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   1347608篇
  免费   101316篇
  国内免费   4845篇
耳鼻咽喉   16956篇
儿科学   43805篇
妇产科学   36508篇
基础医学   199699篇
口腔科学   36073篇
临床医学   130973篇
内科学   260119篇
皮肤病学   26738篇
神经病学   112596篇
特种医学   48684篇
外国民族医学   368篇
外科学   185331篇
综合类   30154篇
现状与发展   3篇
一般理论   460篇
预防医学   115228篇
眼科学   29240篇
药学   100112篇
  8篇
中国医学   3660篇
肿瘤学   77054篇
  2021年   11479篇
  2019年   12091篇
  2018年   16788篇
  2017年   12694篇
  2016年   13713篇
  2015年   15825篇
  2014年   21606篇
  2013年   32830篇
  2012年   45308篇
  2011年   47981篇
  2010年   27790篇
  2009年   25553篇
  2008年   43480篇
  2007年   45739篇
  2006年   45764篇
  2005年   44083篇
  2004年   41975篇
  2003年   39927篇
  2002年   38645篇
  2001年   61075篇
  2000年   62699篇
  1999年   52465篇
  1998年   14695篇
  1997年   13369篇
  1996年   13177篇
  1995年   12500篇
  1994年   11656篇
  1993年   10957篇
  1992年   41614篇
  1991年   40807篇
  1990年   39471篇
  1989年   37370篇
  1988年   34598篇
  1987年   33705篇
  1986年   32163篇
  1985年   30658篇
  1984年   23043篇
  1983年   19593篇
  1982年   11756篇
  1979年   20811篇
  1978年   14817篇
  1977年   12070篇
  1976年   11880篇
  1975年   12112篇
  1974年   14802篇
  1973年   14474篇
  1972年   13357篇
  1971年   12420篇
  1970年   11489篇
  1969年   10413篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
The synopsis of neurogenic lower urinary tract dysfunctions aims to be practical and tries to give some simple algorithms to the physician to help his understanding of the pathophysiology and to guide him towards an easy, functional, preventive and chronological exploration and treatment.  相似文献   
122.
A study was carried out in order to document any abnormalities in the electro-encephalogram (EEG) that might appear in young adolescents who have deliberately inhaled the range of volatile substances loosely referred to as 'glue'. The EEGs of a group of 'street children' being assisted in a Johannesburg shelter were examined. The records were analysed for any clinical abnormalities and also subjected to spectral analysis in order to examine the overall characteristics of frequency, power and spatial distribution. The EEGs clearly revealed that, although at the time of the examination the subjects were ostensibly abstinent, both clinical and normative evidence of continuing brain disturbance was present. It was concluded that glue sniffing is likely to have long term electrocerebral sequelae.  相似文献   
123.
The results of the in vitro fertilisation programme at Tygerberg Hospital for the period April 1983 to January 1988 are presented. Of the 1117 laparoscopies performed, 825 patients reached the transfer stage. A live-birth rate of 9.3% was achieved. The pregnancy rate after transfer of 4 embryos was 25.9% compared with 15.4% after 2 embryos and 10.8% after 3 embryos (P = less than 0.0001). The multiple pregnancy rate was 2.8% in the group receiving 2 embryos and 11.7% and 10.4% in those receiving 3 and 4 embryos, respectively. Of the 77 successful pregnancies (90 babies), 1 baby died at 34 weeks' gestation as the result of abruptio placentae due to preeclampsia and 1 cot death occurred. The only congenital abnormality encountered was a cleft palate.  相似文献   
124.
Nine hundred and three patients undergoing diagnostic peritoneal lavage (DPL) over a 6-year period were retrospectively reviewed to evaluate the utility of the white blood cell (WBC) count in the lavage fluid. Eleven patients (1.2%) had dialysate WBC counts greater than 500/mm3, with erythrocyte counts less than 10(5)/mm3. Nine of these patients who were lavaged within 4 hours of injury had no intra-abdominal pathology. Two patients, lavaged after 4 hours, demonstrated intra-abdominal injury. Two hundred twenty-three patients (24.7%) had grossly clear dialysate which was not sent for laboratory analysis. None of these patients required laparotomy. We conclude that the WBC count in DPL fluid is of no diagnostic value in victims of blunt abdominal trauma who are lavaged within 4 hours of injury. In addition, laboratory analysis of clear dialysate is not required in these patients.  相似文献   
125.
We report a case of recurrent calculi in a Kock pouch continent urinary diversion. An open operation was avoided by successfully excising the Marlex mesh and removing it with the associated calculi in an endoscopic fashion.  相似文献   
126.
127.
Our study was intended to determine whether power Doppler sonography can be considered superior to color Doppler technique in depiction of normal orbital vasculature. Ten healthy volunteers (20 eyes) were examined with a 10 MHz linear probe; each orbital vessel was recorded with both color and power Doppler methods; the images were reviewed independently by all the observers, who agreed that power Doppler clearly is superior to color Doppler technique for evaluation of the anatomy of orbital arteries and veins.  相似文献   
128.
129.
Free-floating clots of the extracranial internal carotid artery are generally considered as surgical emergencies. This retrospective study analyzes six free-floating clots diagnosed by arteriography. Three of these patients had a fixed stroke while the other three had an evolving stroke. Three patients had antecedent ocular or hemispheric transient ischemic attacks. The causes of free-floating clots in the internal carotid artery were atheromatous stenosis in two cases, ulcerated plaque in three cases, and carotid artery dissection in one. All six patients were seen late, approximately 15 hours after their neurologic accident. They were treated with intravenous heparin over a two to five week period. Repeat arteriograms demonstrated complete clot lysis in four instances, while partial lysis was seen in one case. Moderate extension of thrombus occurred in one case only. No further neurologic complications were noted during the treatment by heparin. As indicated by follow-up arteriographic findings, secondary surgery was performed for major carotid lesions and residual clots in five cases. The free-floating thrombus syndrome of the carotid artery should not be considered as a surgical emergency when discovered late in the wake of an acute neurologic accident.  相似文献   
130.
A chemically defined medium for the culture of mature oligodendrocytes   总被引:3,自引:0,他引:3  
A new chemically defined medium consisting of equal parts of Dulbecco modified Eagle's and Ham's F-12 media supplemented with insulin, sodium selenite, putrescine, and D+ galactose, which allows the long-term survival of mature oligodendrocyte pure cultures, is described. Immunohistochemical staining has shown that over 90% of the cells become positive for myelin proteins shortly following subculture. Contaminating astrocytes (2%) do not survive in this medium. Biochemical data have indicated that these purified oligodendrocytes express 2'3'-cyclic nucleotide 3'-phosphohydrolase and UDP-galactose ceramide galactosyltransferase activities. Electron microscopical examination revealed that the oligodendrocytes were mostly of medium-dark type and appeared to be identical to cells cultured in serum-containing medium. The ability to maintain pure oligodendrocyte cultures in such a defined medium will allow investigations concerning exogenous and endogenous factors involved in oligodendrocyte metabolism.  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