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   24063篇
  免费   552篇
  国内免费   5篇
各国政治   868篇
工人农民   1665篇
世界政治   1248篇
外交国际关系   834篇
法律   14891篇
中国共产党   6篇
中国政治   153篇
政治理论   4779篇
综合类   176篇
  2020年   223篇
  2019年   269篇
  2018年   1536篇
  2017年   1513篇
  2016年   1355篇
  2015年   352篇
  2014年   319篇
  2013年   1511篇
  2012年   615篇
  2011年   1338篇
  2010年   1326篇
  2009年   944篇
  2008年   1184篇
  2007年   1171篇
  2006年   516篇
  2005年   519篇
  2004年   622篇
  2003年   626篇
  2002年   446篇
  2001年   664篇
  2000年   544篇
  1999年   478篇
  1998年   251篇
  1997年   178篇
  1996年   217篇
  1995年   197篇
  1994年   216篇
  1993年   198篇
  1992年   321篇
  1991年   354篇
  1990年   341篇
  1989年   283篇
  1988年   322篇
  1987年   271篇
  1986年   318篇
  1985年   281篇
  1984年   240篇
  1983年   229篇
  1982年   182篇
  1981年   190篇
  1980年   128篇
  1979年   177篇
  1978年   129篇
  1977年   114篇
  1976年   96篇
  1975年   123篇
  1974年   132篇
  1973年   103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 46 毫秒
911.
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   
912.
913.
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   
914.
Although the relation between family relationships and the timing of sexual debut has been the focus of many studies, research on mediating factors is scarce. This study examines whether low levels of family cohesion result in an earlier onset of romantic and sexual experiences, and whether the link between family cohesion and an early sexual debut is mediated by early romantic initiation. A longitudinal sample of 314 adolescent girls and 222 boys, aged 12–17 at Wave 1, completed questionnaires at three measurement points with three year intervals. The results showed that sexual debut followed romantic initiation for 77% of the participants. For early adolescent females (aged 12–14), high levels of family cohesion resulted in a later sexual debut and this association was fully mediated by a delay of romantic initiation. Among boys and older girls, timing of romantic initiation did not mediate the link between family cohesion and timing of sexual initiation. Early adolescent girls who have negative relationships with their parents turn to romantic relationships for intimacy and support, which subsequently provide the opportunity for an early sexual debut. Low levels of family cohesion thus primarily precipitate romantic initiation and sexual initiation appears to be secondary to this process among girls in this age group.  相似文献   
915.
916.
Previous studies have indicated homophily in depressive symptoms among adolescent friends, resulting from both peer selection and socialization processes. However, developmental differences and the role of school transitions in these processes have not been elucidated. A sample of 367 (51% female) adolescents was followed from 6th to 11th grade to investigate prospective relationships between adolescents’ and their friends’ depressive symptoms in middle school and in high school. Results revealed that students selected friends with similar levels of depressive symptoms after each school transition. Additionally, friends appeared to socialize adolescents to become more similar in depressive affect in late middle school years. These findings suggest normative selection effects after school transitions, followed by socialization effects in middle school, but not high school.  相似文献   
917.
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   
918.
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   
919.
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   
920.
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   
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