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   22797篇
  免费   682篇
各国政治   904篇
工人农民   870篇
世界政治   1811篇
外交国际关系   774篇
法律   14040篇
中国共产党   2篇
中国政治   118篇
政治理论   4753篇
综合类   207篇
  2020年   293篇
  2019年   340篇
  2018年   436篇
  2017年   521篇
  2016年   558篇
  2015年   385篇
  2014年   468篇
  2013年   2214篇
  2012年   551篇
  2011年   588篇
  2010年   476篇
  2009年   511篇
  2008年   591篇
  2007年   640篇
  2006年   620篇
  2005年   536篇
  2004年   541篇
  2003年   569篇
  2002年   514篇
  2001年   893篇
  2000年   836篇
  1999年   662篇
  1998年   352篇
  1997年   299篇
  1996年   268篇
  1995年   261篇
  1994年   309篇
  1993年   270篇
  1992年   436篇
  1991年   480篇
  1990年   430篇
  1989年   460篇
  1988年   420篇
  1987年   455篇
  1986年   429篇
  1985年   448篇
  1984年   381篇
  1983年   423篇
  1982年   319篇
  1981年   310篇
  1980年   235篇
  1979年   322篇
  1978年   233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
851.
"Current models of the European demo-economic system in pre-industrial times are based on strong assumptions about the predominant patterns of individual life courses. Now recent micro-studies of individual communities make it possible to check whether the actual patterns of life fit these assumptions. The findings for Belm present an amazing blend of confirmations and contradictions. In particular, the connection between marriage and the formation of a new self-supporting household is subject to doubt. Together with the findings of other micro-studies, the evidence for Belm suggests that the assumptions about mechanisms linking marriage to economic resources should be reconsidered, and that there is need for a dialogue between macro-theories and micro-history."  相似文献   
852.
This paper describes a simplified approach to calculating the Bayesian likelihood ratio for the case where two DNA single locus profiles are to be compared. It explains how the calculation allows for band shift and also for the variation in precision with molecular weight. A simple basic theory section explains the principles of the analysis but more detailed explanations are given in an advanced theory section. Experiments on substantial data collections are described which demonstrate the robustness of the method.  相似文献   
853.
854.
Lorraine Benson's body was found beaten and strangled at Raynes Park, Surrey, in December 1988. Considering the possibility of linked offences, a murder squad was set up to work alongside a team already investigating a rape series in the Kingston area. A man's handkerchief left at a site a quarter of a mile from the murder scene was found to be stained with blood and saliva matching that of the victim. A DNA profile was obtained from a stain of nasal mucus on this handkerchief and found to match a suspect later arrested for an attempted rape in the same locality. Also of forensic interest were dust marks made by the zips of the victim's and defendant's coats and identification of the rope used for strangulation.  相似文献   
855.
Adolescent romantic relationships have the potential to affect psychological functioning well into adulthood. This study assessed adolescent romantic relationship qualities as long-term predictors of psychological functioning utilizing a longitudinal multi-method, multi-informant study of 80 participants (59% female; 54% Caucasian, 35% African American, 11% mixed or other race) assessed at age 17 along with their romantic partners and at ages 25–27. Controlling for gender, family income, and baseline mental health, partner-reported hostile conflict at age 17 predicted relative increases in internalizing behaviors from age 17 to 27. In contrast, observed teen support with their partner during a help-seeking task at age 17 predicted relative decreases in externalizing behaviors over time. The results are interpreted as suggesting qualities that may help determine whether adolescent romances have positive vs. negative long-term psychological health implications.  相似文献   
856.
The Bully-Sexual Violence Pathway theory has indicated that bullying perpetration predicts sexual violence perpetration among males and females over time in middle school, and that homophobic name-calling perpetration moderates that association among males. In this study, the Bully-Sexual Violence Pathway theory was tested across early to late adolescence. Participants included 3549 students from four Midwestern middle schools and six high schools. Surveys were administered across six time points from Spring 2008 to Spring 2013. At baseline, the sample was 32.2% White, 46.2% African American, 5.4% Hispanic, and 10.2% other. The sample was 50.2% female. The findings reveal that late middle school homophobic name-calling perpetration increased the odds of perpetrating sexual violence in high school among early middle school bullying male and female perpetrators, while homophobic name-calling victimization decreased the odds of high school sexual violence perpetration among females. The prevention of bullying and homophobic name-calling in middle school may prevent later sexual violence perpetration.  相似文献   
857.
Time spent on social media and making online comparisons with others may influence users’ mental health. This study examined links between parental control over the time their child spends on social media, preadolescents’ time spent browsing social media, preadolescents’ appearance comparisons on social media, and preadolescents’ appearance satisfaction, depressive symptoms, and life satisfaction. Preadolescent social media users (N?=?284, 49.1% female; aged 10–12) and one of their parents completed online surveys. Preadolescents, whose parents reported greater control over their child’s time on social media, reported better mental health. This relationship was mediated by preadolescents spending less time browsing and making fewer appearance comparisons on social media. Parental control over time spent on social media may be associated with benefits for mental health among preadolescents.  相似文献   
858.
There is broad agreement that neighborhood contexts are important for adolescent development, but there is less consensus about their association with adolescent smoking and alcohol use. Few studies have examined associations between neighborhood socioeconomic contexts and smoking and alcohol use while also accounting for differences in family and peer risk factors for substance use. Data drawn from the Seattle Social Development Project (N?=?808), a gender-balanced (female?=?49%), multiethnic, theory-driven longitudinal study originating in Seattle, WA, were used to estimate trajectories of smoking and alcohol use from 5th to 9th grade. Time-varying measures of neighborhood socioeconomic, family, and peer factors were associated with smoking and alcohol use at each wave after accounting for average growth in smoking and alcohol use over time and demographic differences. Results indicated that living in more socioeconomically disadvantaged neighborhoods, lower family income, lower family general functioning, more permissive family smoking environments, and affiliation with deviant peers were independently associated with increased smoking. Lower family functioning, more permissive family alcohol use environments, and deviant peers were independently associated with increased alcohol use. The effect of neighborhood disadvantage on smoking was mediated by family income and deviant peers while the effect of neighborhood disadvantage on alcohol use was mediated by deviant peers alone. Family functioning and family substance use did not mediate associations between neighborhood disadvantage and smoking or alcohol use. The results highlight the importance of neighborhood, family, and peer factors in early adolescent smoking and alcohol use. Future studies should examine the unique association of neighborhood disadvantage with adolescent smoking net of family socioeconomics, functioning, and substance use, as well as peer affiliations. Better understanding of the role of contextual factors in early adolescent smoking and alcohol use can help bolster efforts to prevent both short and long harms from substance use.  相似文献   
859.
Most previous identity research has focused on relationships between identity synthesis, confusion, and psychosocial problems. However, these studies did not take into account Erikson’s notion of identity consolidation, that is, the dynamic interplay between identity synthesis and confusion. This study aimed to examine longitudinal relationships and the directionality of the effects between identity consolidation and psychosocial problems during adolescence, using two waves of longitudinal data from 793 Japanese adolescents (49.7% girls; ages 13–14 and 16–17 at Time 1). A bi-factor latent change model revealed that levels and changes in identity consolidation were negatively associated with levels and changes in psychosocial problems. Furthermore, a bi-factor cross-lagged effects model provided evidence that identity consolidation negatively predicted psychosocial problems, and vice versa. Our study facilitates a better understanding of the importance of identity consolidation in the relations between identity components and psychosocial problems.  相似文献   
860.
Suicide is the second leading cause of death for older adolescents and young adults. Although empirical literature has identified important risk factors of suicidal behavior, it is less understood if changes in risk factors correspond with changes in suicide risk. To address this knowledge gap, we assessed if there were different trajectories of suicidal behavior as youth transition into young adulthood and determined what time-varying risk factors predicted these trajectories. This study used four waves of data spanning approximately 13 years from the National Longitudinal Study of Adolescent Health. The sample included 9027 respondents who were 12–18 years old (M?=?15.26; SD?=?1.76) at Wave 1, 50% male, 17% Hispanic, and 58% White. The results indicated that 93.6% of the sample had a low likelihood for suicide attempts across time, 5.1% had an elevated likelihood of attempting suicide in adolescence but not young adulthood, and 1.3% had an elevated likelihood of attempting suicide during adolescence and adulthood. The likelihood of a suicide attempt corresponded with changes on depression, impulsivity, delinquency, alcohol problems, family and friend suicide history, and experience with partner violence. Determining how suicide risk changes as youth transition into young adulthood and what factors predict these changes can help prevent suicide. Interventions targeting these risk factors could lead to reductions in suicide attempts.  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