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   17942篇
  免费   532篇
各国政治   759篇
工人农民   706篇
世界政治   1485篇
外交国际关系   630篇
法律   10730篇
中国共产党   2篇
中国政治   95篇
政治理论   3884篇
综合类   183篇
  2023年   185篇
  2021年   122篇
  2020年   227篇
  2019年   275篇
  2018年   343篇
  2017年   411篇
  2016年   440篇
  2015年   304篇
  2014年   346篇
  2013年   1818篇
  2012年   426篇
  2011年   448篇
  2010年   368篇
  2009年   399篇
  2008年   471篇
  2007年   480篇
  2006年   469篇
  2005年   409篇
  2004年   411篇
  2003年   431篇
  2002年   394篇
  2001年   693篇
  2000年   623篇
  1999年   520篇
  1998年   290篇
  1997年   249篇
  1996年   212篇
  1995年   213篇
  1994年   254篇
  1993年   228篇
  1992年   346篇
  1991年   379篇
  1990年   327篇
  1989年   353篇
  1988年   319篇
  1987年   337篇
  1986年   348篇
  1985年   336篇
  1984年   301篇
  1983年   323篇
  1982年   262篇
  1981年   241篇
  1980年   183篇
  1979年   252篇
  1978年   172篇
  1977年   148篇
  1976年   133篇
  1975年   121篇
  1974年   136篇
  1973年   118篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
972.
973.
The level of degradation of DNA as a means for determining the time of death has been proposed as a valid adjunct to the classic thanatochronologic methods. The twofold aim of this work was to determine which organ might reveal both a correlation between the percentage of degradation of the DNA and the time lapse since death, and would be easiest to sample and yield the most reproducible results even in technically unfavorable situations such as on-the-spot investigations at the scene of death. A comparison of the spleen, blood, and liver showed that hepatic tissue best meets these specific needs because it shows a virtually linear correlation between the time elapsed since death and the level of degradation of the DNA, and it can easily be sampled at the scene of death by use of a common biopsy needle.  相似文献   
974.
Childhood sporting deaths   总被引:1,自引:0,他引:1  
  相似文献   
975.
Personal identification based on radiographic vertebral features   总被引:4,自引:0,他引:4  
Personal identification of human remains constitutes about 10% of the normal caseload of any forensic medicine practice. Identification can be achieved by a variety of methods, one of which is the comparison of antemortem and postmortem radiographs. There are numerous accounts of cranial and dental radiographic features useful for identification, whereas the availability of postcranial radiographs and especially plates that depict the vertebral column is less widespread among the forensic community. The authors here review the various vertebral features instrumental in positive identification that can be identified on radiographs of the spine.  相似文献   
976.
977.
Death resulting from ruptured cerebral artery aneurysm: 219 cases   总被引:1,自引:0,他引:1  
To characterize the demographics of ruptured cerebral artery aneurysm as a cause of death and to examine the effect of improved diagnostic and therapeutic techniques on the incidence of sudden death associated with the condition, the authors reviewed 219 autopsies performed at the Dallas County Medical Examiner's Office between 1977 and 1997 in which the cause of death was ruptured cerebral artery aneurysm. Ruptured cerebral artery aneurysms accounted for 1.5% of 15,033 natural deaths and 0.4% of all deaths (45,492) followed by autopsy during this period. The majority (56%) of cases occurred in females, with Caucasian females composing the largest group (38%). Seventy-seven percent of cases occurred in individuals between the ages of 31 and 70 years, with the highest concentration in the 41- to 50-year decade (29%). The most common location for ruptured aneurysms was the middle cerebral artery distribution (39%). Multiple aneurysms occurred in 22 (9.1%) cases. Other factors, such as medical history, coexisting disease, symptoms, activity at onset of symptoms, survival time, and toxicology results are also presented. Compared with literature reports before 1980, when ruptured cerebral artery aneurysms were reported as the cause of death in approximately 4% to 5% of sudden natural deaths, the results of this study suggest that despite improved diagnostic and therapeutic techniques during the past two decades, morbidity and mortality from ruptured aneurysms remain a significant health problem.  相似文献   
978.
Neeleman J 《危机》2002,23(3):114-120
The effect of exposure to risk factors for suicidal behavior varies from place to place and from period to period. This may be due to contextual influences, which arise if individuals' suicide risk depends not only on their personal exposure to risk or protective factors, but also on how these are distributed in their social, cultural, economic, or even physical environments. There has been relatively little explicit attention in suicide research for such contextual influences even though they are an important component of the cross-level bias, which can arise when aggregate level associations are assumed to also apply in individuals and vice versa. Contextual effects are conceptually related to the issues of social selection vs. causation, population density, and network effects. Because of a lack of prospective multilevel research, it is unclear exactly which mechanisms underlie the phenomenon that the distribution of risk factors in an individual's context may affect their suicide risk above and beyond their personal exposure. A number of mechanisms, like deviancy amplification, formalization of restraints, and buffering effects of social support are proposed. Contextual effects may result in a concentration of suicide risk in persons when the risk factors they are exposed to become rare--whether spontaneously or through focused prevention. This has important but mostly overlooked implications for population-based prevention strategies.  相似文献   
979.
The authors report on the case of a 18-year-old student who died suddenly and unexpectedly of a pericardial tamponade after perforated ulcer-polypous endocarditis of the aortic valve. The detection of aerococcus urinae--which usually causes urinary tract infection--on the inflamed aortic valve demonstrates an unusual pathogenetic chain linking complexes of findings in the urogenital system and the heart.  相似文献   
980.
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