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   26028篇
  免费   1522篇
  国内免费   5篇
各国政治   1032篇
工人农民   1028篇
世界政治   1838篇
外交国际关系   797篇
法律   17746篇
中国共产党   7篇
中国政治   224篇
政治理论   4647篇
综合类   236篇
  2020年   490篇
  2019年   543篇
  2018年   642篇
  2017年   759篇
  2016年   758篇
  2015年   636篇
  2014年   658篇
  2013年   2504篇
  2012年   667篇
  2011年   767篇
  2010年   841篇
  2009年   814篇
  2008年   728篇
  2007年   734篇
  2006年   786篇
  2005年   662篇
  2004年   641篇
  2003年   667篇
  2002年   583篇
  2001年   996篇
  2000年   806篇
  1999年   706篇
  1998年   368篇
  1997年   282篇
  1996年   286篇
  1995年   285篇
  1994年   322篇
  1993年   299篇
  1992年   507篇
  1991年   546篇
  1990年   510篇
  1989年   476篇
  1988年   488篇
  1987年   424篇
  1986年   490篇
  1985年   465篇
  1984年   413篇
  1983年   381篇
  1982年   308篇
  1981年   303篇
  1980年   241篇
  1979年   303篇
  1978年   210篇
  1977年   176篇
  1976年   156篇
  1975年   189篇
  1974年   191篇
  1973年   159篇
  1972年   145篇
  1971年   143篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
Links between schools’ demographic composition and students’ achievement have been a major policy interest for decades. Using a racially/ethnically diverse sample from the National Longitudinal Study of Adolescent Health (N = 6,302; 54 % females; 53 % White, 21 % African American, 15 % Latino, 8 % Asian American, 2 % other race/ethnicity), we examined the associations between demographic marginalization, students’ later social integration (loneliness at school, school attachment), and educational performance and attainment. Adolescents who were socioeconomically marginalized at school [i.e., having <15 % same-socioeconomic status (SES) peers] had lower cumulative grade point averages across high school and lower educational attainment. A similar disadvantage was observed among students who were both socioeconomically and racially/ethnically marginalized at school (i.e., having <15 % same-SES peers and <15 % same-racial/ethnic peers). Indirect effects were also observed, such that demographic marginalization was linked to poorer school attachment, and poorer school attachment, in turn, was related to poorer academic performance. These results highlight the educational barriers associated with demographic marginalization and suggest potential targets for future intervention efforts.  相似文献   
942.
Alcohol is the most commonly used substance among adolescents in the United States, and adolescent drinking is associated with various health risk behaviors. Given the prevalence and consequences of adolescent drinking, understanding family factors that contribute to adolescent drinking is an important area for research. This study used three waves of data to evaluate a family stress model in which economic hardship is indirectly related to adolescent problem drinking through maternal psychological distress, parenting behaviors, and adolescent externalizing behaviors. Respondents included 300 mothers (71 % Black, 29 % White) and adolescents (51 % male) who were interviewed when adolescents were ages 10, 14, and 16. Structural equation modeling was used to test the hypothesized model and findings supported our hypothesized model. Economic hardship was positively related to maternal psychological distress. Maternal psychological distress was negatively associated with supportive parenting, which in turn was negatively associated with externalizing problems. Externalizing problems were positively associated with problem drinking. In support of our hypothesis regarding indirect effects, economic hardship was indirectly related to problem drinking through maternal psychological distress, parenting behaviors, and adolescent externalizing problems. The findings from this study highlight the role of family processes in adolescent problem drinking.  相似文献   
943.
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   
944.
945.
Understanding the prevalence and correlates of decisional autonomy within specific cultural contexts is necessary to fully comprehend how family processes are embedded within culture. The goals of this study were to describe mothers’ and fathers’ decision-making with adolescents (M = 12.51 years, SD = 0.58; 51% female), including parent-unilateral, joint, and youth-unilateral decision-making, and to examine the socio-cultural and family characteristics associated with these different types of decision-making in 246 Mexican-origin families. Mothers reported more joint and youth-unilateral decision-making and less parent-unilateral decision-making than did fathers. Fathers reported more youth-unilateral decision-making with sons than with daughters. Further, for mothers, more traditional gender role attitudes and higher levels of mother-adolescent conflict were associated with more parent-unilateral and less joint decision-making. In contrast, for fathers, lower levels of respect values were associated with more youth-unilateral decision-making with sons, and higher levels of parent-adolescent warmth were associated with more youth-unilateral decision-making with daughters. The importance of understanding the different correlates of mothers’ and fathers’ decision-making with sons versus daughters is discussed.  相似文献   
946.
Student engagement is an important contributor to school success, yet high school students routinely describe themselves as disengaged. Identifying factors that alter (increase) engagement is a key aspect of improving support for student achievement. This study investigated students’ perceptions of autonomy, teacher connection, and academic competence as predictors of changes in student engagement within the classroom from the start to the end of a course. Participants were 578 (58% female) diverse (67.8% White, 25.2% African American, 5.1% Hispanic, 1.2% Asian American) high school students from 34 classrooms who provided questionnaire data both at the start and the end of a single course. Novel results from a cross-lagged model demonstrated that students who perceived their classrooms as allowing and encouraging their own autonomy in the first few weeks increased their engagement throughout the course, rather than the typical decline in engagement that was demonstrated by students in other classrooms. This finding is unique in that it extended to both students’ perceptions of engagement and observations of student engagement, suggesting a fairly robust pattern. The pertinence of this finding to adolescent developmental needs and its relationship to educational practice is discussed.  相似文献   
947.
An accruing body of evidence supports associations between self-perceived gender typicality and peer relationship difficulties; however, researchers have yet to evaluate peers' perceptions of problem behaviors to gain insight into the social correlates of gender typicality. A short-term longitudinal study was conducted to evaluate associations between gender atypical problem behavior and subsequent peer relational difficulties for 2,076 fifth graders (M age= 10.27; 53% female). Peer nomination methodology was used to assess participants' classroom peer relationships, problem behaviors, and social-emotional characteristics. Findings showed that youth characterized by gender atypical, compared to gender typical, problem behavior (withdrawn boys/aggressive girls vs. withdrawn girls/aggressive boys, respectively) evidenced higher levels of subsequent peer difficulties; moreover, participation in a mutual friendship was associated with decreased risk for peer relationship maladjustment, particularly among youth characterized by gender atypical problem behavior. Results further revealed that, compared to friendless youth, friended youth earned higher prosocial and peer liking scores and, for withdrawn youth, lower emotional sensitivity scores. The present research contributes to our understanding of the potential short-term consequences of youth's gender atypical problem behavior. Findings underscore the need for supplemental conceptualizations of gender typicality as well as multifaceted interventions designed to promote the acceptance of gender nonnormativity, support the development of adaptive peer relationships, and reduce the occurrence of problem behaviors.  相似文献   
948.
Although adolescents often participate in multiple extracurricular activities, little research has examined how the breadth of activities in which an adolescent is involved relates to school-related affect and academic performance. Relying on a large, multi-ethnic sample (N = 864; 55.9% female), the current study investigated linear and non-linear relationships of 11th grade activity participation in four activity domains (academic/leadership groups, arts activities, clubs, and sports) to adolescents’ sense of belonging at school, academic engagement, and grade point average, contemporarily and in 12th grade. Results of multiple regression models revealed curvilinear relationships for sense of belonging at school in 11th and 12th grade, grade point average in 11th grade, and academic engagement in 12th grade. Adolescents who were moderately involved (i.e., in two domains) reported a greater sense of belonging at school in 11th and 12th grade, a higher grade point average in 11th grade, and greater academic engagement in 12th grade, relative to those who were more or less involved. Furthermore, adolescents’ sense of belonging at school in 11th grade mediated the relationship of domain participation in 11th grade to academic engagement in 12th grade. This study suggests that involvement in a moderate number of activity domains promotes positive school-related affect and greater academic performance. School policy implications and recommendations are discussed.  相似文献   
949.
Mexican American youth are at greater risk of school failure than their peers. To identify factors that may contribute to academic success in this population, this study examined the prospective relationships from 5th grade to 7th grade of family (i.e., human capital [a parent with at least a high school education], residential stability, academically and occupationally positive family role models, and family structure) and individual characteristics (i.e., externalizing symptoms, bilingualism, gender, and immigrant status) to the academic performance of 749 Mexican American early adolescents (average age = 10.4 years and 48.7% were girls in 5th grade) from economically and culturally diverse families as these youth made the transition to junior high school. Results indicated that while controlling for prior academic performance, human capital and positive family role models assessed when adolescents were in 5th grade positively related to academic performance in 7th grade. Further, being a girl also was related to greater 7th grade academic success, whereas externalizing symptoms were negatively related to 7th grade academic performance. No other variables in the model were significantly and prospectively related to 7th grade academic performance. Implications for future research and interventions are discussed.  相似文献   
950.
Suicide is a leading cause of death among adolescents, many of whom fail to disclose suicide concerns to adults who might help. This study examined patterns and predictors of help-seeking behavior among adolescents who seriously considered suicide in the past year. 2,737 students (50.9?% female, 46.9?% male; racial distribution 79.5?% Caucasian, 11.9?% Hispanic/Latino, and 3.6?% Black/African-American) from 12 high schools in rural/underserviced communities were surveyed to assess serious suicide ideation (SI) in the past year, disclosure of SI to adults and peers, attempts to get help, attitudes about help-seeking, perceptions of school engagement, and coping support. Help-seeking was defined as both disclosing SI to an adult and perceiving oneself as seeking help. The relationship between adolescents' help-seeking disclosure and (1) help-seeking attitudes and (2) perceptions of social resources was examined among suicidal help-seeking youth, suicidal non-help-seeking youth, and non-suicidal youth. Of the 381 (14?%) students reporting SI, only 23?% told an adult, 29?% sought adult help, and 15?% did both. Suicidal help-seekers were similar to non-suicidal peers on all measures of help-seeking attitudes and social environment perceptions. Positive attitudes about help-seeking from adults at school, perceptions that adults would respond to suicide concerns, willingness to overcome peer secrecy requests, and greater coping support and engagement with the school were associated with students' increased disclosure of SI and help-seeking. This study supports prevention strategies that change student norms, attitudes and social environments to promote help-seeking among adolescents with SI. Promising intervention targets include increasing students' perceptions of the availability and capability of adults to help them, and strengthening students' understanding of how existing resources can help them cope.  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