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   444篇
  免费   24篇
管理学   32篇
民族学   1篇
人口学   46篇
丛书文集   3篇
理论方法论   62篇
综合类   8篇
社会学   303篇
统计学   13篇
  2023年   5篇
  2022年   1篇
  2021年   1篇
  2020年   9篇
  2019年   16篇
  2018年   22篇
  2017年   25篇
  2016年   16篇
  2015年   19篇
  2014年   9篇
  2013年   71篇
  2012年   22篇
  2011年   22篇
  2010年   21篇
  2009年   17篇
  2008年   15篇
  2007年   21篇
  2006年   15篇
  2005年   22篇
  2004年   18篇
  2003年   20篇
  2002年   12篇
  2001年   15篇
  2000年   5篇
  1999年   5篇
  1998年   5篇
  1997年   6篇
  1996年   8篇
  1995年   4篇
  1993年   2篇
  1992年   3篇
  1991年   1篇
  1990年   4篇
  1989年   2篇
  1987年   3篇
  1985年   1篇
  1983年   1篇
  1980年   2篇
  1979年   1篇
  1978年   1篇
排序方式: 共有468条查询结果,搜索用时 15 毫秒
461.
In 2007, UNAIDS corrected estimates of global HIV prevalence downward from 40 million to 33 million based on a methodological shift from sentinel surveillance to population-based surveys. Since then, population-based surveys are considered the gold standard for estimating HIV prevalence. However, prevalence rates based on representative surveys may be biased because of nonresponse. This article investigates one potential source of nonresponse bias: refusal to participate in the HIV test. We use the identity of randomly assigned interviewers to identify the participation effect and estimate HIV prevalence rates corrected for unobservable characteristics with a Heckman selection model. The analysis is based on a survey of 1,992 individuals in urban Namibia, which included an HIV test. We find that the bias resulting from refusal is not significant for the overall sample. However, a detailed analysis using kernel density estimates shows that the bias is substantial for the younger and the poorer population. Nonparticipants in these subsamples are estimated to be three times more likely to be HIV-positive than participants. The difference is particularly pronounced for women. Prevalence rates that ignore this selection effect may be seriously biased for specific target groups, leading to misallocation of resources for prevention and treatment.  相似文献   
462.
463.
In a short‐term longitudinal study of 432 first‐grade children, we examined whether gender interacted with contextual differences (school‐level poverty) and individual differences at school entry (behavioral problems, emotional problems, and social competence) to predict changes in peer physical and relational victimization and receipt of prosocial acts. Gender differences in peer victimization were observed in schools with low levels of student poverty, such that girls showed significant decreases in peer victimization relative to boys. Girls in schools with high levels of student poverty were at greater risk for increases in victimization relative to girls in low‐poverty schools. Individual differences at school entry also contributed to risks for physical (but not relational) victimization. Girls with high levels of behavioral problems and boys with low levels of social competence showed increased risks for physical victimization. We discussed the implications of the present findings for school‐based peer‐victimization prevention programs.  相似文献   
464.
Objective. The goal of this article is to analyze the relationship between religion, measured in terms of religious affiliation and religiosity, and public opinion about same‐sex marriage, civil unions, and a federal constitutional amendment that would prohibit gay marriage. Methods. We use logistic regression with calculated standardized coefficients to analyze data from a nationally representative survey of 1,610 respondents conducted in March–April 2004. Results. Religious variables perform better than demographic measures in models of attitudes about same‐sex unions. Non‐Protestants are much more likely to support same‐sex unions than are Protestants, and individuals with conservative attitudes toward morality and secularism and (to a lesser extent) those who participate actively in religious life are more likely to oppose such unions. On the whole, religious variables play a weaker role in predicting support for a constitutional amendment to prevent gay marriage than they do in predicting attitudes toward same‐sex unions. Conclusions. Religious variables play powerful roles in structuring attitudes about same‐sex unions. Moreover, homosexuality appears to be a major component of the “moral values” discourse that is currently so popular in American politics.  相似文献   
465.
466.
There is considerable debate surrounding the choice of methods to estimate information fraction for futility monitoring in a randomized non-inferiority maximum duration trial. This question was motivated by a pediatric oncology study that aimed to establish non-inferiority for two primary outcomes. While non-inferiority was determined for one outcome, the futility monitoring of the other outcome failed to stop the trial early, despite accumulating evidence of inferiority. For a one-sided trial design for which the intervention is inferior to the standard therapy, futility monitoring should provide the opportunity to terminate the trial early. Our research focuses on the Total Control Only (TCO) method, which is defined as a ratio of observed events to total events exclusively within the standard treatment regimen. We investigate its properties in stopping a trial early in favor of inferiority. Simulation results comparing the TCO method with alternative methods, one based on the assumption of an inferior treatment effect (TH0), and the other based on a specified hypothesis of a non-inferior treatment effect (THA), were provided under various pediatric oncology trial design settings. The TCO method is the only method that provides unbiased information fraction estimates regardless of the hypothesis assumptions and exhibits a good power and a comparable type I error rate at each interim analysis compared to other methods. Although none of the methods is uniformly superior on all criteria, the TCO method possesses favorable characteristics, making it a compelling choice for estimating the information fraction when the aim is to reduce cancer treatment-related adverse outcomes.  相似文献   
467.
Evidence indicates that being overly dependent on the teacher places children's academic and socioemotional development at risk. However, little is known about what predicts dependency on the teacher or how the quality of interactions occurring within the classroom peer system may impact how children relate to their teacher the following school year. The current study tested the proposition that peer victimization may result in negative perceptions of classmates (i.e., peer beliefs), leading to overreliance on teachers. Data were collected from 365 children in the fall and spring of their third/fourth grade year and the fall of their fourth/fifth grade year (195 girls; Mage = 8.92 years; 86.8% white). Peer-reports of peer victimization and self-reports of peer beliefs were collected at each wave of the study. Teacher-reports of dependency were collected in the fall of the first and second years of the study. Path analyses showed that for boys peer victimization directly predicted higher levels of dependency on the next year's teacher, and, for boys and girls, peer victimization indirectly predicted dependency through lower levels of prosocial peer beliefs. Supplemental analyses assessing teacher-child conflict and closeness confirmed that findings were unique to dependency. These results underscore how children's perceptions of their classmates may contribute to dependency in their relationships with teachers and highlight the need for further research into the transactional and cumulative impact of difficulties within peer and teacher relationships.  相似文献   
468.
Studies investigating services for families experiencing complex and multiple problems have emphasized the need for more child-centred support. The aim of this longitudinal study was to investigate whether providing child-centred services (Child and Youth Coaching) combined with family-focused services (Ten for the Future) is effective for children growing up in families experiencing complex and multiple problems. Children's psychosocial skills, emotional and behavioural problems, and the quality of their pedagogical environment were measured at baseline, 6 months and 12 months. Parent and coach reports of children indicated for Child and Youth Coaching (n = 57) and nonindicated children (n = 18) were analysed using repeated measures multilevel models. Both parents and coaches reported improved psychosocial skills of children, but changes were only significant for coach reports. In both reports, no significant decrease in emotional and behavioural problems was observed for both indicated and nonindicated children. Many children still experienced considerable problems at case closure. Furthermore, no significant improvement in quality of the pedagogical environment was observed in both groups. Given the limitations in this study, more research is needed to identify whether these findings can be replicated and attributed to the Child and Youth Coaching and Ten for the Future programmes.  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