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   15026篇
  免费   445篇
各国政治   769篇
工人农民   599篇
世界政治   1003篇
外交国际关系   491篇
法律   9182篇
中国共产党   3篇
中国政治   91篇
政治理论   3193篇
综合类   140篇
  2020年   181篇
  2019年   233篇
  2018年   338篇
  2017年   338篇
  2016年   342篇
  2015年   245篇
  2014年   255篇
  2013年   1644篇
  2012年   354篇
  2011年   371篇
  2010年   328篇
  2009年   353篇
  2008年   396篇
  2007年   370篇
  2006年   425篇
  2005年   366篇
  2004年   366篇
  2003年   356篇
  2002年   352篇
  2001年   460篇
  2000年   424篇
  1999年   335篇
  1998年   210篇
  1997年   204篇
  1996年   176篇
  1995年   169篇
  1994年   169篇
  1993年   191篇
  1992年   284篇
  1991年   324篇
  1990年   295篇
  1989年   312篇
  1988年   282篇
  1987年   316篇
  1986年   306篇
  1985年   302篇
  1984年   279篇
  1983年   293篇
  1982年   196篇
  1981年   181篇
  1980年   162篇
  1979年   196篇
  1978年   147篇
  1977年   128篇
  1976年   121篇
  1975年   117篇
  1974年   131篇
  1973年   134篇
  1972年   116篇
  1969年   97篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
131.
132.
In this article we examine how increasing the reimbursement of physicians and expanding Medicaid eligibility affect access to care for children in Cook County, Illinois, which overlies Chicago. Using Medicaid claims and other data at the zip-code level, we compare the places where Medicaid children live with the places where all the physicians who treat children and those who accept Medicaid patients have their practices. Our findings suggest that the recent changes in legislation are unlikely to benefit extremely poor children, who are more likely to live in depressed inner-city areas, where there are few physicians. "Near-poor" children whose homes are dispersed throughout the county, who are now eligible for Medicaid as a result of the recent changes, are likely to see improvements in their access to care. Further changes in policy, aimed at enhancing the capacity of institutions providing care, could improve access for the children of the inner city.  相似文献   
133.
134.
We report seven fatalities resulting from the ingestion of illicit drugs packaged in condoms, rubber balloons, or plastic bags which were observed in the last 4 years at the Office of the Chief Medical Examiner, State of Maryland. All the victims, with the exception of one, were men ranging in age from 19 to 37 years. There was no racial predominance. No drug paraphernalia was found at any scene. In two cases, seizure-like activity was documented. One victim had recently returned from Nigeria; therefore, Lassa fever was initially suspected. Two of the victims were "body packer" contrabanders who had just arrived from Africa. They used body cavities to hide large amounts of heroin to avoid U.S. Customs. The other five cases were "mini-packers," small-time illicit drug dealers who had swallowed a single bag of cocaine to avoid police detection. The possible mechanism of leaking or rupture of the latex container is discussed.  相似文献   
135.
Analysis of a sample of 1108 radii corresponding to 567 black and white North Americans in the Terry Collection at the Smithsonian Institution demonstrates that the diameter of the radial head is an accurate sex discriminator for human remains. A simple "radial-head method" of sex determination consists of measuring the maximum and minimum diameters of the head and comparing such measurements with the test cutoff points. The subject is female when the maximum radial head diameter (either left or right) is less than or equal to 21 mm, and male when the maximum diameter (either left or right) is greater than or equal to 24 mm. The same decisions apply to the minimum diameters of 20 mm or less and 23 mm or more, respectively. When the maximum diameter is 23 mm or the minimum is 22 mm, the subject is more likely male; when the maximum diameter is 22 mm or the minimum is 21 mm, the subject is more likely female. The sample frequency of any one of these latter diameters is never more than 16%. Cross-validation of the method with a sample of 50 pairs of radii of the Terry Collection, different from the original specimens, resulted in 92% sexing accuracy when using the left radius singly, 94% accuracy when using the right radius singly, and 96% accuracy when using both radii jointly.  相似文献   
136.
During preliminary examination of the body of a homicide victim, a peculiar red "fiber" was noticed and recovered. Initially believing this to be a carpet fiber, the item was subjected to fiber analysis. It was found to be a short coiled particle not like any known natural or synthetic fabric fiber. Subsequent examinations determined this "fiber" to be the larva of a common freshwater midge (Diptera; Chironomidae). Chironomid larvae have been observed on other bodies recovered from freshwater environments. Entomological studies of this organism have led to the conclusion that the presence of chironomid larvae indicates submersion of the body.  相似文献   
137.
Programme based on mathematical model of the process of dead body temperature changing was developed for estimation of postmortem interval. Automatic retrieval of problem solution was performed on programmable microcalculators of "Electronica MK-61" type using adaptive approach. Diagnostical accuracy in case of dead body being preserved in permanent cooling conditions is +/- 3%.  相似文献   
138.
So far, the law in the Federal Republic of Germany still allows the injection of fresh-cell preparations from animals as a roborant to increase the vitality of the organism and to strengthen the body's immune defense system. The use of "sicca-cell" preparations was provisionally forbidden in 1987 by the Federal Health Organization (Bundesgesundheitsamt; BGA). Prohibition of fresh-cell injections would have exceeded the authority of this office, although the same serious reservations also applied in the case of this treatment method. Several publications that have appeared since 1955 have reported serious complications of this therapy, some life-threatening and some even lethal. Two further cases are now added: (1) A woman aged 69 had been receiving treatment with cell injections for 9 years. Immediately after an injection of sicca cells she collapsed and was hospitalized; 7 days thereafter she developed an ascending paralysis with increasing inability to swallow or breathe. She died 25 days after the injection as a consequence of central and peripheral respiratory failure. Autopsy revealed the alterations typical for acute Landry-Guillain-Barré-Strohl syndrome. (2) A 76-year-old healthy woman had been receiving treatment with fresh-cell preparations for several years. After an injection of cell suspensions a painful local swelling was observed. The symptoms were interpreted as the consequence of an iatrogenic local hematoma, and repeated punctures were performed to obtain blood. The patient was transferred to a surgical department for further therapy. Two days after the injection she suddenly died with signs of acute cardiovascular failure. Autopsy revealed the signs of a fulminating clostridial infection and also the characteristic signs of Landry-Guillain-Barré syndrome with involvement of the autonomic nervous system. In both cases the development of an inflammatory process in the peripheral nervous system could be interpreted as an immune-mediated allergic disease, related to the repeated injection of heterologous antigenic material containing nervous tissues. This hypothesis would also explain the two other cases already published and would be consistent with the observed perivenous leukoencephalopathy of the central nervous system. The human disease pictures correspond to the well-established animal models of EAEM (experimental allergic encephalomyelitis) and EAN (experimental allergic neuritis). The pathogenesis is discussed; the major role of the central and peripheral nervous system is stressed, with special reference to the risk of acute autonomic failure. The need for specific autopsy techniques for the investigation of the entire nervous system, including spinal cord, roots, spinal ganglia and peripheral nerves with sympathetic chains, is raised.  相似文献   
139.
140.
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