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   424篇
  免费   7篇
管理学   68篇
人口学   33篇
理论方法论   37篇
综合类   3篇
社会学   231篇
统计学   59篇
  2020年   2篇
  2019年   7篇
  2018年   9篇
  2017年   5篇
  2016年   7篇
  2015年   5篇
  2014年   6篇
  2013年   100篇
  2012年   24篇
  2011年   8篇
  2010年   2篇
  2009年   10篇
  2008年   6篇
  2007年   11篇
  2006年   6篇
  2005年   7篇
  2004年   12篇
  2003年   7篇
  2002年   7篇
  2001年   8篇
  2000年   8篇
  1999年   5篇
  1998年   7篇
  1997年   7篇
  1996年   5篇
  1995年   7篇
  1994年   9篇
  1993年   9篇
  1992年   11篇
  1991年   9篇
  1990年   12篇
  1989年   3篇
  1988年   8篇
  1987年   6篇
  1986年   4篇
  1985年   3篇
  1984年   6篇
  1983年   6篇
  1982年   6篇
  1981年   7篇
  1980年   6篇
  1979年   5篇
  1978年   4篇
  1977年   7篇
  1976年   5篇
  1975年   3篇
  1973年   2篇
  1972年   2篇
  1970年   2篇
  1968年   2篇
排序方式: 共有431条查询结果,搜索用时 265 毫秒
21.
22.
We examined the contribution of relational aggression in adolescents' peer and dating relationships to their psychological and behavioral adjustment. In the Fall and again four months later, 1279 (646 female) grade 9 students reported on relational aggression perpetration and victimization in their romantic and peer relationships, depression/anxiety symptoms (psychological adjustment) and delinquency (behavioral adjustment). Using hierarchical regression analyses, controlling for Time 1 adjustment/behavior, peer relational aggression perpetration predicted depression/anxiety. Dating relational victimization also predicted depression/anxiety, but only for girls. Furthermore, girls who were perpetrators of relational aggression in both peer and dating contexts were most likely to show increases in delinquent behavior. We conclude that dating and peer relationships are not redundant, but make independent and additive contributions to adolescent adjustment. Girls, in particular, may be at greatest risk for poor outcomes when they have relationally aggressive relationships. Results also highlight the need for greater awareness of the complexity and significance of adolescent dating relationships.  相似文献   
23.
Maternal mortality measurement through special census questions will be a common practice in the 2010 census round. To check this information or make it cause-specific, some countries have experimented with follow-up surveys containing verbal autopsies or triangulation with administrative data. However, follow-up studies can be costly and not without complications. In order to assess the benefits, two such experiences are discussed in detail (Bolivia, 2002; and Mozambique 2007–2008) and two others mentioned more briefly (Islamic Republic of Iran, 1996; and Democratic People’s Republic of Korea, 2008). In the former, several problems were apparent. In Mozambique, the follow-up survey used a cluster sample of 4.5% of deaths, from all causes. This design was adequate for the more common causes, but not for maternal mortality. Another problem was the large proportion of invalid cases (35.1%, plus 16% not verifiable) and the likelihood that there was a similar proportion of omitted deaths. The Bolivian census generated many invalid cases and missing ages, due in part to the flawed design of the questionnaire. This overburdened the follow-up, so that only 15% of the census deaths of women of reproductive age unrelated to pregnancy could be investigated. Once the false positives were eliminated, the results seem consistent with Growth Balance analyses, but the many classification errors compromise confidence in the results. Despite this mixed record of outcomes, it is believed that carrying out a limited number of similar studies in the current census round may be valuable, if appropriate lessons are learned from these experiences.  相似文献   
24.
25.
Ralph R. Sell 《Demography》1983,20(3):299-311
Many theories of geographic mobility assume that the change-of-residence process includes a substantial degree of choice. This paper classifies stated reasons for moving from the 1973 through 1977 Annual Housing Survey into forced, imposed, and preference-dominated categories. About 25 percent of residential mobility and 40 percent of migration occurred under conditions of substantial constraint. Mobility was most often constrained by family dynamics; for migration, occupational relocations frequently imposed the decision-to-move process and determined destinations. The volume of constrained movement indicates that its impact upon individuals, population dynamics, and voluntaristic theories of mobility deserves greater consideration.  相似文献   
26.
It is twenty-five years since the passing of Karen Horney. A productive professional who dared to differ with Sigmund Freud, Horney has written clearly and brilliantly, almost in a "common-sensical" style, about the development of neurotic character structure and interpersonal relationships. Her stress on cultural, societal, and family influences has strong implications for theorists and professional practitioners in the field of marriage and the family. Her optimistic view of human nature, especially as it relates to the possibility for change at all ages and stages, should be a continuous inspiration to those helping disturbed individuals, relationships, marriages, and families. This is a tribute to a rare, worthy human being.  相似文献   
27.
Gamma-secretase catalyzes intramembrane proteolysis of the amyloid beta protein precursor, a process closely linked to the development of Alzheimer's disease. This protease also cleaves the transmembrane domain of the Notch receptor as part of a signaling pathway that is essential for proper embryonic development. Recent findings suggest that gamma-secretase is a complex of at least four integral membrane proteins: presenilin, nicastrin, Aph-1, and Pen-2. Assembly of these four components apparently leads to autocleavage of presenilin into two subunits that together compose the intramembranous active site of gamma-secretase. Understanding the mechanism of this unusual enzyme is important, as it is both a key therapeutic target and a founding member of a newly discovered class of intramembrane-cleaving proteases.  相似文献   
28.
A multiple objective linear programming (MOLP) method utilizing interval criterion weights is applied to the problem of media selection. Using this technique, it is possible to analyze a problem more explicitly in terms of the several objectives inherent in many media selection situations. In order to illustrate the interval criterion weights approach, a multiple objective hierarchical media selection model is presented and its computer results discussed. In addition to being able to deal more directly with different decision criteria, a distinguishing feature of the mathematical analysis applied here is that its output enables the media-planner to be presented with a small cluster of candidate media schedules (rather than just one). Then, from this list, the media-planner should be in a position to qualitatively make a final choice as a close approximation to his optimal solution.  相似文献   
29.
The theory and properties of trend-free (TF) and nearly trend-free (NTF) block designs are wel1 developed. Applications have been hampered because a methodology for design construction has not been available.

This article begins with a short review of concepts and properties of TF and NTF block designs. The major contribution is provision of an algorithm for the construction of linear and nearly linear TF block designs. The algorithm is incorporated in a computer program in FORTRAN 77 provided in an appendix for the IBM PC or compatible microcomputer, a program adaptable also to other computers. Three sets of block designs generated by the program are given as examples.

A numerical example of analysis of a linear trend-free balanced incomplete block design is provided.  相似文献   
30.
The area under the receiver operating characteristic curve (AUC) is the most commonly reported measure of discrimination for prediction models with binary outcomes. However, recently it has been criticized for its inability to increase when important risk factors are added to a baseline model with good discrimination. This has led to the claim that the reliance on the AUC as a measure of discrimination may miss important improvements in clinical performance of risk prediction rules derived from a baseline model. In this paper we investigate this claim by relating the AUC to measures of clinical performance based on sensitivity and specificity under the assumption of multivariate normality. The behavior of the AUC is contrasted with that of discrimination slope. We show that unless rules with very good specificity are desired, the change in the AUC does an adequate job as a predictor of the change in measures of clinical performance. However, stronger or more numerous predictors are needed to achieve the same increment in the AUC for baseline models with good versus poor discrimination. When excellent specificity is desired, our results suggest that the discrimination slope might be a better measure of model improvement than AUC. The theoretical results are illustrated using a Framingham Heart Study example of a model for predicting the 10-year incidence of atrial fibrillation.  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