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   1815篇
  免费   83篇
各国政治   135篇
工人农民   55篇
世界政治   224篇
外交国际关系   107篇
法律   793篇
中国政治   5篇
政治理论   565篇
综合类   14篇
  2023年   10篇
  2022年   13篇
  2021年   15篇
  2020年   28篇
  2019年   40篇
  2018年   50篇
  2017年   58篇
  2016年   72篇
  2015年   55篇
  2014年   49篇
  2013年   360篇
  2012年   56篇
  2011年   52篇
  2010年   68篇
  2009年   52篇
  2008年   62篇
  2007年   83篇
  2006年   67篇
  2005年   61篇
  2004年   69篇
  2003年   49篇
  2002年   43篇
  2001年   27篇
  2000年   39篇
  1999年   27篇
  1998年   22篇
  1997年   26篇
  1996年   22篇
  1995年   21篇
  1994年   23篇
  1993年   14篇
  1992年   14篇
  1991年   16篇
  1990年   20篇
  1989年   12篇
  1988年   16篇
  1987年   18篇
  1986年   14篇
  1985年   11篇
  1984年   9篇
  1983年   10篇
  1982年   20篇
  1981年   12篇
  1979年   12篇
  1978年   11篇
  1975年   6篇
  1974年   6篇
  1971年   6篇
  1970年   8篇
  1969年   9篇
排序方式: 共有1898条查询结果,搜索用时 640 毫秒
101.
The effect of improving the environment may be greater inequities in our society. Current environmental programs maintain this inequity, proposed environmental programs may make things worse, and even if we do improve the environment, contentment may decrease. A political coalition of environmental and equity enthusiasts may provide a viable way out of these dilemmas.  相似文献   
102.
103.
In this article we examine how post-industrial Britain and Denmark undertake vocational training for low-skilled retail workers. Specifically, we evaluate whether leaders in training skilled industrial workers are also doing the best job with low-skilled service workers. While Danish retail is increasingly becoming a haven for low-skilled workers, British workers are gaining in skills levels with the transition to services even in the retail sector. While some suggest that social democratic countries have sacrificed the political interests of low-skilled workers in order to protect core manufacturing workers, we find no evidence of this. Rather, the high expectations of vocational training in Denmark have forged barriers to the easy admission of low-skilled service workers, while the British system provides more entry points for vocational training at different levels. The structures of coordination that had narrowed the gap between white-collar and blue-collar manufacturing workers during the industrial age are creating new cleavages in the post-industrial economy.  相似文献   
104.
With few exceptions, prior explanations of racially disparate punishment have followed a dichotomous approach (i.e., African American versus Caucasian), due in part to the limitations of existing data. Researchers have either excluded Latino/a, defendants or treated them as a monolithic group. Consequently, there is not much on Latinos/as, whose experiences with the criminal and juvenile justice systems differ from those of African American and Caucasian. This article expands on current literature by providing a thorough overview of existing literature on Latino/as. It critiques this body of literature and lists ten common methodological flaws that may contribute to findings of equal treatment. Finally, it provides a concise summary of the main subgroups within the umbrella term ‘Latino/a’ to highlight the heterogeneity within this classification.  相似文献   
105.
A rapid and sensitive method using LC-MS/MS triple stage quadrupole for the determination of traces of amphetamine (AP), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA, “ecstasy”), 3,4-methylenedioxyethamphetamine (MDEA), and N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine (MBDB) in hair, blood and urine has been developed and validated. Chromatography was carried out on an Uptisphere ODB C18 5 μm, 2.1 mm × 150 mm column (Interchim, France) with a gradient of acetonitrile and formate 2 mM pH 3.0 buffer. Urine and blood were extracted with Toxitube A® (Varian, France). Segmented scalp hair was treated by incubation 15 min at 80 °C in NaOH 1 M before liquid–liquid extraction with hexane/ethyl acetate (2/1, v/v). The limits of quantification (LOQ) in blood and urine were at 0.1 ng/mL for all analytes. In hair, LOQ was <5 pg/mg for MA, MDMA, MDEA and MBDB, at 14.7 pg/mg for AP and 15.7 pg/mg for MDA. Calibration curves were linear in the range 0.1–50 ng/mL in blood and urine; in the range 5–500 pg/mg for MA, MDMA, MDEA and MBDB, and 20–500 pg/mg for AP and MDA. Inter-day precisions were <13% for all analytes in all matrices. Accuracy was <20% in blood and urine at 1 and 50 ng/mL and <10% in hair at 20 and 250 pg/mg. This method was applied to the determination of MDMA in a forensic case of single administration of ecstasy to a 16-year-old female without her knowledge during a party. She suffered from hyperactivity, sweating and agitation. A first sample of urine was collected a few hours after (T + 12 h) and tested positive to amphetamines by immunoassay by a clinical laboratory. Blood and urine were sampled for forensic purposes at day 8 (D + 8) and scalp hair at day 60 (D + 60). No MDMA was detected in blood, but urine and hair were tested positive, respectively at 0.42 ng/mL and at 22 pg/mg in hair only in the segment corresponding to the period of the offence, while no MDA was detectable. This method allows the detection of MDMA up to 8 days in urine after single intake.  相似文献   
106.
107.
108.
If mobile content is going to be a success, it is important that the content provided to the end users is of high quality and that it creates value for the end users. Therefore, it is important that the content producers can protect their copyrights in order to be able to earn money on the production of high value content. Due to “Everything-over-IP” (i.e. a single Internet Protocol platform for both voice and data traffic) and convergence, including the extension of the media sector to the mobile sector, more distribution channels are made available for content. In this situation, DRM can play an important role as it enables the content producers to better control and bill their content although it is distributed over several different distribution channels and networks.This paper looks at the possibilities of DRM for the development of mobile content markets. It will in detail look at the current legal problems and possibilities that are associated with DRM and mobile content, i.e. the national borders due to national legal systems, the harmonisation at EU level, the problems with copies for personal use, the enabling of control over copyrights and the legal protection of DRM systems. Based on the analysis of the legal situation, the outcomes on the development of mobile content markets are analysed.  相似文献   
109.
110.
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