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   5603篇
  免费   110篇
管理学   771篇
民族学   16篇
人才学   6篇
人口学   533篇
丛书文集   16篇
理论方法论   497篇
综合类   65篇
社会学   2590篇
统计学   1219篇
  2021年   37篇
  2020年   75篇
  2019年   113篇
  2018年   118篇
  2017年   189篇
  2016年   115篇
  2015年   83篇
  2014年   105篇
  2013年   950篇
  2012年   203篇
  2011年   150篇
  2010年   110篇
  2009年   110篇
  2008年   123篇
  2007年   138篇
  2006年   121篇
  2005年   124篇
  2004年   119篇
  2003年   88篇
  2002年   118篇
  2001年   136篇
  2000年   106篇
  1999年   126篇
  1998年   102篇
  1997年   105篇
  1996年   78篇
  1995年   81篇
  1994年   94篇
  1993年   79篇
  1992年   91篇
  1991年   77篇
  1990年   88篇
  1989年   79篇
  1988年   93篇
  1987年   86篇
  1986年   78篇
  1985年   85篇
  1984年   72篇
  1983年   73篇
  1982年   67篇
  1981年   64篇
  1980年   58篇
  1979年   74篇
  1978年   60篇
  1977年   50篇
  1976年   59篇
  1975年   57篇
  1974年   35篇
  1973年   38篇
  1971年   30篇
排序方式: 共有5713条查询结果,搜索用时 42 毫秒
141.
A random effects model for analyzing mixed longitudinal count and ordinal data is presented where the count response is inflated in two points (k and l) and an (k,l)-Inflated Power series distribution is used as its distribution. A full likelihood-based approach is used to obtain maximum likelihood estimates of parameters of the model. For data with non-ignorable missing values models with probit model for missing mechanism are used.The dependence between longitudinal sequences of responses and inflation parameters are investigated using a random effects approach. Also, to investigate the correlation between mixed ordinal and count responses of each individuals at each time, a shared random effect is used. In order to assess the performance of the model, a simulation study is performed for a case that the count response has (k,l)-Inflated Binomial distribution. Performance comparisons of count-ordinal random effect model, Zero-Inflated ordinal random effects model and (k,l)-Inflated ordinal random effects model are also given. The model is applied to a real social data set from the first two waves of the national longitudinal study of adolescent to adult health (Add Health study). In this data set, the joint responses are the number of days in a month that each individual smoked as the count response and the general health condition of each individual as the ordinal response. For the count response there is incidence of excess values of 0 and 30.  相似文献   
142.
143.
The authors examined the central hypothesis that students’ early perceptions of support and sense of engagement in math classes and math activities strongly influence the broadening or narrowing of their math interest. The focus was on the first wave of qualitative data collected from 5th‐, 7th‐, and 9th‐grade students during the 2007–2008 academic year as part of a longitudinal study. Findings indicate the importance of using group work and extrinsic motivation in middle school math classes to broaden interest; peer classroom behavior was often a detractor of math interest.  相似文献   
144.
The estimated vector autoregressive (VAR) model is sensitive to model misspecifications, resulting to biased and inconsistent parameter estimates. This article extends the Bayesian averaging of classical estimates, a robustness procedure in cross-section data, to a vector time-series that is estimated using a large number of asymmetric VAR models. The proposed procedure was applied to simulated data from various forms of model misspecifications. The results of the simulation suggest that, under misspecification problems, particularly if an important variable and moving average (MA) terms were omitted, the proposed procedure gives robust results and better forecasts than the automatically selected equal lag-length VAR model.  相似文献   
145.
146.
Intrusive sexual behaviors (ISBs) are a specific type of problematic sexual behavior characterized by the invasive nature of the acts (e.g., touching others’ private parts, attempting intercourse; Friedrich, 1997). The limited amount of research on ISBs has focused on sexual abuse history as the primary predictor. However, Friedrich, Davies, Feher, and Wright (2003) found that ISBs in children up to age 12 were related to four broad conceptual factors: (a) exposure to sexual content, (b) exposure to violent behavior, (c) family adversity, and (d) child vulnerabilities. The current study sought to replicate Friedrich’s study using a clinical sample of 217 preschool-aged children (ages two to six). Results supported variables from within the child vulnerabilities construct (externalizing behaviors, βEXT = 0.032, p = 0.001), post-traumatic stress disorder (PTSD) criteria met (βPTSD = 0.177, p = 0.02), and an inverse relationship with age (βAGE = ?0.206, p = 0.024). These results highlight the importance of considering childhood behavioral patterns and reactivity to traumatic events as correlates of ISBs in young children.  相似文献   
147.
The aim of this study was to investigate the role of drinking in two Norwegian workplaces, focusing on how the drinking may contribute to both social integration and marginalization of employees. The two workplaces were a division of a multinational oil company and a public library both located in one of Norway's larger cities. Data were collected through ethnographic fieldwork, including using participant observation, qualitative interviews, and brief surveys. Work-related drinking was found to be common in both workplaces and played a significant role in a wide range of social situations in the twilight zone between normal working hours and leisure. Drinking was regulated by dominant workplace alcohol cultural ideals, but also involved opposition to these ideals. The results of this study have demonstrated that different forms of drinking (and non-drinking) may lead to both social integration and marginalization – or even exclusion of groups of employees or individual employees.  相似文献   
148.
Efforts to improve child survival in lower-income countries typically focus on fundamental factors such as economic resources and infrastructure provision, even though research from post-industrial countries confirms that family instability has important health consequences. We tested the association between maternal union instability and children’s mortality risk in Africa, Latin America and the Caribbean, and Asia using children’s actual experience of mortality (discrete-time probit hazard models) as well as their experience of untreated morbidity (probit regression). Children of divorced/separated mothers experience compromised survival chances, but children of mothers who have never been in a union generally do not. Among children of partnered women, those whose mothers have experienced prior union transitions have a higher mortality risk. Targeting children of mothers who have experienced union instability—regardless of current union status—may augment ongoing efforts to reduce childhood mortality, especially in Africa and Latin America where union transitions are common.  相似文献   
149.
Measures of statistical divergence are used to assess mutual similarities between distributions of multiple variables through a variety of methodologies including Shannon entropy and Csiszar divergence. Modified measures of statistical divergence are introduced throughout the present article. Those modified measures are related to the Lin–Wong (LW) divergence applied on the past lifetime data. Accordingly, the relationship between Fisher information and the LW divergence measure was explored when applied on the past lifetime data. Throughout this study, a number of relations are proposed between various assessment methods which implement the Jensen–Shannon, Jeffreys, and Hellinger divergence measures. Also, relations between the LW measure and the Kullback–Leibler (KL) measures for past lifetime data were examined. Furthermore, the present study discusses the relationship between the proposed ordering scheme and the distance interval between LW and KL measures under certain conditions.  相似文献   
150.
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