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   1581篇
  免费   40篇
管理学   281篇
民族学   5篇
人口学   173篇
丛书文集   13篇
理论方法论   153篇
综合类   6篇
社会学   782篇
统计学   208篇
  2020年   12篇
  2019年   25篇
  2018年   22篇
  2017年   41篇
  2016年   27篇
  2015年   26篇
  2014年   25篇
  2013年   254篇
  2012年   36篇
  2011年   35篇
  2010年   34篇
  2009年   40篇
  2008年   50篇
  2007年   49篇
  2006年   44篇
  2005年   43篇
  2004年   59篇
  2003年   36篇
  2002年   41篇
  2001年   34篇
  2000年   36篇
  1999年   37篇
  1998年   28篇
  1997年   25篇
  1996年   28篇
  1995年   34篇
  1994年   36篇
  1993年   28篇
  1992年   26篇
  1991年   20篇
  1990年   16篇
  1989年   14篇
  1988年   15篇
  1987年   22篇
  1986年   16篇
  1985年   31篇
  1984年   25篇
  1983年   26篇
  1982年   25篇
  1981年   20篇
  1980年   15篇
  1979年   12篇
  1978年   19篇
  1977年   19篇
  1976年   13篇
  1975年   16篇
  1974年   19篇
  1970年   8篇
  1968年   7篇
  1967年   7篇
排序方式: 共有1621条查询结果,搜索用时 15 毫秒
51.
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   
52.
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   
53.
Objective: The ways that college students cope with stress, particularly interpersonal stress, may be a critical factor in determining which students are at risk for impairing mental health disorders. Using a control-based model of coping, the present study examined associations between interpersonal stress, coping strategies, and symptoms. Participants: A total of 135 undergraduate students from 2 universities. Methods: Interpersonal stress, coping strategies, depression, anxiety, and somatization were assessed via self-report. Results: Students reporting more interpersonal stress reported more depression, anxiety, and somatization, and they reported less use of engagement coping strategies and greater use of disengagement coping strategies. Engagement coping strategies accounted for a significant portion of the association between interpersonal stress and mental health symptoms. Unexpectedly, coping strategies did not moderate the association between stress and mental health symptoms. Conclusion: Interventions designed to improve students' coping strategies may be an effective way to reduce mental health problems on college campuses.  相似文献   
54.
Disproportionality in special education includes the underrepresentation and overrepresentation of children by gender, economic status, race, ethnicity, language, and culture. This article reviews literature on disproportionality in the United States, Germany, Kenya, and India. Societal views of disability, classism, racism, and inequitable assessment are among the factors that contribute to disproportionality. Preventative medicine, equitable access to resources, ethical and effective assessment procedures, and educational practices that are gender equitable and culturally responsive may reduce the problem of disproportionality.  相似文献   
55.
A three-level growth-curve model was applied to estimate perceived impact growth trajectories, using multi-year data from project and school surveys on outcome and program implementation collected from 59 sites and approximately 1165 participating schools in the Safe Schools and Healthy Students Initiative. Primary interest is to determine whether and how project-level and school-level correlates affect schools’ perceptions of the Initiative's effectiveness over time when the effects of the pre-grant environmental conditions, grant operations, and near-term outcomes are considered. Coordination and service integration, comprehensive programs and activities for early childhood development, and change in school involvement were found to be significant predictors of school-perceived overall impact when the effect of poverty was considered. Partnership functioning, perceived importance of school resources, and school involvement were found to be significant predictors of school-perceived impact on substance use prevention when the effect of poverty was considered.  相似文献   
56.
The inclusion of technology in the classroom is an increasingly important feature of effective instruction. The implementation of Common Core Standards in many states also requires teachers to consider new pedagogical strategies to support meaningful learning. This article explores the intersection between technology demands and curricular change by examining apps that can be used to support Common Core State Standards instruction in history/social studies. Specifically, the authors highlight several apps that they presented at a professional development workshop for six to twelve history/social studies teachers and discuss the teachers' feedback regarding the strengths and limitations of apps to support their instruction. Conclusions are drawn and recommendations for history/social studies teachers using apps in the classroom are provided.  相似文献   
57.
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   
58.
The organizational behavior management literature has yielded few stimulus preference assessment methodologies for use with employees. The current investigation compared three preference assessments (ranking, survey, and multiple stimulus without replacement procedures) found in the organizational behavior management literature for their ability to predict reinforcers for direct care staff members’ behavior. In the first experiment all assessments were effective for predicting reinforcers, but the results were limited by a lack of control items in the assessment. In the second experiment the survey and ranking assessments both proved to be effective for identifying reinforcers and neutral or ineffective stimuli. Implications of these results and directions for future research are discussed.  相似文献   
59.
Lead is a recognized neurotoxicant, but estimating effects at the lowest measurable levels is difficult. An international pooled analysis of data from seven cohort studies reported an inverse and supra‐linear relationship between blood lead concentrations and IQ scores in children. The lack of a clear threshold presents a challenge to the identification of an acceptable level of exposure. The benchmark dose (BMD) is defined as the dose that leads to a specific known loss. As an alternative to elusive thresholds, the BMD is being used increasingly by regulatory authorities. Using the pooled data, this article presents BMD results and applies different statistical techniques in the analysis of multistudy data. The calculations showed only a limited variation between studies in the steepness of the dose‐response functions. BMD results were quite robust to modeling assumptions with the best fitting models yielding lower confidence limits (BMDLs) of about 0.1–1.0 μ g/dL for the dose leading to a loss of one IQ point. We conclude that current allowable blood lead concentrations need to be lowered and further prevention efforts are needed to protect children from lead toxicity.  相似文献   
60.
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