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   1326篇
  免费   71篇
各国政治   72篇
工人农民   57篇
世界政治   103篇
外交国际关系   110篇
法律   729篇
中国政治   10篇
政治理论   306篇
综合类   10篇
  2023年   19篇
  2022年   25篇
  2021年   16篇
  2020年   39篇
  2019年   53篇
  2018年   48篇
  2017年   67篇
  2016年   69篇
  2015年   43篇
  2014年   61篇
  2013年   187篇
  2012年   64篇
  2011年   48篇
  2010年   42篇
  2009年   42篇
  2008年   51篇
  2007年   65篇
  2006年   49篇
  2005年   57篇
  2004年   42篇
  2003年   36篇
  2002年   42篇
  2001年   19篇
  2000年   18篇
  1999年   23篇
  1998年   13篇
  1997年   11篇
  1996年   8篇
  1995年   14篇
  1994年   9篇
  1993年   4篇
  1992年   20篇
  1991年   7篇
  1990年   6篇
  1989年   10篇
  1988年   8篇
  1987年   6篇
  1986年   8篇
  1985年   6篇
  1984年   3篇
  1983年   7篇
  1982年   4篇
  1981年   2篇
  1980年   4篇
  1975年   3篇
  1973年   2篇
  1969年   3篇
  1966年   3篇
  1962年   1篇
  1955年   1篇
排序方式: 共有1397条查询结果,搜索用时 15 毫秒
851.
Abstract

This article measured opportunity inequality in Brazil by combining a series of theoretical and empirical tools. The database was built using a two-sample instrumental variable (TSIV), developed by Angrist and Krueger. After that, the axiomatic approach put forward by O'Neill et al. was used, in which the estimation of children's income distribution function is conditional on their fathers' wages. The inference process was based on nonparametric local logistic regression. The results indicate that Brazil has a high level of opportunity inequality. In other words, in the context of intergenerational mobility, those whose fathers belong to lower income strata have to expend greater effort in order to attain a certain income level.  相似文献   
852.
853.
This article presents the results of a systematic review and meta-analysis on the effects of treatment programmes for drug abusing offenders in Europe, using stringent eligibility criteria to control for threats to internal validity. A literature search of approximately 37,000 titles revealed 15 sound evaluations from six countries, containing 3953 participants. There were significant positive overall effects of treatment on crime (d=0.47) and illicit drug use (d=0.38). Most evaluations originated from the UK and evaluated primarily substitution therapy-based treatment. Evaluations of other interventions were a minority. Our findings support the use of treatment programmes among substance-abusing offenders. However, these results are limited to a small set of programmes from very few countries. Therefore, sound evaluations on a range of treatments across Europe are needed.  相似文献   
854.
The analysis of the constituents of fingerprints has been described numerous times, mainly with the purpose of determining the aging effect on fingerprints or showing the differences between donors or groups of donors. In this paper we describe the use of derivatized amino acids to determine the efficacy of the visualization reagents 1,8-diazafluoren-9-one (DFO) and ninhydrin. At present certain conditions are used for the application of these reagents, as determined by trial-and-error investigations, to the effect on fingerprints. The recovery of amino acids from a porous surface can be used as a measure for the efficacy of a visualization agent.In this paper we describe a method for the determination of the amount of amino acid left after reaction with well known fingerprint visualization reagents. This will allow a more scientific approach to method development for fingermark enhancement techniques. Furthermore, investigations on the influence of the concentration of fingermark amino acids, the order of application of and exposure time to reagents and the influence of age of the amino acids were carried out. These studies have resulted in a broader understanding of the mechanism involved in visualization of fingermarks using DFO and ninhydrin.  相似文献   
855.
This work evaluates cocaine purity and the concentration ranges of adulterants and inorganic constituents for 31 street cocaine samples seized in two different regions of Brazil from July 2008 to May 2010. Cocaine and adulterants, such as caffeine, lidocaine and benzocaine, were quantified by Gas chromatography–mass spectrometry (GC–MS), and the inorganic constituents were determined by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) and ion chromatography (IC). The cocaine concentrations in the samples seized in the Amazonas state (AM samples) ranged from 154 to 978 mg g? 1, and these samples did not contain any of the adulterants studied. The cocaine concentrations in the samples seized in the Minas Gerais state (MG samples) ranged from 63.9 to 753 mg g? 1. Caffeine was the main adulterant found in 76% of the MG samples, ranging in concentration from 5.5 to 645.3 mg g? 1. Lidocaine was found in 66.7% of the MG samples, with concentrations ranging from 16.3 to 576.7 mg g? 1. Benzocaine was found in only one MG sample, at a concentration of 84.8 mg g? 1. Fourteen elements were identified by ICP-OES, and a wide variation was observed in the concentrations of Ca, Mg, Na, P, Al, Fe, Mn and Zn. Pearson Product–moment Correlations between the analytes allowed the constituents to be associated with the chemicals used in the manufacturing of cocaine and with some common diluents. The study of the purity of cocaine and the presence and concentration of adulterants and inorganic constituents is important because the latter can have deleterious effects on health.  相似文献   
856.
Private security companies' growing participation in U.S. and international military missions has raised concern about whether the private security industry is subject to sufficient controls. Industry self-regulation is often proposed as part of a multilayered framework of regulations to govern PSCs. But what can self-regulation contribute to regulation of the private security industry? This matters because privatization in the security realm has moved beyond understandings of the proper breakdown of public and private functions concerning the use of force. This article assesses what self-regulation can contribute to the control of this industry and whether the private security industry lends itself to effective self-regulation. It concludes that the private security industry does not exhibit the capacity to adopt and implement effective self-regulation on its own. If self-regulation is to complement state and international regulation, participation in the design and oversight of self-regulation must be broadened beyond private security companies alone.  相似文献   
857.
We studied sexually dimorphic differences in the ilium using geometric morphometric analysis of 10 osteometric landmarks recorded by multislice computed tomography, based on three‐dimensional reconstructions of 188 children (95 boys, 93 girls) of mixed origins living in the area of Toulouse, southern France, and ranging in age from 1 to 18 years. We used geometric morphometrics methodology first to test sexual dimorphism in size (centroid size) and shape (Procrustes residuals) and second to examine patterns of shape change with age (development) and size change with age (growth). On the basis of statistical significance testing, the ilium shape became sexually dimorphic at 11 years of age, although visible shape differences were observed as early as 1 year of age. There was no statistically significant difference in size between sexes. Trajectories of shape (development) and size (growth) differed throughout ontogeny and between sexes.  相似文献   
858.
Dipterous fly larvae (maggots) are frequently collected from a corpse during a criminal investigation. Previous studies showed that DNA analysis of the gastrointestinal contents of maggots might be used to reveal the identity of a victim. However, this approach has not been used to date in legal investigations, and thus its practical usefulness is unknown. A badly burned body was discovered with its face and neck colonized by fly larvae. Given the condition of the body, identification was not possible. Short tandem repeat (STR) typing was performed using the gastrointestinal contents of maggots collected from the victim and was compared to STR profiles obtained from the alleged father. The probability of paternity was 99.685%. Thus, this comparative DNA test enabled the conclusive identification of the remains. This is the first reported case of analysis of human DNA isolated from the gastrointestinal tract of maggots used to identify a victim in a criminal case.  相似文献   
859.
We deal in this article with the relationship between ETA attacks and electoral support for Batasuna, its political wing. We show that the relationship is twofold, since the geographical distribution of electoral support for the terrorists affects the location of ETA attacks, but violence also influences electoral support for the terrorist cause. On the one hand, when ETA chooses a location for its attacks, it takes into account the electoral strength of Batasuna. Our results show that the higher the vote for Batasuna in a municipality, the more likely members of the security forces will be killed there. With regard to the targeting of civilians, the relationship is curvilinear. ETA kills civilians in municipalities that are polarized, where support for Batasuna falls short of being hegemonic. On the other hand, our results also show that ETA attacks have an effect on the size of its support community. When ETA kills members of the security forces, voters punish the Batasuna party electorally. In the case of civilians, it depends on the specifics of the various campaigns. We find that when ETA kills informers and drug-dealers, the vote for Batasuna increases. ETA's killing of non-nationalist politicians, however, decreases Batasuna's vote share.  相似文献   
860.
ABSTRACT

The global distribution of Christians is expected to change by 2050, with the largest proportion of Christians – more than a billion – residing in sub-Saharan Africa. Historical and empirical studies have argued for a positive relationship between the proportion of Christians – Protestants in particular – and the development of liberal democracy. A key explanation for this positive influence is cultural, namely the valuing of the individual. Could the growth in Christianity have the potential to influence democratic development and good governance in the sub-Saharan region? To test our hypotheses – (1) sub-Saharan states with proportionally larger Protestant populations are more likely to have higher levels of democracy and good governance, and (2) sub-Saharan states with growing Protestant populations are more likely to have increasing levels of democracy and good governance – we employ a longitudinal and cross-sectional study (a panel of data) using data from the World Christian Database, Polity IV and the International Country Risk Guide. Our data show that the population share of Protestants is positively related with both levels of and growth in democracy and good governance. With the spread of Protestantism we could expect the future improvement of democracy and governance in the region.  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