全文获取类型
收费全文 | 7118篇 |
免费 | 460篇 |
专业分类
各国政治 | 336篇 |
工人农民 | 222篇 |
世界政治 | 462篇 |
外交国际关系 | 231篇 |
法律 | 5011篇 |
中国政治 | 34篇 |
政治理论 | 1247篇 |
综合类 | 35篇 |
出版年
2020年 | 156篇 |
2019年 | 166篇 |
2018年 | 176篇 |
2017年 | 207篇 |
2016年 | 210篇 |
2015年 | 196篇 |
2014年 | 179篇 |
2013年 | 736篇 |
2012年 | 153篇 |
2011年 | 168篇 |
2010年 | 206篇 |
2009年 | 222篇 |
2008年 | 162篇 |
2007年 | 157篇 |
2006年 | 167篇 |
2005年 | 158篇 |
2004年 | 176篇 |
2003年 | 158篇 |
2002年 | 137篇 |
2001年 | 311篇 |
2000年 | 252篇 |
1999年 | 225篇 |
1998年 | 97篇 |
1997年 | 64篇 |
1996年 | 69篇 |
1995年 | 80篇 |
1994年 | 86篇 |
1993年 | 87篇 |
1992年 | 151篇 |
1991年 | 156篇 |
1990年 | 145篇 |
1989年 | 156篇 |
1988年 | 122篇 |
1987年 | 137篇 |
1986年 | 124篇 |
1985年 | 132篇 |
1984年 | 101篇 |
1983年 | 116篇 |
1982年 | 82篇 |
1981年 | 79篇 |
1980年 | 55篇 |
1979年 | 109篇 |
1978年 | 69篇 |
1977年 | 58篇 |
1976年 | 50篇 |
1975年 | 47篇 |
1974年 | 55篇 |
1973年 | 55篇 |
1972年 | 44篇 |
1968年 | 40篇 |
排序方式: 共有7578条查询结果,搜索用时 15 毫秒
821.
D Resnick F Hellman H Mirchandani D B Goodman 《The American journal of forensic medicine and pathology》1991,12(3):200-203
Serum samples were available from 492 of 1,058 cadavers seen at the Philadelphia Medical Examiner's Office between August 4 and December 15, 1989. These sera were tested for the presence of antibodies to human immunodeficiency virus (HIV) by enzyme-linked immunosorbent assay (ELISA) and Western blot. The overall prevalence of HIV in the autopsy population was 2.24%. The following populations showed increased prevalence as compared to the total sampled population: blacks (3.60%, p less than 0.01), males (2.51%, n.s.), and homicide victims (3.74%, n.s.). Seroprevalence data from this study are compared with those from earlier studies of other related populations, with regard to overall prevalence and risk factor analysis. 相似文献
822.
823.
824.
This paper examines the relationship between race and violent crime by directly modeling the racial gap in homicide offending for large central cities for 1990. We evaluate the role of black‐white differences in aspects of both disadvantage and resources in explaining which places have wider racial disparities in lethal violence. The results show that where residential segregation is higher, and where whites' levels of homeownership, median income, college graduation, and professional workers exceed those for blacks to a greater degree, African Americans have much higher levels of homicide offending than whites. Based on these results, we conclude that the racial homicide gap is better explained by the greater resources that exist among whites than by the higher levels of disadvantage among blacks. 相似文献
825.
Comment on the meaning of 'proof beyond a reasonable doubt' 总被引:1,自引:0,他引:1
826.
827.
Bruce Budowle Leonard T Nhari Tamyra R Moretti Shingirai B Kanoyangwa Eunita Masuka Debra A Defenbaugh Jill B Smerick 《Forensic Science International Supplement Series》1997,90(3):3145
Allele frequencies for six tetrameric short tandem repeat (STR) loci CSF1PO, TPOX, THO1, D3S1358, VWA, and FGA were determined in a Black African sample population from Zimbabwe. All loci are highly polymorphic and meet Hardy-Weinberg expectations. An inter-class correlation test analysis detected only one departure from independence out of 15 pair-wise comparisons of the six loci (i.e., CSF1PO/VWA loci, P=0.026). The allele frequency data at four of the six STR loci in the Black African sample population are similar to African American data. 相似文献
828.
829.
830.