全文获取类型
收费全文 | 68330篇 |
免费 | 2995篇 |
专业分类
各国政治 | 4456篇 |
工人农民 | 2841篇 |
世界政治 | 6122篇 |
外交国际关系 | 3780篇 |
法律 | 31799篇 |
中国共产党 | 9篇 |
中国政治 | 752篇 |
政治理论 | 20625篇 |
综合类 | 941篇 |
出版年
2021年 | 403篇 |
2020年 | 1154篇 |
2019年 | 1509篇 |
2018年 | 1656篇 |
2017年 | 1950篇 |
2016年 | 2151篇 |
2015年 | 1819篇 |
2014年 | 2094篇 |
2013年 | 10468篇 |
2012年 | 1589篇 |
2011年 | 1701篇 |
2010年 | 1807篇 |
2009年 | 2047篇 |
2008年 | 1710篇 |
2007年 | 1690篇 |
2006年 | 1874篇 |
2005年 | 1763篇 |
2004年 | 1656篇 |
2003年 | 1450篇 |
2002年 | 1509篇 |
2001年 | 1627篇 |
2000年 | 1365篇 |
1999年 | 1239篇 |
1998年 | 1107篇 |
1997年 | 984篇 |
1996年 | 952篇 |
1995年 | 918篇 |
1994年 | 921篇 |
1993年 | 946篇 |
1992年 | 980篇 |
1991年 | 1014篇 |
1990年 | 953篇 |
1989年 | 974篇 |
1988年 | 962篇 |
1987年 | 980篇 |
1986年 | 965篇 |
1985年 | 1030篇 |
1984年 | 947篇 |
1983年 | 983篇 |
1982年 | 885篇 |
1981年 | 835篇 |
1980年 | 658篇 |
1979年 | 704篇 |
1978年 | 590篇 |
1977年 | 527篇 |
1976年 | 490篇 |
1975年 | 407篇 |
1974年 | 413篇 |
1973年 | 416篇 |
1972年 | 361篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
371.
The primary aim of this paper is to review the literature on preadolescent friendships in order to examine the relationship between preadolescent friendships and social support in adulthood. Social supports are important to health, both directly and as a stress buffer. Few studies, however, have specifically examined adult social supports from the perspective of their developmental precursors and critical developmental periods. Some data indicate that the preadolescent period may be of particular importance to the development of adult social skills and ties. Observational and empirical studies of preadolescent peer relationships, and in particular best friendships, suggest unique and critical contributions to adult social relatedness. Present research is suggestive but is insufficient to validate preadolescence as a critical period in adult social relatedness. Our review has implications for better understanding the mechanisms by which preadolescent friendships effect adult social support—an important mediator of the effects of stress on health. Further longitudinal study is needed.Received Ph.D. from University of Maryland. Research interests are social supports and psychological responses to trauma and disaster.Received M.D. from Yale University. Research interests are social supports and traumatic stress. 相似文献
372.
We tested competing hypotheses derived from Gottfredson and Hirschis (1990) general theory and Moffitt's (1993a) developmental theory of antisocial behavior. The developmental theory argues that different factors give rise to antisocial behavior at different points in the life course. In contrast, the general theory maintains that the factor underlying antisocial behavior (i.e., criminal propensity) is the same at all ages. To test these competing predictions, we used longitudinal data spanning from age 5 to age 18 for the male subjects in the Dunedin Multidisciplinary Health and Development Study. Using reports from three sources (parents, teachers, and the boys themselves), we estimated second-order confirmatory factor models of antisocial behavior. These models provided consistent support for the developmental theory, showing that separate latent factors underlie childhood and adolescent antisocial behavior. Moreover, we found that these childhood and adolescent factors related in ways predicted by Moffitt's developmental theory to four correlates of antisocial behavior: Childhood antisocial behavior was related more strongly than adolescent antisocial behavior to low verbal ability, by per activity, and negative/impulsive personality, whereas adolescent antisocial behavior was related more strongly than childhood antisocial behavior to peer delinquency. The two underlying latent factors also showed the predicted differential relations to later criminal convictions: Childhood antisocial behavior was significantly more strongly associated with convictions for violence, while adolescent antisocial behavior was significantly more strongly associated with convictions for nonviolent offenses. 相似文献
373.
374.
This study examines the unfair trade decisions of the InternationalTrade Commission (ITC) and how they have been affected by Congress.It begins by identifying the means Congress can use to influenceITC decisions and then estimates both the extent to which thesemeans have been used and the extent to which they have shaped theITC's behavior. The study reaches two conclusions. First, Congresshas tried to shape the ITC's behavior, but it has not tried tomicromanage this behavior. Second, while the ITC's behavior hasbeen influenced by Congress, congressional influence is not asimportant as other factors, such as statutory criteria. 相似文献
375.
This methodological paper presents the utility of survival analysis methods to provide age adjustment in the analysis of domestic violence data. These methods improve the estimation of lifetime probability of domestic violence, improve identification of patterns of first victimization over the lifespan, and provide methods of testing risk factors for first victimization while adjusting for the respondents' age. Most importantly, these methods allow a new investigation of recall bias. Results suggest that lifetime probability of abuse may have been substantially underestimated in previous studies because of problems in recall/disclosure encountered by middle-aged women. 相似文献
376.
Presented in this paper are the initial results involving the use of the nose or outer ear as temperature measurement sites to determine the postmortem period of the human corpse. Simple mathematical models for both sites are developed based on cooling curves of five corpses. Analysis of errors between actual and calculated postmortem intervals suggest that in its present form, the described methods would not be suitable for use in accurately determining the time since death of human corpses. 相似文献
377.
378.
379.
D Callahan 《American journal of law & medicine》1992,18(1-2):1-13
Proposals to ration health care in the United States meet a number of objections, symbolic and literal. Nonetheless, an acceptance of the idea of rationing is a necessary first step toward universal health insurance. It must be understood that universal health care requires an acceptance of rationing, and that such an acceptance must precede enactment of a program, if it is to be economically sound and politically feasible. Commentators have argued that reform of the health care system should come before any effort to ration. On the contrary, rationing and reform cannot be separated. The former is the key to the latter, just as rationing is the key to universal health insurance. 相似文献
380.