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   2981篇
  免费   48篇
各国政治   145篇
工人农民   65篇
世界政治   183篇
外交国际关系   71篇
法律   2081篇
中国政治   21篇
政治理论   440篇
综合类   23篇
  2020年   31篇
  2019年   24篇
  2018年   27篇
  2017年   34篇
  2016年   48篇
  2015年   25篇
  2014年   49篇
  2013年   236篇
  2012年   68篇
  2011年   74篇
  2010年   42篇
  2009年   39篇
  2008年   66篇
  2007年   81篇
  2006年   75篇
  2005年   80篇
  2004年   81篇
  2003年   75篇
  2002年   78篇
  2001年   167篇
  2000年   129篇
  1999年   83篇
  1998年   36篇
  1997年   29篇
  1995年   23篇
  1994年   29篇
  1993年   29篇
  1992年   72篇
  1991年   78篇
  1990年   69篇
  1989年   95篇
  1988年   94篇
  1987年   77篇
  1986年   84篇
  1985年   69篇
  1984年   42篇
  1983年   47篇
  1982年   28篇
  1981年   41篇
  1979年   36篇
  1978年   23篇
  1977年   37篇
  1976年   23篇
  1975年   35篇
  1974年   33篇
  1973年   34篇
  1972年   37篇
  1971年   28篇
  1969年   26篇
  1968年   25篇
排序方式: 共有3029条查询结果,搜索用时 15 毫秒
931.
932.
Abstract: This article challenges the notion that contemporary conditions are so new that there are no useful lessons to be learned from administrative history. Beginning with the observation that many recent innovations in public organizations were foreshadowed under the United Canadas, 1841–1867, it asks why they were gradually abandoned over the first century of Confederation, only to be revived recently. For reasons of efficiency and democratic governance, the department became the keystone organization of Canadian public administration, and bureaucracy the key decision‐making technology. Changes in economic conditions, technology, élite ideology and political culture led to the introduction of public management as an alternative to bureaucracy. Neither form has met all the needs of politicians, public servants and citizens. One lesson of the past is that other values, like representativeness, will assert themselves with the result that the system will continue to evolve. Sommaire: Cet article conteste la notion voulant que les conditions contemporaines sont si nouvelles qu'il n'y a pas de leçon utile à chercher dans I'histoire administrative. Partant de I'observation que plusieurs innovations récentes en organisation publique avaient leur pendant sous les Canadas Unis, 1841–1867, I'article cherche à comprendre pourquoi celles‐ci furent graduellement abandonnées pendant le premier siècle de la Confédération puis redécouvertes récemment. Pour des raisons d'efficience et de gouveme démocratique, le ministère devint I'organisation de préférence au sein de I'administration publique canadienne, tandis que la bureaucratie devint le mode décisionnel préféré. Des changements aux conditions économiques, à la technologie, à I'idélogie des élites et à la culture politique ont menéà I'introdudion du management public comme alternative à la bureaucratie. Aucun de ces changements n'a satisfait tous les besoins des politiciens, des fonctionnaires et des citoyens. Le passé suggère que d'autres valeurs, telle la représentativité, vont s'imposer, poussant le système àévoluer encore.  相似文献   
933.
Three commercially available integrated rapid DNA instruments were tested as a part of a rapid DNA maturity assessment in July of 2018. The assessment was conducted with sets of blinded single-source reference samples provided to participants for testing on the individual rapid platforms within their laboratories. The data were returned to the National Institute of Standards and Technology (NIST) for review and analysis. Both FBI-defined automated review (Rapid DNA Analysis) and manual review (Modified Rapid DNA Analysis) of the datasets were conducted to assess the success of genotyping the 20 Combined DNA Index System (CODIS) core STR loci and full profiles generated by the instruments. Genotype results from the multiple platforms, participating laboratories, and STR typing chemistries were combined into a single analysis. The Rapid DNA Analysis resulted in a success rate of 80% for full profiles (85% for the 20 CODIS core loci) with automated analysis. Modified Rapid DNA Analysis resulted in a success rate of 90% for both the CODIS 20 core loci and full profiles (all attempted loci per chemistry). An analysis of the peak height ratios demonstrated that 95% of all heterozygous alleles were above 59% heterozygote balance. For base-pair sizing precision, the precision was below the standard 0.5 bp deviation for both the ANDE 6C System and the RapidHIT 200.  相似文献   
934.
Intraosseous T1-weighted (T1W) and short-tau inversion recovery (STIR) magnetic resonance imaging (MRI) signal intensity changes—so-called bone marrow edema—may be able to differentiate antemortem and postmortem fractures in human forensic imaging. The primary objective of this study was to investigate this hypothesis using an animal model. Three juvenile Landrace pigs were anesthetized and underwent MRI of both tibiae and both radii using a 1.5 T magnet. T1W, T2-weighted (T2W), STIR, and T2* sequences were included. Antemortem fractures were induced in both tibiae and postmortem fractures in both radii, and MRI was repeated. Two board-certified radiologists blinded to fracture group jointly evaluated the images for intraosseous and soft tissue signal intensity changes. Sensitivity (Se) and specificity (Sp) in identifying antemortem fractures were calculated based on intraosseous, soft tissue, and combined intraosseous and soft tissue signal intensity changes. Intraosseous and soft tissue signal intensity changes, when present, were hyperintense in all sequences. Intraosseous hyperintensity in T1W and T2W sequences yielded Sp of 100% for antemortem fractures. Regardless of sequence, soft tissue hyperintensity was comparatively more sensitive than intraosseous hyperintensity. Sensitivity for each sequence could be maximized by assessment of soft tissue and intraosseous hyperintense signals together; for the T1W sequence, such assessment optimized diagnostic utility yielding a Se of 100% and Sp of 83%. In summary, MRI—particularly the T1W sequence—can differentiate antemortem and postmortem fractures and may be a useful adjunct to the forensic analyses of fractures.  相似文献   
935.
We present two cases of elevator-related deaths that occurred in two different elevators, and deaths were caused by a similar, but unusual, mechanism. An elevator is a platform or compartment housed in a shaft for raising and lowering people or things to different levels. Elevator-related deaths and injuries are rarely reported in the literature. In most of these cases, cause of death was attributed to falls. It seems that most of the elevator accidents may be attributed to factors related to device maintenance inadequacies or even to device malfunctioning. In our cases, both elevator cars were not equipped with full-length inner doors, thus allowing both accidents to occur. Since 2014, the European Union adopted a relative directive, which imposes the need to equip all elevators with such full-length doors. The enforcement of the above-mentioned EU Directive is crucial, in order to prevent similar accidents in the future.  相似文献   
936.
Decentralization is argued to enhance citizen–government relationships and, thus, to lead to higher levels of citizen trust. General purpose policing encompasses various services that might be assigned to different levels of governments. The literature lacks generalizable studies of the effects of the structural arrangements of police systems on police performance. This study is a cross‐national exploration of the relationship between the varying degrees of police decentralization and police performance as measured by citizen trust in the police. It uses a measure of decentralization of police systems based on the tiers of government with some control over police. Results show that, in the 72 sample countries, the relationship between citizen trust in police and decentralized police systems is not statistically significant. However, when the countries are categorized by the Human Development Index, decentralized police systems tend to be positively related to citizen trust in the more developed countries but inversely in the less developed countries.  相似文献   
937.
938.
939.
Cocaine in Wayne County Medical Examiner's cases   总被引:1,自引:0,他引:1  
We determined the incidence of detection of cocaine or its metabolites in Wayne County (Michigan) Medical Examiner's cases from 1984 to 1987. Over this four-year period there was a significant (P less than 0.01) increase each year in evidence of recent cocaine use in this population, reaching 38.3% of all tested cases in 1987. Much of this increase was accounted for by homicide victims, especially those in their third or fourth decade of life, of whom 58.6 and 56.3%, respectively, tested positive in 1987. There was a large increase in recent cocaine use in teenage homicide victims in 1987, having previously changed little from 1984 to 1986. In victims of drug abuse, recent cocaine use also increased significantly (p less than 0.01) each year, reaching 47.6% in 1987, generally in combination with heroin. Although deaths attributed solely to cocaine were not as common, they also increased significantly each year from 4 in 1984 to 25 in 1987. Compared with the general population, those who use cocaine in Wayne County are more likely than those who do not to die prematurely, often as a result of violence.  相似文献   
940.
In this article serologic characteristics of monoclonal antibodies with anti-N specificity is given. Antibodies are directed to homologous sequence of N-form of A glycophorine (group-specific N-antigen) and B glycophorine, expressed both on N- and on M-erythrocytes. Higher titre and avidity of monoclonal antibodies with anti-N specificity in relation to erythrocytes with N-phenotype make it possible to detect N-antigen in material subjected to expert evaluation.  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