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   8121篇
  免费   199篇
各国政治   442篇
工人农民   238篇
世界政治   531篇
外交国际关系   311篇
法律   5168篇
中国共产党   1篇
中国政治   32篇
政治理论   1504篇
综合类   93篇
  2023年   164篇
  2021年   76篇
  2020年   80篇
  2019年   96篇
  2018年   150篇
  2017年   176篇
  2016年   191篇
  2015年   139篇
  2014年   155篇
  2013年   862篇
  2012年   235篇
  2011年   213篇
  2010年   177篇
  2009年   186篇
  2008年   218篇
  2007年   199篇
  2006年   209篇
  2005年   164篇
  2004年   180篇
  2003年   169篇
  2002年   180篇
  2001年   324篇
  2000年   285篇
  1999年   227篇
  1998年   83篇
  1997年   108篇
  1996年   81篇
  1995年   81篇
  1994年   91篇
  1993年   81篇
  1992年   159篇
  1991年   182篇
  1990年   160篇
  1989年   177篇
  1988年   151篇
  1987年   145篇
  1986年   163篇
  1985年   127篇
  1984年   127篇
  1983年   133篇
  1982年   77篇
  1981年   75篇
  1979年   113篇
  1978年   64篇
  1977年   62篇
  1975年   67篇
  1974年   82篇
  1973年   78篇
  1972年   67篇
  1971年   66篇
排序方式: 共有8320条查询结果,搜索用时 781 毫秒
841.
A gas chromatographic/mass spectrometric (GC/MS) procedure is described for the detection and measurement of delta 9-tetrahydrocannabinol, 11-hydroxy-delta 9-tetrahydrocannabinol, and 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid in blood, or 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid in urine. About 50% of all homicide victims and motor vehicle drivers killed in Bexar County in 1985 were tested for the presence of cannabinoids. Of 130 homicides and 69 drivers tested, blood was analyzed primarily in all but 15 and 3 cases, respectively. In these latter cases, blood analyzed after urine was found to be positive. Of the homicide victims, 44 (34%), and of all drivers, 19 (28%), tested were positive for one or more of the cannabinoids. As a separate group, 16 motorcycle drivers tested had 38% positive as compared with 25% of the other vehicle drivers. Ethyl alcohol was present in 55% of the drivers, and in 63% of the homicide victims. Drugs other than alcohol or cannabinoids were found in 10% of the drivers, and in 12% of the homicide victims.  相似文献   
842.
843.
844.
We identify and elaborate a conceptual distinction between capability for self-control and the desire to exercise it, and employ data from a city survey to explore the empirical viability of such a differentiation. Separate scales measuring ability and desire to exercise self-control both prove to be significant and moderately strong predictors of several measures of criminal/deviant behavior, showing independent, cumulative, and interactive relationships with each other. For some measures of crime/deviance, self-control capability is most effective when the individual's interest in exercising self-control is low but its effect is greatly reduced or eliminated when desire to exercise self-control desire is high. Combinations of capability for self-control and interest in exercising it prove to be particularly good predictors of the absolute level of misbehavior.  相似文献   
845.
846.
847.
Studying dipterans at the scene of a death can provide essential information for interpreting the evidence and help to reconstruct the events happened to a corpse in the past. Molecular tools have been employed for identification at specific levels in the cases of cryptic species or poorly conserved specimens. Identification of specimens is essential in forensic entomology since each species has a specific growth rate, which determines the calculation of the minimum post mortem interval (minPMI). In addition, phylogeographic reconstruction within a species can help to differentiate the haplotypes from a geographic area, thereby helping to clarify the possible relocation of a corpse. The morphological identification of Sarcophagidae species is often difficult, especially for the females. This is an important Diptera family since some of its species are among the first to reach a corpse, especially in warm areas. In this study, we compared the sarcophagids found in human corpses in forensic cases in Alicante (southeast of Spain) with specimens collected from baited traps in the same area and surrounding provinces. In total, 189 specimens were collected, comprising 72 from forensic cases and 117 from baited traps. Molecular identification was conducted by sequencing the cox1 mitochondrial gene and analyzing the sequences using ABGD, GMYC, and BIN species delimitation methods. The median joining algorithm in the PopART program was used to construct phylogeographic networks. Eight species in the family Sarcophagidae were identified. The most widely collected species were Sarcophaga argyrostoma and Sarcophaga tibialis. The haplotype networks obtained for these species did not indicate a clear geographic distribution of haplotypes. The S. argyrostoma samples from Alcoy were clearly isolated. The results demonstrated that this method is useful for identifying Sarcophagidae samples in forensic investigations and it can be employed for minPMI estimation.  相似文献   
848.
Since 2002, the U.S. Office of Personnel Management has used the Federal Employee Viewpoint Survey (FEVS) to monitor efforts by federal executive agencies to manage human capital. Public management researchers have used FEVS data to produce dozens of peer‐reviewed publications on a range of topics of interest to policy makers, practitioners, and academics. Despite the proliferation of these empirical studies, the field of public management until now has lacked a critical assessment of the FEVS and of how researchers have used the data. In this article, the authors discuss the strengths of the FEVS and the opportunities this survey has created for public management researchers. Despite important contributions made to the literature using the data, there are weaknesses in the content, design, and implementation of the FEVS. The authors offer a set of recommendations for refining the survey and its implementation with the aim of improving the quality and value of the data. In doing so, they hope to foster a dialogue between public management researchers and the Office of Personnel Management on the future of the FEVS and to forge a stronger link between these two communities.  相似文献   
849.
850.
Each year, thousands of units are lost from the assisted rental housing inventory through deterioration and default, subsidy expiration, and market-rate conversion. While a good deal of research and data collection has focused on identifying at-risk developments, less is known about what happens to former assisted developments after they exit income and rent restrictions. This article uses a survey of former assisted properties in Florida to identify their postsubsidy trajectories—that is, as to whether developments continue as rental housing, are converted to condominiums, or leave the housing stock through vacancy and demolition; and for those that continue as rental housing, whether they continue to offer affordable rents. Using logistic regression models, the article examines the property, housing market, and neighborhood characteristics that determine these trajectories. The results show that smaller properties, those that have been out of subsidy programs longer, and those in stronger neighborhood housing markets are more likely to be converted to condominiums. Among developments that continue as rental housing, those that previously had more stringent rent restrictions, those in strong rental submarkets, and those with better transit access tend to become unaffordable compared with previous rent limits.  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