全文获取类型
收费全文 | 31666篇 |
免费 | 1439篇 |
专业分类
各国政治 | 1340篇 |
工人农民 | 1342篇 |
世界政治 | 2397篇 |
外交国际关系 | 1069篇 |
法律 | 20206篇 |
中国共产党 | 3篇 |
中国政治 | 167篇 |
政治理论 | 6328篇 |
综合类 | 253篇 |
出版年
2021年 | 157篇 |
2020年 | 582篇 |
2019年 | 641篇 |
2018年 | 828篇 |
2017年 | 880篇 |
2016年 | 990篇 |
2015年 | 706篇 |
2014年 | 804篇 |
2013年 | 3277篇 |
2012年 | 809篇 |
2011年 | 850篇 |
2010年 | 803篇 |
2009年 | 850篇 |
2008年 | 860篇 |
2007年 | 877篇 |
2006年 | 878篇 |
2005年 | 760篇 |
2004年 | 780篇 |
2003年 | 701篇 |
2002年 | 720篇 |
2001年 | 1175篇 |
2000年 | 1086篇 |
1999年 | 876篇 |
1998年 | 487篇 |
1997年 | 384篇 |
1996年 | 367篇 |
1995年 | 374篇 |
1994年 | 396篇 |
1993年 | 367篇 |
1992年 | 564篇 |
1991年 | 601篇 |
1990年 | 572篇 |
1989年 | 563篇 |
1988年 | 556篇 |
1987年 | 550篇 |
1986年 | 587篇 |
1985年 | 583篇 |
1984年 | 495篇 |
1983年 | 476篇 |
1982年 | 394篇 |
1981年 | 366篇 |
1980年 | 303篇 |
1979年 | 426篇 |
1978年 | 260篇 |
1977年 | 219篇 |
1976年 | 193篇 |
1975年 | 205篇 |
1974年 | 241篇 |
1973年 | 183篇 |
1972年 | 182篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
941.
J Schlumbohm 《The History of the Family》1996,1(1):81-95
"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
942.
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
943.
J Potter 《Journal - Forensic Science Society》1992,32(3):249-255
944.
J E Allard 《Journal - Forensic Science Society》1992,32(1):49-58
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
945.
Nicole A. Anderson Amy M. Bohnert Amy Governale 《Journal of youth and adolescence》2018,47(8):1697-1711
Research examining factors that predict youth’s involvement in organized activities is very limited, despite associations with positive outcomes. Using data from 1043 youth (49% female; 46.4% Hispanic, 35.4% African American, 14.0% Caucasian, and 4.2% other) from the Project on Human Development in Chicago Neighborhoods, this study examined how characteristics of parents (supervision, warmth) and neighborhoods (perceived neighborhood safety and collective efficacy) predict patterns of adolescents’ involvement in organized activities concurrently (i.e., intensity) and longitudinally (i.e., type and breadth). Parental supervision predicted adolescents’ participation in organized activities across multiple waves. Neighborhood violence was positively associated with concurrent participation in organized activities after controlling for socioeconomic status (SES), whereas higher neighborhood collective efficacy predicted greater breadth in organized activity participation across time. These findings have important implications regarding how to attract and sustain organized activity participation for low-income, urban youth. 相似文献
946.
Naoise Mac Giollabhui Johanna Nielsen Sam Seidman Thomas M. Olino Lyn Y. Abramson Lauren B. Alloy 《Journal of youth and adolescence》2018,47(10):2129-2142
Hopelessness is implicated in multiple psychological disorders. Little is known, however, about the trajectory of hopelessness during adolescence or how emergent future orientation may influence its trajectory. Parallel process latent growth curve modelling tested whether (i) trajectories of future orientation and hopelessness and (ii) within-individual change in future orientation and hopelessness were related. The study was comprised of 472 adolescents [52% female, 47% Caucasian, 47% received free lunch] recruited at ages 12–13 who completed measures of future orientation and hopelessness at five annual assessments. The results indicate that a general decline in hopelessness across adolescence occurs quicker for those experiencing faster development of future orientation, when controlling for age, sex, low socio-economic status in addition to stressful life events in childhood and adolescence. Stressful childhood life events were associated with worse future orientation at baseline and negative life events experienced during adolescence were associated with both an increase in the trajectory of hopelessness as well as a decrease in the trajectory of future orientation. This study provides compelling evidence that the development of future orientation during adolescence is associated with a faster decline in hopelessness. 相似文献
947.
Nicole M. Schmidt Marvin D. Krohn Theresa L. Osypuk 《Journal of youth and adolescence》2018,47(10):2009-2026
Residential mobility is one documented stressor contributing to higher delinquency and worse educational outcomes. Sensitive period life course models suggest that certain developmental stages make individuals more susceptible to the effects of an exposure, like residential mobility, on outcomes. However, most prior research is observational, and has not examined heterogeneity across age or gender that may inform sensitive periods, even though it may have important implications for the etiology of adolescent development. Moreover, there are important translational implications for identifying the groups most vulnerable to residential mobility to inform how to buffer adverse effects of moving. In this study, low-income families were randomized to residential mobility out of public housing into lower poverty neighborhoods using a rental subsidy voucher (“experimental voucher condition”), and were compared to control families remaining in public housing. The sample was comprised of 2829 youth (51% female; 62% Non-Hispanic Black, 31% Hispanic, 7% other race). At baseline, youth ranged from 5 to 16 years old. This study hypothesized that random assignment to the housing voucher condition would generate harmful effects on delinquency and educational problems, compared to the control group, among boys who were older at baseline. The results confirmed this hypothesis: random assignment to the experimental voucher condition generating residential mobility caused higher delinquency among boys who were 13–16 years old at baseline, compared to same-age, in-place public housing controls. However, residential mobility did not affect delinquency among girls regardless of age, or among boys who were 5–12 years old at baseline. The pattern of results for educational problems was similar but weaker. Families with teenage boys are particularly vulnerable to residential transitions. Incorporating additional supports into housing programs may help low-income, urban families to successfully transition to lower poverty neighborhoods. 相似文献
948.
Jasmine Fardouly Natasha R Magson Carly J Johnco Ella L Oar Ronald M Rapee 《Journal of youth and adolescence》2018,47(7):1456-1468
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
949.
Laura M. Padilla-Walker Sarah M. Coyne Savannah L. Kroff Madison K. Memmott-Elison 《Journal of youth and adolescence》2018,47(2):445-459
The goal of the current study was to examine the protective role that maternal media monitoring might have for adolescents. This was done by considering whether styles of media monitoring either directly reduced media use, or whether they buffered the associations between aggressive media use and adolescents’ prosocial behavior, aggression, and delinquency. Participants were 681 adolescents from two cities in the United States (51% female; 73% white), and their mothers, who provided data at two different time points, 2 years apart (when adolescents were roughly ages 13 and 15). Mixture modeling results revealed that mothers used four different styles of media monitoring made up of combinations of active and restrictive monitoring as well as forms of co-use. Styles that included active monitoring and connective co-use (i.e., engaging in media with the intent to connect with children) were directly associated with less media use, and moderated links between adolescents’ media use and behavioral outcomes concurrently but not longitudinally. The discussion was focused on the strength of considering multiple strategies of media monitoring together, and how this approach can inform future research in the area of parental media monitoring. 相似文献
950.
Christopher Cambron Rick Kosterman Richard F. Catalano Katarina Guttmannova J. David Hawkins 《Journal of youth and adolescence》2018,47(2):369-382
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