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   768篇
  免费   47篇
管理学   89篇
民族学   3篇
人口学   73篇
丛书文集   3篇
理论方法论   90篇
综合类   8篇
社会学   442篇
统计学   107篇
  2023年   5篇
  2022年   3篇
  2021年   8篇
  2020年   17篇
  2019年   40篇
  2018年   41篇
  2017年   48篇
  2016年   32篇
  2015年   27篇
  2014年   26篇
  2013年   133篇
  2012年   22篇
  2011年   37篇
  2010年   22篇
  2009年   25篇
  2008年   17篇
  2007年   21篇
  2006年   23篇
  2005年   15篇
  2004年   13篇
  2003年   13篇
  2002年   23篇
  2001年   16篇
  2000年   23篇
  1999年   14篇
  1998年   16篇
  1997年   16篇
  1996年   17篇
  1995年   3篇
  1994年   5篇
  1993年   8篇
  1992年   15篇
  1991年   6篇
  1990年   7篇
  1987年   7篇
  1986年   3篇
  1985年   2篇
  1984年   4篇
  1983年   11篇
  1982年   5篇
  1981年   3篇
  1979年   3篇
  1978年   2篇
  1977年   3篇
  1975年   4篇
  1973年   3篇
  1969年   1篇
  1967年   1篇
  1966年   2篇
  1964年   1篇
排序方式: 共有815条查询结果,搜索用时 171 毫秒
1.
Understanding the risk of biological invasions associated with particular transport pathways and source regions is critical for implementing effective biosecurity management. This may require both a model for physical connectedness between regions, and a measure of environmental similarity, so as to quantify the potential for a species to be transported from a given region and to survive at a destination region. We present an analysis of integrated biosecurity risk into Australia, based on flights and shipping data from each global geopolitical region, and an adaptation of the “range bagging” method to determine environmental matching between regions. Here, we describe global patterns of environmental matching and highlight those regions with many physical connections. We classify patterns of global invasion risk (high to low) into Australian states and territories. We validate our analysis by comparison with global presence data for 844 phytophagous insect pest species, and produce a list of high‐risk species not previously known to be present in Australia. We determined that, of the insect pest species used for validation, the species most likely to be present in Australia were those also present in geopolitical regions with high transport connectivity to Australia, and those regions that were geographically close, and had similar environments.  相似文献   
2.
Population and Environment - Human activity is a major driver of change and has contributed to many of the challenges we face today. Detailed information about human population distribution is...  相似文献   
3.
We describe a risk-based analytical framework for estimating traffic fatalities that combines the probability of a crash and the probability of fatality in the event of a crash. As an illustrative application, we use the methodology to explore the role of vehicle mix and vehicle prevalence on long-run fatality trends for a range of transportation growth scenarios that may be relevant to developing societies. We assume crash rates between different road users are proportional to their roadway use and estimate case fatality ratios (CFRs) for the different vehicle-vehicle and vehicle-pedestrian combinations. We find that in the absence of road safety interventions, the historical trend of initially rising and then falling fatalities observed in industrialized nations occurred only if motorization was through car ownership. In all other cases studied (scenarios dominated by scooter use, bus use, and mixed use), traffic fatalities rose monotonically. Fatalities per vehicle had a falling trend similar to that observed in historical data from industrialized nations. Regional adaptations of the model validated with local data can be used to evaluate the impacts of transportation planning and safety interventions, such as helmets, seat belts, and enforcement of traffic laws, on traffic fatalities.  相似文献   
4.
Summary. We develop a general methodology for tilting time series data. Attention is focused on a large class of regression problems, where errors are expressed through autoregressive processes. The class has a range of important applications and in the context of our work may be used to illustrate the application of tilting methods to interval estimation in regression, robust statistical inference and estimation subject to constraints. The method can be viewed as 'empirical likelihood with nuisance parameters'.  相似文献   
5.
With its roots in American pragmatism, symbolic interactionism has created a distinctive perspective and produced numerous important contributions and now offers significant prospects for the future. In this article, I review my intellectual journey with this perspective over forty years. This journey was initiated within the American society, sociology, and symbolic interaction of circa 1960. I note many of the contributions made by interactionists since that time, with particular focus on those who have contributed to the study of social organization and social process. I offer an agenda for the future based on currently underdeveloped areas that have potential. These are inequality orders, institutional analysis, collective action across space and time, and the integration of temporal and spatial orders. The article concludes with calls for further efforts at cross‐perspective dialogues, more attention to feminist scholars, and an elaborated critical pragmatism.  相似文献   
6.
Using information gathered during fieldwork on New York lesbian and gay film festival organizations, this paper argues that scholarship on identity has not paid sufficient attention to the organizational mediation of collective identity. The shape of collective identity—how internal instabilities and diversities are accommodated, in this case—depends not only on the emergent characteristics of the “collective,” but also on the resolution of challenges particular to organizational fields. Two very differently conceived lesbian and gay festival organizations, sites at which decision making about collective identity is ongoing and self-conscious, are examined. The analysis traces how each responds to two related tasks: maintaining community legitimacy, which requires racial diversification, and surviving within an altered institutional environment. Rather than imposition from “above” or construction from “below,” the adaptive responses by organizations (to changes in both community expectations and the resource environment) transform the collective identity formulations reaching public visibility. Earlier versions of this paper were presented at the Colloquium Series of the Center for Lesbian and Gay Studies, City University of New York, 1995, and at the Annual Meeting of the American Sociological Association, Washington, DC, 1995.  相似文献   
7.
8.
9.
This paper examines how the Chinese state's prenatal health care campaigns of the early 1950s attempted to redefine women's social and political roles. The replacement of local midwifing practices with a uniform birthing method in order to radically reduce infant and mother mortality entailed complex ramifications regarding the relationship of women vis-a-vis the state. Campaigns involved demonizing "traditional" midwifing, promoting a statistical vision of female reproductivity and children as national resources, and the isolation of individual mothers as directly responsible to the state for managing reproduction for the national interest. In sum, a physiological definition of gender was used to open women's bodies to state management. Utopic visions of painless childbirth and of the socialist nation as a giant new family were used to promote participation in grassroots campaigns, but the sources also point to forms of local resistance to the micro-level reorganization of power these campaigns intended.  相似文献   
10.
Local linear curve estimators are typically constructed using a compactly supported kernel, which minimizes edge effects and (in the case of the Epanechnikov kernel) optimizes asymptotic performance in a mean square sense. The use of compactly supported kernels can produce numerical problems, however. A common remedy is ridging, which may be viewed as shrinkage of the local linear estimator towards the origin. In this paper we propose a general form of shrinkage, and suggest that, in practice, shrinkage be towards a proper curve estimator. For the latter we propose a local linear estimator based on an infinitely supported kernel. This approach is resistant against selection of too large a shrinkage parameter, which can impair performance when shrinkage is towards the origin. It also removes problems of numerical instability resulting from using a compactly supported kernel, and enjoys very good mean squared error properties.  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