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   195篇
  免费   16篇
各国政治   16篇
工人农民   9篇
世界政治   17篇
外交国际关系   11篇
法律   112篇
政治理论   46篇
  2021年   2篇
  2020年   4篇
  2019年   3篇
  2018年   3篇
  2017年   11篇
  2016年   11篇
  2015年   6篇
  2014年   4篇
  2013年   29篇
  2012年   10篇
  2011年   7篇
  2010年   6篇
  2009年   13篇
  2008年   10篇
  2007年   13篇
  2006年   14篇
  2005年   15篇
  2004年   9篇
  2003年   8篇
  2002年   9篇
  2001年   5篇
  2000年   3篇
  1999年   1篇
  1995年   1篇
  1994年   3篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1989年   2篇
  1988年   1篇
  1985年   2篇
  1980年   1篇
  1975年   1篇
  1973年   1篇
排序方式: 共有211条查询结果,搜索用时 281 毫秒
81.
This research examines the utility of patella outline shape for matching 3D scans of patellae to knee radiographs using elliptical Fourier analysis and subjective methods of human visual comparison of patellae across radiographs for identification purposes. Repeat radiographs were captured of cadaver's knees for visual comparison before patellae were extracted and skeletonized for quantitative comparisons. Quantitative methods provided significant narrowing down of the candidate pool to just a few potential matches (<5% of original sample), while the human analysts showed high capacity for correctly matching radiographs, irrespective of educational level (positive predictive value = 99.8%). The successful computerized matching based on a single quantified patella trait (outline shape) helps explain the potency achieved by subjective visual examination. This work adds to a growing body of studies demonstrating the value of single isolated infracranial bones for human identification via radiographic comparison.  相似文献   
82.
83.
Change in perspective between antemortem and postmortem imaging sessions (radiograph to radiograph and surface scan to radiograph) may cause different 2D renderings of the same osseous element complicating comparisons for identification. In this study, clavicle shape changes due to radiographic positioning and 3D laser scanning were examined in 20 right‐side specimens, as pertinent to chest radiograph comparisons. Results indicate substantial changes in clavicle form with short source‐to‐image receptor distance, elevation of the element from the image receptor, and movement of the element away from the center beam (10% mean square for shape). Although quantitative shape differences were small when the clavicle was in close opposition to the image receptor (3% mean square), important qualitative differences remained with large distances from the center beam (e.g., conoid tubercle presence/absence). The significance of these results for image superimposition and computer‐automated‐shape‐based searches of radiographic libraries to find matching candidates is discussed.  相似文献   
84.
Empirical evidence suggests that the propensity to cooperate in common pool resource dilemmas is higher for small, homogeneous groups with efficacious monitoring and sanctioning mechanisms. Given that transition from socialist to market economies is associated with larger, more heterogeneous groups with diluted opportunities for monitoring and sanctioning, individuals in later-stage transition economies may be expected to be less cooperative than their early-stage counterparts. However, evidence from experiments conducted with subjects in two economies at different stages of transition suggests that this may not be the case. These findings have implications for both theorists and practitioners alike.  相似文献   
85.
The overlay of a skull and a face image for identification purposes requires similar subject‐to‐camera distances (SCD) to be used at both photographic sessions so that differences in perspective do not compromise the anatomical comparisons. As the facial photograph is the reference standard, it is crucial to determine its SCD first and apply this value to photography of the skull. So far, such a method for estimating the SCD has been elusive (some say impossible), compromising the technical validity of the superimposition procedure. This paper tests the feasibility of using the palpebral fissure length and a well‐established photographic algorithm to accurately estimate the SCD from the facial photograph. Recordings at known SCD across a 1–10 m range (repeated under two test conditions) demonstrate that the newly formulated method works: a mean SCD estimation error of 7% that translates into <1% perspective distortion error between estimated and actual conditions.  相似文献   
86.
The combination of leniency programmes, high sanctions, complaints from customers and private actions for damages, has proven very successful at uncovering and punishing cartel agreements in United States Antitrust Law. Countless jurisdictions are being encouraged to adopt these ‘conventional’ enforcement tools, in the absence of an international competition authority. This paper identifies three issues which may undermine the universal efficacy of these cartel laws: (i) corruption and organized crime; (ii) social norms that are sympathetic to collusive practices; (iii) collectivist business cultures built on personal relationships.  相似文献   
87.
International Environmental Agreements: Politics, Law and Economics - Major new multilateral environmental agreements (MEAs) have entered into force in 2016, including the Paris Agreement (PA)...  相似文献   
88.
Abstract:  Authentic black-powder muzzle-loader weapons or replicas are used today primarily for re-enactments of historic battles. A lay actor playing the role of a Prussian infantryman sustained life-threatening gunshot injuries during a recent re-enactment of a historic battle of the Sixth Coalition. As only blank historic muzzle-loading weaponry was used, the origin of the missile causing the wounding was initially unclear. Further investigation revealed a ramrod that had been propelled out of the barrel of another gunner's smooth-bore gun as cause of injury. The ramrod was hurled on a trajectory of more than 20 m, breaking the victim's shouldered barrel and hitting the victim resulting in severe abdominal, thoracic, and upper limb injuries. The critical incidents while handling muzzle-loading weaponry leading to premature discharge are elucidated. Furthermore, this report demonstrates how actual diagnostics and subsequent surgical treatment enabled this infantryman to survive an injury to which his comrades-in-arms would have succumbed 200 years ago.  相似文献   
89.
Research and standardisation in nanotechnology: evidence from Germany   总被引:1,自引:0,他引:1  
Nanoscience and nanotechnology are science fields which are growing extremely dynamically. Germany occupies the top position in Europe and is only second to the US worldwide, which can be attributed to growing research promotion by the state. Based on a general conceptual framework on the role of different types of standards in the research process and technology life cycle, we argue that the market success of nanotechnology applications depends very much on the development of corresponding standards, which clarify not only terminology, measurement and testing methods, but also regulate safety and health aspects and specify interfaces. Other countries, European and international standardisation organisations have launched first initiatives rather early. However, Germany was not able to translate its excellent starting position in nanotechnology research into a leading position in standardisation initiatives, which pave the way for future commercialisation of nanotechnology and also the basis for the next generation of research activities. Based on a survey among stakeholders of German nanotechnology research, we are able not only to provide a first empirical validation of our conceptual model on the role of standards in the research process, but also to define the major problems at the interface between research and standardisation, and finally, to recommend possible options for their solution.
Knut BlindEmail:
  相似文献   
90.
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