全文获取类型
收费全文 | 7500篇 |
免费 | 180篇 |
专业分类
各国政治 | 396篇 |
工人农民 | 196篇 |
世界政治 | 502篇 |
外交国际关系 | 309篇 |
法律 | 4692篇 |
中国共产党 | 1篇 |
中国政治 | 20篇 |
政治理论 | 1469篇 |
综合类 | 95篇 |
出版年
2020年 | 63篇 |
2019年 | 84篇 |
2018年 | 129篇 |
2017年 | 140篇 |
2016年 | 158篇 |
2015年 | 116篇 |
2014年 | 135篇 |
2013年 | 834篇 |
2012年 | 208篇 |
2011年 | 207篇 |
2010年 | 163篇 |
2009年 | 173篇 |
2008年 | 200篇 |
2007年 | 187篇 |
2006年 | 189篇 |
2005年 | 151篇 |
2004年 | 157篇 |
2003年 | 158篇 |
2002年 | 167篇 |
2001年 | 307篇 |
2000年 | 280篇 |
1999年 | 220篇 |
1998年 | 83篇 |
1997年 | 105篇 |
1996年 | 80篇 |
1995年 | 82篇 |
1994年 | 93篇 |
1993年 | 84篇 |
1992年 | 159篇 |
1991年 | 176篇 |
1990年 | 155篇 |
1989年 | 173篇 |
1988年 | 147篇 |
1987年 | 142篇 |
1986年 | 166篇 |
1985年 | 126篇 |
1984年 | 126篇 |
1983年 | 131篇 |
1982年 | 78篇 |
1981年 | 76篇 |
1980年 | 57篇 |
1979年 | 112篇 |
1978年 | 66篇 |
1977年 | 64篇 |
1976年 | 57篇 |
1975年 | 68篇 |
1974年 | 81篇 |
1973年 | 78篇 |
1972年 | 70篇 |
1971年 | 60篇 |
排序方式: 共有7680条查询结果,搜索用时 15 毫秒
881.
882.
883.
884.
885.
886.
887.
888.
Isolation of deoxyribonucleic acid (DNA) from saliva and forensic science samples containing saliva. 总被引:4,自引:0,他引:4
D J Walsh A C Corey R W Cotton L Forman G L Herrin C J Word D D Garner 《Journal of forensic sciences》1992,37(2):387-395
Saliva and saliva-stained materials were examined as potential sources of deoxyribonucleic acid (DNA) for DNA analysis and identity testing. In this paper, the authors demonstrate that DNA was isolated and DNA banding patterns suitable for DNA typing were obtained from fresh saliva and various saliva-stained materials, such as envelopes, buccal swabs, gags, and cigarettes. Furthermore, DNA and DNA banding patterns were obtained from actual forensic evidentiary samples containing mixed saliva/semen stains. The DNA banding patterns obtained from saliva or saliva-stained material were indistinguishable from the patterns obtained from blood or hair from the same individual. Intact DNA was readily isolated and DNA banding patterns were obtained from saliva stored at -20 degrees C and dried saliva stains stored under varying conditions. We conclude that saliva and saliva-stained material can be good sources of DNA for analysis and for DNA typing in certain forensic settings. 相似文献
889.
E I Rogaev E Iu Syrokvasheva M G Pimenov T V Stegnova 《Sudebno-meditsinskaia ekspertiza》1992,35(1):10-14
Blood stains on a knife were identified by DNA genotyposcopy. The statistical validation method has confirmed that the blood stains on material evidence belonged to the victim, the probability of random coincidence being less than 10(-11). The efficacy of using hypervariable locus-specific DNA probes and the possibility of detecting DNA impressions in blood stains stored for more than 3 months have been demonstrated. 相似文献
890.
Charles D. Delorme Jr. David R. Kamerschen Herbert G. Thompson Jr. 《Public Choice》1992,73(4):385-396
This paper tests empirically the Ramsey version of the public-interest theory of regulation by examining the pricing practices in the nuclear power industry, using a 1985 cross-sectional sample of 40 electric utilities. Other researchers have avoided this segment of the industry because of difficulties with nuclear fuel data, or perceived differences in the underlying production function. We show that regulators respond to political influences according to the Stigler-Peltzman version of regulation and that Ramsey pricing cannot be validated, at least for the nuclear segment of the electric power industry. 相似文献