首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2133篇
  免费   112篇
各国政治   176篇
工人农民   140篇
世界政治   242篇
外交国际关系   147篇
法律   1112篇
中国政治   6篇
政治理论   408篇
综合类   14篇
  2023年   26篇
  2022年   17篇
  2021年   38篇
  2020年   72篇
  2019年   93篇
  2018年   126篇
  2017年   146篇
  2016年   138篇
  2015年   90篇
  2014年   122篇
  2013年   372篇
  2012年   107篇
  2011年   90篇
  2010年   55篇
  2009年   46篇
  2008年   74篇
  2007年   86篇
  2006年   62篇
  2005年   49篇
  2004年   67篇
  2003年   44篇
  2002年   31篇
  2001年   35篇
  2000年   36篇
  1999年   24篇
  1998年   18篇
  1997年   10篇
  1996年   8篇
  1995年   13篇
  1994年   8篇
  1993年   10篇
  1992年   9篇
  1991年   9篇
  1990年   9篇
  1989年   5篇
  1988年   4篇
  1987年   7篇
  1986年   6篇
  1985年   5篇
  1984年   8篇
  1979年   4篇
  1974年   7篇
  1973年   5篇
  1972年   7篇
  1970年   5篇
  1967年   4篇
  1966年   4篇
  1965年   4篇
  1958年   3篇
  1957年   3篇
排序方式: 共有2245条查询结果,搜索用时 15 毫秒
911.
912.
A custom-built ion mobility spectrometer has been used to obtain the IMS spectra of cocaine, heroin, amphetamine sulfate and LSD at different drug concentrations and desorption temperatures. Practical detection limits for these four drugs were obtained as a function of desorber temperature and for heroin as a function of analysis time. Spectral and ionization interferences for each of the four drugs of interest were determined. Spectral interferences by innocuous materials are few; ionization interferences occur only at very high ratios of the mass of innocuous material to that of the drug of interest.  相似文献   
913.
914.
915.
916.
In this article the authors present some preliminary findings from a comparative study of police recorded violent crimes in Stockholm and Basel. They present the first results from a comparative analysis of the situational context, the ecology of crime, and of offender residences in these cities. There is impressive evidence of basic similarities in the situational context of violent crime and the residential distribution of violent offenders. Yet there are also significant differences, some of which may have interesting implications for crime prevention. Firstly, violent crime seems to be more highly concentrated during weekend nights in Stockholm than in Basel. Secondly, they find evidence that the presence of weapons in a community increases the risk of more serious outcomes of violent events. Efforts to reduce the availability of weapons may thus have significant effects on the outcomes of violence, but not necessarily on its frequency. Thirdly, they show that offenders in both cities are highly concentrated in socially disorganised communities with few economic and social resources.  相似文献   
917.
This study concerns the determination of morphine concentrations in fly larvae reared on rabbits administered different concentrations of morphine and a correlation between concentrations of the drug in larvae and tissues. Three rabbits (R1, R2 and R3) were given dosages of 12.5, 25.0 and 50.0 mg/h of morphine over a 3 h period via continuous ear artery perfusion. These dosages and time of perfusion were calculated to create tissue concentrations of morphine similar to those encountered in human death due to overdose. Morphine blood level plateau was attained after 1 h of perfusion. A fourth rabbit was used as a control. To evaluate drug concentrations, tissues were sampled using a coelioscopic technique. Approximately 400 eggs of Lucilia sericata, all of the same age category, were placed in eyes, nostrils and mouth of each rabbit carcass. Larvae and puparia were regularly collected from each rabbit for toxicological analysis. The concentrations of the drug in the tissues sampled were determined to be similar to those normally encountered in human overdoses and were correlated with the dosage of morphine that had been administered. Morphine was detected in all larvae and pupae fed on tissues from carcasses administered morphine, except for puparia from the colony fed on the R1 animal which received 12.5 mg/h dosage of morphine. All samples from the control rabbit were negative for morphine. Concentrations of morphine in larvae reared on rabbit carcasses containing morphine were 30 to 100 times lower than the concentrations found in the tissues. A correlation between the tissue concentrations and larval concentrations was found in only 3rd instar larvae (80 to 140 h following hatching). No correlations were found between administered dosages, tissue concentrations and younger larvae, prepuparial larvae or puparia.  相似文献   
918.
Is local politics local? French evidence   总被引:2,自引:0,他引:2  
Abstract. In advanced democracies, are local political decisions determined by local events? Or are they really shaped by national forces? For the United States case, the evidence on this question is mixed. For the French case, the focus here, the evidence is also mixed, but less hard. In fact, for cantonal elections, in many ways archtypical local affairs, relevant systematic findings are virtually absent. We ask whether the cantonal elections of the Fifth Republic can be better understood as national, rather than local, contests. Our analysis leads us to the conclusion that the basic answer is, ‘yes’. There appear several theoretical reasons for this, which we give an account of. Further, we go on to show that cantonal races can actually serve as barometers to forecast upcoming national races.  相似文献   
919.
920.
Journal of Chinese Political Science - It is no secret that EU member states cannot come to terms on a unified China-policy. Most studies on EU-China relations come to the conclusion that...  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号