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   8287篇
  免费   236篇
各国政治   476篇
工人农民   250篇
世界政治   618篇
外交国际关系   359篇
法律   5140篇
中国共产党   1篇
中国政治   19篇
政治理论   1568篇
综合类   92篇
  2020年   103篇
  2019年   128篇
  2018年   194篇
  2017年   195篇
  2016年   207篇
  2015年   148篇
  2014年   182篇
  2013年   951篇
  2012年   246篇
  2011年   235篇
  2010年   175篇
  2009年   184篇
  2008年   225篇
  2007年   204篇
  2006年   215篇
  2005年   170篇
  2004年   181篇
  2003年   180篇
  2002年   179篇
  2001年   327篇
  2000年   305篇
  1999年   227篇
  1998年   88篇
  1997年   106篇
  1996年   81篇
  1995年   85篇
  1994年   100篇
  1993年   87篇
  1992年   162篇
  1991年   182篇
  1990年   160篇
  1989年   173篇
  1988年   152篇
  1987年   147篇
  1986年   165篇
  1985年   127篇
  1984年   126篇
  1983年   131篇
  1982年   81篇
  1981年   75篇
  1980年   59篇
  1979年   116篇
  1978年   66篇
  1977年   63篇
  1976年   56篇
  1975年   67篇
  1974年   81篇
  1973年   80篇
  1972年   68篇
  1971年   64篇
排序方式: 共有8523条查询结果,搜索用时 46 毫秒
991.
Adult male Wistar rats were treated with either 0.1 or 3 mg/kg body weight X day of digoxin for five days, then killed and stored at 4 degrees C for 12 h in an attempt to mimic the normal preautopsy procedures in our hospital. In rats treated with 0.1 mg/kg body weight X day, the antemortem serum digoxin concentrations (SDC) were 1.1 +/- 0.4 ng/mL while the 12-h postmortem concentration was markedly increased (16.3 +/- 5.9 ng/mL) (P less than 0.01). In rats treated with 3 mg/kg body weight X day, SDC was not changed significantly (11.2 +/- 4.8 ng/mL antemortem and 13.3 +/- 6 ng/mL postmortem). Postmortem redistribution of digoxin was assessed by injection of 125I-labelled digoxin with or without pretreatment with the unlabelled drug. The results indicate that after death passive redistribution of digoxin may take place. When the SDC are within the therapeutic or low toxic range, digoxin may reenter the blood. High antemortem serum concentrations of digoxin may prevent such passive redistribution. Therefore, antemortem digoxin intoxication cannot be reliably inferred on the basis of high postmortem levels of the drug. Digoxin intoxication can be ruled out when postmortem SDC remain within the therapeutic range. The above changes cast doubt on some of the forensic and cardiologic literature, which has in the past been based on incorrect assumptions concerning postmortem behavior of digoxin.  相似文献   
992.
993.
994.
In the identification of persons living or dead, or of skulls, the technique of photographic superimposition of laboratory images on existing original portraits has frequently been used. The applicability of the technique and the confidence in the results have always depended very much on the professional acceptance and experience of forensic specialists. Defined preconditions, improved methods and clear-cut directions on how to posture the head or the skull and how to magnify its photographic laboratory image, not only help to standardize and simplify procedures, but also increase the accuracy and credibility of the resulting diagnoses. A systematic approach with standard photographic equipment is presented. The validity of the results is discussed.  相似文献   
995.
Two rapid and reliable electrophoretic techniques for PGM1 and EsD typing on ultrathin polyacrylamide gels are described. They have been based on non-equilibrium pH gradient electrophoresis and on the addition of chemical spacers (EPPS for PGM1 and HEPES for EsD) to the gel mixture.  相似文献   
996.
National estimates of time trends and age trends in self-reported illegal behavior in the United States are compared with corresponding figures for arrests. The self-report data are from Monitoring the Future, an annual national survey of high school seniors. The analysis of time trends covers 1975 through 1985 for a sample of over 3,000 respondents per year, studied at a constant age. The analysis of age trends covers ages 17 through 23 for samples of 300 to 1,200 per year. Both self-report and arrest measures reveal substantial declines in illegal behavior throughout this age span, with the exception of arrests for assault. Both methods also indicate that rates of assault increased from 1975 through 1985, a finding that has not previously been reported. Time trends for other offenses were erratic.  相似文献   
997.
This article discusses Capgras syndrome and its association with harmful and potentially harmful behaviors. Phenomenological and psychodynamic analysis of a series of cases will highlight danger signals that may be present in Capgras patients.  相似文献   
998.
A method is described for the determination of glyoxalase I phenotypes in liquid blood and dry bloodstains. The frequencies of glyoxalase I phenotypes in various populations of S.E. England are included.  相似文献   
999.
Equipment for annealing casework sized glass particles is described. Investigations were carried out using a simple muffle furnace, a temperature programmed furnace and a metal sample holder. Because they produced a uniform and reproducible thermal environment, best results were obtained from a combination of the temperature programmed furnace and the metal sample holder. Refractive index changes for window and toughened glass specimens were investigated and a simple, reproducible annealing routine for casework was devised.  相似文献   
1000.
Ultrasonic determinations were made of facial tissue thicknesses in 50 healthy American caucasoid children, ranging in age from 4 to 15. Twenty measurements were taken at sites along the median, right sagittal, and right lateral planes. A static scanner was used in the B-mode. Three measurements significantly increased with age, the mid-philtrum (rs = 0.43, p less than 0.01) in females, the mental sulcus (rs = 0.30, p less than 0.05) in males, and the frontal eminence (rs = 0.32, p less than 0.05) in both sexes. Moreover, 25% of the measurements, while not statistically significant, decreased with increasing age. These data provide a basis for facial reproductions in caucasoid children.  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