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   3339100篇
  免费   257102篇
  国内免费   12152篇
耳鼻咽喉   49099篇
儿科学   101309篇
妇产科学   90963篇
基础医学   464624篇
口腔科学   97759篇
临床医学   303698篇
内科学   644928篇
皮肤病学   69449篇
神经病学   273712篇
特种医学   132227篇
外国民族医学   1293篇
外科学   503984篇
综合类   92363篇
现状与发展   30篇
一般理论   1324篇
预防医学   258135篇
眼科学   80759篇
药学   253473篇
  64篇
中国医学   11115篇
肿瘤学   178046篇
  2018年   34868篇
  2017年   27331篇
  2016年   29830篇
  2015年   34776篇
  2014年   49303篇
  2013年   71947篇
  2012年   96809篇
  2011年   102613篇
  2010年   60710篇
  2009年   57671篇
  2008年   95440篇
  2007年   102234篇
  2006年   103046篇
  2005年   101050篇
  2004年   95786篇
  2003年   92547篇
  2002年   91099篇
  2001年   150922篇
  2000年   156274篇
  1999年   133032篇
  1998年   38659篇
  1997年   35341篇
  1996年   34363篇
  1995年   33114篇
  1994年   30914篇
  1993年   28503篇
  1992年   105467篇
  1991年   101754篇
  1990年   98684篇
  1989年   95489篇
  1988年   88727篇
  1987年   87389篇
  1986年   83195篇
  1985年   79423篇
  1984年   60011篇
  1983年   51120篇
  1982年   31056篇
  1981年   27834篇
  1979年   56819篇
  1978年   40181篇
  1977年   34369篇
  1976年   31763篇
  1975年   34480篇
  1974年   41908篇
  1973年   40162篇
  1972年   38002篇
  1971年   35403篇
  1970年   33433篇
  1969年   31375篇
  1968年   28865篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Usher syndrome: clinical findings and gene localization studies   总被引:3,自引:0,他引:3  
The issue of genetic heterogeneity is a critical problem in the localization of the gene(s) for Usher syndrome. Based on the data obtained on families studied to date, the differences between type I and type II Usher syndrome appear quite distinct with regard to auditory and vestibular function. Although the majority of families can be confidently diagnosed as typical type I or type II, clinical investigations revealed four families with findings that did not fit into either of the two more common subtypes. These findings emphasize the critical importance of an in-depth clinical analysis concomitant with the linkage investigation to assure accurate subtyping of Usher syndrome. Based on an analysis of only those families with definite type I or type II Usher syndrome, approximately 17% of the genome can be excluded as a potential site of the gene for type I, and 14% can be excluded as the site for the type II gene. This study will continue until the Usher gene(s) is successfully localized.  相似文献   
992.
This paper reports the results of an experimental study modeled after a study conducted by Kaplan et al. The hypothesis tested was: Adolescents who receive a social learning intervention (SLI) will show greater improvement in metabolic control of their diabetes than will adolescents who receive only traditional diabetes instruction. Thirty-four adolescents between the ages of 12 and 16 who attended a midwestern camp were randomly divided into two groups. Both groups attended a daily 1-hour teaching session about diabetes. Later each day, the experimental group received an SLI consisting of role modeling to help the subjects circumvent peer pressure. To determine metabolic control, HbA1 values were determined before and 3 1/2 months after the intervention. The control group showed no significant difference in HbA1 values, while the experimental group showed a decrease in metabolic control.  相似文献   
993.
994.
Gram negative endotoxins play a contributory role in the syndrome which results from over consumption of carbohydrates by horses and ponies. Since the antibiotic polymyxin B exerts a direct anti-endotoxin effect by chemically modifying the active lipid A moiety of endotoxin, it might be expected to protect horses after carbohydrate overload and provide a new therapeutic and experimental tool for this condition. The present study was undertaken to evaluate the effect of polymyxin B on hemostatic, hemodynamic, acid-base, and clinical aspects of the syndrome resulting from carbohydrate overload. Experimentally-induced carbohydrate overload resulted in lactic acidosis, hypercoagulability, hypovolemic shock and lameness. Although there was a slight delay in the onset of clinical signs resulting from experimental carbohydrate overload in treated animals, polymyxin B administered iv at 2.5 mg/kg every 6 hr failed to significantly ameliorate the coagulopathy, acidosis, lameness and shock induced by alimentary carbohydrate overload.  相似文献   
995.
The authors studied the clinical features and outcome at 6 months in 191 patients with subarachnoid hemorrhage (SAH) from ruptured aneurysms. Aneurysm repair (AR) was undertaken in 123 cases (64.4%). In the non-AR group (n = 68), 48.5% of the patients were 70 years of age or older, compared with 12.2% in the AR group. The duration from onset to admission was less than 3 hours in 48 non-AR cases (70.6%) and in 42 AR cases (34.1%). Among non-AR patients, 63.2% were Hunt and Hess grade IV or V, whereas the figure for AR patients was only 14.7%. By 6 months after SAH, 94.1% of non-AR patients had died, and the remainder were vegetative or severely disabled. In contrast, only 15.4% in the AR group died, and over 50% showed good recovery. The large majority of non-AR patients were treated conservatively because they were judged to be poor surgical risks and, among these patients, nearly one half were elderly. In the 10 elderly patients considered good surgical candidates, vasospasm was the most common reason (70%) for not performing AR.  相似文献   
996.
A case of tumoral calcinosis simulating osteomyelitis and associated with bunion formation in a 20-year-old female is presented. The most striking findings in this patient were the soft tissue calcifications. There was no evidence of any of the known causes of heterotopic calcifications. This kind of simulation between tumoral calcinosis bunion formation and osteomyelitis has not been previously described.  相似文献   
997.
Herniation of a thoracic disc in an acromegalic giant is reported. Degenerative changes in the spine in association with dorsal kyphosis, and the additional strain, resulted in the disc prolapse.  相似文献   
998.
999.
1000.
The estimation of breakthrough time for multicomponent organic solvent vapors on activated carbon fixed beds is significantly complicated and difficult. This paper describes a simple estimation method of breakthrough time for the first component (foremost breakthrough component) in two- or three-component organic solvent vapors on an activated carbon fixed bed. The breakthrough time for the first component was expressed by the harmonic mean value of the breakthrough times in each pure component. Estimated breakthrough times were compared with the experimental ones.  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