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   11890篇
  免费   300篇
管理学   1715篇
民族学   57篇
人才学   2篇
人口学   1216篇
丛书文集   63篇
教育普及   2篇
理论方法论   1035篇
现状及发展   1篇
综合类   142篇
社会学   5669篇
统计学   2288篇
  2023年   79篇
  2021年   59篇
  2020年   172篇
  2019年   236篇
  2018年   271篇
  2017年   372篇
  2016年   303篇
  2015年   200篇
  2014年   251篇
  2013年   2057篇
  2012年   400篇
  2011年   329篇
  2010年   277篇
  2009年   269篇
  2008年   315篇
  2007年   298篇
  2006年   266篇
  2005年   283篇
  2004年   268篇
  2003年   237篇
  2002年   267篇
  2001年   301篇
  2000年   298篇
  1999年   290篇
  1998年   200篇
  1997年   181篇
  1996年   173篇
  1995年   177篇
  1994年   138篇
  1993年   161篇
  1992年   186篇
  1991年   156篇
  1990年   163篇
  1989年   190篇
  1988年   160篇
  1987年   142篇
  1986年   158篇
  1985年   176篇
  1984年   172篇
  1983年   168篇
  1982年   130篇
  1981年   103篇
  1980年   108篇
  1979年   140篇
  1978年   86篇
  1977年   85篇
  1976年   88篇
  1975年   79篇
  1974年   77篇
  1973年   72篇
排序方式: 共有10000条查询结果,搜索用时 31 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.
Organizational scholars increasingly recognize the value of employing historical research. Yet the fields of history and organization studies struggle to reconcile. In this paper, the authors contend that a closer connection between these two fields is possible if organizational historians bring their role in the construction of historical narratives to the fore and open up their research decisions for discussion. They provide guidelines to support this endeavor, drawing on four criteria that are prevalent within interpretive organization studies for developing the trustworthiness of research: credibility; confirmability; dependability; and transferability. In contrast to the traditional use of trustworthiness criteria to evaluate the quality of research, the authors advance the criteria to encourage historians to generate more transparent narratives. Such transparency allows others to comprehend and comment on the construction of narratives, thereby building trust and understanding. Each criterion is converted into a set of guiding principles to enhance the trustworthiness of historical research, pairing each principle with a practical technique gleaned from a range of disciplines within the social sciences to provide practical guidance.  相似文献   
3.
4.
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   
5.
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   
6.
7.
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   
8.
Close to 20 percent of the Swedish population are of immigrant origin; one in eight is foreign‐born. About 45 percent of all immigrants originate from outside Europe and most of these have entered the country as refugees or relatives of refugees. Issues connected to immigration, including the number of immigrants, settlement patterns and level of social integration of ethnic minorities, have been much discussed in Sweden in recent decades. This paper focuses on the integration of Latin American immigrants in Sweden. It compares the level of integration – measured as educational achievement, labour market participation, income and housing – experienced by first and second generation migrants. I use register information allowing me to include all 1st and 2nd generation Latin Americans that have lived in Sweden between 1990 and 2006 (in total 127,000 individuals). Data are longitudinal, which means that individuals can be followed over time. I make use of the longitudinal material in order to study changes in residential patterns and in attempts to explain educational and employment outcomes for second generation Latin Americans. The general conclusion of the paper is that in terms of integration, LAC immigrants have an intermediate position compared to other immigrant categories; they are often better off than people from Africa and the Middle East but clearly below the level experienced by some other migrants, especially those from Western Europe. This cannot be explained by level of education. The average level of education is high for first generation immigrants from LA countries. For many people, the level of labour market participation and income increase over time but one important result of this analysis is that second generation Latin Americans seem to do less well in Sweden compared to many other second generation migrants.  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