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   1346759篇
  免费   105064篇
  国内免费   5083篇
耳鼻咽喉   23307篇
儿科学   42874篇
妇产科学   37735篇
基础医学   178064篇
口腔科学   33367篇
临床医学   122522篇
内科学   285819篇
皮肤病学   34497篇
神经病学   112141篇
特种医学   53834篇
外国民族医学   350篇
外科学   227632篇
综合类   22765篇
现状与发展   74篇
一般理论   528篇
预防医学   92710篇
眼科学   32108篇
药学   81857篇
  1篇
中国医学   2204篇
肿瘤学   72517篇
  2021年   11753篇
  2020年   11011篇
  2019年   11364篇
  2018年   19500篇
  2017年   16889篇
  2016年   18600篇
  2015年   22907篇
  2014年   35306篇
  2013年   45753篇
  2012年   45663篇
  2011年   48215篇
  2010年   36713篇
  2009年   38754篇
  2008年   47043篇
  2007年   47815篇
  2006年   49850篇
  2005年   47019篇
  2004年   44418篇
  2003年   40499篇
  2002年   38488篇
  2001年   47158篇
  2000年   47244篇
  1999年   41770篇
  1998年   16673篇
  1997年   15292篇
  1996年   14907篇
  1995年   14004篇
  1994年   12461篇
  1993年   11518篇
  1992年   31805篇
  1991年   30334篇
  1990年   29392篇
  1989年   28130篇
  1988年   26176篇
  1987年   25690篇
  1986年   24767篇
  1985年   23416篇
  1984年   18452篇
  1983年   15933篇
  1982年   11001篇
  1981年   9653篇
  1979年   16334篇
  1978年   12224篇
  1977年   10482篇
  1976年   9692篇
  1975年   10493篇
  1974年   12237篇
  1973年   11703篇
  1972年   10971篇
  1971年   10024篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
121.
122.
123.
124.
125.
Omeprazole is a member of a new class of substituted benzimidazoles. These agents inhibit the proton pump in the gastric parietal cell, blocking the final step in the gastric acid secretory pathway. Omeprazole has been investigated for the treatment of gastric ulcer, duodenal ulcer, gastroesophageal reflux, and various hypersecretory states. The prolonged inhibition of gastric acid secretion allows for once-daily dosing in patients with peptic ulcer disease and gastroesophageal reflux, and once- or twice-daily dosing in patients with Zollinger-Ellison syndrome. Compared with currently available therapies, omeprazole is well tolerated and demonstrates a more rapid ulcer healing rate. It is superior to conventional therapies in the treatment of Zollinger-Ellison syndrome. Side effects are infrequent when the drug is used for the short-term management of ulcers.  相似文献   
126.
Case report 506   总被引:1,自引:0,他引:1  
  相似文献   
127.
Electrocardiographic symptoms were evaluated in 53 patients with an additional left-ventricular chorda (ALVC), detected by two-dimensional echocardiography. Signs of early ventricular repolarization (EVR) were identified in 45 (84.9%) patients. A transverse ALVC was more common in EVR-free patients (87.5%), as compared to patients with ALVC + EVR combinations (51.1%; p less than 0.05).  相似文献   
128.
Summary: This is the first report of the largest study of blood pressure measurement in pregnancy in a New Zealand population using standardized definitions and methodology. Over 3,800 women who delivered in an 8-month period in the Wellington region were included in the study. Blood pressure measurement and the presence of oedema and proteinuria were recorded from booking until delivery and in the puerperium. Only 2.7% of women were unable to be contacted after delivery for details on outcomes. The results established normal ranges for blood pressure throughout pregnancy. The data show that Mood pressure greater than 140/90 until 35 weeks' gestation is outside 2 standard deviations at all gestations and justifies using these measurements as the definition of hypertension in pregnancy. The fall in blood pressure in the 2nd trimester was less than 1 mm Ffg per week in both the systolic and diastolic pressures. This fall was smaller than previously recorded in other studies. Gestational hypertension was the commonest blood pressure abnormality occurring in 15.2% of the population. This represented 69% of the pregnant women with a hypertensive disorder. The overall incidence of both gestational hypertension and preeclampsia was 18.5% which is higher than reported in other parts of the world. In this study obesity was significantly associated with hypertensive disorders in pregnancy. An arm circumference of >33 cm, one of the measurements of obesity, was found in 6.8% of the study population. Even after the effect of arm circumference was taken into account, hypertensive disorders were also more common in Pacific Island women. Ankle oedema was significantly associated with the development of both gestational hypertension and preeclampsia but the incidence of oedema was noted in only 11.9% of the subjects.  相似文献   
129.
The adult mammalian central nervous system (CNS) lacks the capacity to support axonal regeneration. There is increasing evidence to suggest that astrocytes, the major glial population in the CNS, may possess both axon-growth promoting and axon-growth inhibitory properties and the latter may contribute to the poor regenerative capacity of the CNS. In order to examine the molecular differences between axon-growth permissive and axon-growth inhibitory astrocytes, a panel of astrocyte cell lines exhibiting a range of axon-growth promoting properties was generated and analysed. No clear correlation was found between the axon-growth promoting properties of these astrocyte cell lines with: (i) the expression of known neurite-outgrowth promoting molecules such as laminin, fibronectin andN-cadherin; (ii) the expression of known inhibitory molecules such tenascin and chondroitin sulphate proteoglycan; (iii) plasminogen activator and plasminogen activator inhibitor activity; and (iv) growth cone collapsing activity. EM studies on aggregates formed from astrocyte cell lines, however, revealed the presence of an abundance of extracellular matrix material associated with the more inhibitory astrocyte cell lines. When matrix deposited by astrocyte cell lines was assessed for axon-growth promoting activity, matrix from permissive lines was found to be a good substrate, whereas matrix from the inhibitory astrocyte lines was a poor substrate for neuritic growth. Our findings, taken together, suggest that the functional differences between the permissive and the inhibitory astrocyte cell lines reside largely with the ECM.  相似文献   
130.
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