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   1548篇
  免费   100篇
管理学   190篇
民族学   12篇
人口学   144篇
丛书文集   16篇
理论方法论   220篇
综合类   20篇
社会学   930篇
统计学   116篇
  2023年   19篇
  2022年   12篇
  2021年   17篇
  2020年   42篇
  2019年   53篇
  2018年   64篇
  2017年   98篇
  2016年   75篇
  2015年   48篇
  2014年   62篇
  2013年   241篇
  2012年   61篇
  2011年   72篇
  2010年   55篇
  2009年   41篇
  2008年   66篇
  2007年   58篇
  2006年   52篇
  2005年   48篇
  2004年   64篇
  2003年   37篇
  2002年   45篇
  2001年   29篇
  2000年   25篇
  1999年   18篇
  1998年   21篇
  1997年   15篇
  1996年   19篇
  1995年   11篇
  1994年   15篇
  1993年   14篇
  1992年   15篇
  1991年   14篇
  1990年   12篇
  1989年   9篇
  1988年   6篇
  1987年   15篇
  1986年   4篇
  1985年   6篇
  1984年   6篇
  1983年   5篇
  1982年   11篇
  1981年   4篇
  1980年   6篇
  1978年   6篇
  1977年   5篇
  1976年   5篇
  1975年   3篇
  1974年   4篇
  1971年   3篇
排序方式: 共有1648条查询结果,搜索用时 15 毫秒
151.
Reforms which increase the stock of education in a society have long been held by policy‐makers as key to improving rates of intergenerational social mobility. Yet, despite the intuitive plausibility of this idea, the empirical evidence in support of an effect of educational expansion on social fluidity is both indirect and weak. In this paper we use the raising of the minimum school leaving age from 15 to 16 years in England and Wales in 1972 to estimate the effect of educational participation and qualification attainment on rates of intergenerational social class mobility. Because, in expectation, children born immediately before and after the policy was implemented are statistically exchangeable, the difference in the amount of education they received may be treated as exogenously determined. The exogenous nature of the additional education gain means that differences in rates of social mobility between cohorts affected by the reform can be treated as having been caused by the additional education. The data for the analysis come from the ONS Longitudinal Study, which links individual records from successive decennial censuses between 1971 and 2001. Our findings show that, although the reform resulted in an increase in educational attainment in the population as a whole and a weakening of the association between attainment and class origin, there was no reliably discernible increase in the rate of intergenerational social mobility.  相似文献   
152.
This exploratory study examines the effects of rural and urban population change on forest cover at the local level across the southern United States. Using county‐level data from the National Land Cover Database and other U.S. government sources, we regressed the total area of forest cover on rural and urban population size in spatial panel models with two‐way fixed effects. When we controlled for several other factors, including the number of forestry operations at the county level, regression results indicate that urban change had no effect, but rural population size was positively related to total forest area, and this effect was most pronounced in and around Georgia. Thus, in areas of the southern United States, rural growth was associated with afforestation, not deforestation. We speculate on how this unusual finding contributes to the debate between ecological modernization and urban political economy implicated in previous cross‐national research.  相似文献   
153.
Most existing research theorizes individual factors as predictors of perceived job insecurity. Incorporating contextual and organizational factors at an information technology organization where a merger was announced during data collection, we draw on status expectations and crossover theories to investigate whether managers' characteristics and insecurity shape their employees' job insecurity. We find having an Asian as opposed to a White manager is associated with lower job insecurity, whereas managers' own insecurity positively predicts employees' insecurity. Also contingent on the organizational climate, managers' own tenure buffers, and managers' perceived job insecurity magnifies insecurity of employees interviewed after a merger announcement, further specifying status expectations theory by considering context.  相似文献   
154.
The Best Linear Unbiased Predictor (BLUP) in mixed models is a function of the variance components and they are estimated using maximum likelihood (ML) or restricted ML methods. Nonconvergence of BLUP would occur due to a drawback of the standard likelihood-based approaches. In such situations, ML and REML either do not provide any BLUPs or all become equal. To overcome this drawback, we provide a generalized estimate (GE) of BLUP that does not suffer from the problem of negative or zero variance components, and compare its performance against the ML and REML estimates of BLUP. Simulated and published data are used to compare BLUP.  相似文献   
155.
ABSTRACT

Social media data are increasingly used by researchers to gain insights on individuals’ behaviors and opinions. Platforms like Twitter provide access to individuals’ postings, networks of friends and followers, and the content to which they are exposed. This article presents the methods and results of an exploratory study to supplement survey data with respondents’ Twitter postings, networks of Twitter friends and followers, and information to which they were exposed about e-cigarettes. Twitter use is important to consider in e-cigarette research and other topics influenced by online information sharing and exposure. Further, Twitter metadata provide direct measures of user’s friends and followers as opposed to survey self-reports. We find that Twitter metadata provide similar information to survey questions on Twitter network size without inducing recall error or other measurement issues. Using sentiment coding and machine learning methods, we find Twitter can elucidate on topics difficult to measure via surveys such as online expressed opinions and network composition. We present and discuss models predicting whether respondents’ tweet positively about e-cigarettes using survey and Twitter data, finding the combined data to provide broader measures than either source alone.  相似文献   
156.
We provide evidence on the existence of short-run trade diversion effects towards third countries as a consequence of tariff shocks. We exploit sudden policy changes in the context of the trade dispute between the United States and China in 2018. Based on a data set covering monthly product-level information on US imports from 30 countries for the period 2016 until May 2019, we employ a difference-in-differences estimation framework. Doing so, we can show a strong negative direct effect of US tariffs on US imports from China, but do not find evidence for significant short-run trade diversion effects towards third countries.  相似文献   
157.
158.
Objectives. We aim to understand why blacks are significantly less likely than whites to perpetuate their middle-class status across generations. To do so, we focus on the potentially different associations between parental job loss and youth's educational attainment in black and white middle-class families.Methods. We use data from the Panel Study of Income Dynamics (PSID), following those children “born” into the survey between 1968 and 1979 and followed through age 21. We conduct multivariate regression analyses to test the association between parental job loss during childhood and youth's educational attainment by age 21.Results. We find that parental job loss is associated with a lesser likelihood of obtaining any postsecondary education for all offspring, but that the association for blacks is almost three times as strong. A substantial share of the differential impact of job loss on black and white middle-class youth is explained by race differences in household wealth, long-run measures of family income, and, especially, parental experience of long-term unemployment.Conclusions. These findings highlight the fragile economic foundation of the black middle class and suggest that intergenerational persistence of class status in this population may be highly dependent on the avoidance of common economic shocks.  相似文献   
159.
160.
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