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   7306篇
  免费   172篇
  国内免费   1篇
管理学   924篇
民族学   33篇
人口学   760篇
丛书文集   32篇
理论方法论   661篇
综合类   90篇
社会学   3572篇
统计学   1407篇
  2023年   40篇
  2020年   97篇
  2019年   141篇
  2018年   168篇
  2017年   252篇
  2016年   178篇
  2015年   124篇
  2014年   160篇
  2013年   1301篇
  2012年   229篇
  2011年   206篇
  2010年   146篇
  2009年   134篇
  2008年   147篇
  2007年   141篇
  2006年   170篇
  2005年   152篇
  2004年   148篇
  2003年   136篇
  2002年   153篇
  2001年   164篇
  2000年   168篇
  1999年   173篇
  1998年   137篇
  1997年   133篇
  1996年   126篇
  1995年   110篇
  1994年   107篇
  1993年   109篇
  1992年   107篇
  1991年   121篇
  1990年   122篇
  1989年   141篇
  1988年   82篇
  1987年   106篇
  1986年   92篇
  1985年   113篇
  1984年   94篇
  1983年   101篇
  1982年   79篇
  1981年   79篇
  1980年   73篇
  1979年   77篇
  1978年   81篇
  1977年   56篇
  1976年   61篇
  1975年   59篇
  1974年   56篇
  1973年   44篇
  1971年   38篇
排序方式: 共有7479条查询结果,搜索用时 46 毫秒
11.
Journal of Population Research - This paper details efforts to link administrative records from the Internal Revenue Service (IRS) to American Community Survey (ACS) and 2010 Census microdata for...  相似文献   
12.
13.
14.
In this paper, we are studying social identities within a cross-national framework as they are reflected in values regarding social institutions. We compare value items to infer similarities and differences between Japan and the US, but more importantly we analyze value configurations, using factor analysis, as an expression of underlying cultural expectations. We also argue that the way values are transmitted further defines the distinctive cultural basis of social identities. Using a unique data set, The Generations Survey , we propose to contribute theoretically and methodologically to understanding the role of culture in postmodern societies. Our research, based on identical national surveys collected in 1995, provides a systematic way to compare values in two countries. The research builds on and specifies existing ethnographic case studies and in-depth interviews around a variety of themes that shape social identities such as the link between family and work expectations, the role of ethical values in business, the importance of national identification, and the meaning of community involvement. The paper concludes by suggesting that despite homogenizing trends and surface similarities, cultural distinctiveness persists in the ways values cluster and is transmitted in the family, shaping the social identities of Japanese and US respondents.  相似文献   
15.
Institutional Constraints and Deforestation: An Application to Mexico   总被引:1,自引:0,他引:1  
Following North (1990), this article hypothesizes that effective rural institutions may impose additional costs on tropical deforestation through agricultural conversion. This allows a formal agricultural household analysis of institutional constraints on deforestation and therefore a method of empirically testing whether there is any significant difference in the actual level of forest land conversion under institutional constraints compared to the level of conversion under pure open access. A dynamic panel analysis for agricultural planted area in Mexico at state level and over the 1960–85 period confirms that institutional constraints on land clearing affected deforestation during the pre-NAFTA era.  相似文献   
16.
17.
18.
Spatial variation in soil inorganic nitrogen across an arid urban ecosystem   总被引:4,自引:1,他引:3  
We explored variations in inorganic soil nitrogen (N) concentrations across metropolitan Phoenix, Arizona, and the surrounding desert using a probability-based synoptic survey. Data were examined using spatial statistics on the entire region, as well as for the desert and urban sites separately. Concentrations of both NO3-N and NH4-N were markedly higher and more heterogeneous amongst urban compared to desert soils. Regional variation in soil NO3-N concentration was best explained by latitude, land use history, population density, along with percent cover of impervious surfaces and lawn, whereas soil NH4-N concentrations were related to only latitude and population density. Within the urban area, patterns in both soil NO3-N and NH4-N were best predicted by elevation, population density and type of irrigation in the surrounding neighborhood. Spatial autocorrelation of soil NO3-N concentrations explained 49% of variation among desert sites but was absent between urban sites. We suggest that inorganic soil N concentrations are controlled by a number of ‘local’ or ‘neighborhood’ human-related drivers in the city, rather than factors related to an urban-rural gradient.  相似文献   
19.
Leaving school prematurely is often claimed to be among the most negative consequences of early marriage and pregnancy for girls in less developed countries. However, an analysis of the relative frequency with which these events actually occur or are named as reasons for leaving school reveals that, at least in the case of francophone Africa, they explain no more than 20 per cent of dropouts. To the extent that demographic events trump school or family factors as determinants of school-leaving, our data indicate that it is union formation--defined by the DHS as first marriage or cohabitation--rather than childbirth that is more likely to have this effect. 'Schoolgirl pregnancy' typically accounts for only between 5 and 10 per cent of girls' departures from school. Furthermore, the risks of leaving school because of pregnancy or marriage have declined over time with the decline in rates of early marriage and childbearing.  相似文献   
20.
Parameter design or robust parameter design (RPD) is an engineering methodology intended as a cost-effective approach for improving the quality of products and processes. The goal of parameter design is to choose the levels of the control variables that optimize a defined quality characteristic. An essential component of RPD involves the assumption of well estimated models for the process mean and variance. Traditionally, the modeling of the mean and variance has been done parametrically. It is often the case, particularly when modeling the variance, that nonparametric techniques are more appropriate due to the nature of the curvature in the underlying function. Most response surface experiments involve sparse data. In sparse data situations with unusual curvature in the underlying function, nonparametric techniques often result in estimates with problematic variation whereas their parametric counterparts may result in estimates with problematic bias. We propose the use of semi-parametric modeling within the robust design setting, combining parametric and nonparametric functions to improve the quality of both mean and variance model estimation. The proposed method will be illustrated with an example and simulations.  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