全文获取类型
收费全文 | 19676篇 |
免费 | 553篇 |
专业分类
各国政治 | 918篇 |
工人农民 | 817篇 |
世界政治 | 1332篇 |
外交国际关系 | 609篇 |
法律 | 12075篇 |
中国共产党 | 3篇 |
中国政治 | 122篇 |
政治理论 | 4179篇 |
综合类 | 174篇 |
出版年
2020年 | 210篇 |
2019年 | 319篇 |
2018年 | 409篇 |
2017年 | 467篇 |
2016年 | 464篇 |
2015年 | 326篇 |
2014年 | 368篇 |
2013年 | 2040篇 |
2012年 | 459篇 |
2011年 | 504篇 |
2010年 | 408篇 |
2009年 | 486篇 |
2008年 | 538篇 |
2007年 | 504篇 |
2006年 | 512篇 |
2005年 | 480篇 |
2004年 | 484篇 |
2003年 | 458篇 |
2002年 | 460篇 |
2001年 | 688篇 |
2000年 | 641篇 |
1999年 | 469篇 |
1998年 | 286篇 |
1997年 | 254篇 |
1996年 | 254篇 |
1995年 | 238篇 |
1994年 | 237篇 |
1993年 | 244篇 |
1992年 | 401篇 |
1991年 | 430篇 |
1990年 | 415篇 |
1989年 | 415篇 |
1988年 | 384篇 |
1987年 | 386篇 |
1986年 | 418篇 |
1985年 | 409篇 |
1984年 | 381篇 |
1983年 | 363篇 |
1982年 | 249篇 |
1981年 | 218篇 |
1980年 | 190篇 |
1979年 | 256篇 |
1978年 | 163篇 |
1977年 | 173篇 |
1976年 | 158篇 |
1975年 | 127篇 |
1974年 | 150篇 |
1973年 | 157篇 |
1972年 | 140篇 |
1969年 | 108篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
42.
43.
The remains of an unidentified female neonate were discovered in a field in central Missouri. Examination revealed bilateral absence of the parietal bones. A search of the literature describing similar defects suggests that the present case represents a unique condition, described here for the first time. 相似文献
44.
45.
46.
Prior studies of recidivism have focused almost exclusively on individual‐level characteristics of offenders and their offenses to explore the correlates of reoffending. Notably absent from these studies are measures reflecting the neighborhood contexts in which individuals live. The current research addresses this shortcoming. Using data on a sample of ex‐offenders in Multnomah County, Oregon (Portland and surrounding area) in conjunction with 2000 census data, we answer two questions. First, which individual‐level factors influence rates of recidivism? Second, to what extent does neighborhood socioeconomic status account for variation in the reoffending behavior of ex‐prisoners that is not explained by their individual‐level characteristics? We find that those who return to disadvantaged neighborhoods recidivate at a greater rate while those who return to resource rich or affluent communities recidivate at a lesser rate, controlling for individual‐level factors. 相似文献
47.
48.
Flipping burgers or flipping pages? Student employment and academic attainment in post-Soviet Latvia
Latvian higher education has undergone a dramatic transition since 1991. This study employs a survey of nearly 1000 social science students studying in 13 different institutions in Latvia to consider the impact of the increase in the number of students who are working while studying. Evidence indicates employment has a strong and significant negative impact on school performance, and the negative impact increases as weekly hours worked increase. This manifests itself through reduced class attendance and reduced time spent in independent study. Finally, we find that the probability of student employment is most significantly affected by the availability of financial aid, gender, ethnicity, and age. 相似文献
49.
50.