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   22733篇
  免费   680篇
各国政治   900篇
工人农民   863篇
世界政治   1808篇
外交国际关系   772篇
法律   13996篇
中国共产党   2篇
中国政治   118篇
政治理论   4747篇
综合类   207篇
  2020年   292篇
  2019年   340篇
  2018年   434篇
  2017年   518篇
  2016年   556篇
  2015年   384篇
  2014年   467篇
  2013年   2208篇
  2012年   549篇
  2011年   587篇
  2010年   474篇
  2009年   510篇
  2008年   590篇
  2007年   638篇
  2006年   618篇
  2005年   535篇
  2004年   537篇
  2003年   569篇
  2002年   514篇
  2001年   890篇
  2000年   834篇
  1999年   661篇
  1998年   352篇
  1997年   298篇
  1996年   268篇
  1995年   261篇
  1994年   308篇
  1993年   269篇
  1992年   435篇
  1991年   478篇
  1990年   430篇
  1989年   458篇
  1988年   420篇
  1987年   453篇
  1986年   429篇
  1985年   448篇
  1984年   380篇
  1983年   421篇
  1982年   317篇
  1981年   306篇
  1980年   232篇
  1979年   319篇
  1978年   231篇
  1977年   197篇
  1976年   174篇
  1975年   160篇
  1974年   185篇
  1973年   169篇
  1972年   146篇
  1971年   139篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
891.
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   
892.
The longitudinal effects among self and identity processes, and between these processes and internalizing symptoms, are not well understood. As a result, the present study was designed to ascertain the over-time effects among identity commitment, reconsideration of commitments, and self-concept clarity, as well as to map the interplay of these self and identity processes with anxiety and depressive symptoms in early adolescence. A sample of 923 Dutch adolescents (mean age 12.4 years at Time 1; 49.3% female) participated at each of five annual assessments. Multivariate growth curve and cross-lagged panel models indicated that the association between self-concept clarity and commitment was bidirectional, that reconsideration occurs based on problems or dissatisfaction with self-concept clarity and with identity commitments, and that self-concept clarity (but not commitment or reconsideration) temporally precedes depressive and anxiety symptoms. Results are discussed in terms of the structure of the self-system and its associations with internalizing symptoms.  相似文献   
893.
Why do politicians in Mexico switch parties? The party‐switching literature suggests that politicians generally switch parties for office‐seeking or policy‐seeking motives, whereas literature on the Mexican party system suggests that switching may be related to party system realignment during the democratic transition. Using data on party switching across the political careers of politicians who served as federal deputies between 1997 and 2009, this study argues that party switching in Mexico can primarily be explained by the office‐seeking behavior of ambitious politicians. Only in rare instances do politicians switch parties because of policy disagreements, and party system realignment fails to explain a large number of party switches. This article also suggests that the ban on consecutive re‐election encourages party switching; after every term in office, Mexican politicians have the opportunity to re‐evaluate their party affiliation to continue their careers.  相似文献   
894.
Labor market dualism—the segmentation of workers between formal, legally protected employment and informal, unprotected status—has long drawn attention from scholars and policymakers in Latin America. This article argues that lasting patterns of economic and political segmentation of workers arose earlier in the region's history than has previously been understood, well before the classic “incorporation” period. Late‐nineteenth‐century practices for the recruitment and retention of workers shaped Latin America's first sets of labor laws, most notably those governing union organization and individual worker job stability. Subsequently, these first laws served as important templates for development, constraining and conditioning the labor codes adopted under mass‐based politics. Using historical data drawn from Chile, Peru, and Argentina, this article shows how differing recruitment practices and variation in the extension of effective suffrage rights and electoral participation shaped early legal labor market segmentation and inequality in Latin America.  相似文献   
895.
Recent media attention has increased interest in behavioral, mental health, and academic correlates of involvement in bullying. Yet, there has not been much interest in investigating the co-occurrence of other health-risk behaviors, such as gang membership, weapon carrying, and substance use. The potential influence of contextual factors, such as youth ethnicity, urbanicity, and school characteristics, also has been overlooked in previous research. The current study examined different subtypes of involvement in bullying—as primarily a victim, as primarily a bully, as both a victim and bully, and no involvement—and the association with significant health-risk behaviors, including engaging in violence and substance use, as well as academic problems. The analyses use self-report data from 16,302 adolescents (50.3 % female, 62.2 % Caucasian, 37.8 % African American) enrolled in 52 high schools. A series of three-level HLM analyses revealed that bullies and bully/victims were generally at greatest of risk of being involved in violence, engaging in multiple types of substance use, and having academic problems. These findings extend prior research by emphasizing a potential link between involvement in bullying and multiple health-risk behaviors, particularly among urban and African American high school youth.  相似文献   
896.
Research on the role of race and urbanicity in bullying involvement has been limited. The present study examined bullying involvement subgroups that relate to race, urbanicity, and the perceived reason for the bullying. Self-report data were collected from 10,254 middle school youth (49.8 % female; 62.4 % Caucasian, 19.0 % African American, and 5.6 % Hispanic) and latent class analyses were used to identify three subtypes of bullying involvement: low involvement (50 %), victim (31.3 %), and bully-victim (18.7 %). Irrespective of urbanicity (urban vs. non-urban), African American youth were more likely to be members of either the victim or bully-victim classes than the low involvement class. Further exploration of the community context suggested that urbanicity was associated with the increased likelihood of having been racially bullied. Urban bully-victims were also more likely to have been bullied about money than non-urban bully-victims. Findings underscore the importance of addressing both race and urbanicity for culturally sensitive prevention programming.  相似文献   
897.
The positive youth development perspective, a strength-based relational developmental systems model that focuses on mutually influential relationships between individuals and contexts, has been used to study thriving across the second decade of life. However, more attention has been paid empirically to identifying the features of the individual (e.g., intentional self regulation, hope, or purpose) or to enumerating the role of context-general ecological assets than to the nature of individual-context relationships linked to thriving within specific contexts. The goal of this special section is to provide initial research reports about context-specific instances of the thriving process. The research focuses on two contexts where many youth spend a considerable amount, and often the majority, of their time—school and out-of-school time sports activities.  相似文献   
898.
The United States Supreme Court’s recent decision relating to violent video games revealed divisions within the scientific community about the potential for negative effects of such games as well as the need for more, higher quality research. Scholars also have debated the potential for violent games to have positive effects such as on visuospatial cognition or math ability. The current study sought to extend previous literature by using well-validated clinical outcome measures for relevant constructs, which have generally been lacking in past research. Cross-section data on aggression, visuospatial cognition, and math achievement were available for a sample of 333 (51.7 % female) mostly Hispanic youth (mean age = 12.76). Prospective 1-year data on aggression and school GPA were available for 143 (46.2 % female) of those youth. Results from both sets of analysis revealed that exposure to violent game had neither short-term nor long-term predictive influences on either positive or negative outcomes. A developmental analysis of the cross-sectional data revealed that results did not differ across age categories of older children, preadolescents or adolescents. Analysis of effect sizes largely ruled out Type II error as a possible explanation for null results. Suggestions for new directions in the field of video game research are proffered.  相似文献   
899.
Depression is a common and debilitating disorder in adolescence. Sleep disturbances and depression often co-occur with sleep disturbances frequently preceding depression. The current study investigated whether catastrophic worry, a potential cognitive vulnerability, mediates the relationship between adolescent sleep disturbances and depressive symptoms, as well as whether there are gender differences in this relationship. High school students, ages 16–18, n = 1,760, 49 % girls, completed annual health surveys including reports of sleep disturbance, catastrophic worry, and depressive symptoms. Sleep disturbances predicted depressive symptoms 1-year later. Catastrophic worry partially mediated the relationship. Girls reported more sleep disturbances, depressive symptoms, and catastrophic worry relative to boys. The results, however, were similar regardless of gender. Sleep disturbances and catastrophic worry may provide school nurses, psychologists, teachers, and parents with non-gender specific early indicators of risk for depression. Several potentially important practical implications, including suggestions for intervention and prevention programs, are highlighted.  相似文献   
900.
This article identifies the arrest trajectories of youth from ages 12 through 24 years old and tests hypotheses derived from Moffitt’s developmental taxonomic theory of crime concerning the impact of various emotional disturbances on the specific trajectories of the youth involved. The study uses exclusively administrative data sets and includes a gender and racially diverse sample of 10,360 youth (30.7 % females) who were arrested at least once between ages 12 and 24 in the early 2000s. Latent class growth analysis was employed in order to identify distinct arrest trajectories of youth in the sample. Multinomial logistic regression was used to identify diagnostic and other characteristics associated with membership in the specific trajectories predicted by Moffitt’s theory. Five trajectory classes were identified, 3 of which were consistent with taxonomic theory including high and classic adolescence limited trajectory classes and a “snared adolescence limited class” described more recently by Moffitt. The distribution of youth among the 5 classes was very different for those with and without emotional disturbances. Youth with emotional disturbances in their late adolescent years were more likely to fall into the high arrest trajectory class and much less likely to fall into the low arrest trajectory class. Compared to youth without an emotional disturbance, youth with psychotic disorders were more than twice as likely to fall into the high as into the low arrest trajectory class. Youth with disruptive behavior disorders were more than twice as likely to fall into the high and intermediate classes as into the low trajectory class. Anxiety and depressive disorders were not associated with significantly greater likelihood of falling into any one of the trajectory classes. Youth in the snared adolescence limited class were more likely than those in the classic adolescence limited class to be male, black versus white and in the foster care enrollment category lending some support to Moffitt’s conceptualization of this class as an adolescence limited class composed of youth who are snared by involvement in the criminal justice and or social services systems. Implications of these results for public policy and the study of adolescence 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