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   1450814篇
  免费   116252篇
  国内免费   4283篇
耳鼻咽喉   18720篇
儿科学   47464篇
妇产科学   42024篇
基础医学   205043篇
口腔科学   38395篇
临床医学   129681篇
内科学   293610篇
皮肤病学   33993篇
神经病学   120465篇
特种医学   55211篇
外国民族医学   466篇
外科学   216220篇
综合类   34832篇
现状与发展   4篇
一般理论   487篇
预防医学   112204篇
眼科学   32022篇
药学   101915篇
  9篇
中国医学   4300篇
肿瘤学   84284篇
  2021年   12441篇
  2019年   12729篇
  2018年   17755篇
  2017年   13634篇
  2016年   15298篇
  2015年   17333篇
  2014年   24263篇
  2013年   35405篇
  2012年   48080篇
  2011年   50658篇
  2010年   29775篇
  2009年   28524篇
  2008年   46569篇
  2007年   49068篇
  2006年   49426篇
  2005年   47780篇
  2004年   45493篇
  2003年   43188篇
  2002年   41530篇
  2001年   73931篇
  2000年   75396篇
  1999年   62413篇
  1998年   17355篇
  1997年   15708篇
  1996年   15843篇
  1995年   15012篇
  1994年   13596篇
  1993年   12751篇
  1992年   46294篇
  1991年   43873篇
  1990年   41873篇
  1989年   39945篇
  1988年   36505篇
  1987年   35672篇
  1986年   33151篇
  1985年   31493篇
  1984年   24024篇
  1983年   20175篇
  1982年   12304篇
  1981年   10866篇
  1979年   20872篇
  1978年   14674篇
  1977年   12162篇
  1976年   11435篇
  1975年   11682篇
  1974年   14073篇
  1973年   13632篇
  1972年   12722篇
  1971年   11551篇
  1970年   10983篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
101.
The Authors examine the correlation between hypertensive disorders of pregnancy and fetal growth. The results of a study of 342 pregnancies, confirm a significant correlation between hypertension and fetal growth retardation. These findings, so evident in moderate and severe hypertension, have also been confirmed in cases of mild hypertension. The medical treatment also in the pregnancies with mild hypertension, and a larger utilisation of operative deliveries, determined a decrease in perinatal mortality and morbidity.  相似文献   
102.
Fifteen cases of microtuboplasty were done as outpatient procedures at low cost and with increased patient convenience. Advances in outpatient surgery at free-standing surgery centers have allowed many new patient care innovations, and microsurgery should now be considered an outpatient procedure for gynecologic patients. Outpatient microtuboplastic surgery is not only feasible but perhaps preferable to that done as an inpatient procedure.  相似文献   
103.
104.
Background : The clinical course of chronic hepatitis B is variable. Patients with hepatic decompensation, bridging necrosis or an alpha-fetoprotein level greater than 100 ng/mL during an exacerbation of hepatitis have a high risk of developing cirrhosis. This study was conducted to evaluate the effect of colchicine in the prevention of cirrhosis in such patients.
Methods : Patients with risk factor(s) were randomized to receive either colchicine 5 mg/week or no specific treatment, the end point being development of cirrhosis.
Results : After a follow up period of 4 years, the treatment group had a marked reduction in exacerbations of acute hepatitis (32% vs. 63%/patient/year, P <0.005). Seven out of 38 patients in the treatment group and 10 out of 27 patients in the control group developed cirrhosis. The calculated cumulative incidence of cirrhosis by the end of first, second, third and fourth years in the treatment group was 8.7, 18.6, 32 and 32%, respectively. The corresponding figures in the control group were 30, 35.5, 46.3 and 73.2%, respectively, with a P -value of 0.057.
Conclusions : The results suggest that colchicine may prevent cirrhosis in chronic hepatitis B patients with risk factor(s), possibly by suppressing exacerbations of hepatitis through an anti-inflammatory effect.  相似文献   
105.
106.
107.
108.
Birth weight on 12,644 singleton infants from 6,196 sibships born in Maryland between 1980 and 1984 were used to estimate the effects of nine maternal and infant covariates on the sibship correlation in birth weight. Assuming a homogeneous correlation across all families, the estimated intraclass correlation was 0.4664 (+/- 0.0099). This high sibship correlation makes it possible to predict, with reasonable accuracy, the birth weight of a child given information on previous sibs, as well as covariates on the mother and/or infant pertinent to a given pregnancy. The reduction in variance associated with incorporating information on the nine covariates used here was approximately equal to that obtained by conditioning on a single previous sib. Testing for heterogeneity in correlation among different groups of families showed that a crude measure of parity (first live birth vs. other), time between births, mother's marital status, and maternal age at the birth of the last child significantly influenced the sibship correlation in birth weight.  相似文献   
109.
110.
One of our patients had trouble maintaining therapeutic and safe levels of theophylline, even though we were careful in planning and monitoring her drug regimen. This case report shows how we were able to use principles of pharmacokinetics to distinguish among plausible explanations for her experience. We discovered that she was not taking the drug consistently as prescribed and that supervised administration resolved apparent contradictions between doses and serum levels. We believe that physicians can use the same information and methods that we used to get better and safer results from theophylline therapy.  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