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   26039篇
  免费   1523篇
  国内免费   5篇
各国政治   1032篇
工人农民   1029篇
世界政治   1838篇
外交国际关系   797篇
法律   17754篇
中国共产党   7篇
中国政治   224篇
政治理论   4650篇
综合类   236篇
  2020年   491篇
  2019年   543篇
  2018年   642篇
  2017年   759篇
  2016年   761篇
  2015年   636篇
  2014年   658篇
  2013年   2505篇
  2012年   667篇
  2011年   767篇
  2010年   841篇
  2009年   814篇
  2008年   728篇
  2007年   737篇
  2006年   787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   286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
951.
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   
952.
Youth who participate in service activities differ from those who do not on a number of key demographic characteristics like socio-economic status and other indicators of risk; and most studies demonstrating positive outcomes among service participants employ small non-representative samples. Thus, there is little evidence as to whether the outcomes associated with service participation are similar among students with varying levels of risk. The National Household Education Survey of 1999, a large nationally representative cross-sectional data set that focused on community service, was analyzed to investigate associations between the risk status of 4,306 adolescent students (50.2% female; 63.3% European American, M age?=?15.9), their participation in community service, and their academic adjustment, behavioral problems, and civic knowledge. Because adolescents who participate in service differ from those who do not with respect to demographic characteristics, propensity score analyses were used to correct for potential selection bias in the examination of these relationships. Analyses tested competing theoretical models of service??protective versus compensatory??among students at varying levels of risk, and suggested that service acts as a compensatory factor with respect to academic, behavioral, and civic outcomes. Propensity score analyses revealed patterns suggesting that, in some cases, students with certain demographic profiles that are themselves related to the likelihood of service participation may benefit from service participation more than others. Findings are discussed in terms of their significance for adolescent development, for planning service programs, and for educational policy.  相似文献   
953.
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   
954.
Despite evidence that neighborhoods confer both risk and resilience for youth development, the existing neighborhood research has a number of methodological limitations including lack of diversity in neighborhoods sampled and neighborhood characteristics assessed. The purpose of this study was to address these methodological limitations of existing research and to examine the relationship of neighborhood structural and social characteristics to family-level social processes and teacher-reported social competence during early adolescence. The study sample of 3,624 fifth graders (51?% girls) was ethnically diverse, including roughly even proportions of non-Hispanic White, non-Hispanic Black, and Hispanic youth. Neighborhood measures included economic disadvantage derived from the U.S. Census, physical and social disorder obtained by direct observation, and social capital from parental reports. Family-level social processes included parent reported family cohesion and youth reported maternal and paternal nurturance. We found that neighborhood factors significantly associated with youth social aggression and social competence but not social withdrawal, after controlling for individual demographic characteristics and parenting factors. There was limited evidence of moderation of family influences by neighborhood characteristics as well as the moderation of neighborhood effects by children’s gender. Neighborhood physical disorder was associated with increased social aggression among boys but with increased social withdrawal among girls. Implications of the study’s findings for research on neighborhoods and adolescent development and the development of preventive interventions are discussed.  相似文献   
955.
Research has linked the role of education to delinquency, but much of the focus has been on general population samples and with little attention to demographic differences. Employing a cumulative disadvantage framework that integrates elements of informal social control and labeling theories, this article examines whether academic achievement serves as a positive turning point and re-directs juvenile delinquents away from subsequent offending. Attention is also given to race/sex contingencies. Using a sample of 4,147 delinquents released from Florida correctional institutions (86% male, 57% non-White, average age at release = 16.8 years), propensity score analysis yielded two findings: youth with above average academic achievement while incarcerated were significantly more likely to return to school post-release, and youth with above average attendance in public school were significantly less likely to be re-arrested in the 1-year post-release period. While the academic gains were pronounced among African-American males, the preventive effects of school attendance are similar across race and sex, suggesting that education can be a part of a larger prevention effort that assists juvenile delinquents in successful community re-entry.  相似文献   
956.
There is increasing interest in how universities are governed, externally and internally (Austin and Jones 2016). Drawing on a comparative case study of the governance of six major Canadian universities and the literature, this article describes the impact of federal research and innovation policy and programs on universities and reflects on Ottawa's role. We suggest that the federal government participates in the external governance of universities, but in a way that differs significantly from provincial governments. Canadian federalism appears to be generally beneficial for university autonomy and examination of its operation sheds light on factors that enable universities to sustain their autonomy.  相似文献   
957.
This article explores the potential of using children’s perceptions of distance to reflect a gendered understanding of remoteness. Data collected from 1,549 children in Tanzania concerning their perceptions of remoteness in relation to accessibility of school, health care, and water resources were analysed in reference to their impact on school attendance and performance. Gendered variability in perceived distances to services by children may indicate that remoteness is as much of a social issue as it is a geographic phenomenon, in that girls perceive distance and time between home and destination to be further than boys who travel approximately the same distance.  相似文献   
958.

Young adulthood represents a developmental period with disproportionately heightened risk of losing a job. Young adult unemployment has been linked to increased mental health problems, at least in the short term. However, their possible long-term impacts, often referred as “scarring effects,” have been understudied, possibly underestimating the magnitude of mental health burden that young adult unemployment generates. This longitudinal study examined whether duration of unemployment during young adulthood is associated with later mental health disorders, after accounting for mental and behavioral health problems in childhood. Furthermore, the current study investigated whether childhood neighborhood characteristics affect this association and if so, in what specific functional ways. Data were drawn from a longitudinal study of developmental outcomes in a community sample in Seattle. Data collection began in 1985 when study participants were elementary students and involved yearly assessments in childhood and adolescence (ages 10–16) and then biennial or triennial assessments (ages 18–39; N?=?677 at age 39; 47% European American, 26% African American, 22% Asian American, and 5% Native American; 49% female). The current study findings suggest that duration of unemployment across young adulthood increased mental health problems at age 39, regardless of gender. Childhood neighborhood characteristics, particularly their positive aspect, exerted independent impacts on adult mental health problems beyond unemployment experiences across young adulthood. The current findings indicate a needed shift in service profiles for unemployed young adults—a comprehensive approach that not only facilitates reemployment but also addresses mental health needs to help them to cope with job loss. Further, the present study findings suggest that childhood neighborhoods, particularly positive features such as positive neighborhood involvement, may represent concrete and malleable prevention targets that can curb mental health problems early in life.

  相似文献   
959.
Journal of Youth and Adolescence - The development of social behavior could be affected by stressful parenting. The mineralocorticoid receptor, one of the two main receptors for the stress hormone...  相似文献   
960.
Journal of Youth and Adolescence - In the original publication, the legends for Figs 4 and 5 were incorrect, such that each regression line was mislabeled with the incorrect country. Below are the...  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