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   24479篇
  免费   733篇
各国政治   1069篇
工人农民   1001篇
世界政治   1889篇
外交国际关系   828篇
法律   14779篇
中国共产党   5篇
中国政治   128篇
政治理论   5276篇
综合类   237篇
  2020年   304篇
  2019年   369篇
  2018年   497篇
  2017年   580篇
  2016年   602篇
  2015年   416篇
  2014年   476篇
  2013年   2525篇
  2012年   597篇
  2011年   624篇
  2010年   507篇
  2009年   554篇
  2008年   661篇
  2007年   649篇
  2006年   653篇
  2005年   596篇
  2004年   600篇
  2003年   598篇
  2002年   559篇
  2001年   877篇
  2000年   822篇
  1999年   657篇
  1998年   392篇
  1997年   346篇
  1996年   302篇
  1995年   295篇
  1994年   330篇
  1993年   314篇
  1992年   476篇
  1991年   528篇
  1990年   464篇
  1989年   479篇
  1988年   450篇
  1987年   472篇
  1986年   479篇
  1985年   467篇
  1984年   413篇
  1983年   442篇
  1982年   335篇
  1981年   308篇
  1980年   251篇
  1979年   341篇
  1978年   232篇
  1977年   207篇
  1976年   184篇
  1975年   171篇
  1974年   194篇
  1973年   186篇
  1972年   164篇
  1970年   133篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
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   
982.
983.
Everyday interactions with same-racial/ethnic others may confer positive benefits for adolescents, but the meaning of these interactions are likely influenced by individual differences and larger structural contexts. This study examined the situation-level association between contact with same-ethnic others and anxiety symptoms among a diverse sample of 306 racial/ethnic minority adolescents (Mage = 14 years; 66 % female), based on (1) individual differences in ethnic identity centrality and (2) developmental histories of transitions in diversity between elementary, middle, and high school. The results indicated that at the level of the situation, when adolescents interacted with more same-ethnic others, they reported fewer anxiety symptoms. Further, for adolescents who had experienced a transition in school diversity, the positive benefits of contact with same-ethnic others was only conferred for those who felt that their ethnicity was very important to them. The importance of examining individual differences within larger developmental histories to understand the everyday experiences of ethnic minority adolescents are discussed.  相似文献   
984.
This article focuses on the degree to which friends’ influence on substance use is conditioned by the consistency between their behavior and that of schoolmates (individuals enrolled in the same school, but not identified as friends), contributing to the literature on the complexity of interactive social influences during adolescence. Specifically, it hypothesizes that friends’ influence will diminish as their norms become less similar to that of schoolmates. The authors also propose that this conditioning relationship is related to the density of the friendship group. This study uses data from the National Longitudinal Survey of Adolescent Health (AddHealth) (n ~ 8,000, 55 % female) to examine the interactive relationship between friend and schoolmate influences on adolescent substance use (smoking and drinking). The sample contains students ranging from age 11 to 22 and is 60 % White. The findings demonstrate that, as the substance use of the friendship group becomes more dissimilar from schoolmates’ substance use, the friendship group’s influence on adolescent substance use diminishes. Further, the results demonstrate that this conditioning relationship does not emerge when the friendship group is highly dense.  相似文献   
985.
Prior research has identified a vast number of correlates for delinquent behavior during adolescence, yet a considerable number of errors in prediction remain. These errors suggest that behavioral development among a portion of youths is not well understood, with some exhibiting resilience and others a heightened vulnerability to risks. Examining cases that do not confirm prediction outcomes provides an opportunity to achieve a greater understanding of the relationships between risk factors and delinquency, which can be used to improve theoretical explanations of behavior. This study explores the contribution of genetic and environmental factors to differences in individual responses to cumulative risk for delinquency among a sample of adolescent twins (N = 784 pairs, 49 % female) in the National Longitudinal Study of Adolescent Health. The results indicate that additive genetic and unique environmental factors significantly contribute to variation in responses to cumulative risk across 14 risk factors spanning individual, familial, and environmental domains. When analyzed separately, the majority of the difference between vulnerable youths and the overall population was attributed to genetic influences, while differences between resilient youths and the population were primarily attributed to environmental influences. The findings illustrate the importance of examining both genetic and environmental influences in order to enhance explanations of adolescent offending.  相似文献   
986.
There is limited research that has examined experimentally the effects of muscular images on adolescent boys’ body image, with no research specifically examining the effects of music television. The aim of the current study was to examine the effects of viewing muscular and attractive singers in music video clips on early, mid, and late adolescent boys’ body image, mood, and schema activation. Participants were 180 boys in grade 7 (mean age = 12.73 years), grade 9 (mean age = 14.40 years) or grade 11 (mean age = 16.15 years) who completed pre- and post-test measures of mood and body satisfaction after viewing music videos containing male singers of muscular or average appearance. They also completed measures of schema activation and social comparison after viewing the clips. The results showed that the boys who viewed the muscular clips reported poorer upper body satisfaction, lower appearance satisfaction, lower happiness, and more depressive feelings compared to boys who viewed the clips depicting singers of average appearance. There was no evidence of increased appearance schema activation but the boys who viewed the muscular clips did report higher levels of social comparison to the singers. The results suggest that music video clips are a powerful form of media in conveying information about the male ideal body shape and that negative effects are found in boys as young as 12 years.  相似文献   
987.
Empirical evidence suggests that religiousness is related negatively to adolescent substance use; yet, we know little about how such protective effects might occur. The current study examined whether parents’ and adolescents’ religiousness are associated positively with parental, religious, and self-monitoring, which in turn are related to higher self-control, thereby related to lower adolescent substance use. Participants were 220 adolescents (45 % female) who were interviewed at ages 10–16 and again 2.4 years later. Structural equation modeling analyses suggested that higher adolescents’ religiousness at Time 1 was related to lower substance use at Time 2 indirectly through religious monitoring, self-monitoring, and self-control. Higher parents’ religiousness at Time 1 was associated with higher parental monitoring at Time 2, which in turn was related to lower adolescent substance use at Time 2 directly and indirectly through higher adolescent self-control. The results illustrate that adolescents with high awareness of being monitored by God are likely to show high self-control abilities and, consequently, low substance use. The findings further suggest that adolescents’ religiousness as well as their religious environments (e.g., familial context) can facilitate desirable developmental outcomes.  相似文献   
988.
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   
989.
Some Aboriginal youth are at disproportionate risk of using substances and developing abuse and dependence disorders. However, not all Aboriginal youth misuse substances and limited research has examined the protective factors conferring against substance use among these youth. The present study aimed to identify protective factors related to the alcohol use trajectories from early adolescence to emerging adulthood among off-reserve Canadian Aboriginal youth. Participants (N = 330; 50.3% male) aged 12–23 were selected from cycles 2–7 of Statistics Canada’s NLSCY. Multilevel modeling was employed to identify protective factors for two constructs of alcohol use. Participation in weekly activities and optimism were found to be protective for both the frequency of alcohol use and heavy drinking trajectories. Attendance of religious services was also found to be protective for heavy drinking behaviors. In contrast, positive peer relationships were a risk factor for frequency of alcohol use, but not heavy drinking. The results provide preliminary evidence of important developmental factors to integrate into substance use intervention programs targeting Aboriginal youth.  相似文献   
990.
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   
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