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   263600篇
  免费   10712篇
  国内免费   729篇
耳鼻咽喉   3850篇
儿科学   7435篇
妇产科学   6233篇
基础医学   37189篇
口腔科学   9310篇
临床医学   15955篇
内科学   59231篇
皮肤病学   7629篇
神经病学   21883篇
特种医学   6272篇
外国民族医学   3篇
外科学   30056篇
综合类   1448篇
一般理论   57篇
预防医学   29956篇
眼科学   6496篇
药学   20287篇
中国医学   1279篇
肿瘤学   10472篇
  2023年   1451篇
  2022年   2233篇
  2021年   5515篇
  2020年   2937篇
  2019年   5443篇
  2018年   8134篇
  2017年   5051篇
  2016年   5055篇
  2015年   5673篇
  2014年   7185篇
  2013年   10525篇
  2012年   16691篇
  2011年   17841篇
  2010年   9284篇
  2009年   7232篇
  2008年   14260篇
  2007年   15175篇
  2006年   14301篇
  2005年   14006篇
  2004年   12821篇
  2003年   11957篇
  2002年   11238篇
  2001年   7591篇
  2000年   8344篇
  1999年   6637篇
  1998年   1424篇
  1997年   1054篇
  1996年   923篇
  1992年   3211篇
  1991年   2803篇
  1990年   2690篇
  1989年   2296篇
  1988年   2155篇
  1987年   2004篇
  1986年   2034篇
  1985年   1854篇
  1984年   1342篇
  1983年   1165篇
  1979年   1495篇
  1978年   999篇
  1975年   1051篇
  1974年   1381篇
  1973年   1423篇
  1972年   1330篇
  1971年   1310篇
  1970年   1196篇
  1969年   1286篇
  1968年   1308篇
  1967年   1172篇
  1966年   1013篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
22.
23.
The present authors investigated the excretion, distribution and pharmacokinetics of the novel potential antirheumatic agent flobufen and its active metabolite after p.o. and i.v. doses of 2, 10 and 50 mg/kg administered to rats. The drug is resorbed well from the digestive tract and mostly it is metabolized to the principal metabolite M, which is only slowly excreted from the organism mainly by renal clearance. Within the whole dose range the kinetics of the drug is linear. Binding of flobufen and M to proteins is high (95-99%). The highest concentrations of radioactive metabolites (mostly M) were found in the plasma, liver, lungs, kidneys, connective tissue and inflammatory foci. The penetration of metabolites through the placenta and excretion in human milk are relatively important.  相似文献   
24.
25.
26.
Summary In cases where a reconstruction of defects in the larynx, oral cavity, the pharynx or in the ear region has been performed using skin flaps, a temporary fistula is formed at the point of entry.This fistula can be closed later after the flap has taken and the flap pedicle dissected.We would like to demonstrate with some examples that with the use of deepithelisation it is possible to achieve a primary wound closure. This way no temporary fistula results and additional surgery is avoided in many cases.Furthermore flap deepithelisation offers a way to bring good vascularised tissue under the skin and cover subcutaneous defects, for example those after radiotherapy.

Die Veröffentlichung des Manuskripts soll in Laryngol Rhinol Otol (Stuttg) erfolgen  相似文献   
27.
28.
Summary In this work, we have studied the time-course of the effects of pharmacological administration of ovarian steroids on tyrosine hydroxylase (TH) activity in the limbic forebrain of ovariectomized rats. Administration of estradiol produced a late decrease in TH activity. This effect was found 24 hours after the last steroid injection, disappearing at 32 hours. It was antagonized by progesterone, since a single injection of this steroid to estradiol-pretreated rats reversed to control values the estradiol-induced decrease. Nevertheless, the administration of progesterone after estradiol treatment caused a short-time decrease in the limbic activity of TH, which was observed 4 hours after the last steroid injection, disappearing subsequently. On the other hand, the administration of progesterone alone produced a biphasic effect, with a reduction at 24 hours, followed by an increase at 32 hours. These effects were only observed in the animals non-treated with estradiol, disappearing with a previous treatment with estrogens. Hence, it can be concluded that both ovarian steroids may affect the limbic TH activity. Thus, estradiol produced a late inhibitory effect on the activity of this enzyme, which was antagonized by progesterone. Administration of the last one to estradiol-treated rats produced a short-time inhibitory effect, whereas its administration to non-treated rats produced a late biphasic effect (inhibition followed by stimulation), which was not observed in estradiol-treated rats.  相似文献   
29.
Melatonin, a pineal hormone, released photoperiodically, was administered systemically in rats, previously implanted with semimicroelectrodes into six different brain structures. The multiunit electrical activity of these structures was recorded for 10 min before and 60 min after melatonin administration in unanesthetized, freely moving rats. Different melatonin doses (100, 200, 500, and 1000 micrograms/kg) produced changes in the electrical activity of all tested structures. However, amygdala, rostral hypothalamus and mesencephalic reticular formation showed the most important changes. The main effect induced by melatonin was a dose-related decrease of the spontaneous electrical activity. The significance of these effects is discussed within the context of the behavioral and endocrinological effects of melatonin.  相似文献   
30.
V Váradi  L Karmazsin 《Orvosi hetilap》1989,130(24):1251-1255
Prenatal, intrapartum and postnatal factors were investigated in less than 32 gestational age preterm infants known to have periventricular haemorrhage or periventricular leukomalacia. The diagnoses were established on cranial ultrasonography and/or autopsy. Factors associated with periventricular haemorrhage were: postnatal severe hypercapnia, acidosis and hypoxia. In the periventricular leukomalacia group the incidence of antepartum and intrapartum hypoxia and/or ischaemia (antepartum haemorrhage) were significantly higher than in the control group.  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