全文获取类型
收费全文 | 3480篇 |
免费 | 62篇 |
专业分类
各国政治 | 99篇 |
工人农民 | 96篇 |
世界政治 | 155篇 |
外交国际关系 | 100篇 |
法律 | 2679篇 |
中国政治 | 18篇 |
政治理论 | 358篇 |
综合类 | 37篇 |
出版年
2020年 | 36篇 |
2019年 | 35篇 |
2018年 | 62篇 |
2017年 | 42篇 |
2016年 | 70篇 |
2015年 | 30篇 |
2014年 | 53篇 |
2013年 | 253篇 |
2012年 | 91篇 |
2011年 | 133篇 |
2010年 | 80篇 |
2009年 | 62篇 |
2008年 | 108篇 |
2007年 | 124篇 |
2006年 | 109篇 |
2005年 | 88篇 |
2004年 | 122篇 |
2003年 | 114篇 |
2002年 | 110篇 |
2001年 | 150篇 |
2000年 | 134篇 |
1999年 | 103篇 |
1998年 | 20篇 |
1995年 | 17篇 |
1993年 | 27篇 |
1992年 | 62篇 |
1991年 | 83篇 |
1990年 | 85篇 |
1989年 | 91篇 |
1988年 | 95篇 |
1987年 | 89篇 |
1986年 | 75篇 |
1985年 | 77篇 |
1984年 | 67篇 |
1983年 | 58篇 |
1982年 | 24篇 |
1981年 | 20篇 |
1979年 | 30篇 |
1978年 | 33篇 |
1977年 | 22篇 |
1976年 | 27篇 |
1975年 | 28篇 |
1974年 | 37篇 |
1973年 | 37篇 |
1972年 | 35篇 |
1971年 | 36篇 |
1970年 | 38篇 |
1969年 | 32篇 |
1968年 | 27篇 |
1967年 | 18篇 |
排序方式: 共有3542条查询结果,搜索用时 15 毫秒
171.
Two cases of sudden, unexpected death resulting from coronary artery dissection have been reported. Since sudden and unexpected death falls within medical examiners' jurisdiction, the systematic autopsy examination of such cases offers an opportunity to evaluate this entity as well as other rare causes of natural death. A review of the literature concerning the subject has been presented. 相似文献
172.
173.
Two intravenous amphetamine abusers had fatal, rapidly progressive cerebral mucormycosis with abscess formation in the presence of absolute lymphopenia. Postmortem examination confirmed the primary nature of the fungal cerebritis, documented by postmortem culture and histology. The clinical and pathologic features of these cases are compared to previously reported occurrences of primary fungal cerebritis (and abscess) among intravenous drug abusers, including cocaine users. Primary fungal cerebritis associated with intravenous abuse of stimulant drugs is discussed as a possible variant of the acquired immunodeficiency syndrome. 相似文献
174.
175.
176.
177.
178.
179.
180.
The authors investigated the dimensions and mechanisms of belonging relevant to motivation and achievement among high school students representing 4 ethnic groups. Using survey data from 9th to 12th grade students (N = 5,494) attending 7 ethnically-diverse high schools, structural equation modeling was employed to explore, independently for each ethnic group, the relationships between students’ perceptions of their belonging (encompassing relationships with teachers and peers, extracurricular involvement, and perceived ethnic-based discrimination), motivation (efficacy beliefs and valuing school activities), and academic success. All 4 measures of belonging were significant for European-American and Latino students. However, friendship nominations were not significant for all groups, suggesting potential variability in perspectives across ethnic groups. The strength of the structural model postulating belonging as a mediator, including statistically significant indirect paths, supported the hypothesis that the belonging construct accounted for much of the relationship between student motivation and success across groups.Beverly Faircloth is a doctoral candidate of the University of North Carolina at Chapel Hill. Her research interests include the developmental and motivational processes that support adolescent school engagement in ethnically diverse settings.Jill Hamm is an Assistant Professor at the University of North Carolina at Chapel Hill. She received her Ph.D. from the University of Wisconsin-Madison in 1996. Her research interests are adolescents’ peer relations in ethnically diverse schools and classrooms. 相似文献