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   24499篇
  免费   567篇
  国内免费   5篇
各国政治   896篇
工人农民   1705篇
世界政治   1373篇
外交国际关系   826篇
法律   15092篇
中国共产党   6篇
中国政治   156篇
政治理论   4845篇
综合类   172篇
  2020年   224篇
  2019年   281篇
  2018年   1546篇
  2017年   1522篇
  2016年   1368篇
  2015年   361篇
  2014年   334篇
  2013年   1545篇
  2012年   634篇
  2011年   1348篇
  2010年   1331篇
  2009年   958篇
  2008年   1203篇
  2007年   1192篇
  2006年   559篇
  2005年   564篇
  2004年   648篇
  2003年   657篇
  2002年   482篇
  2001年   676篇
  2000年   554篇
  1999年   483篇
  1998年   256篇
  1997年   182篇
  1996年   224篇
  1995年   203篇
  1994年   223篇
  1993年   200篇
  1992年   323篇
  1991年   354篇
  1990年   341篇
  1989年   289篇
  1988年   321篇
  1987年   271篇
  1986年   319篇
  1985年   282篇
  1984年   240篇
  1983年   230篇
  1982年   181篇
  1981年   190篇
  1980年   129篇
  1979年   177篇
  1978年   129篇
  1977年   114篇
  1976年   97篇
  1975年   124篇
  1974年   133篇
  1973年   104篇
  1972年   100篇
  1969年   98篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
921.
Experiences with racism are a common occurrence for African American youth and may result in negative self perceptions relevant for the experience of depressive symptoms. This study examined the longitudinal association between perceptions of racism and depressive symptoms, and whether perceived academic or social control mediated this association, in a community epidemiologically-defined sample of urban African American adolescents (N = 500; 46.4% female). Structural equation modeling revealed that experiences with racism were associated with low perceived academic control, which in turn was associated with increased depressive symptoms. Findings suggest that experiences with racism can have long lasting effects for African American youth’s depressive symptoms, and highlight the detrimental effects of experiences with racism for perceptions of control in the academic domain. Implications for intervention are discussed.
Sharon F. LambertEmail:
  相似文献   
922.
This study examined the association between cigarette smoking and dieting behaviors and trends in that association among US adolescents in grades 9–12 between 1999 and 2007. Youth Risk Behavior Survey datasets were analyzed using the multivariable logistic regression method. The sample size of each survey year ranged from 13,554 to 15,273 with girls representing 49–51% of the sample (N = 71,854). About 62% of the entire study participants were whites and 14% were blacks. Prevalence estimates of current smoking and corresponding 95% confidence intervals were computed across four comparison groups formed by gender and body weight. Extreme dieting was an independent predictor of smoking. Extreme dieters showed a higher variability of smoking behavior than their peers. The magnitude of the association between smoking and extreme dieting became smaller in recent years among adolescents but remained unchanged among non-overweight girls over that same time period. When adolescent smoking behavior is examined, the intensity of dieting behavior should be considered within its association with other co-occurring unhealthy behaviors.  相似文献   
923.
Considerable research has focused on the reliability and validity of informant reports of family behavior, especially maternal reports of adolescent problem behavior. None of these studies, however, has based their orientation on a theoretical model of interpersonal perception. In this study we used the social relations model (SRM) to examine family members’ reports of each others’ externalizing and internalizing problem behavior. Two parents and two adolescents in 69 families rated each others’ behavior within a round-robin design. SRM analysis showed that within-family perceptions of externalizing and internalizing behaviors are consistently due to three sources of variance; perceiver, target, and family effects. A family/contextual effect on informant reports of problem behavior has not been previously reported.  相似文献   
924.
The main purpose of this study was to examine the extent to which middle and late adolescents’ depressive symptoms predict their later school burnout and, in turn, the extent to which school burnout predicts depressive symptoms. Drawing on data gathered at ages 15–19 in two-three-wave longitudinal studies, we investigated cross-lagged paths between school burnout and depressive symptoms. In Study 1 the participants were 15-year-old adolescents (Time 1: N = 611, Time 2: N = 614, Time 3: N = 725) who completed the School Burnout Inventory and depressive symptoms twice during their final term of comprehensive school and once after the transition to upper secondary high school or vocational school. In Study 2 the participants were 17-year-old adolescents whose school burnout and depressive symptoms were measured three times annually (Time 1: N = 474, Time 2: N = 412, Time 3: N = 414) during their 3 years of secondary education. Results of both studies revealed moderate stability for both school burnout and depressive symptoms. They also showed that school burnout more strongly predicted subsequent depressive symptoms later on than vice versa. Lastly, they revealed cumulative cycles between school burnout and depressive symptoms.  相似文献   
925.
926.
Youth with same-sex desire undergo a process of narrative engagement as they construct configurations of identity that provide meaning and coherence with available sexual taxonomies. This article presents a theoretical analysis and four case studies centering on the relationship among context, desire, and identity for youth with same-sex desire. Through an interpretive, holistic analysis of the personal narratives of youth, we examine the integration of same-sex desire, behavior, and identity in the general life story and the selective appropriation of elements of “master narratives” of sexual identity development. Narratives were characterized by challenges to integrate desire, behavior, and identity into a configuration that conformed to the received sexual taxonomy. Implications for theory and further research on sexual identity development are discussed.  相似文献   
927.
Peer victimization is a well-known national and international problem, contributing to a range of emotional, social, and behavioral consequences. Using structural equation modeling, the authors tested a theoretical model suggesting that psychological distress and student engagement mediate the association between the experience of victimization and concurrent academic achievement. Participants were 469 (46.4 % male, 53.6 % female) 6th to 8th grade students, from randomly selected classrooms in 11 middle schools in a southeastern school district. Structural equation models of the hypothesized effects demonstrated adequate fit to the data, with both symptoms of psychological distress and engagement mediating the relationship between victimization and academic achievement. In general, the results suggest that victimization predicts diminished academic achievement by way of psychological distress and poorer engagement in classroom and academic tasks. However, the direct relationship between victimization and measures of achievement lacked significance across many correlational and path analyses conducted. These findings have implications for researchers and practitioners in understanding how psychological distress and student engagement are associated with the academic performance of students who experience peer victimization.  相似文献   
928.
Research indicates that subjective perceptions of socioeconomic status (SES) affect aspects of health and behavior. There has been little research attention to how objective (e.g., education) and subjective aspects of SES may differ in their influence on the substance use of adolescent immigrants. The present study examined whether the associations between subjective SES and substance use, and between parental education and substance use varied by immigrant generation. Data were derived from the 2011 Ontario Student Drug Use and Health Survey, a representative survey of students in the 7th to 12th grade. The sample for this study consisted of 9177 students 12–19 years of age; 48.4 % were female, 66.4 % were White/European, 5.2 % Black/Afro-Caribbean, 16.4 % Asian and 12 % other. Results indicated that subjective SES was more strongly associated with cannabis and alcohol use among first-generation immigrants than among adolescents of other immigrant generations even after adjusting for parental education. First-generation immigrants with low subjective SES had a lower probability of cannabis and regular alcohol use, but there was no difference in use between immigrant generations at high subjective SES. The associations between parental education and cannabis and alcohol use did not significantly vary with immigrant generation. The findings highlight the importance of status beliefs among adolescents, particularly among first-generation immigrants, and suggest that further research attention to such beliefs would enhance our understanding of SES and its links to adolescent health risk behaviors.  相似文献   
929.
930.
This study examined the links between parental divorce, quality of maternal parenting, spousal relationships and middle adolescent romantic competence in 80 mother-adolescent daughter pairs (40 divorced). Mothers were asked to describe their attitudes and behaviors with regard to their daughters’ romantic behavior. In addition, mothers were interviewed about their own romantic experiences when they were at the age of their daughters. Adolescent girls (mean age = 16.98 years; range 16–18) were administered a comprehensive interview about romantic competence. Findings indicated that adolescent girls from divorced families showed lower levels of romantic competence, which were expressed in their behavior, attitudes toward relationships and skill in handling those relationships. Divorce was found to have had an adverse effect on girls’ romantic competence, whereas continued adaptive parenting and spousal relationships alleviated the effect of divorce. Mothers’ coherent representation of their own adolescent romantic experiences also alleviated the effect of divorce on daughters’ romantic behavior. Results show the important role of family relationships in fostering romantic competence among adolescent girls.  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