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   138321篇
  免费   3903篇
  国内免费   2篇
财政金融   26218篇
工业经济   11608篇
计划管理   22284篇
经济学   29726篇
综合类   1481篇
运输经济   978篇
旅游经济   2493篇
贸易经济   23881篇
农业经济   6145篇
经济概况   17103篇
信息产业经济   7篇
邮电经济   302篇
  2021年   851篇
  2020年   1646篇
  2019年   2398篇
  2018年   2412篇
  2017年   2581篇
  2016年   2750篇
  2015年   2127篇
  2014年   3444篇
  2013年   15379篇
  2012年   4268篇
  2011年   4233篇
  2010年   3771篇
  2009年   4354篇
  2008年   3938篇
  2007年   3320篇
  2006年   3611篇
  2005年   3591篇
  2004年   3136篇
  2003年   2935篇
  2002年   2879篇
  2001年   2687篇
  2000年   2657篇
  1999年   2502篇
  1998年   2364篇
  1997年   2408篇
  1996年   2263篇
  1995年   2045篇
  1994年   2066篇
  1993年   2039篇
  1992年   2114篇
  1991年   2032篇
  1990年   1876篇
  1989年   1710篇
  1988年   1637篇
  1987年   1655篇
  1986年   1739篇
  1985年   2501篇
  1984年   2386篇
  1983年   2184篇
  1982年   2063篇
  1981年   1991篇
  1980年   1941篇
  1979年   1898篇
  1978年   1684篇
  1977年   1645篇
  1976年   1410篇
  1975年   1314篇
  1974年   1196篇
  1973年   1195篇
  1972年   903篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Sequels have become a profitable strategy in the U.S. motion picture industry because of their strong name recognition. However, while the established positioning of a sequel may help insulate it from competing firms' advertising messages, its familiarity may cause moviegoers to be more easily satiated with advertising from the sequel. Therefore, this study examines how sequels differ from original concept movies in terms of their ad effectiveness. We focus our analysis on pre-launch periods, given these periods' importance in shaping the financial outcomes of motion pictures. We consider the weekly online search volume of a movie as a measure of consumer interest in it, and thus as an intermediate response to pre-launch advertising. We then develop a model that assumes ad effectiveness can decline, due to copy and repetition wearout, and increase, due to forgetting, over time. We find that copy wearout is greater for original movies, while repetition wearout and forgetting are greater for sequels. These findings suggest that sequels should allocate more in early pre-launch periods and less immediately before release, relative to originals, to maximize pre-launch consumer interest.  相似文献   
12.
Quality & Quantity - Within-subject designs (WSDs) remain unpopular in psychology. Social psychologists have argued that they create “demand” and “order” effects....  相似文献   
13.
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   
14.

This paper examines the extent of social interactions in an individual’s decision to undergo mammography. Using Behavioral Risk Factors Surveillance System surveys from 1993 to 2016, the effect of other female screening behavior on an individual’s decision to have a routine breast cancer screening was measured by calculating the size of a so called “social multiplier” in mammography. A vector of social multipliers was estimated in the use of mammograms in the past 1–2 years by taking the ratio of group-level effects of exogenous explanatory variables to individual-level effects of the same variables. Peer groups were defined as same-aged women living in the same state. Three age groups of women were considered: 40–49, 50–74, and 75 and older. Several econometric approaches were used to analyze the effect of social interactions on mammography use, including ordinary least squares, fixed effects, and split-sample instrumental variable. For all women, evidence was found of social interactions associated with individual’s education, employment, and poor health. In addition, number of age-group-specific social multipliers was found. The strongest evidence of spillover in mammography was found for women ages 75 and older. Policy makers should be aware that, in the presence of a social multiplier, the value of any type of screening intervention is higher than the one that would be measured at the individual-level.

  相似文献   
15.
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   
16.
17.
18.
Objective: This study was to determine if calcium fortification yields a higher price per serving in grocery store products. Researchers compared store brand to national brand grocery products in relation to cost in order to examine if calcium values were similar between store brand and national brand products. Methods: A total of 112 store brand and 211 national brand grocery products were collected from three low (national chain store), middle and high priced (Virginia and North Carolina regional store) grocery venues. Products were compared using price and calcium percentage per serving. ANOVA was used to determine between store brand and national brand for price per serving and calcium content, and between grocery venues. Results: National brand fortified products had a significantly lower mean price per serving when compared to national brand non-fortified products (p = 0.0002). There was no statistical difference between store brand fortified and non-fortified products (p = 0.9256). Low priced store brand products had the lowest mean price per serving ($0.34 ±0.24). Conclusions: This study found store brand products have similar calcium content as national brand products. Product cost was lower at low priced store compared to middle and high priced stores.  相似文献   
19.
Consumer “multihoming” (watching two TV channels, or buying two news magazines) has surprisingly important effects on market equilibrium and performance in (two‐sided) media markets. We show this by introducing consumer multihoming and advertising finance into the classic circle model of product differentiation. When consumers multihome (attend more than one platform), media platforms can charge only incremental value prices to advertisers. Entry or merger leaves consumer prices unchanged under consumer multihoming, but leaves advertiser prices unchanged under single‐homing: Multihoming flips the side of the market on which platforms compete. In contrast to standard circle results, equilibrium product variety can be insufficient under multihoming.  相似文献   
20.
We investigate the effects of environmental policy (Climate Change Act – CCA), sustainable development frameworks (Global Reporting Initiative – GRI; UN Global Compact – UNGC) and corporate governance (CG) mechanisms on environmental performance (carbon reduction initiatives – CRIs; actual carbon performance – GHG emissions) of UK listed firms. We use the generalized method of moments (GMM) estimation technique to analyse data consisting of 2245 UK firm‐year observations over the 2002–2014 period. First, we find that the CCA has a positive effect on CRIs, and this effect is stronger in better‐governed firms. Second, we find that the GRI‐based framework is positively associated with CRIs. Third, we find that firms with poor CG structures have lower actual carbon performance compared with their better‐governed counterparts. Overall, our evidence suggests that firms can symbolically conform to environmental policy (CCA) and sustainable development frameworks (GRI, UNGC) by engaging in CRIs without necessarily improving actual environmental performance (GHG emissions) substantively. Copyright © 2017 John Wiley & Sons, Ltd and ERP Environment  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