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   13884篇
  免费   98篇
管理学   2045篇
民族学   128篇
人才学   1篇
人口学   2691篇
丛书文集   31篇
理论方法论   823篇
综合类   306篇
社会学   6249篇
统计学   1708篇
  2023年   18篇
  2021年   23篇
  2020年   54篇
  2019年   77篇
  2018年   1714篇
  2017年   1732篇
  2016年   1149篇
  2015年   114篇
  2014年   112篇
  2013年   722篇
  2012年   405篇
  2011年   1239篇
  2010年   1117篇
  2009年   841篇
  2008年   921篇
  2007年   1087篇
  2006年   81篇
  2005年   312篇
  2004年   335篇
  2003年   285篇
  2002年   196篇
  2001年   89篇
  2000年   89篇
  1999年   70篇
  1998年   58篇
  1997年   58篇
  1996年   72篇
  1995年   61篇
  1994年   54篇
  1993年   50篇
  1992年   45篇
  1991年   52篇
  1990年   42篇
  1989年   40篇
  1988年   66篇
  1987年   57篇
  1986年   26篇
  1985年   39篇
  1984年   46篇
  1983年   57篇
  1982年   32篇
  1981年   35篇
  1980年   29篇
  1979年   34篇
  1978年   39篇
  1977年   31篇
  1976年   35篇
  1975年   28篇
  1974年   18篇
  1972年   17篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
We employ vector autoregressive techniques to determine the current state of the labor queue. Unemployment rate differentials have narrowed in recent years, potentially due to a change in the queue ordering, though a tight labor market and a stable queue would yield similar results. We find no evidence that the queue ordering has changed, which brings into question the resiliency of gains made by minority groups. We employ the same techniques to reveal the state of the queue across geographic regions and find that substantial differences exist across regions, implying variation in the relative labor force status of demographic groups.  相似文献   
32.
33.
34.
The authors review the trends in the use of computers in the delivery and support of career guidance and counseling identified at the symposium International Perspectives on Career Development. The papers presented emphasized that 20th‐century computer‐based systems continue to be used, mainly delivered via the World Wide Web. These systems are enhanced through audio, video, graphics, strategies to provide needs assessment, and support by cybercounselors or expert system design. The papers also revealed a new trend: the use of elegant Web sites to store and search immense libraries of resources needed by professionals and clients and to facilitate communication and collaboration among professionals in cyberspace. Concerns, issues, and resources related to many areas, including the readiness of clients to use computer‐based systems, were also raised; existing sources of guidelines are noted.  相似文献   
35.
Point processes are the stochastic models most suitable for describing physical phenomena that appear at irregularly spaced times, such as the earthquakes. These processes are uniquely characterized by their conditional intensity, that is, by the probability that an event will occur in the infinitesimal interval (t, t+Δt), given the history of the process up tot. The seismic phenomenon displays different behaviours on different time and size scales; in particular, the occurrence of destructive shocks over some centuries in a seismogenic region may be explained by the elastic rebound theory. This theory has inspired the so-called stress release models: their conditional intensity translates the idea that an earthquake produces a sudden decrease in the amount of strain accumulated gradually over time along a fault, and the subsequent event occurs when the stress exceeds the strength of the medium. This study has a double objective: the formulation of these models in the Bayesian framework, and the assignment to each event of a mark, that is its magnitude, modelled through a distribution that depends at timet on the stress level accumulated up to that instant. The resulting parameter space is constrained and dependent on the data, complicating Bayesian computation and analysis. We have resorted to Monte Carlo methods to solve these problems.  相似文献   
36.
Silphids in urban forests: Diversity and function   总被引:2,自引:0,他引:2  
Wolf  Jordan M.  Gibbs  James P. 《Urban Ecosystems》2004,7(4):371-384
Many ecologists have examined the process of how urbanization reduces biological diversity but rarely have its ecological consequences been assessed. We studied forest-dwelling burying beetles (Coleoptera: Silphidae)—a guild of insects that requires carrion to complete their life cycles—along an urban-rural gradient of land use in Maryland. Our objective was to determine how forest fragmentation associated with urbanization affects (1) beetle community diversity and structure and (2) the ecological function provided by these insects, that is, decomposition of vertebrate carcasses. Forest fragmentation strongly reduced burying beetle diversity and abundance, and did so far more pervasively than urbanization of the surrounding landscape. The likelihood that beetles interred experimental baits was a direct, positive function of burying beetle diversity. We conclude that loss of burying beetle diversity resulting from forest fragmentation could have important ecological consequences in urban forests.  相似文献   
37.
In non-experimental research, data on the same population process may be collected simultaneously by more than one instrument. For example, in the present application, two sample surveys and a population birth registration system all collect observations on first births by age and year, while the two surveys additionally collect information on women’s education. To make maximum use of the three data sources, the survey data are pooled and the population data introduced as constraints in a logistic regression equation. Reductions in standard errors about the age and birth-cohort parameters of the regression equation in the order of three-quarters are obtained by introducing the population data as constraints. A halving of the standard errors about the education parameters is achieved by pooling observations from the larger survey dataset with those from the smaller survey. The percentage reduction in the standard errors through imposing population constraints is independent of the total survey sample size.  相似文献   
38.
39.
This paper investigates whether EU research programmes have led to innovations in European social research. This is based on an assessment of a group of EU‐funded projects on the changing nature of work in Europe. EU‐funded projects have contributed to the creation of a European social space for European researchers, but at the cost of consolidating English as the lingua franca of European social research. Such projects tend to involve heterogeneous research actors and are oriented towards policy issues. To some extent they are therefore representative of a ‘Mode 2’ form of knowledge production. More clearly, they have ensured that social research about Europe is no longer simply comparative research. The new EU Sixth Framework Programme on RTD will undermine many of these achievements through its focus on conventional definitions of ‘excellence’ and the insistence on large‐scale research instruments.  相似文献   
40.
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