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   1338791篇
  免费   112535篇
  国内免费   6374篇
耳鼻咽喉   16705篇
儿科学   43012篇
妇产科学   36559篇
基础医学   183642篇
口腔科学   36276篇
临床医学   120710篇
内科学   278614篇
皮肤病学   31893篇
神经病学   110520篇
特种医学   55546篇
外国民族医学   274篇
外科学   210422篇
综合类   31530篇
现状与发展   2篇
一般理论   414篇
预防医学   106635篇
眼科学   28140篇
药学   93726篇
  5篇
中国医学   2228篇
肿瘤学   70847篇
  2018年   13386篇
  2017年   10641篇
  2016年   12801篇
  2015年   14302篇
  2014年   19959篇
  2013年   29748篇
  2012年   36258篇
  2011年   38913篇
  2010年   24388篇
  2009年   23916篇
  2008年   36373篇
  2007年   38797篇
  2006年   39918篇
  2005年   38513篇
  2004年   36742篇
  2003年   35840篇
  2002年   33847篇
  2001年   66058篇
  2000年   67926篇
  1999年   56589篇
  1998年   16723篇
  1997年   15019篇
  1996年   16015篇
  1995年   16232篇
  1994年   15098篇
  1993年   14153篇
  1992年   47098篇
  1991年   45748篇
  1990年   43971篇
  1989年   41816篇
  1988年   38758篇
  1987年   38082篇
  1986年   35860篇
  1985年   34635篇
  1984年   26358篇
  1983年   22108篇
  1982年   13847篇
  1981年   12448篇
  1980年   11718篇
  1979年   23545篇
  1978年   17073篇
  1977年   14385篇
  1976年   13184篇
  1975年   13723篇
  1974年   16093篇
  1973年   15397篇
  1972年   14173篇
  1971年   13036篇
  1970年   11880篇
  1969年   11104篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
APACHE II score and abdominal sepsis. A prospective study   总被引:7,自引:0,他引:7  
Therapeutic trials for intra-abdominal sepsis require pretreatment stratification; physiologic scoring has been recently proposed for this purpose. We have prospectively tested the validity of one such scoring system, namely, the Acute Physiology and Chronic Health Evaluation (APACHE II). As part of a larger database, we correlated APACHE II scores with mortality in 100 patients hospitalized for generalized peritonitis or abdominal abscess. Use of steroids was recorded because of our suspicion that steroids increase mortality but blunt the physiologic response to sepsis. Thirty-one patients died, including 12 of 19 patients receiving steroids. Stepwise discriminant analysis revealed that the APACHE II score and steroid use were each independently associated with the rate of mortality. We report a prospective validation of pretreatment APACHE II scoring in abdominal sepsis. Steroid use is an independent risk factor.  相似文献   
93.
Clinical versus ultrasonographic evaluation of scrotal disorders   总被引:1,自引:0,他引:1  
Clinical and ultrasonographic examinations of scrotal disorders were compared in 166 patients in order to determine their ability to distinguish between those diseases requiring surgery and those requiring clinical follow-up only. Ultrasound examinations were efficient in discriminating between normal and pathological findings. Extra-testicular lesions were readily differentiated from testicular ones. Although both clinical and ultrasonographic examinations had high sensitivity (90%) in detecting testicular cancer, the number of false positive findings was smaller after ultrasound examination. This gave a predictive value of a positive test of 53% after ultrasound examination but only 33% after clinical examination. Ultrasound examination may, therefore, reduce the number of surgical explorations in the scrotum and should be performed in patients with suspected testicular pathology based on history and palpatory findings.  相似文献   
94.
Malignant tumors of the bones   总被引:2,自引:0,他引:2  
  相似文献   
95.
96.
97.
The Dundee Memory Clinic was established in 1991. This paper reviews the diagnosis of the first 150 attenders and compares the findings with those of other memory clinics.  相似文献   
98.
99.
Choristomas, masses of normal tissues in aberrant locations, contain smooth muscle fibers and fibrous tissues. We describe the MR imaging features of two choristomas located in the internal auditory canals and arising from the facial and vestibulocochlear nerves. Both lesions enhanced with contrast material. In one case, enhancement was seen in the geniculate ganglion and greater superficial petrosal nerve. In the other, a medial component enhanced less than the lateral component did.  相似文献   
100.
The ability of three Porphyromonas spp., seven Prevotella spp., seven Fusobacterium spp. and two related Bacteroides spp. (B. levii and B. macacae) to degrade an extensive range of synthetic endo-, amino- and diamino peptidase substrates linked to the fluorescent leaving group 7-amido-4-methylcoumarin (NHMec) was investigated. Many more species than was previously recognized exhibited peptidase activities, albeit at lower levels than those already described for Porphyromonas gingivalis. Detection of chymotrypsin-like activity was dependent on which of three NHMec-linked substrates was used, but all species exhibited degradative activity with at least one of these substrates. Elastase-like activity was detected in all species though not all species reacted with each of the elastase substrates. Glycylprolyl peptidase activity was detected in all of the species tested with the exception of F. mortiferum, F. gonidiaformans, F. naviforme and F. necrophorum. While the detection of peptidase activities does not appear to be useful for the differentiation of species within the genera Bacteroides and Prevotella, its ability to differentiate species of the genus Porphyromonas or Fosobacterium further investigation.  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