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   17472篇
  免费   1225篇
各国政治   712篇
工人农民   844篇
世界政治   1154篇
外交国际关系   536篇
法律   12252篇
中国共产党   2篇
中国政治   105篇
政治理论   3002篇
综合类   90篇
  2021年   87篇
  2020年   430篇
  2019年   447篇
  2018年   563篇
  2017年   582篇
  2016年   668篇
  2015年   507篇
  2014年   534篇
  2013年   1821篇
  2012年   483篇
  2011年   507篇
  2010年   538篇
  2009年   557篇
  2008年   512篇
  2007年   505篇
  2006年   524篇
  2005年   437篇
  2004年   431篇
  2003年   361篇
  2002年   404篇
  2001年   678篇
  2000年   604篇
  1999年   482篇
  1998年   239篇
  1997年   177篇
  1996年   193篇
  1995年   190篇
  1994年   171篇
  1993年   179篇
  1992年   306篇
  1991年   313篇
  1990年   294篇
  1989年   277篇
  1988年   307篇
  1987年   263篇
  1986年   324篇
  1985年   316篇
  1984年   246篇
  1983年   229篇
  1982年   180篇
  1981年   158篇
  1980年   146篇
  1979年   219篇
  1978年   115篇
  1977年   92篇
  1976年   76篇
  1975年   96篇
  1974年   125篇
  1973年   83篇
  1972年   81篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
We have demonstrated that skin viability decreases at a measurable rate following death in an animal model. The decreased skin viability was measured by fluorescein diacetate and ethidium bromide using fluorescence emission spectroscopy. There is significant decrease of the fluorescence intensity of the fluorescein diacetate assay between the 1-4 h, the 6-24 h, and the >40 h time points postmortem. For times between 6-24 h and >40 h postmortem the ethidium bromide assay showed consistent and significant increases in signal. The fluorescence measurements in this study showed that under the experimental conditions the time of death could be determined for <4, 6-24, and >40 hapotmotrem. The application of these assays in the field will require further study of the environmental factors.  相似文献   
992.
993.
Russian and foreign methods used in forensic medicine for detection of the semen in stains on material evidences are compared. The potentialities of quantitative immunofluorescence test for detection of the semen in stains on material evidences, developed at Bureau for Forensic Medical Expert Evaluations of the Leningrad region, are described. Unlike other methods used in Russia, this method detects the semen in stains in the absence of spermatozoa and in stains with very low amount of the semen. Our modification allows objective recording of the results with computer processing. The method is cheaper than its foreign analogs and its sensitivity is similar to them.  相似文献   
994.
995.
996.
Rapid developments in the area of biotechnology within the next decade are likely to have a significant impact on Canadian society. This article outlines the practical and ethical issues that will need to be addressed in the face of scientific advances, and contemplates the development of an appropriate policy framework in this regard. Surveying the approaches to policy development taken thus far, the author notes the underlying need for greater transparency and public participation. Rational and effective policies will only result from additional basic scientific data being made available to a more informed and engaged Canadian public.  相似文献   
997.
A protocol for comparative analysis of heroin making use of chromatographic methods and infra-red spectroscopy is presented.  相似文献   
998.
999.
A rare and potentially fatal cause of hematemesis is fistula formation between the esophagus and the vascular system. A case report of a 39-year-old woman with congenital aortic arch anomalies hospitalized for treatment of head injuries demonstrates the potential for iatrogenic esophageal trauma to initiate fistula formation between the esophagus and an anomalous arterial system. A literature review revealed 6 other cases of vascular-esophageal fistulae caused by nasogastric esophageal intubation. It is concluded that aortic arch anomalies increase the risk of esophageal injury and subsequent fistula formation from nasogastric esophageal intubation. In addition, the clinical features and pathologic findings of vascular-esophageal fistulae are reviewed.  相似文献   
1000.
Two cases of unexpected childhood death due to hemolytic uremic syndrome are reported. A 21-month-old girl who was discovered dead in bed following a short illness was found at autopsy to have overwhelming sepsis resulting from transmural colitis. Escherichia coli serotype 0157A was isolated from the intestine, and renal changes of hemolytic uremic syndrome were found. A 4-year-old girl died suddenly in hospital from intracranial hemorrhage while being treated for hemolytic uremic syndrome-related renal failure. Culture of urine and feces grew verocytotoxin producing E. coli. These cases demonstrate that hemolytic uremic syndrome may be a rare cause of unexpected childhood death and that the diagnosis may not be established prior to autopsy. Postmortem culture of tissues and fluids in cases of suspected sepsis in children may be essential in establishing this diagnosis, because histologic evaluation may be compromised by profound sepsis and tissue putrefaction. Accuracy in diagnosis may have significant public health and medicolegal consequences.  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