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   264888篇
  免费   9491篇
  国内免费   2198篇
耳鼻咽喉   3560篇
儿科学   8938篇
妇产科学   7292篇
基础医学   34579篇
口腔科学   7546篇
临床医学   23483篇
内科学   48843篇
皮肤病学   5473篇
神经病学   17871篇
特种医学   13181篇
外国民族医学   117篇
外科学   37005篇
综合类   4942篇
现状与发展   5篇
一般理论   50篇
预防医学   21069篇
眼科学   5942篇
药学   19327篇
  36篇
中国医学   1603篇
肿瘤学   15715篇
  2022年   1778篇
  2021年   2548篇
  2020年   1838篇
  2019年   1890篇
  2018年   5505篇
  2017年   5577篇
  2016年   5048篇
  2015年   6988篇
  2014年   7241篇
  2013年   6849篇
  2012年   14895篇
  2011年   10161篇
  2010年   5462篇
  2009年   6718篇
  2008年   6265篇
  2007年   7298篇
  2006年   7278篇
  2005年   15191篇
  2004年   16048篇
  2003年   11558篇
  2002年   6478篇
  2001年   5182篇
  2000年   2581篇
  1999年   6839篇
  1998年   1422篇
  1992年   7278篇
  1991年   7452篇
  1990年   7672篇
  1989年   7249篇
  1988年   6763篇
  1987年   6493篇
  1986年   6216篇
  1985年   5522篇
  1984年   3797篇
  1983年   3100篇
  1982年   1218篇
  1979年   3973篇
  1978年   2497篇
  1977年   1928篇
  1976年   1667篇
  1975年   2600篇
  1974年   3221篇
  1973年   2828篇
  1972年   2818篇
  1971年   2807篇
  1970年   2609篇
  1969年   2516篇
  1968年   2287篇
  1967年   2234篇
  1966年   1955篇
排序方式: 共有10000条查询结果,搜索用时 22 毫秒
991.
992.
993.
The ulcerogenic effect of five different salts of alprenolol were tested against placebo in a porcine oesophageal test model. The salts with high water solubility, such as the hydrochloride and the fumarate, gave rise to the highest plasma concentrations of alprenolol and evoked serious oesophageal lesions, while the salts with low solubility-the benzoate, maleate and sebacate-had no irritative effect on the oesophagus. The plasma levels of alprenolol were much higher following administration of alprenolol hydrochloride in the oesophagus than after an identical intraduodenal dose of the same salt possibly because of the avoidance of the first-pass degradation during oesophageal absorption.  相似文献   
994.
995.
996.
This paper describes performance and results of a collaborative study in which the solid-phase enzyme immunoassay was tested in order to determine specific IgE under practical conditions. All titres of specific IgE can be differentiated in a reproducible way with high significance.  相似文献   
997.
998.
Radioreceptor assay (RRA) was used to evaluate serum antimuscarinic activity in 10 healthy volunteers after a single dose of scopolamine hydrobromide (ScHBr) solution, 0.02 mg/kg, by a new oral administration method. Cardiac, antisialogogue, and subjective effects of the drug were also recorded. Although clinically useful antisialogogue and sedative effects were obtained 40 to 60 minutes after the administration of ScHBr, no reliable antimuscarinic activity was evaluated in serum samples for up to 3 hours. Clinically useful sedative and antisialogogue effects can be reached by gastrointestinal absorption of ScHBr solution.  相似文献   
999.
The radiological appearance of mostly broad-based polyps in the rectosigmoid was studied in 35 patients. In all patients the diagnosis was histologically confirmed after surgical treatment. Conclusions on the histological tumour status could not be drawn either from surface structure, broadness of base and retraction of base, or from the base/height ratio. Stenosing growth, however, was seen relatively more often with carcinomas than with benign lesions. The discovery and identification of five carcinomas having a size of up to 2 cm illustrates the need for complete removal and histological processing of even seemingly negligible residues of polypous processes in the rectosigmoid.  相似文献   
1000.
Whole sympathetic superior cervical ganglia of 14- and 15-day-old rat embryos were cultured in a collagen gel medium for 24 h with or without explants of heart atrium from the same animals or from newborn rats. The extent of nerve fibre outgrowth was estimated by counting the number of nerve fibres crossing each arc of a sector drawn in the microscope ocular. Only few nerve fibres extended from the ganglia of the 14-day-old embryos cultured in the pure control medium. Addition of exogenous nerve growth factor did not stimulate the poor growth. While the growth of nerve fibres in the presence of atrium explants of newborn rats did not significantly differ from that in cultures without any target tissue, the presence of atrium explants of the same, 14-day-old, embryo resulted in clearly enhanced fibre outgrowth from the ganglia, which was inhibited by antiserum to the nerve growth factor. The ganglia of 15-day-old embryos cultured without target tissue in the control medium produced only sparse fibre outgrowth which was excessively increased by exogenous nerve growth factor. Coculture with atrium explants of 15-day-old embryos or newborn rats produced an increased overall nerve fibre growth, as well as predominance of those fibres growing toward the target tissue. The growth-promoting effect of the atrium of 15-day-old embryos was only partially prevented by antiserum to the nerve growth factor, while that elicited by newborn rat atrium was totally inhibited.(ABSTRACT TRUNCATED AT 250 WORDS)  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