation and that this, in turn, stimulates higher levels of eco-innovation. In other words, we model the company reputation motive as a key mediator in the relationship between family ownership and firm-level eco-innovation. To account for family firm heterogeneity, we also model the moderating role of owners’ intention to pass the business on to the next family generation (transgenerational intentions) and of the extent to which these owners reside in the firm’s local community (local embeddedness). As theoretical backdrop, our study builds on institutional theory and the mixed gamble logic. To test our hypotheses, we use a large sample of German firms and nonlinear moderated mediation regression analysis. Results reveal that family ownership is positively related to the introduction of eco-innovations by firms, in part because of the stronger emphasis being placed on the company’s reputation. We find that this effect is strongest when the owning-family has transgenerational intentions. As such, this study advances our understanding of firm-level drivers of eco-innovation. In view of the prevalence of family-owned firms and the mounting importance of ecological sustainability, it is valuable to extend knowledge on the contingent and indirect effect of family ownership on eco-innovation.  相似文献   
7.

We develop a dynamic model of information transmission and aggregation in social networks in which continued membership in the network is contingent on the accuracy of opinions. Agents have opinions about a state of the world and form links to others in a directed fashion probabilistically. Agents update their opinions by averaging those of their connections, weighted by how long their connections have been in the system. Agents survive or die based on how far their opinions are from the true state. In contrast to the results in the extant literature on DeGroot learning, we show through simulations that for some parameterizations the model cycles stochastically between periods of high connectivity, in which agents arrive at a consensus opinion close to the state, and periods of low connectivity, in which agents’ opinions are widely dispersed.

  相似文献   
8.
Despite the importance of good collaborative relationships in interorganisational projects, clients and contractors often develop adversarial relationships due to perceptual distance about key project issues. In this case study research, we investigated how perceptual distance emerges and changes over time, and how the collaborative relationship between client and contractor develops alongside these dynamics. In this exploration, we built upon agency theory and stewardship theory as complementary perspectives for understanding client-contractor collaborative relationships. We gathered quantitative and qualitative data in two projects, conducting three assessments in about one year. We found that perceptual distance increased and decreased over time, and that a reduction was typically associated with the collaborative relationship being characterized by stewardship rather than agency. These findings suggest that a regular assessment and evaluation of partners’ perceptions of critical project issues is warranted to timely detect and counteract perceptual distance. Moreover, partners would best adopt a stewardship orientation to reduce perceptual distance, although this may take considerable effort given the distributive nature of many pre-project negotiations.  相似文献   
9.
Sell  Friedrich L.  Stiefl  Jürgen 《Intereconomics》2021,56(4):237-242
Intereconomics - Only a few years ago, it was a widespread belief that globalisation would trigger processes of democratisation worldwide. However, even old and established democracies such as the...  相似文献   
10.
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