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   24375篇
  免费   732篇
各国政治   1064篇
工人农民   987篇
世界政治   1878篇
外交国际关系   824篇
法律   14743篇
中国共产党   5篇
中国政治   127篇
政治理论   5244篇
综合类   235篇
  2020年   302篇
  2019年   367篇
  2018年   495篇
  2017年   577篇
  2016年   599篇
  2015年   410篇
  2014年   473篇
  2013年   2510篇
  2012年   597篇
  2011年   620篇
  2010年   505篇
  2009年   553篇
  2008年   659篇
  2007年   643篇
  2006年   649篇
  2005年   594篇
  2004年   600篇
  2003年   597篇
  2002年   558篇
  2001年   874篇
  2000年   819篇
  1999年   653篇
  1998年   387篇
  1997年   346篇
  1996年   301篇
  1995年   293篇
  1994年   329篇
  1993年   313篇
  1992年   475篇
  1991年   526篇
  1990年   464篇
  1989年   478篇
  1988年   450篇
  1987年   471篇
  1986年   479篇
  1985年   466篇
  1984年   412篇
  1983年   439篇
  1982年   335篇
  1981年   306篇
  1980年   248篇
  1979年   340篇
  1978年   231篇
  1977年   207篇
  1976年   183篇
  1975年   171篇
  1974年   194篇
  1973年   186篇
  1972年   163篇
  1970年   133篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
901.
"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   
902.
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   
903.
904.
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   
905.
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   
906.
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   
907.
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   
908.
Policymakers have actively pursued urban renewal and dispersal programs to deconcentrate poverty in urban neighborhoods. Relocation strategies lead to new housing opportunities and may encourage employment opportunities for relocated residents if resourceful contacts and job information become more easily available after the move. This study provides an innovative evaluation of the early impacts of involuntary relocation programs in the Netherlands on the housing careers, earnings and employment rates of forced relocatees. It establishes a quasi-experimental design by employing unique longitudinal individual-level population registry data from Statistics Netherlands: forced relocatees are tracked and matched to a control group consisting of similar residents that were not forced to move. A difference-in-difference design shows that forced relocatees are living in less deprived neighborhoods after the move. However, we find no conclusive evidence that this upgrade in housing leads to more socioeconomic opportunities for the forced relocatees.  相似文献   
909.
Fair Market Rents (FMRs), calculated for an entire metropolitan region, are used to establish payment standards for the Housing Choice Voucher (HCV) program. In response to recent criticism that FMRs do not represent rent disparity and restrict households from moving to high-opportunity areas, a new rule introducing Small Area Fair Market Rents (SAFMRs) has been issued. SAFMRs are based on ZIP codes to reflect local market rents and increase the number of payment standards used to administer the HCV program. The purpose of this research is to determine whether the number of payment standards can be reduced by consolidating ZIP codes, while adhering to the primary objectives of the SAFMR rule. The ZIP code grouping process conducted offers one method for reducing the number of payment standards needed to implement the new rule; however, the rent analysis reveals the over- and underestimation of SAFMRs for some ZIP codes.  相似文献   
910.
There is strong evidence that land use regulations constrain housing production. We know less about how real estate developers respond to specific zoning provisions. I compare the characteristics of new multifamily housing with baseline land use regulations in two sets of rail station areas in Los Angeles. I supplement this building-scale analysis with expert interviews. I find that developers were most sensitive to density restrictions and parking requirements. The average development in the Vermont/Western area had 112% of the maximum allowable residential density and 94% of the minimum required parking. Koreatown’s average development had 99% of the maximum density and 88% of the required parking. But, there was variation by area and whether a building was affordable or market rate, apartment or condominium, and by development size. Additionally, regulatory implementation can matter as much as the written regulations themselves. I recommend that cities take an evidence-based approach to reforming regulations and implementation processes.  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