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   1887篇
  免费   118篇
各国政治   167篇
工人农民   118篇
世界政治   224篇
外交国际关系   140篇
法律   1008篇
中国政治   6篇
政治理论   327篇
综合类   15篇
  2023年   24篇
  2022年   16篇
  2021年   34篇
  2020年   62篇
  2019年   86篇
  2018年   112篇
  2017年   131篇
  2016年   126篇
  2015年   82篇
  2014年   116篇
  2013年   332篇
  2012年   100篇
  2011年   85篇
  2010年   54篇
  2009年   41篇
  2008年   69篇
  2007年   84篇
  2006年   58篇
  2005年   42篇
  2004年   60篇
  2003年   42篇
  2002年   29篇
  2001年   31篇
  2000年   30篇
  1999年   17篇
  1998年   17篇
  1997年   8篇
  1996年   6篇
  1995年   13篇
  1994年   7篇
  1993年   10篇
  1992年   7篇
  1991年   7篇
  1990年   7篇
  1989年   4篇
  1987年   6篇
  1986年   3篇
  1985年   4篇
  1984年   6篇
  1983年   2篇
  1982年   3篇
  1977年   2篇
  1976年   2篇
  1975年   2篇
  1974年   4篇
  1972年   4篇
  1971年   3篇
  1967年   3篇
  1966年   3篇
  1965年   2篇
排序方式: 共有2005条查询结果,搜索用时 15 毫秒
281.
The spontaneous conversion of γ-butyrolactone (GBL) to γ-hydroxybutyric acid (GHB) in seven different Swedish tap waters was investigated. The waters used in the study were selected to represent the diversity among Swedish tap waters as well as possible, which was enabled by principal component analysis (PCA) of a number of water quality parameters. GBL solutions (5, 25 and 50% v/v) were prepared in each of the tap waters and in deionized water and the formation of GHB was followed over time. The GHB quantifications were made using a CZE method, employing a carrier electrolyte consisting of 25mM benzoic acid, 54mM tris(hydroxymethyl)aminomethane (Tris) and 1.7mM tetradecyltrimethylammonium bromide (TTAB), which was developed as a part of the current study. Data evaluation showed that the formation of GHB was largely dependent on the type of tap water. For example, there was a negative correlation between the kinetics of the GHB formation and the alkalinity of the tap waters (r(2)=0.990). This could be explained by a faster decrease in pH in the waters with low buffering capacity (i.e. low alkalinity), which catalysed the hydrolysis of GBL. Equilibrium was reached after 40-250 days depending on the initial GBL concentration and the type of tap water. The level of the equilibrium appeared to be dependent on the initial GBL concentration and ranged from 26 to 37%. Gained knowledge on the levels of the GHB/GBL equilibrium and the kinetics of the formation of GHB in tap water solutions of GBL, including the influence of the tap water quality, may be useful information for casework with the GHB/GBL problem in focus.  相似文献   
282.
Age estimation of living individuals has become one of the big issues of forensic anthropology. The increase of children and adolescents with no valid proof of their chronological age is a legal concern to many countries, especially in situations of illegal immigration, sub adult delinquency and juvenile work. For this purpose, the use of radiological methods for evaluation of skeletal maturation is particularly useful. In this study we compare the two of the most common methods applied in age estimation by hand/wrist radiographs: the Radiographic Atlas of Skeletal Development of the Hand and Wrist made by Greulich and Pyle (GP), 1959,and the Sempé method developed for computer--Maturos 4.0 (MT) program. These methods were applied to a sample of 230 radiographs of the hand and wrist from Portuguese children and adolescents of known sex age and age, aged between 12 and 20 years, who performed medical examination at the University of Coimbra Hospitals during 2005. The methods achieved different performances, depending on the age group. Between 12 and 15 years the bone age with the MT program is closer to the chronological age, whereas in older ages the GP Atlas method is more trustworthy. At the ages with legal consequences in Portugal (16 and 18 years) the GP Atlas method is most accurate, namely to decide whether an individual is younger or older than 18 years. Around 16 years old, although there are doubts in relation to the accuracy of both methods, GP Atlas seems to perform better.  相似文献   
283.
Recent research suggests that attitudes toward police hinge upon the procedures officers use in their interactions with the public. Using survey data collected from a sample of adults arrested and booked into a local jail in Washington County, Arkansas, this paper examines some of the factors that influence arrestees’ satisfaction with police. Results reveal that the most important factor influencing arrestees’ opinions of police was their belief in the benevolence of police actions, followed by their perceptions of the effectiveness of police, whether or not their arresting officer treated them with respect, racial group membership, and total household income. These findings lend support to the “normative” or “process-based” model of policing. The authors discuss the implications of these findings for police and jail administrators.  相似文献   
284.
285.
Renée C. Fox 《Society》2011,48(1):77-77

Society’s Books of Note

Society’s Books of Note November/December 2010  相似文献   
286.
287.
Organised criminality is a great concern for national/international security. The demonstration of complex crimes is increasingly dependant on knowledge distributed within law-enforcement agencies and scientific disciplines. This separation of knowledge creates difficulties in reconstructing and prosecuting such crimes. Basic interdisciplinary research in drug intelligence combined with crime analysis, forensic intelligence, and traditional law enforcement investigation is leading to important advances in crime investigation support. Laboratory results constitute one highly dependable source of information that is both reliable and testable. Their operational use can support investigation and even provide undetected connections or organisation of structure. The foremost difficulties encountered by drug analysts are not principally of a chemical or analytical nature, but methodologies to extract parameters or features that are deemed to be crucial for handling and contextualising drug profiling data. An organised memory has been developed in order to provide accurate, timely, useful and meaningful information for linking spatially and temporally distinct events on a national and international level (including cross-border phenomena). Literature has already pointed out that forensic case data are amenable for use in an intelligence perspective if data and knowledge of specialised actors are appropriately organised, shared and processed. As a particular form of forensic case data, the authors' research focuses on parameters obtained through the systematic physical and chemical profiling of samples of illicit drugs. The procedure is used to infer and characterise links between samples that originate from the same and different seizures. The discussion will not, however, focus on how samples are actually analysed and compared as substantial literature on this topic already exists. Rather, attention is primarily drawn to an active and close collaboration between magistrates, forensic scientists, law enforcement investigators and crime analysts from different institutions with the aim of generating, using and validating relevant profiling case data as integral part of investigative and crime analysis processes. Original advances are highlighted through experiences from criminal investigations of offences related to the unlawful importation, exportation, supply and possession of illicit drugs.  相似文献   
288.
Rupture of a varicose vein is a rare cause of sudden death. It occurs when the failure of venous valves causes an increase in venous pressure great enough to provoke rupture of the blood vessel. When it does happen, the victim is often found surrounded by a pool of blood, and the examination of the scene can mislead the forensic team to think of violent death. Until now, the bloodstain patterns in these fatal cases have not been described. An examination of the bloodstain pattern in a case of fatal varicose vein rupture in an 84-year-old man is here reported.  相似文献   
289.
The body of an unidentified elderly woman was found trapped in a floodgate. Prior to autopsy, full-body multislice computed tomography (MSCT) was performed for study of bone lesions and cause of death. Age was estimated by analysis of the sternal end of the fourth rib and of the pubic symphyseal medial articular surfaces. The results were then compared with the autopsy findings. MSCT was superior to autopsy in diagnosis of traumatic bone lesions and also revealed dental anomalies and signs of drowning. Age estimation gave a similar result for both methods. This case report illustrates the potential value of MSCT for medico-legal investigations of death: diagnosis of injuries, possibility of determining the cause of death, and anthropological study in order to estimate age or to visualize features likely to enable identification of a corpse.  相似文献   
290.
Abstract: Postmortem human chorionic gonadotrophin (HCG) blood assay can confirm postmortem diagnosis of pregnancy or document situations in which HCG levels are elevated. In some cases, however, blood sampling is not possible at autopsy. In this study, HCG was quantified by enzyme‐linked fluorescent assay (ELFA) in the bile (n = 5), vitreous humor (n = 4), and postmortem blood (n = 4) of five pregnant women. There were no false negatives in the pregnant subjects (n = 5) or false positives in controls (n = 34), enabling this test to be recommended for routine use in forensic contexts in which the detection of elevated HCG levels could be of interest.  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