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   12633篇
  免费   315篇
管理学   1850篇
民族学   58篇
人才学   3篇
人口学   1286篇
丛书文集   72篇
教育普及   1篇
理论方法论   1094篇
现状及发展   1篇
综合类   153篇
社会学   6125篇
统计学   2305篇
  2023年   82篇
  2021年   62篇
  2020年   185篇
  2019年   237篇
  2018年   281篇
  2017年   397篇
  2016年   312篇
  2015年   200篇
  2014年   274篇
  2013年   2165篇
  2012年   418篇
  2011年   357篇
  2010年   298篇
  2009年   278篇
  2008年   327篇
  2007年   312篇
  2006年   282篇
  2005年   291篇
  2004年   295篇
  2003年   248篇
  2002年   297篇
  2001年   301篇
  2000年   310篇
  1999年   302篇
  1998年   202篇
  1997年   187篇
  1996年   185篇
  1995年   183篇
  1994年   156篇
  1993年   171篇
  1992年   188篇
  1991年   168篇
  1990年   184篇
  1989年   202篇
  1988年   178篇
  1987年   153篇
  1986年   173篇
  1985年   184篇
  1984年   179篇
  1983年   177篇
  1982年   134篇
  1981年   127篇
  1980年   119篇
  1979年   156篇
  1978年   101篇
  1977年   99篇
  1976年   105篇
  1975年   94篇
  1974年   88篇
  1973年   77篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Damage models for natural hazards are used for decision making on reducing and transferring risk. The damage estimates from these models depend on many variables and their complex sometimes nonlinear relationships with the damage. In recent years, data‐driven modeling techniques have been used to capture those relationships. The available data to build such models are often limited. Therefore, in practice it is usually necessary to transfer models to a different context. In this article, we show that this implies the samples used to build the model are often not fully representative for the situation where they need to be applied on, which leads to a “sample selection bias.” In this article, we enhance data‐driven damage models by applying methods, not previously applied to damage modeling, to correct for this bias before the machine learning (ML) models are trained. We demonstrate this with case studies on flooding in Europe, and typhoon wind damage in the Philippines. Two sample selection bias correction methods from the ML literature are applied and one of these methods is also adjusted to our problem. These three methods are combined with stochastic generation of synthetic damage data. We demonstrate that for both case studies, the sample selection bias correction techniques reduce model errors, especially for the mean bias error this reduction can be larger than 30%. The novel combination with stochastic data generation seems to enhance these techniques. This shows that sample selection bias correction methods are beneficial for damage model transfer.  相似文献   
2.
3.
We employ two population‐level experiments to accurately measure opposition to immigration before and after the economic crisis of 2008. Our design explicitly addresses social desirability bias, which is the tendency to give responses that are seen favorably by others and can lead to substantial underreporting of opposition to immigration. We find that overt opposition to immigration, expressed as support for a closed border, increases slightly after the crisis. However, once we account for social desirability bias, no significant increase remains. We conclude that the observed increase in anti‐immigration sentiment in the post‐crisis United States is attributable to greater expression of opposition rather than any underlying change in attitudes.  相似文献   
4.

A common assertion in the nonprofit literature is that nonprofit organizations can become more efficient, effective, and sustainable by embracing social entrepreneurship in their operational and strategic posture. In this article, we examine whether the mere label of social entrepreneurship results—with no actual organizational differences—in an increase in positive attributions associated with a nonprofit organization, an effect we call the social entrepreneurship bias. We experimentally test for the existence of a social entrepreneurship bias by examining how the label of social entrepreneurship alters how people judge a nonprofit’s effectiveness and decide how to allocate scarce donation funds.

  相似文献   
5.
6.
Lifetime Data Analysis - Frailty models are generally used to model heterogeneity between the individuals. The distribution of the frailty variable is often assumed to be continuous. However, there...  相似文献   
7.
8.
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   
9.
Explicitly aimed at understanding and controlling molecular and cellular processes at the root of senescence and biological aging, regenerative medicine aspires to artificially reproduce the biological processes that enable the body to regenerate itself. This no longer involves conserving the body's state of balance by combating disease, as in clinical medicine, but rather fighting degeneration itself. From stem cell research to gene therapy to the production of replacement tissues, regenerative medicine perfectly corresponds to the logic of biomedicalization specific to postmodern society. Based on a series of 18 interviews conducted with Canadian researchers and clinicians in the field of regenerative medicine, this article seeks to understand representations of the aging body among researchers in this field. Seen from a strictly negative angle, aging is assimilated by researchers to an inevitable catastrophe that nevertheless must be combated. More closely observing the theoretical model of regenerative biology and the types of treatments developed, it can be observed, however, that this medicine of the future does not target the elderly, but rather promises youth the ability to regenerate themselves to avoid aging.  相似文献   
10.
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