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   23074篇
  免费   1282篇
各国政治   895篇
工人农民   1000篇
世界政治   1562篇
外交国际关系   727篇
法律   15888篇
中国共产党   2篇
中国政治   143篇
政治理论   4013篇
综合类   126篇
  2021年   115篇
  2020年   480篇
  2019年   521篇
  2018年   660篇
  2017年   700篇
  2016年   786篇
  2015年   576篇
  2014年   647篇
  2013年   2338篇
  2012年   608篇
  2011年   654篇
  2010年   652篇
  2009年   672篇
  2008年   655篇
  2007年   676篇
  2006年   689篇
  2005年   561篇
  2004年   575篇
  2003年   521篇
  2002年   535篇
  2001年   890篇
  2000年   808篇
  1999年   645篇
  1998年   309篇
  1997年   231篇
  1996年   263篇
  1995年   246篇
  1994年   231篇
  1993年   230篇
  1992年   426篇
  1991年   433篇
  1990年   402篇
  1989年   401篇
  1988年   415篇
  1987年   383篇
  1986年   430篇
  1985年   432篇
  1984年   341篇
  1983年   339篇
  1982年   258篇
  1981年   234篇
  1980年   200篇
  1979年   294篇
  1978年   176篇
  1977年   146篇
  1976年   125篇
  1975年   130篇
  1974年   176篇
  1973年   134篇
  1971年   111篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
The possible contribution of poppy seed foods to positive opiate urinalysis results, especially from foods available in the Pacific Rim area, has recently become an issue for the U.S. Army Forensic Toxicology Drug Testing Laboratory in Hawaii. To assess the likelihood of this possible contribution, seven different poppy seed food products were consumed by male and female volunteers, and urine specimens were collected at time increments up to either 24 or 72 h. Specimens were evaluated for opiates using Roche Abuscreen radioimmunoassay (RIA), and all RIA positive specimens were analyzed for morphine and codeine using gas chromatography/mass spectrometry (GC-MS). Poppy seed cake, bagels, muffins, and rolls did not contain sufficient quantities of poppy seeds to give rise to opiate positive specimens by U.S. Department of Defense (DOD) GC-MS cutoff levels (morphine = 4000 ng/mL, codeine = 2000 ng/mL), although a number of specimens were positive by National Institute on Drug Abuse (NIDA) cutoff levels (morphine and codeine = 300 ng/mL). However, ingestion of poppy seed streusel or Danish pastry led to confirmed morphine and codeine positive specimens, irrespective of the use of DOD or NIDA confirmation cutoff values. In addition, significant amounts of codeine were observed in a number of these specimens. These findings argue against the unqualified application of previously published quantitative guidelines for eliminating poppy seed ingestion as a possible cause for a positive opiate urinalysis result.  相似文献   
52.
The main aim of this paper is to advance knowledge and (especially) theories about developmental and life‐course criminology (DLC). First, I review the widely accepted DLC findings that all DLC theories have been designed to explain. Second, I review more contentious and unresolved empirical DLC issues that might present challenges to DLC theories. Third, I describe my own DLC theory and specify how it addresses key empirical and theoretical questions. Fourth, I summarize five important DLC theories, by Catalano and Hawkins, Sampson and Laub, Moffitt, LeBlanc, and Thornberry and Krohn. Fifth, I identify differences in assumptions and predictions between my theory and the other five theories. Finally, I recommend a detailed comparison of the key features of all DLC theories, of their answers to key empirical and theoretical questions, and of their predictions regarding key unresolved empirical DLC issues.  相似文献   
53.
54.
55.
Offender assessment and classification is becoming an increasingly important part of correctional supervision and intervention. Over the last several decades, several different methods and “generations” of offender classification have emerged. Of most value appear to be third-generation, actuarial, dynamic risk/need assessments. With any new correctional strategy, however, there is a need to investigate the use of these risk/need assessments on offender subgroups in order to inform issues, such as reliability and prevalence of criminogenic risk factors. The present study utilized data that were gathered using the Level of Service Inventory-Revised (LSI-R). Results and comparisons of these assessments were investigated and presented for Native American and non-Native American offenders as well as male and female offenders. Discussion of the results, implications, and recommendations for further research are presented.  相似文献   
56.
Esophageal and tracheal fistulas, which occur in 0.05% of medicolegal autopsies, were demonstrated in three cases by a postmortem radiographic technique using silicone rubber/lead oxide as a contrasting medium that vulcanizes at room temperature. In one 83-year-old male, a tracheoesophageal fistula was detected, which had developed after surgical repair of an esophageal rupture caused by a flexible fiberoptic endoscope. In a second case, carcinoma of the esophagus in a 78-year-old male had eroded the trachea and arcus of the aorta creating a fatal tracheoesophagoaortic fistula. In a third case, 55-year-old female developed a tracheobrachicephalic artery fistula as a result of an infiltrating cystic adenocarcinoma of the trachea, resulting in a fatal hemorrhage into the trachea. The results of this study indicate that diagnostic radiologic methods using a vulcanized contrasting medium are useful in supplementing normal dissection in autopsy cases with suspected fistulas of the esophagus or trachea.  相似文献   
57.
58.
59.
Cubitt  Robin P. 《Public Choice》1997,93(1-2):165-178
Economics Research Centre, School of Economic and Social Studies, University of East Anglia, Norwich NR4 7TJ, U.K. The paper investigates the claim of Gylfason and Lindbeck (Public Choice, 1994) that a stagflationary bias arises from the interaction between monetary policymaking and wagesetting if, among other things, the government and unions share a concern for inflation. It uses a game theoretic model of this interaction, in which the government plays an economy-wide union. Though simple, this nests several other models as special cases. In that corresponding to Gylfason and Lindbeck's model, the factors which they identify are shown to be sufficient for stagflationary bias, in a specified sense. However, for the union to care about inflation is not a necessary condition. The main result of the paper concerns the more general model. It establishes a set of necessary and sufficient conditions for stagflationary bias, as previously defined. These conditions do not include a shared concern for inflation. The paper comments briefly on the significance of this result for stagflation and economic modelling.  相似文献   
60.
A minisatellite probe, MZ 1.3, detecting hypervariable fragment patterns was isolated from a human genomic library. A repetitive sequence of 27 bp length was identified which is contained in the probe approx. 40 times. The MZ 1.3 repeat shows variable homology of 53-73% to the repetitive sequence of the protein III gene of the bacteriophage M13 genome. Polymorphic restriction fragment patterns were found with MZ 1.3 using the enzymes Hinf I, BstN I, Hae III, Mbo I, PstI/Pvu II, and Rsa I. An average of 18 polymorphic fragments was observed using Hinf I as enzyme. The band sharing frequency after Hinf I digestion among unrelated individuals was determined to be 23.8 +/- 7.2%. An example for the application of MZ 1.3 to paternity testing in an incest case is given. The probe can be used with radioactive or non-radioactive detection systems. An approach is presented to compare polymorphic fragment patterns from individuals obtained by independent gel runs on the basis of relative band positions (RBP) and calculated in a computerized analysis.  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