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   10555篇
  免费   291篇
各国政治   397篇
工人农民   378篇
世界政治   710篇
外交国际关系   285篇
法律   6701篇
中国政治   67篇
政治理论   2220篇
综合类   88篇
  2020年   102篇
  2019年   155篇
  2018年   190篇
  2017年   218篇
  2016年   212篇
  2015年   161篇
  2014年   182篇
  2013年   941篇
  2012年   215篇
  2011年   263篇
  2010年   210篇
  2009年   266篇
  2008年   268篇
  2007年   269篇
  2006年   261篇
  2005年   241篇
  2004年   234篇
  2003年   242篇
  2002年   235篇
  2001年   423篇
  2000年   366篇
  1999年   294篇
  1998年   158篇
  1997年   122篇
  1996年   136篇
  1995年   132篇
  1994年   133篇
  1993年   134篇
  1992年   232篇
  1991年   251篇
  1990年   240篇
  1989年   248篇
  1988年   225篇
  1987年   223篇
  1986年   262篇
  1985年   256篇
  1984年   229篇
  1983年   214篇
  1982年   151篇
  1981年   127篇
  1980年   113篇
  1979年   151篇
  1978年   85篇
  1977年   111篇
  1976年   95篇
  1975年   71篇
  1974年   89篇
  1973年   83篇
  1972年   77篇
  1971年   69篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
972.
Nuclear spin tomography since its beginnings in the seventies has steadily gained in importance as a method of examination in medical diagnostics as it produces a picture. In the field of forensic medicine the NMR technique as used for anatomic-anthropologic issues attempting to identify skulls this is a valuable supplement to an extension of the existing methods of investigation. The results of a measurement of the thickness of soft facial tissue in a live test person is shown as compared to measures obtained by sonography.  相似文献   
973.
Demographic and trend analysis of 881 consecutive suicides in blacks and whites is presented. For the years 1975 through 1984, the suicide rate was 15.1/100 000 and did not significantly change. White males were overrepresented in all age groups, had an overall suicide rate of 34.9, and showed a small but statistically significant increase in rate which was not accounted for by any specific age group. White females, in general, were represented in proportion to their prevalence in the population, and those ages 20 to 24 demonstrated an increasing suicide rate which was small. Black males were at highest risk in their twenties, showed no significant trends, and were also represented near their prevalence in the population. Black females of all ages were underrepresented, and had low suicide rates which decreased with time. No significant rate changes were noted for teenagers or the elderly. Firearms was the method of choice in all groups, although methods varied with age, race, and sex, and male children preferred hanging. Small but significant increases were noted for the prevalence of nondrug methods in females and carbon monoxide deaths in white males. Similarities and differences to larger scale studies are discussed. Suicide may have characteristics unique to given geographical areas and pervasive to all areas. The authors advocate study and publication of local data to clarify further the nature of suicide.  相似文献   
974.
Low nanogram and picogram quantities of cocaine metabolite equivalents were detected in extracts from perspiration stains, menstrual bloodstains, and hair using radioimmunoassay. The theory of drug inclusion in hair and its significance are discussed.  相似文献   
975.
976.
The interpretation of bloodstain patterns at crime scenes has received increased attention in recent years. Important to an understanding of this is knowledge of the fundamentals of blood droplet formation and impact dynamics. A review of the literature reveals that a considerable amount of work has been done with aqueous drop dynamics. Workers in the forensic science area seem to have been unaware of this. In addition, some of the most important and comprehensive early work with blood droplet dynamics seems to have been forgotten. It is not cited in more recent publications dealing with bloodstain pattern interpretation. This literature is reviewed and discussed as well. The present study presents results of experiments with blood droplet dynamics and high-speed photographs of blood droplet impacts on stationary target surfaces. Some longstanding misconceptions of importance to forensic scientists engaged in crime scene reconstruction are discussed.  相似文献   
977.
978.
A method for the demonstration of the topographical distribution of phenobarbital at the cellular level in various tissues was established. Mice that had been exposed to various doses of phenobarbital by intraperitoneal injection were killed, and their tissues were fixed with 0.1 M phosphate buffer solution (pH 7.4) containing paraformaldehyde and glutaraldehyde. Thereafter, paraffin and frozen sections were made and stained by the indirect immunoperoxidase method using antisera obtained from commercial sources and used for the immunochemical assay of the blood level of phenobarbital in clinical medicine. A specific positive reaction was observed solely in testing the intoxicated tissues, and this reaction was inhibited when phenobarbital was added to the antisera. The minimal sensitivity of the positive reaction, which can be discerned by observing the stained slides macroscopically, was in the range of 10 mg/kg. Thus, the diagnosis of phenobarbital intoxication in the forensic autopsy can be made by immunohistochemistry. A positive reaction was found in various tissue cells, including nerve cells, myelin sheaths, glia cells, hepatocytes, cells of the alveolar and bronchial wall, epithelial cells of the distal part of the renal tubules, and so forth. Endothelial cells of the capillaries in all tissues gave a strong positive reaction. The immunocytochemical electron microscopy of the hepatocytes revealed that the positive reaction in the cytoplasm was located solely in the intraluminal space of the smooth endoplasmic reticulum. These results indicate some interesting aspects of the pharmacokinetics of phenobarbital in vivo. It is expected that the antisera, which are used widely for the assay of the blood concentration of various drugs (phenobarbital, amphetamines, morphine, and so forth), may be regarded as excellent reagents for immunocytochemistry. This clearly indicates that morphological evidence in toxicology, which had so far remained obscure, can be easily obtained by applying these antisera against various drugs.  相似文献   
979.
Chloroquine concentrations in blood and tissues were examined in overdose and non-overdose cases to determine appropriate ranges for interpretation. Twenty-nine literature overdose cases and 8 non-overdose literature cases were compared with this laboratory's findings. The results indicate significant postmortem redistribution of chloroquine. Combining this laboratory's results and the literature results indicates that using a liver concentration of 150 mg/kg as a cutoff between overdose and non-overdose concentrations properly identified 30 of the 34 published cases containing liver chloroquine and 19 of the 20 presented cases.  相似文献   
980.
One December morning the naked bodies of two alcoholics were found on an open place in the center of the city of Essen. The phenomenon of paradoxical undressing due to vital hypothermia is described and the significant influence of alcohol on hypothermia and confusion in connection with hypothermia is pointed out. Compared to the results of other authors, external and internal signs of lethal hypothermia were analysed in a retrospective series of 30 cases (autopsy material in the region of Essen, investigation period from 1979-1989).  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