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   1712篇
  免费   536篇
各国政治   109篇
工人农民   5篇
世界政治   25篇
外交国际关系   88篇
法律   1455篇
中国共产党   2篇
中国政治   8篇
政治理论   534篇
综合类   22篇
  2024年   1篇
  2023年   4篇
  2022年   4篇
  2021年   49篇
  2020年   63篇
  2019年   167篇
  2018年   141篇
  2017年   128篇
  2016年   155篇
  2015年   139篇
  2014年   136篇
  2013年   301篇
  2012年   207篇
  2011年   146篇
  2010年   94篇
  2009年   61篇
  2008年   107篇
  2007年   91篇
  2006年   97篇
  2005年   24篇
  2004年   23篇
  2003年   33篇
  2002年   17篇
  2001年   15篇
  2000年   11篇
  1999年   11篇
  1998年   5篇
  1997年   1篇
  1996年   2篇
  1995年   1篇
  1989年   2篇
  1986年   3篇
  1985年   3篇
  1984年   2篇
  1983年   1篇
  1982年   2篇
  1981年   1篇
排序方式: 共有2248条查询结果,搜索用时 46 毫秒
31.
The literature on public‐private partnerships (PPP) has proliferated in recent years. However, confusion about the actual meaning of PPP still abounds. As a consequence, contradicting findings and statements about PPP flourish in the literature. This article reviews the literature, and argues that there are different streams of PPP research which operate with qualitatively different notions of the PPP concept. Accordingly the literature is divided into four different PPP ‘approaches’. By doing so the article offers some clarification concerning an increasingly complex concept. The article concludes that an authoritative definition of PPP – one that can encompass all the different variations of the concept currently in use – is not logically possible.  相似文献   
32.
Why are some local governments more successful than others in managing resources and delivering services? And even more vitally, how can malfunctioning governments be reformed so that they perform their responsibilities more effectively? This article contributes to our understanding of theses overarching questions by exploring the interactions between political institutions and public sector performance in the context of decentralisation and local governance. It shows–both theoretically and empirically–that performance outcomes are determined by the extent to which people can hold their governments accountable through political institutions. The basic hypothesis underlying this research is that political accountability, either by encouraging sanctions upon non‐compliant public agents or simply by reducing the informational gap regarding government activities, will create forceful incentives for elected officials and civil servants to reduce opportunistic behaviour and improve performance. Using a cross‐sectional regression the hypothesis is empirically tested against evidence from newly empowered local governments in Indonesia. The empirical findings broadly support our hypotheses. Improved public services on the ground, both in terms of quantity and quality, require informed and well functioning decision‐making processes that allocate resources to priority areas that meet the demand of the broader community. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
33.
It may be difficult to distinguish the cause of death in drowning cases without specific findings. The aim of this study was to explore the forensic value of thoracic postmortem computed tomography (PMCT) using routine images and three-dimensional (3D) image reconstructions. The imaging data of PMCT examinations of six drowning cadavers, aged 21–54 years, were analyzed. Twelve victims of sudden death from coronary artery disease (CAD) were chosen as a control group. After 3D bilateral lung images were reconstructed using image processing software, an interactive medical image control system was used to measure and analyze parameters including lung volume, lung volume ratio, mean CT value of the whole lung, and lung CT value distribution curves. Lung volume and lung volume ratio were used to assess the shape changes of the lung. Lung CT value distribution curves showed the corresponding number of pixels of the different CT values in the lung image. Lung volume was not significantly larger in drowning cases (mean 2 958 cm3) than in controls (mean 2 342 cm3). Lung volume ratio values in the drowning group (mean 0.3156) were greater than those in the control group (mean 0.2763); (P = 0.02). There was no significant difference between the drowning and control group in the mean CT value of the whole lung. There were differences between lung CT value distribution curves in drowning victims and controls, with drowning victims showing a single peak and CAD cases showing a bimodal distribution. Thoracic PMCT is helpful for the forensic medical diagnosis of drowning. Lung volume ratio and lung CT value distribution are potential indicators to distinguish between drowning and CAD.  相似文献   
34.
Virtual anthropology (VA) is based on applying anthropological methods currently used to analyse bones to 3D models of human remains. While great advances have been made in this endeavour in the past decade, several interrogations concerning how reliable these models are and what their proper use should be remain unanswered. In this research, a fundamental assumption of VA has been investigated: if the way we perceive and apply an anthropological method is truly similar when looking at bones macroscopically and through various 3D media. In order to answer, 10 skulls of known age and sex were scanned using a computed tomography (CT) scanner and a 3D surface scanner. Two observers separately applied a defined staging method to eight suture sites on these skulls, first looking at the bone macroscopically, then at the 3D surface scan, and finally on the CT scan. Two rounds of observation were carried out by each observer. Intra- and inter-observer error were evaluated, and two sample t-tests used to evaluate if the different types of medium used yielded significantly different observations. The results show a high degree of inter-observer error, and that data obtained from 3D surface scans differ from macroscopic observation (confidence level 95%, P ≤ 0.05). CT scans, in these settings, yielded results comparable to those obtained through macroscopic observations. These results offer many possibilities for future research, including indications on the kind of anthropological methods and anatomical landmarks that might be reliably transferable to the virtual environment. All current methods used in traditional anthropology should be tested, and if they prove unreliable, new techniques to analyse bones from virtual models should be developed.

Key points

  • Large discrepancies between observation on dry bones and computer-generated 3D models (surface scans or CT scans) could lead to the re-evaluation of the suitability of traditional anthropological methods for application on 3D models.
  • This preliminary study evaluates whether macroscopic, 3D surface scans, and CT scans viewings generate different observations.
  • The results indicate that the data are not always coherent across all three media of observation.
  • Explanations include the aspect given to the bone by the 3D software, differences between handling bones in real life versus on a computer, and level of expertise of the observers.
  相似文献   
35.
This paper examines the reliability of Structure from Motion (SfM) photogrammetry as a tool in the capture of forensic footwear marks. This is applicable to photogrammetry freeware DigTrace but is equally relevant to other SfM solutions. SfM simply requires a digital camera, a scale bar, and a selection of oblique photographs of the trace in question taken at the scene. The output is a digital three-dimensional point cloud of the surface and any plastic trace thereon. The first section of this paper examines the reliability of photogrammetry to capture the same data when repeatedly used on one impression, while the second part assesses the impact of varying cameras. Using cloud to cloud comparisons that measure the distance between two-point clouds, we assess the variability between models. The results highlight how little variability is evident and therefore speak to the accuracy and consistency of such techniques in the capture of three-dimensional traces. Using this method, 3D footwear impressions can, in many substrates, be collected with a repeatability of 97% with any variation between models less than ~0.5 mm.  相似文献   
36.
Trigger pull is the force that needs to be exerted on the trigger to discharge a firearm. The measurement of trigger pull can assist in the evaluation of the safety, function, and manufacturing characteristics associated with a firearm during the forensic firearm examination process. Nonetheless, the accuracy and uncertainty of trigger pull measurements may be affected by the measuring device, test procedure, and environmental conditions. In this work, an innovative finger-trigger interface device was developed to facilitate accurate trigger pull measurements. The idea was to reduce the variation related to the position of the measurement device on the trigger in existing measuring methods and devices. Three force sensors based on different technologies were initially evaluated. While two of the three sensors failed to produce data, the miniature capacitive plate sensor exhibited high precision and a linear response over the range of typical trigger pulls. To examine the effects of the finger-trigger interface on trigger pull measurement, different sensor housing prototypes were designed in silico and 3D printed for the construction of three finger-trigger interface devices. The performance of each finger-trigger interface device was evaluated by measuring the trigger pulls of several selected firearms and comparing the data to a previously published study. Our preliminary results demonstrated the novel finger-trigger interface device offered a new way to measure trigger pull in situ with acceptable accuracy and precision.  相似文献   
37.
This research note presents three newly interconnected and expanded datasets on interest groups’ (IGs) access to the Swiss political decision‐making process: (1) extra‐parliamentary committee seats occupied by IGs (1980, 2000, 2010), (2) parliamentary (committee) seats occupied by IG representatives (1992‐2015), and (3) consultation replies submitted by IGs (2008‐11). We show that the Swiss system of interest intermediation adapted to the multiplication and organizational consolidation of citizen groups, which defend non‐producer interests and do not provide selective benefits to their members (e.g. environmental groups). The share of access granted to citizen groups has increased in both the administration and parliament, across all federal departments and most legislative committees. Moreover, citizen groups benefit from a larger share of access in the recently revitalized parliament, compared to the administration. This suggests that economic groups’ decline in power is also related to the rise of citizen groups.  相似文献   
38.
Involvement in custody cases that include accusations of parental alienation—whether as an evaluator, expert witness, lawyer, judge, therapist, provider of a specialized intervention, or researcher—incurs both professional and personal risks. Some risks relate to false negative or false positive identifications of parental alienation that can lead to regulatory agency complaints and public condemnation by the parent who feels wronged by the case outcome. Other risks stem from providing services in an emerging area of practice and working with children who overtly oppose repairing the relationship with their rejected parent. These risks include: unfounded accusations of mistreating children; negatively biased commentary and sensationalist attacks in the media and in social media, professional conferences and journals, and in courtroom testimony; harassment, vilification, and invasion of privacy; threats of violence and public humiliation; shunning and rumor spreading by colleagues; and complaints to regulatory agencies. This article examines circumstances, beliefs, and dynamics that give rise to these risks, suggests precautions to reduce the risk of false accusations against professionals, and offers recommendations for dealing with regulatory agencies. Criticisms that a court or service provider has mistreated a child merit careful scrutiny in the context of the case evidence and empirical data. While some interventions for alienated children raise legitimate concerns, others have been maligned by anecdotal complaints that studies show do not represent the experience of most participants.  相似文献   
39.
40.
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