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   4516篇
  免费   73篇
  国内免费   3篇
管理学   505篇
民族学   27篇
人口学   400篇
丛书文集   26篇
理论方法论   336篇
综合类   87篇
社会学   1975篇
统计学   1236篇
  2023年   30篇
  2021年   24篇
  2020年   73篇
  2019年   135篇
  2018年   118篇
  2017年   202篇
  2016年   120篇
  2015年   107篇
  2014年   120篇
  2013年   937篇
  2012年   148篇
  2011年   120篇
  2010年   82篇
  2009年   104篇
  2008年   100篇
  2007年   88篇
  2006年   79篇
  2005年   79篇
  2004年   73篇
  2003年   57篇
  2002年   87篇
  2001年   91篇
  2000年   77篇
  1999年   92篇
  1998年   79篇
  1997年   68篇
  1996年   58篇
  1995年   76篇
  1994年   58篇
  1993年   62篇
  1992年   71篇
  1991年   75篇
  1990年   78篇
  1989年   62篇
  1988年   45篇
  1987年   46篇
  1986年   51篇
  1985年   58篇
  1984年   57篇
  1983年   41篇
  1982年   39篇
  1981年   34篇
  1980年   41篇
  1979年   49篇
  1978年   38篇
  1977年   28篇
  1976年   23篇
  1974年   23篇
  1973年   20篇
  1971年   21篇
排序方式: 共有4592条查询结果,搜索用时 0 毫秒
981.
Abstract

Objective: To evaluate feasibility of integrating Bedsider.org, a web-based contraceptive decision support tool, at a university health clinic (UHC). Participants: Female students (ages 18–29) seeking contraceptive care at the UHC were enrolled in September 2015 (n?=?46). Methods: Providers recruited eligible patients during reproductive healthcare visits and introduced Bedsider. Surveys were administered immediately following the visit and a follow-up 2–4?weeks later. Electronic health records through 6?weeks post-enrollment were extracted. Results: Most patients had positive views toward Bedsider and appreciated receiving information during their UHC encounters. None were using long-acting reversible contraceptives (LARC) at enrollment. At follow-up, two patients self-reported IUD use. Among those recently sexually active, use of more effective contraceptive methods increased from 65% to 74%; 11% had initiated or were scheduled to receive a LARC. Conclusion: Bedsider can be feasibly integrated into UHC visits and may support women’s selection of more effective contraceptive methods, including LARCs.  相似文献   
982.
ABSTRACT

An ideal of involved fatherhood has become popular in the developed countries, but even countries like Finland that have introduced an individual father’s quota to parental leave are far from gender equality in parents’ leave practices. Lack of support and negative attitudes at workplaces or pressure at work are among the obstacles to fathers’ leave take-up. The study used survey data from fathers and interviews at workplaces to explore the role of work and workplaces among the many aspects related to fathers’ possibilities of taking leave. The results showed that fathers’ income and workplace characteristics were associated with taking leave. Few fathers mentioned employers’ objection as a hinder. Father’s recent unemployment and anticipated difficulty of taking a long time off played a more important role. At workplaces, the obstacles to taking long leave were related to fathers’ ideals about a committed worker and to the nature and organizing of work. Additionally, the leave exceeding fathers’ quota might not be understood as ‘for fathers’. The spouse’s situation and fathers’ gendered perceptions about parental responsibilities were also important for leave practices. The findings suggest that policy development towards a longer father’s quota could make fathers’ care responsibilities visible also at workplaces.  相似文献   
983.
This article examines the history of media sociology in the U.S., through a critical analysis of articles published in the major sociology journals during the twentieth century. I argue that media sociology has been at its most vibrant when its goal has been to understand the dominant cultural structures that shape the public sphere. Robert Park was the first sociologist to adopt this perspective, with his research on newspapers and the power of the press. This interest continued into the 1950s, with research on media and propaganda. By the 1960s, however, concern had shifted away from the public character of media, focusing instead on the ways in which social factors intervened between media messages and society. While important, this shift in analytical focus ultimately led to a more reductionist media sociology, which failed to explore how media provided a distinctive type of social output. There is evidence that a less reductionist media sociology has begun to emerge since the 1990s, with the rise of cultural sociology and theories of the public sphere. This new media sociology could increase its visibility within mainstream sociology by making more explicit connections to the Chicago School tradition, and by claiming Robert Park as its classical founder.  相似文献   
984.
Legionnaires' disease (LD), first reported in 1976, is an atypical pneumonia caused by bacteria of the genus Legionella, and most frequently by L. pneumophila (Lp). Subsequent research on exposure to the organism employed various animal models, and with quantitative microbial risk assessment (QMRA) techniques, the animal model data may provide insights on human dose-response for LD. This article focuses on the rationale for selection of the guinea pig model, comparison of the dose-response model results, comparison of projected low-dose responses for guinea pigs, and risk estimates for humans. Based on both in vivo and in vitro comparisons, the guinea pig (Cavia porcellus) dose-response data were selected for modeling human risk. We completed dose-response modeling for the beta-Poisson (approximate and exact), exponential, probit, logistic, and Weibull models for Lp inhalation, mortality, and infection (end point elevated body temperature) in guinea pigs. For mechanistic reasons, including low-dose exposure probability, further work on human risk estimates for LD employed the exponential and beta-Poisson models. With an exposure of 10 colony-forming units (CFU) (retained dose), the QMRA model predicted a mild infection risk of 0.4 (as evaluated by seroprevalence) and a clinical severity LD case (e.g., hospitalization and supportive care) risk of 0.0009. The calculated rates based on estimated human exposures for outbreaks used for the QMRA model validation are within an order of magnitude of the reported LD rates. These validation results suggest the LD QMRA animal model selection, dose-response modeling, and extension to human risk projections were appropriate.  相似文献   
985.
Summary.  The main statistical problem in many epidemiological studies which involve repeated measurements of surrogate markers is the frequent occurrence of missing data. Standard likelihood-based approaches like the linear random-effects model fail to give unbiased estimates when data are non-ignorably missing. In human immunodeficiency virus (HIV) type 1 infection, two markers which have been widely used to track progression of the disease are CD4 cell counts and HIV–ribonucleic acid (RNA) viral load levels. Repeated measurements of these markers tend to be informatively censored, which is a special case of non-ignorable missingness. In such cases, we need to apply methods that jointly model the observed data and the missingness process. Despite their high correlation, longitudinal data of these markers have been analysed independently by using mainly random-effects models. Touloumi and co-workers have proposed a model termed the joint multivariate random-effects model which combines a linear random-effects model for the underlying pattern of the marker with a log-normal survival model for the drop-out process. We extend the joint multivariate random-effects model to model simultaneously the CD4 cell and viral load data while adjusting for informative drop-outs due to disease progression or death. Estimates of all the model's parameters are obtained by using the restricted iterative generalized least squares method or a modified version of it using the EM algorithm as a nested algorithm in the case of censored survival data taking also into account non-linearity in the HIV–RNA trend. The method proposed is evaluated and compared with simpler approaches in a simulation study. Finally the method is applied to a subset of the data from the 'Concerted action on seroconversion to AIDS and death in Europe' study.  相似文献   
986.
987.
About half of injured workers choose not to file workers' compensation claims. This is thought to result from their use of health insurance instead of workers' compensation. However, the data suggest that insured workers are actually less likely to file than their more vulnerable uninsured counterparts. We found that this relationship emerges as the result of employer characteristics and, in particular, that employers who offer health insurance to employees are more likely to have workers who file claims; this is much more important than the insurance status of workers themselves or fixed worker characteristics. ( JEL I1, J3)  相似文献   
988.
In this paper, we consider chain ratio and regression type estimators for estimating median in survey sampling. We find expressions for the variance of the chain-ratio and chain-regression type estimators considered in the present investigation. The optimum values of the first phase and second phase sample sizes are also obtained for the fixed cost of survey. The relative efficiency of chain-ratio and chain-regression type estimators have been studied in comparison to ratio and regression type estimators of median proposed by Singh, Joarder and Tracy (2001).  相似文献   
989.
990.
Record values can be viewed as order statistics from a sample whose size is determined by the values and the order of occurrence of observations. They are closely connected with the occurrence times of a corresponding non-homogenous Poisson process and reliability theory. In this paper, the information properties of record values are presented based on Shannon information. Several upper and lower bounds for the entropy of record values are obtained. It is shown that, the mutual information between record values is distribution free and is computable using the distribution of the record values of the sequence from the uniform distribution.  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