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   988篇
  免费   24篇
管理学   173篇
民族学   3篇
人口学   101篇
丛书文集   7篇
理论方法论   108篇
综合类   6篇
社会学   474篇
统计学   140篇
  2020年   7篇
  2019年   14篇
  2018年   11篇
  2017年   18篇
  2016年   21篇
  2015年   15篇
  2014年   8篇
  2013年   163篇
  2012年   19篇
  2011年   20篇
  2010年   18篇
  2009年   25篇
  2008年   29篇
  2007年   32篇
  2006年   23篇
  2005年   20篇
  2004年   29篇
  2003年   22篇
  2002年   30篇
  2001年   19篇
  2000年   23篇
  1999年   19篇
  1998年   15篇
  1997年   14篇
  1996年   15篇
  1995年   15篇
  1994年   19篇
  1993年   19篇
  1992年   15篇
  1991年   15篇
  1990年   11篇
  1989年   13篇
  1988年   12篇
  1987年   18篇
  1986年   13篇
  1985年   20篇
  1984年   15篇
  1983年   21篇
  1982年   20篇
  1981年   17篇
  1980年   12篇
  1979年   13篇
  1978年   16篇
  1977年   16篇
  1976年   8篇
  1975年   11篇
  1974年   15篇
  1972年   6篇
  1968年   7篇
  1967年   5篇
排序方式: 共有1012条查询结果,搜索用时 12 毫秒
31.
The large differences in youth smoking behavior across ethnic and racial groups are often overlooked in debates about prevention. This study examines how the determinants of the onset of smoking vary by race and ethnicity. Academic success is strongly associated with lower smoking rates among white youth, but this is not as true for Hispanics and African-Americans. Cultural assimilation may be an important determinant of smoking for Hispanics. Price increases do not appear to reduce smoking onset among white youth, but the results provide some support that higher prices will reduce smoking among Hispanic and African-American youth.  相似文献   
32.
This article presents some of the community-based artwork of a group of men with learning disabilities, who aimed to challenge some of the misconceptions associated with learning disabilities. People with learning disabilities regularly face many forms of direct and indirect stigma. The consequences of such negative perceptions may affect individuals’ social relationships and ensure that barriers are strengthened which prevent their full inclusion. The men in this project used a series of visual and creative methods to challenge some of these misconceptions by telling stories through art, demonstrating skill through photography, using poetry to talk about sexual identity and improvising drama and filmmaking to challenge stigma, and through sculpture expressed their voices. Thus, by doing so, they were able to challenge some of the stigma associated with learning disabilities, indicating that community-based arts research is a valuable way in which to promote the voices of people with learning disabilities.  相似文献   
33.
Tropical forested ecosystems provide multiple ecosystem services to rural and urban landscapes, with carbon storage gaining particular attention. Deforestation due to rural-urban transitions may lead to a reduction in carbon storage ability. Coastal mangrove forests are particularly at risk from deforestation due to their location in the rapidly urbanizing coastal zone, and the city state of Singapore is an extreme example, losing as much as 90 % of its original mangrove cover due to land reclamation and reservoir construction. Knowledge of mangrove ecosystem services may allow better conservation, restoration and incorporation of remaining mangrove patches into the urban landscape. Focusing on the regulating ecosystem service of carbon storage, mangrove carbon stocks have been estimated for Singapore using a combination of field and remote sensing techniques. Biomass carbon showed substantial spatial variation, with old, contiguous mangrove patches containing a higher density of biomass carbon than fragmented, river-fringing or restored mangroves. In total, national biomass carbon equated to 116,117.1 megagrams of carbon (Mg C), and a coarse estimate of the total carbon stock (including soil carbon) suggests that Singapore’s mangroves may store 450,571.7 Mg C. While lower than other regional estimates focused on natural, oceanic mangroves, this is a significant carbon stock for a disturbed, urban mangrove system, and may be equivalent to the average annual carbon emissions of 621,000 residents. This analysis, alongside a review of other urban forest studies, highlights the importance of forested ecosystems such as mangroves in providing a carbon storage ecosystem service to urban areas.  相似文献   
34.
Deterministic goal programs for employee scheduling decisions attempt to minimize expected operating costs by assigning the ideal number of employees to each feasible schedule. For each period in the planning horizon, managers must first determine the amount of labor that should be scheduled for duty. These requirements are often established with marginal analysis techniques, which use estimates for incremental labor costs and shortage expenses. Typically, each period in the planning horizon is evaluated as an independent epoch. An implicit assumption is that individual employees can be assigned to schedules with as little as a single period of work. If this assumption violates local work rules, the labor requirements parameters for the deterministic goal program may be suboptimal. As we show in this research, this well-known limitation can lead to costly staffing and scheduling errors. We propose an employee scheduling model that overcomes this limitation by integrating the labor requirements and scheduling decisions. Instead of a single, externally determined staffing goal for each period, the model uses a probability distribution for the quantity of labor required. The model is free to choose an appropriate staffing level for each period, eliminating the need for a separate goal-setting procedure. In most cases this results in better, less costly decisions. In addition, the proposed model easily accommodates both linear and nonlinear under- and overstaffing penalties. We use simple examples to demonstrate many of these advantages and to illustrate the key techniques necessary to implement our model. We also assess its performance in a study of more than 1,700 simulated stochastic employee scheduling problems.  相似文献   
35.
36.
This article analyses two participatory projects designed to engage older women in the creation of new imagery of old age. While it was hoped that this imagery would offer an ‘alternative’ to mainstream depictions or indeed offer older women a presence amidst the much noted absence of images of older women, the brief left it open to the professional photographers recruited to the project and to the participants themselves to direct the representations. In recent years, critical gerontologists have repeatedly called for artistic challenges to conventional ways of imaging old age. By working with two groups of older women, the intention was that ‘ordinary’ older women (non-celebrity, non-artist) could be included in that challenge and imagery created which would show the lives of older women honestly. In the case of the two projects described here, professional photographers were enlisted to give visual form to the women's views on ageing and their lives as older women and deliver ‘exhibition quality’ images. Important factors in determining the types of images produced included the artistic style and preferences of the photographers and their respective ages, both of which are explored here. In-depth analysis of some of the images produced shows that while they did not succumb to the usual ‘heroes of ageing’/‘bodily decline’ binary (Featherstone & Hepworth, 2005), they did not escape other dualistic categorisations. The images can be broadly viewed as nostalgic/melancholic or humorously carnivalesque. This finding is evidence of how difficult it is to create ‘alternative’ images of older women which defy established modes of categorisation.  相似文献   
37.
Several researchers have proposed solutions to control type I error rate in sequential designs. The use of Bayesian sequential design becomes more common; however, these designs are subject to inflation of the type I error rate. We propose a Bayesian sequential design for binary outcome using an alpha‐spending function to control the overall type I error rate. Algorithms are presented for calculating critical values and power for the proposed designs. We also propose a new stopping rule for futility. Sensitivity analysis is implemented for assessing the effects of varying the parameters of the prior distribution and maximum total sample size on critical values. Alpha‐spending functions are compared using power and actual sample size through simulations. Further simulations show that, when total sample size is fixed, the proposed design has greater power than the traditional Bayesian sequential design, which sets equal stopping bounds at all interim analyses. We also find that the proposed design with the new stopping for futility rule results in greater power and can stop earlier with a smaller actual sample size, compared with the traditional stopping rule for futility when all other conditions are held constant. Finally, we apply the proposed method to a real data set and compare the results with traditional designs.  相似文献   
38.
In the societal debate surrounding voluntary euthanasia or physician‐assisted suicide, there is a concern that older people will be left exposed to any legislation, subject to either faint suggestion or outright coercion from familial or professional carers. Whilst it is critical to take account of older people's potential vulnerability to any current or proposed assisted suicide legislation, there is a parallel strand of research exploring another relationship which older people can have with this debate: one of activism. Sociological research has shown that older people make up the “rank and file” of those active within the right‐to‐die movement. One of the stated motivations of some older people requesting hastened death has been that, in spite of an absence of life‐threatening disease, they feel “tired of life” or that they have lived a “completed life” and feel ready to die. The notion of suicide for reasons of longevity and being tired of life are becoming increasingly significant given the fact of global ageing. This article brings together empirical and theoretical research on the phenomenon of old age rational suicide in order to develop an underexplored area in both the sociology of death and the sociology of ageing.  相似文献   
39.
2005年,卡特里娜和丽塔两大飓风侵袭路易斯安那州的新奥尔良市,成为美国历史上造成损失最大的灾难之一。这一貌似自然灾害的危害事件,其实孕育于新奥尔良的长期发展之中。一部新奥尔良发展史,既是人类利用土地、河流、森林、海洋等自然实体并与自然环境搏斗以建立城市、发展航运和工商业的历史,也是这些自然实体及其哺育的众多生命不断受侵蚀以至戕害的历史。这既是一部人类文明史,也是一部环境灾难史。在这里,人类借助水利工程控制自然而建立起来的文明,由于损害了生态系统的健康,削弱了其自然防护能力,结果反而加剧了人类无法避免的自然灾害的危害。因此,飓风造成的损失不只是取决于风暴之力,也取决于人们对土地的所作所为。而保持新奥尔良生机的努力,并不需要一味地与自然相搏,与自然合作,也是一种有益的尝试。  相似文献   
40.
We estimate a mixed logit model of the demand for local news service. Results provide evidence that suggest the representative consumer values more diverse news, more coverage of multicultural issues, and more information on community news, and has a distaste for advertising. Demand estimates are used to calculate the impact on consumer welfare from a marginal decrease in the number of independent television stations that lowers the amount of diversity, multiculturalism, community news, and advertising. Consumer welfare decreases, but the losses are smaller in large markets. For example, small‐market consumers lose $45 million annually while large‐market consumers lose $13 million. (JEL C9, C25, L13, L82, L96)  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