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   553548篇
  免费   35960篇
  国内免费   695篇
耳鼻咽喉   7549篇
儿科学   18264篇
妇产科学   14790篇
基础医学   91089篇
口腔科学   15435篇
临床医学   47658篇
内科学   101644篇
皮肤病学   12931篇
神经病学   39758篇
特种医学   20050篇
外国民族医学   79篇
外科学   83066篇
综合类   8720篇
一般理论   126篇
预防医学   41429篇
眼科学   12933篇
药学   42861篇
中国医学   1037篇
肿瘤学   30784篇
  2018年   5537篇
  2016年   4732篇
  2015年   5181篇
  2014年   6975篇
  2013年   10788篇
  2012年   14598篇
  2011年   16136篇
  2010年   9280篇
  2009年   8761篇
  2008年   15381篇
  2007年   16506篇
  2006年   16702篇
  2005年   16077篇
  2004年   15564篇
  2003年   14886篇
  2002年   14662篇
  2001年   25332篇
  2000年   26461篇
  1999年   21720篇
  1998年   5935篇
  1997年   5117篇
  1996年   5370篇
  1995年   4963篇
  1994年   4617篇
  1992年   16555篇
  1991年   17170篇
  1990年   17245篇
  1989年   16515篇
  1988年   15237篇
  1987年   15111篇
  1986年   14275篇
  1985年   13622篇
  1984年   10114篇
  1983年   8661篇
  1982年   4842篇
  1981年   4499篇
  1979年   9867篇
  1978年   7204篇
  1977年   6075篇
  1976年   5876篇
  1975年   6675篇
  1974年   7981篇
  1973年   7438篇
  1972年   7241篇
  1971年   6903篇
  1970年   6363篇
  1969年   6074篇
  1968年   5726篇
  1967年   5162篇
  1966年   4610篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
On the basis of experience with the treatment of more than 1,500 patients with post-burn defects, deformities, and trophic ulcers, the authors distinguished types of affection in which the traditional methods are ineffective. These 133 patients were subjected to plasty with ++cutaneo-fascial grafts; the zones of donor areas from which the grafts are taken are determined. Plasty with ++cutaneo-fascial grafts is indicated in defects of the face, deformity of the neck, total adduction contracture of the arm, defect of the breast, and affections of the hand, leg, and foot. Concrete grafts and the site from which they are taken for restoration of certain regions of the body are suggested. ++Cutaneo-fascial grafts make it possible to restore the shape, function, and the skin of the involved region.  相似文献   
52.
53.
Regional effects of craniotomy on cerebral circulation and metabolism, such as regional cerebral blood flow (rCBF), regional cerebral oxygen consumption (rCMRO2), regional oxygen extraction fraction (rOEF), and regional cerebral blood volume (rCBV) were examined by a PET (positron emission tomography) study concerning surgery that was performed on unruptured aneurysm patients. Eight patients with intracranial un-ruptured aneurysms were studied pre- and post-operatively by the 15O labelled-gas steady-state method, using HEADTOME-III. All patients underwent aneurysmal surgery performed by the transsylvian approach. There was a significant increase in the mean OEF values taken from the whole-brains of 8 patients, but there was not a significant change in CBF, CMRO2 or CBV. The increase in OEF was caused by decrease of O2 content, which was caused by post-operative decrease in the Hb value. So, this OEF increase was not the direct effect of craniotomy. In 2 patients, the rCBF and rCMRO2, in the fronto-temporal region (where craniotomy was performed) increased post-operatively. This regional effect suggests transient reactive hyperemia following compressive ischemia during the operative procedure, and metabolic demands for recovery of brain function. In 2 other patients, who had relatively low rCBFs during the pre-operative study, rCBF and rCMRO2 in the bi-frontal region had decreased more at the post-operative study. This change appears to have been caused by removal of cerebrospinal fluid and depression of the frontal lobe. From this study, it becomes evident that the regional effect of craniotomy on cerebral circulation and metabolism is not so great, when adequate microsurgical techniques are used.  相似文献   
54.
Management of splenic injuries in children has evolved over the past two decades. Splenectomies or splenorrhaphies are now performed infrequently, with the majority of hemodynamically stable children with splenic injuries managed nonoperatively. This article reviews the imaging features of acute splenic injuries in children as well as the appearance of healing splenic injuries. Follow-up evaluation and outcomes in children with splenic injuries also are addressed.  相似文献   
55.
56.
57.
The response of single detergent treated bovine retinal pigment epithelial cells in culture to ATP was measured with an image analyser. The most pronounced contraction was produced by 1.0 mM ATP with most change taking place in the first 10 min. At 1 h the area had decreased by about 33%, perimeter 22% and maximum length 25%. By way of comparison rabbit skin fibroblasts had a decreased area of approximately 40%, perimeter 25% and maximum length 22%. Bovine aortic smooth muscle cells on the other hand decreased in area by 55%, perimeter 40% and maximum length 36%. It is hoped that this assay may be used to evaluate drugs which could counteract contractile events in proliferative vitreoretinopathy.  相似文献   
58.
Maya families from Guatemala migrated to the United States in record numbers from the late 1970s to the early 1990s. Births to Maya immigrant women have created a sizable number of Maya American children. The height and sitting height of 5 to 12 years children (n = 431) were measured in 1999 and 2000. Leg length was estimated and the sitting height ratio was calculated. These data were compared with a sample of Maya children living in Guatemala measured in 1998 (n = 1,347). Maya American children are currently 11.54 cm taller and 6.83 cm longer‐legged, on average, than Maya children living in Guatemala. Consequently, the Maya Americans have a significantly lower average sitting height ratio (i.e., relatively longer legs in proportion to length of the head and trunk) than do the Maya in Guatemala. These results add support to the hypothesis that both the height and body proportions of human populations are sensitive indicators of the quality of the environment for growth. Am. J. Hum. Biol. 14:753–761, 2002. © 2002 Wiley‐Liss, Inc.  相似文献   
59.
60.
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