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   1438769篇
  免费   116851篇
  国内免费   5257篇
耳鼻咽喉   18585篇
儿科学   46886篇
妇产科学   41289篇
基础医学   203293篇
口腔科学   38306篇
临床医学   129836篇
内科学   287495篇
皮肤病学   33706篇
神经病学   117954篇
特种医学   54940篇
外国民族医学   477篇
外科学   212977篇
综合类   38621篇
现状与发展   13篇
一般理论   490篇
预防医学   112572篇
眼科学   32220篇
药学   102068篇
  38篇
中国医学   6128篇
肿瘤学   82983篇
  2021年   12939篇
  2019年   12768篇
  2018年   17688篇
  2017年   13816篇
  2016年   15221篇
  2015年   17454篇
  2014年   24229篇
  2013年   35037篇
  2012年   47749篇
  2011年   50304篇
  2010年   29852篇
  2009年   28365篇
  2008年   45800篇
  2007年   48278篇
  2006年   48714篇
  2005年   46942篇
  2004年   44519篇
  2003年   42580篇
  2002年   40883篇
  2001年   73597篇
  2000年   74930篇
  1999年   61878篇
  1998年   17174篇
  1997年   15600篇
  1996年   15712篇
  1995年   14896篇
  1994年   13481篇
  1993年   12640篇
  1992年   45920篇
  1991年   43531篇
  1990年   41561篇
  1989年   39588篇
  1988年   36224篇
  1987年   35387篇
  1986年   32884篇
  1985年   31290篇
  1984年   23837篇
  1983年   20030篇
  1982年   12212篇
  1981年   10784篇
  1979年   20712篇
  1978年   14580篇
  1977年   12086篇
  1976年   11365篇
  1975年   11620篇
  1974年   13990篇
  1973年   13534篇
  1972年   12635篇
  1971年   11469篇
  1970年   10910篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
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   
102.
103.
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   
104.
105.
106.
107.
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   
108.
109.
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   
110.
A rotating contact lens holder for the three-mirror Goldmann lens permits circular examination of the fundus or chamber angle without having to change the position of the fingers on the edge of the lens. The contact lens holder consists of an outer polygonal ring hold by the thumber and index finger. An inner rotating ring holds the contact lens. Continuous rotation of the contact lens is performed with the free middle Finger. This device permits circular examination of the retina without interruption of fixation. The instrument improves not only the speed but also the reliability of the examination.  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