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   285篇
  免费   15篇
各国政治   19篇
工人农民   12篇
世界政治   35篇
外交国际关系   27篇
法律   158篇
中国政治   4篇
政治理论   43篇
综合类   2篇
  2023年   3篇
  2022年   4篇
  2021年   6篇
  2020年   7篇
  2019年   8篇
  2018年   6篇
  2017年   12篇
  2016年   10篇
  2015年   12篇
  2014年   10篇
  2013年   49篇
  2012年   13篇
  2011年   15篇
  2010年   3篇
  2009年   8篇
  2008年   16篇
  2007年   21篇
  2006年   17篇
  2005年   15篇
  2004年   15篇
  2003年   12篇
  2002年   3篇
  2001年   3篇
  2000年   6篇
  1999年   2篇
  1998年   4篇
  1997年   5篇
  1996年   1篇
  1995年   2篇
  1994年   2篇
  1992年   1篇
  1990年   2篇
  1985年   1篇
  1984年   1篇
  1977年   2篇
  1975年   1篇
  1973年   1篇
  1968年   1篇
排序方式: 共有300条查询结果,搜索用时 15 毫秒
41.
Allele frequencies, together with some parameters of forensic interest were estimated for nine STRs included in the AmpF/STR Profiler kit (CSF1PO, D3S1358, D5S818, D7S820, D13S317, FGA, TH01, TPOX and vWA) in a sample of 215 unrelated individuals from Cartagena (Colombia). For all loci, no significant deviations from Hardy-Weinberg equilibrium were observed. Comparative analysis results between our data and those from other Colombian and African population samples revealed significant differences, except with two Colombian Caribbean Coast sub-regions.  相似文献   
42.
An ethanol-based fixative (FineFIX) has been used, together with rapid microwave-stimulated processing, in postmortem material, resulting in a rapid fixation and processing of the tissues with morphology, histochemical stains, and immunocytochemistry comparable to formalin-fixed material. Furthermore, this alternative fixation gives better DNA recovery in higher amounts if compared with DNA extracted from formalin-fixed tissue, particularly advantageous in forensic pathology.  相似文献   
43.
Fifty shopping bags, commonly encountered in the packaging of drug doses, were characterized by thickness measurements, infrared spectroscopy and differential scanning calorimetry. By these very straightforward and inexpensive techniques, without sample preparation, nearly all the considered samples could be discriminated. Ninety-seven percent of the possible pairs of white, apparently similar dull polymer films were differentiated. The rather large degree of variability existing in grocery bags, even though they are mass produced, was shown, confirming that these items can be useful in tracing the source of illicit drug doses.  相似文献   
44.
This article examines whether the payoff from engaging in innovation‐generating activities is contingent on an organization's level of customer and learning orientation. The authors suggest that innovative activity is associated with higher public service quality when the level of customer and learning orientation within the focal organization is high. They test this hypothesis by drawing on a novel panel data set covering all public nonspecialist hospital organizations in England. Using dynamic panel data estimation techniques, the authors find strong support for a direct relationship between innovative activity and public service quality and for a moderating role of both customer and learning orientation. These findings call for a contingency perspective on public sector innovation and highlight some of the boundary conditions that need to be in place if public service organizations are to benefit fully from their innovative activities.  相似文献   
45.
46.
When writing ink is placed on a substrate, a drying process begins. This process is dependent on the composition of the ink and of the substrate. Lociciro et al. provide an equation that describes the drying process based on models developed by earlier investigators. The work given here develops an equation for the drying process that is based on a different and rather simple model. This model considers the evaporation of a solution in an opened vertical container (e.g., a beaker) and consists of a volatile, non-hygroscopic solvent with a non-volatile solute dissolved in it. Three assumptions are made: (a) the rate of evaporation is proportional to the vapor pressure of the solution and to the solution's exposed surface area, (b) this solution vapor pressure is proportional to the solvent vapor pressure with the proportionality constant being the solvent mole fraction (Raoult's law), and (c) a small fraction of the solvent remains trapped in the solute after evaporation ceases. What results is a differential equation, which, when solved, gives the solvent weight W(t) as an implicit function. What emerges naturally from this treatment is the fact that the function W(t) can have a point of maximum acceleration. Prior to this point the drying process is fast and after this point, the drying process is slow. An approximation to W(t) is taken to be the sum of two exponential functions, one describing the fast drying region and the second describing the subsequent slow drying region. Upon including an additive constant, this approximation turns out to be similar to, but not the same as that provided by Lociciro et al. However, their equivalence is shown and then tested using the two inks examined by Lociciro et al. (the drying of a Bic and a Staedtler blue ballpoint ink). The examples of (solvent+solute) systems ("inks") given here consist of the solvent (2-phenoxyethanol) and a solute such as a dye (crystal violet) or a polymer resin such as synthetic resin SK or polyvinyl butyral. In the case of polymers, the Raoult's law assumption is replaced with one developed by the Flory-Huggins theory of solutions. Saturation and film formation, both of which slow the evaporation rate, are also discussed.  相似文献   
47.
Scholars concur that conditional cash transfer (CCT) programs have a strong proincumbent effect among beneficiaries. Although no study has properly focused on the overall effect of cash transfers on incumbents' national vote shares, most scholars have deduced that this effect is positive; i.e., that cash transfers lead to the expansion of incumbents' electoral bases. This article analyzes survey data from nearly all Latin American countries and confirms that beneficiaries of CCT programs are more likely to support incumbents. However, it also shows that CCT programs may induce many voters who were previously incumbent supporters to vote for the opposition. As a consequence, the overall impact of cash transfers on incumbents' vote shares is indeterminate; it depends on the balance between both patterns of behavioral changes among voters. This study is the first to report evidence that cash transfer programs may have significant anti‐incumbent effects.  相似文献   
48.
Democracy and dictatorship revisited   总被引:2,自引:0,他引:2  
We address the strengths and weaknesses of the main available measures of political regime and extend the dichotomous regime classification first introduced in Alvarez et al. (Stud. Comp. Int. Dev. 31(2):3–36, 1996). This extension focuses on how incumbents are removed from office. We argue that differences across regime measures must be taken seriously and that they should be evaluated in terms of whether they (1) serve to address important research questions, (2) can be interpreted meaningfully, and (3) are reproducible. We argue that existing measures of democracy are not interchangeable and that the choice of measure should be guided by its theoretical and empirical underpinnings. We show that the choice of regime measure matters by replicating studies published in leading journals.  相似文献   
49.
The Mexican Constitution, in the Poder Legislativo, grants state legislatures the authority to introduce legislation (iniciativas de ley) in the federal congress. In this paper the authors examine this powerful mechanism through which the Mexican state legislatures can directly influence policymaking at the federal level. Using a new data set of state-led initiatives, this work: describes the frequency with which iniciativas are introduced; describes the substance, timing, and final disposition of these state-led initiatives; and explains which factors affect the probability of presenting a state-led initiative. The authors find that party competition and partisan divisions at the state and federal levels play a significant role in the use of iniciativas de los congresos estatales. The authors’ study of this peculiar authority granted to the Mexican states contributes to the rich discussion of the changing role of the states in the era of Mexico’s nuevo federalismo.  相似文献   
50.
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