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61.
62.
This article looks at the use of institutionalized public–private partnership (PPP) arrangements by local governments for the delivery of different types of infrastructure. It starts by analyzing the mixed company model from a theoretical point of view, in particular the potential for internal regulation and the achievement of a relational agreement. Then, after discussing the practicalities of crafting this type of governance structure, four Portuguese case studies are examined. The empirical evidence on mixed companies operating in the water, waste, transportation, and education sectors shows that the extreme complexity involved in the whole life‐cycle management of these companies usually leads to a poor protection of the public interest.  相似文献   
63.
Abstract

It is clear that attempts to discern consumer attitudes toward neighborhood form yield only ambiguity. Denser, more walkable residential environments are impossible to define in a universally applicable manner because of the unique characteristics of an individual neighborhood and its relationship to a region's climate, tradition, and heritage. Consumer preferences are likewise ambiguous and contradictory; this is simply due to many Americans’ lack of personal familiarity with compact, walkable neighborhoods.  相似文献   
64.
为研究铅、镉联合对新生大鼠大脑皮质神经细胞的脂质过氧化损伤及N-乙酰半胱氨酸(N-ace-tylcysteine,NAC)的保护效应,以体外培养的新生大鼠原代大脑皮质神经细胞为试验对象,分17个组进行了不同铅、镉浓度的染毒和保护试验,染毒时间为12 h.经超声波粉碎细胞后,测定神经细胞超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)、乙酰胆碱酯酶(TChE)活性和丙二醛(MDA)含量.结果表明,与对照组比较,铅、镉单独染毒组GSH-Px、SOD和TChE活性随染毒越量的增加呈逐渐下降趋势(P<0.05),而CAT活性及MDA含量则呈升高趋势(P<0.05),两者之间具有明显的剂量一效应关系;铅、镉联合染毒对神经细胞GSH-Px、SOD、TChE、CAT活性和MDA含量的改变均较相应的铅、镉单独染毒更为明显,部分组间有显著差异(P<0.05);NAC保护组的MDA含量显著低于相应的染毒组(P<0.05),SOD、GSH-Px、TChE和CAT活性不同程度地高于相应的染毒组,但部分组间差异不显著(P>0.05).铅、镉联合对新生大鼠大脑皮质神经细胞的氧化损伤表现协同毒性效应,NAC可以提高神经细胞的抗氧化能力,对铅、镉及其联合暴露所致的脂质过氧化损伤有一定的保护作用,但保护作用不明显.  相似文献   
65.
在传统公共行政学的组织理论中,一个基本的理论前提就是假设人类的行为是理性的,因而对组织的研究总是局限于研究基于人类理性所产生的规范和制度.而自从弗洛伊德创立精神分析方法以来,很多的学者开始运用这一方法来解释组织的行为,创立了精神分析的组织理论.其中,戴蒙德就是著名的代表.精神分析方法在组织理论研究中的运用,拓宽了公共行政研究的视野和思路.但同时也把组织理论从传统发展到了另一个极端,那就是过于强调人类行为的非理性,使得对组织的研究易于陷入不可知的状态。可见,精神分析方法对于公共行政学是有意义的。  相似文献   
66.
One of the tasks of a forensic anthropologist is to sort human bone fragments from other materials, which can be difficult when dealing with highly fragmented and taphonomically modified material. The purpose of this research is to develop a method using handheld X‐ray fluorescence (HHXRF) spectrometry to distinguish human and nonhuman bone/teeth from nonbone materials of similar chemical composition using multivariate statistical analyses. The sample materials were derived primarily from previous studies: human bone and teeth, nonhuman bone, nonbiological materials, nonbone biological materials, and taphonomically modified materials. The testing included two phases, testing both the reliability of the instrument and the accuracy of the technique. The results indicate that osseous and dental tissue can be distinguished from nonbone material of similar chemical composition with a high degree of accuracy (94%). While it was not possible to discriminate rock apatite and synthetic hydroxyapatite from bone/teeth, this technique successfully discriminated ivory and octocoral.  相似文献   
67.
68.
Alcohol consumption is widely believed to influence criminal activity, and numerous sociological, criminological, and psychological studies demonstrate an apparent positive correlation between drinking and crime. Using a multiattribute model of offender and victim behavior, this study examines the theoretical effects of changes in the price of alcohol on the incidence of crimes committed for economic gain. It is shown that in the general case price effects do not result in an unambiguous decrease in the rates of crime or victimization even when the models are constructed to impose a bias towards the finding of a causal negative price effect. Using a modified model of the drinking offender that imposes even further structure on the model, it is shown that the realization and magnitude of a negative equilibrium alcohol price effect will likely depend upon the implementation of complementary alcohol control policies. The implications of the theoretical analysis to policy implementation and empirical research are also considered.  相似文献   
69.

Purpose

Much of the research on peer influence has examined the relationship between peer associations and delinquency. Relatively little empirical research has addressed the effects of delinquent behavior on peer intimacy and time spent with peers. Our research attempts to fill these gaps in the literature as we hypothesize that, net of peer delinquency, delinquents spend more time with their peers but are less closely attached to their peers.

Methods

Using data from two waves of the National Youth Survey (NYS), we present two sets of regression models to account for selection bias resulting from whether respondents reported having friends. To assess the stability of our findings, we supplement our presented findings with extensive use of alternate estimation strategies.

Results

Conclusions regarding our hypotheses do not vary by estimation strategy. Delinquents spend more time with their peers, but delinquents and non-delinquents do not report differences in closeness to their peers.

Conclusions

Given our control variables, our finding introduces complexity in the causal priority between time spent with peers and delinquency. Prior delinquency may be a predictor of more time with peers, but partly as an avenue for opportunities for crime, not for the sake of friendship.  相似文献   
70.
Inkjet ink analysis is the best way to discriminate between printed documents, or even though more difficult, to connect an inkjet printed document with a brand or model of printers. Raman spectroscopy and laser desorption mass spectrometry (LDMS) have been demonstrated as powerful tools for dyes and pigments analysis, which are ink components. The aim of this work is to evaluate the aforementioned techniques for inkjet inks analysis in terms of discriminating power, information quality, and nondestructive capability. So, we investigated 10 different inkjet ink cartridges (primary colors and black), 7 from the HP manufacturer and one each from Epson, Canon and Lexmark. This paper demonstrates the capabilities of three methods: Raman spectroscopy, LDMS and MALDI-MS. Raman spectroscopy, as it is preferable to try the nondestructive approach first, is successfully adapted to the analysis of color printed documents in most cases. For analysis of color inkjet inks by LDMS, we show that a MALDI matrix (9-aminoacridine, 9AA) is needed to desorb and to ionize dyes from most inkjet inks (except Epson inks). Therefore, a method was developed to apply the 9AA MALDI matrix directly onto the piece of paper while avoiding analyte spreading. The obtained mass spectra are very discriminating and lead to information about ink additives and paper compositions. Discrimination of black inkjet printed documents is more difficult because of the common use of carbon black as the principal pigment. We show for the first time the possibility to discriminate between two black-printed documents coming from different, as well as from the same, manufacturers. Mass spectra recorded from black inks in positive ion mode LDMS detect polyethylene glycol polymers which have characteristic mass distributions and end groups. Moreover, software has been developed for rapid and objective comparison of the low mass range of these positive mode LDMS spectra which have characteristic unknown peaks.  相似文献   
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