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   18828篇
  免费   296篇
  国内免费   3篇
管理学   2626篇
民族学   75篇
人才学   3篇
人口学   1707篇
丛书文集   78篇
理论方法论   1623篇
综合类   190篇
社会学   8952篇
统计学   3873篇
  2023年   87篇
  2022年   84篇
  2020年   251篇
  2019年   327篇
  2018年   447篇
  2017年   588篇
  2016年   414篇
  2015年   327篇
  2014年   431篇
  2013年   3316篇
  2012年   574篇
  2011年   498篇
  2010年   427篇
  2009年   349篇
  2008年   421篇
  2007年   416篇
  2006年   417篇
  2005年   400篇
  2004年   339篇
  2003年   326篇
  2002年   353篇
  2001年   457篇
  2000年   451篇
  1999年   394篇
  1998年   328篇
  1997年   284篇
  1996年   313篇
  1995年   296篇
  1994年   309篇
  1993年   275篇
  1992年   308篇
  1991年   341篇
  1990年   329篇
  1989年   282篇
  1988年   319篇
  1987年   290篇
  1986年   253篇
  1985年   286篇
  1984年   306篇
  1983年   285篇
  1982年   213篇
  1981年   174篇
  1980年   179篇
  1979年   225篇
  1978年   179篇
  1977年   149篇
  1976年   131篇
  1975年   112篇
  1974年   137篇
  1973年   110篇
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
41.
This paper proposes a developmental framework for foster parents and outlines four distinct growth stages. Such a framework can be of value to program administrators who are required to assess foster parent development during the crucial matching process. To draw a distinction between each developmental stage, specific instrumental tasks and indicators are outlined.  相似文献   
42.
This article explores the relationship between parental psychological control and parental autonomy granting, and the relations between these constructs and indicators of adolescent psychosocial functioning, in a sample of 9,564 adolescents from grades 9 to 12. Participants completed a comprehensive parenting questionnaire as well as several measures of psychosocial adjustment. Confirmatory factor analyses of the parenting items revealed discrete factors for psychological control and autonomy granting, suggesting that these are distinct parenting constructs rather than opposite ends of a parental control continuum. Moreover, structural equation modeling showed that these factors were weakly correlated and differentially related to adolescent internalizing symptoms. Findings have implications for future conceptualization and measurement of psychological control and autonomy granting, and for research examining their effects on adolescent development.  相似文献   
43.
44.
In the development of many diseases there are often associated random variables which continuously reflect the progress of a subject towards the final expression of the disease (failure). At any given time these processes, which we call stochastic covariates, may provide information about the current hazard and the remaining time to failure. Likewise, in situations when the specific times of key prior events are not known, such as the time of onset of an occult tumour or the time of infection with HIV-1, it may be possible to identify a stochastic covariate which reveals, indirectly, when the event of interest occurred. The analysis of carcinogenicity trials which involve occult tumours is usually based on the time of death or sacrifice and an indicator of tumour presence for each animal in the experiment. However, the size of an occult tumour observed at the endpoint represents data concerning tumour development which may convey additional information concerning both the tumour incidence rate and the rate of death to which tumour-bearing animals are subject. We develop a stochastic model for tumour growth and suggest different ways in which the effect of this growth on the hazard of failure might be modelled. Using a combined model for tumour growth and additive competing risks of death, we show that if this tumour size information is used, assumptions concerning tumour lethality, the context of observation or multiple sacrifice times are no longer necessary in order to estimate the tumour incidence rate. Parametric estimation based on the method of maximum likelihood is outlined and is applied to simulated data from the combined model. The results of this limited study confirm that use of the stochastic covariate tumour size results in more precise estimation of the incidence rate for occult tumours.  相似文献   
45.
We propose a new modified (biased) cross-validation method for adaptively determining the bandwidth in a nonparametric density estimation setup. It is shown that the method provides consistent minimizers. Some simulation results are reported on which compare the small sample behavior of the new and the classical cross-validation selectors.  相似文献   
46.
The authors investigated the prevalence of recurrent pain in a college student sample. Of the 1,564 students surveyed, 467 (29%) indicated that they had experienced recurrent pain at an intensity that was mostly in the mild-to-moderate range. Students who reported having recurrent pain were significantly older and more depressed than students who did not indicate they suffered from recurrent pain. Pain intensity was positively correlated (r = .14) with depression among the students who reported having recurrent pain. Implications of the findings for future research, treatment, and health promotion efforts are discussed.  相似文献   
47.
This study investigated the gender-specific, self-reported sexual behaviors and attitudes of never-married college students attending a southeastern university in 1973 and 1988. Data were collected by means of a mailed questionnaire that remained essentially unchanged for both years. The authors found that both men and women reported an increase in heterosexual relationships that included sexual intercourse and a decrease in nonsexual relationships with the other gender. The majority of the students perceived themselves as adequately informed about sexuality and satisfied with their relationships, although the proportion of men who reported being satisfied with their relationships declined over the 15 years. The students indicated that sexuality education should focus primarily on information about AIDS and on preparation for marriage.  相似文献   
48.
Bivariate probit estimates with partial observability identify the factors influencing the worker’s decision to seek a state or local government job and the factors influencing the government’s decision to hire particular workers. The estimates routinely confirm the presence of a local job queue but confirm the presence of a state job queue only when the role of unionization is explicitly recognized. Our results suggest that the net benefits from local and state government employment are greater than those from private sector employment. The estimates also indicate that local governments disproportionately hire racial minorities relative to the local governments’ pool of applicants but indicate no such relationship for state governments. The authors thank Dale Belman, Jugal Ghorai, and Matt Higgins for help on this and related work. We also thank the referee and the editor for useful suggestions.  相似文献   
49.
A large number of states adopted tort reforms in the mid-1980s to limit the dramatic surge in insurance losses and premiums. Evidence based on liability insurance data by state indicates that these reforms substantially influenced general liability insurance. The levels of losses, premiums, and loss ratios (a measure of insurance profitability) all reflected the impact of the reforms. The large-scale reform efforts in 1986 were particularly influential. Medical malpractice insurance was much less sensitive to the reform efforts.  相似文献   
50.
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