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   1956311篇
  免费   152368篇
  国内免费   3286篇
耳鼻咽喉   27142篇
儿科学   60932篇
妇产科学   55512篇
基础医学   288957篇
口腔科学   56323篇
临床医学   178885篇
内科学   375630篇
皮肤病学   41141篇
神经病学   158623篇
特种医学   75020篇
外国民族医学   419篇
外科学   288820篇
综合类   46481篇
现状与发展   4篇
一般理论   805篇
预防医学   159549篇
眼科学   45245篇
药学   145136篇
  6篇
中国医学   3431篇
肿瘤学   103904篇
  2018年   19404篇
  2016年   16601篇
  2015年   19220篇
  2014年   26962篇
  2013年   41349篇
  2012年   55967篇
  2011年   59409篇
  2010年   34531篇
  2009年   32917篇
  2008年   56138篇
  2007年   60469篇
  2006年   59949篇
  2005年   58786篇
  2004年   56918篇
  2003年   54612篇
  2002年   52971篇
  2001年   83570篇
  2000年   85088篇
  1999年   72030篇
  1998年   21015篇
  1997年   19188篇
  1996年   19472篇
  1995年   18269篇
  1994年   17288篇
  1993年   16235篇
  1992年   58954篇
  1991年   57843篇
  1990年   56348篇
  1989年   54521篇
  1988年   50910篇
  1987年   50054篇
  1986年   47609篇
  1985年   45445篇
  1984年   34944篇
  1983年   30315篇
  1982年   18516篇
  1981年   16926篇
  1979年   34370篇
  1978年   25170篇
  1977年   21002篇
  1976年   19390篇
  1975年   21132篇
  1974年   25878篇
  1973年   25196篇
  1972年   24047篇
  1971年   22278篇
  1970年   21206篇
  1969年   20194篇
  1968年   18568篇
  1967年   16864篇
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
951.
952.
本文介绍香港九龙海底铁路建设中高气压作业与减压病发病情况。该工程有11条坑道,共计259 448个高压工作日,减压288 140人次,发生减压病1 534例。根据不同的工作压力,以暴露次数、高压工作日数及暴露4小时以上次数3种方法分别计算减压病发病率。结果表明:各种方法计算出的发病率都有随工作压力增高而上升的趋势,说明现用的减压表对不同的工作压力达不到同样的预防效果。本文还对3大主要工种和14个小工种的减压病作了分析。  相似文献   
953.
A model of ischemic hepatic failure in Sprague-Dawley rats (SD) with 100% mortality has been developed by one-hour occlusion of the right portal vein and hepatic artery followed by left 70% hepatectomy. The intrasplenic injection of 40 x 10(6) syngeneic adult or three-day neonatal single liver cell suspensions decreased the mortality from 100% to 50% and 36%, respectively. Mortality decreased with increasing time from the intrasplenic injection of neonatal liver cells to the time of acute hepatic ischemia. Mortality also decreased with increasing interval between hepatic ischemia and removal of the transplanted liver cells by splenectomy. Intrasplenic injection of graded doses of neonatal liver cells decreased mortality from 75% at a dose of 10 x 10(6) cells, to 36% at 160 x 10(6) cells. Treatment of neonatal liver cells with metabolic inhibitors did not significantly affect their ability to reverse acute hepatic ischemia.  相似文献   
954.
In 1985, we initiated a prospective clinical trial to evaluate the risk of recurrence for superficial bladder cancer. Up to now, 41 patients subjected to TUR have subsequently been monitored by immunocytology with a monoclonal antibody (mab 486 p) recently developed in our laboratory. Of these patients, 15 (36.6%) remained marker-negative and received no prophylactic therapy. There was only one recurrence (6.7%) in this subset of patients, whereas 10 out of 26 (38.5%) marker-positive patients have so far developed recurrent malignancies. In all cases, the conversion of immunocytological characteristics preceded visible recurrence by 2-5 months. These preliminary results indicate that immunocytology might make it possible to identify patients at low risk of recurrence more accurately than has so far been feasible with standard cytology or flow-cytometry.  相似文献   
955.
The effect of oxitropium bromide (Ba253), a quaternary scopolamine derivative, on the resting tonus and agonist-induced contraction of isolated guinea pig airway smooth muscle and on the anaphylactic release of histamine and immunoreactive leukotrienes (i-LTs) from lung fragments were investigated and compared with those of Sch1000, atropine and isoproterenol. Ba253 dose-dependently inhibited the acetylcholine (ACh)-induced contraction of the isolated trachea and lung parenchyma. The degree of inhibitory potency was similar to that of Sch1000 and 10 times higher than that of atropine. Ba253 minimally influenced the resting tonus or contractions induced by other agonists including histamine, serotonin and LTD4. Sch1000 and atropine had similar or slightly stronger inhibitory effects on the tonus and contractions than Ba253. On the other hand, low concentrations of isoproterenol solely relaxed the resting tonus and inhibited the the agonist-induced contractions of both preparations. Neither Ba253 nor Sch1000 inhibited the anaphylactic release of histamine and LTs from both guinea pig and human lung fragments, but both mediator releases from either species were slightly inhibited with dose-dependency by atropine and potently inhibited by isoproterenol. From these results, it is suggested that Ba253 is a relatively specific antagonist to cholinergic receptors and might be possibly effective as an inhalant for asthma.  相似文献   
956.
957.
958.
959.
The dissociation of visuospatial neglect and neglect dyslexia.   总被引:5,自引:3,他引:2       下载免费PDF全文
A right-handed man with a left hemisphere lesion extending into the right hemisphere, with evidence of both a left-sided neglect dyslexia and right-sided visuospatial neglect is reported. When copying simple geometric designs he omitted to copy figures on the right-hand side of the page, when bisecting lines he tended to bisect the line to the left of the line's actual centre. He had a neglect dyslexia which was characterised by paralexic errors affecting the beginning (that is, left) of words. The occurrence of these two phenomena provides evidence of a dissociation of these forms of neglect. The findings are discussed in relation to the possible mechanisms of unilateral neglect.  相似文献   
960.
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