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   22849篇
  免费   682篇
各国政治   915篇
工人农民   868篇
世界政治   1845篇
外交国际关系   777篇
法律   14032篇
中国共产党   2篇
中国政治   119篇
政治理论   4766篇
综合类   207篇
  2020年   292篇
  2019年   343篇
  2018年   436篇
  2017年   522篇
  2016年   561篇
  2015年   387篇
  2014年   470篇
  2013年   2231篇
  2012年   554篇
  2011年   591篇
  2010年   476篇
  2009年   511篇
  2008年   592篇
  2007年   643篇
  2006年   622篇
  2005年   539篇
  2004年   541篇
  2003年   575篇
  2002年   518篇
  2001年   892篇
  2000年   836篇
  1999年   663篇
  1998年   352篇
  1997年   299篇
  1996年   269篇
  1995年   263篇
  1994年   308篇
  1993年   270篇
  1992年   436篇
  1991年   478篇
  1990年   430篇
  1989年   458篇
  1988年   420篇
  1987年   453篇
  1986年   431篇
  1985年   450篇
  1984年   380篇
  1983年   422篇
  1982年   317篇
  1981年   308篇
  1980年   235篇
  1979年   321篇
  1978年   233篇
  1977年   197篇
  1976年   174篇
  1975年   162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 375 毫秒
901.
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   
902.
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   
903.
A reformer most of her life, Lydia Maria Child advanced the rights of women, Native Americans, and African Americans in such works as History of the Condition of Women in Various Ages and Nations (1835), Hobomok (1823), and An Appeal in Favor of That Class of Americans Called Africans (1833).  相似文献   
904.
Positive relationships with parents and nonparental adults have the potential to bolster Black adolescents’ socio-emotional well-being. Though each type of intergenerational relationship has been linked to more positive youth outcomes, few studies have examined the interactive influences of parenting and natural mentoring relationships on the socio-emotional development of Black youth. In the current study, we examined associations between involved-vigilant parenting and the psychological well-being and social skills of Black early adolescents (n = 259; 58 % female; mean age = 13.56, SD = .96) across types of natural mentoring relationships. Using K-means cluster analysis, we identified two types of mentoring relationships (less connected and more connected) based on relationship length, involvement, closeness, and frequency of contact. Youth with more connected mentoring relationships (n = 123) had higher psychological well-being and social skills than youth with no mentor (n = 64) or less connected mentors (n = 72). Youth without a natural mentor and youth with less connected mentors did not differ in their levels of social skills or psychological well-being. Structural equation modeling was conducted to determine if associations between involved-vigilant parenting and youths’ psychological well-being and social skills varied among youth with a more connected mentoring relationship in comparison to youth without a mentor or with a less connected mentor, controlling for participants’ gender, age, school, and parental education. The positive associations between involved-vigilant parenting and adolescents’ psychological well-being and social skills were weaker among adolescents with a more connected mentoring relationship in comparison to their peers without or with a less connected mentoring relationship. These results suggest that youth may be more strongly influenced by involved-vigilant parenting in the absence of a strongly connected natural mentoring relationship.  相似文献   
905.
Sipping alcohol during childhood may be a marker of differentiation as regards children’s future risk of underage drinking; yet very little is known about alcohol use when it occurs among elementary school-aged children. The purpose of the present study is to examine alcohol sipping behavior in a sample of third-grade school children to learn whether sipping is associated with attributes that could increase children’s likelihood of further underage drinking. We collected telephone interview data from 1,050 mothers and their third grade children (mean age 9.2 years; 48.2 % male) residing in the Southeastern United States. The majority of mothers were White non-Hispanic (69.02 %) or Black non-Hispanic (21.3 %); most (85 %) lived in households shared with fathers or other adult caretakers. We hypothesized that children who sip alcohol would score lower than abstinent peers on indicators of competence and score higher on indicators of exposure to alcohol-specific socialization by parents and peers. A multivariate model controlling for frequency of parent alcohol use and demographic covariates showed that children who had sipped alcohol were significantly less likely than abstinent peers to affirm indicators of competence and significantly more likely to affirm indicators of exposure to alcohol specific socialization by parents and by same age peers. These preliminary findings suggest that developmental attributes associated with risk of underage drinking begin to differentiate at least as young as middle childhood. Research is needed to test prospectively for continuity between alcohol risk attributes present in middle childhood and future alcohol use.  相似文献   
906.
Social cognitive models examining academic and career outcomes emphasize constructs such as attitude, interest, and self-efficacy as key factors affecting students’ pursuit of STEM (science, technology, engineering and math) courses and careers. The current research examines another under-researched component of social cognitive models: social support, and the relationship between this component and attitude and self-efficacy in math and science. A large cross-sectional design was used gathering data from 1,552 participants in four adolescent school settings from 5th grade to early college (41 % female, 80 % white). Students completed measures of perceived social support from parents, teachers and friends as well as their perceived ability and attitudes toward math and science. Fifth grade and college students reported higher levels of support from teachers and friends when compared to students at other grade levels. In addition, students who perceived greater social support for math and science from parents, teachers, and friends reported better attitudes and had higher perceptions of their abilities in math and science. Lastly, structural equation modeling revealed that social support had both a direct effect on math and science perceived abilities and an indirect effect mediated through math and science attitudes. Findings suggest that students who perceive greater social support for math and science from parents, teachers, and friends have more positive attitudes toward math and science and a higher sense of their own competence in these subjects.  相似文献   
907.
Victims of child abuse and neglect are at an increased risk of involvement with the juvenile justice and adult correctional systems. Yet, little is known about the continuation and trajectories of offending beyond initial contact with law enforcement. Neglect likely plays a critical role in continued offending as parental monitoring, parental rejection and family relationships are instrumental in explaining juvenile conduct problems. This study sought to determine whether neglect is associated with recidivism for moderate and high risk juvenile offenders in Washington State. Statewide risk assessments and administrative records for child welfare, juvenile justice, and adult corrections were analyzed. The sample was diverse (24 % female, 13 % African American, 8 % Hispanic, 5 % Native American) and included all moderate and high risk juvenile offenders screened by juvenile probation between 2004 and 2007 (n = 19,833). Official records from child protection were used to identify juvenile offenders with a history of child neglect and to identify juvenile offenders with an ongoing case of neglect. Event history models were developed to estimate the risk of subsequent offending. Adolescents with an ongoing case neglect were significantly more likely to continue offending as compared with youth with no official history of neglect. These findings remain even after controlling for a wide range of family, peer, academic, mental health, and substance abuse covariates. Interrupting trajectories of offending is a primary focus of juvenile justice. The findings of the current study indicate that ongoing dependency issues play a critical role in explaining the outcomes achieved for adolescents in juvenile justice settings. The implications for improved collaboration between child welfare and juvenile justice are discussed.  相似文献   
908.
Experiences with perceived discrimination (e.g., perceptions of being treated unfairly due to race or ethnicity) are expected to impact negatively youths’ prosocial development. However, resilience often occurs in light of such experiences through cultural factors. The current longitudinal study examined the influence of perceived discrimination on the emergence of Mexican American adolescents’ later prosocial tendencies, and examined the mediating role of Mexican American values (e.g., familism, respect, and religiosity). Participants included 749 adolescents (49 % female) interviewed at 5th, 7th, and 10th grade. Results of the current study suggested that, although perceived discrimination was associated negatively with some types of prosocial tendencies (e.g., compliant, emotional, and dire) and related positively to public prosocial helping, the associations were mediated by youths’ Mexican American values. Directions for future research are presented and practical implications for promoting adolescents’ resilience are discussed.  相似文献   
909.
As a fictional personality trading as ‘Mrs Pomeroy’, Jeannette Scalé dominated London's elite beauty market through the late nineteenth century. By 1906, her control over the expansive commercial empire had collapsed, as new company owners publicly accused her of pecuniary ambitions unbefitting her sex. This article charts Scalé's extraordinary transformation into London's leading complexion specialist, exploring the gender conventions regulating both the beauty business and middle-class female enterprise at the fin de siècle. An investigation of the ‘Mrs Pomeroy’ character reveals businesswomen's changing opportunities in England's ‘modernizing’ retail market, opportunities engendered through new systems of advertising, growing anonymity in the expanding urban scene, and novel forms of self-representation that did not necessarily impinge upon businesswomen's respectability.  相似文献   
910.
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