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   2351538篇
  免费   171319篇
  国内免费   3335篇
耳鼻咽喉   32063篇
儿科学   75917篇
妇产科学   62723篇
基础医学   348302篇
口腔科学   63656篇
临床医学   211534篇
内科学   457480篇
皮肤病学   51751篇
神经病学   185362篇
特种医学   88087篇
外国民族医学   489篇
外科学   354160篇
综合类   47535篇
现状与发展   12篇
一般理论   849篇
预防医学   182819篇
眼科学   54363篇
药学   175229篇
  11篇
中国医学   4584篇
肿瘤学   129266篇
  2021年   19049篇
  2019年   19616篇
  2018年   27129篇
  2017年   20417篇
  2016年   22800篇
  2015年   25683篇
  2014年   36166篇
  2013年   54065篇
  2012年   74787篇
  2011年   79528篇
  2010年   47126篇
  2009年   44635篇
  2008年   74682篇
  2007年   79534篇
  2006年   80334篇
  2005年   77818篇
  2004年   74411篇
  2003年   71725篇
  2002年   69392篇
  2001年   108754篇
  2000年   111463篇
  1999年   93499篇
  1998年   26995篇
  1997年   23659篇
  1996年   24057篇
  1995年   22720篇
  1994年   20895篇
  1993年   19713篇
  1992年   72006篇
  1991年   70072篇
  1990年   68393篇
  1989年   65668篇
  1988年   60309篇
  1987年   59133篇
  1986年   55222篇
  1985年   53011篇
  1984年   39315篇
  1983年   33404篇
  1982年   19862篇
  1979年   35867篇
  1978年   25652篇
  1977年   21230篇
  1976年   20332篇
  1975年   21818篇
  1974年   26148篇
  1973年   24802篇
  1972年   23200篇
  1971年   22037篇
  1970年   20247篇
  1969年   19316篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
The effect of proteases inhibitors, epsilon-amino-caproic acid and gordox, on reproduction of rotavirus SA-11 in MA-104 cells was studied by enzyme immunoassay. These inhibitors were shown to exert an inhibiting effect on rotavirus reproduction.  相似文献   
952.
953.
954.
The purpose of this study was to evaluate a new fluorescence polarization immunoassay, TDx, for digitoxin by comparing the results of this assay with those of a radioimmunoassay (RIA). Thirty-three serum samples were obtained from 15 patients during, and for 4 weeks after, a 4-week course of digitoxin therapy. Each sample was separated by centrifugation, coded, and frozen until analysis. At the time of analysis, each sample was divided and analyzed simultaneously by TDx and RIA. Nine samples yielded results less than 2 ng/ml (limit of assay sensitivity) by one or both methods and were excluded from further data analysis. Linear regression analysis of the results of the remaining 24 paired samples (x = TDx, y = RIA) revealed a strong correlation coefficient of r2 = 0.95, slope = 0.95, and a y intercept of -0.99 (y = -0.99 + 0.95x). Additionally, the TDx results were lower than the RIA values in only five of 33 paired samples; and these occurred in four patients who had a significantly lower mean estimated creatinine clearance than that of the other 11 patients (39.0 +/- 9.1 ml/min/1.73 m2 vs. 63.3 +/- 11.8 ml/min/1.73 m2, p less than 0.01). The TDx system is a comparable alternative to the RIA method, but differences in specificity and sensitivity may exist and should be evaluated more thoroughly.  相似文献   
955.
956.
Trends in analgesic self-poisoning in West-Fife, 1971-1985   总被引:1,自引:0,他引:1  
All admissions for analgesic self-poisoning to a district poisons unit over a 15-year period have been reviewed. During this time overdose with analgesic drugs increased to represent almost half of all admissions for self-poisoning. The types of analgesics taken in overdose also changed significantly during the period of this review. Aspirin and Distalgesic poisoning declined in incidence and more cases of self-poisoning by paracetamol and non-steroidal anti-inflammatory agents were seen. The impact of these changes on the medical management and outcome of deliberate self-poisoning is analysed. The reasons behind the trends described in this paper are assessed and their implications for future prevention and treatment are discussed.  相似文献   
957.
958.
959.
960.
Cardiovascular function was studied in anaesthetised male rats which received 50 micrograms/ml of arsenic (as sodium arsenate) in deionised drinking water for 320 days. High urinary excretion of arsenic was found at the end of treatment and the metal accumulated considerably in the kidneys and liver, which both presented slight alterations. No histopathological modifications were evident in other organs. Base line blood pressure, cardiac inotropism, and chronotropism and cardiovascular reactivity to noradrenaline, acetylcholine, angiotensin II, bradykinin, histamine, and serotonin did not differ in exposed or in control animals. In the exposed group, however, there was potentiation of the effects of vascular beta-adrenoceptor stimulation and a reduction in the vascular responsiveness to angiotensin I. Chronic arsenic exposure did not affect the baroreflex sensitivity but was able to induce sympathetic hyperactivity or hypersensitivity, or both, possibly associated with an antivagal action. Our results might help to explain the cardiovascular alterations seen in people chronically exposed to high concentrations of arsenic.  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