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   1381篇
  免费   136篇
  国内免费   9篇
耳鼻咽喉   7篇
儿科学   51篇
妇产科学   11篇
基础医学   147篇
口腔科学   49篇
临床医学   160篇
内科学   343篇
皮肤病学   41篇
神经病学   67篇
特种医学   164篇
外国民族医学   1篇
外科学   172篇
综合类   54篇
预防医学   142篇
眼科学   9篇
药学   62篇
中国医学   1篇
肿瘤学   45篇
  2021年   8篇
  2020年   12篇
  2019年   16篇
  2018年   23篇
  2017年   26篇
  2016年   27篇
  2015年   39篇
  2014年   28篇
  2013年   47篇
  2012年   51篇
  2011年   58篇
  2010年   48篇
  2009年   62篇
  2008年   50篇
  2007年   40篇
  2006年   36篇
  2005年   39篇
  2004年   52篇
  2003年   29篇
  2002年   27篇
  2001年   23篇
  2000年   20篇
  1999年   29篇
  1998年   59篇
  1997年   68篇
  1996年   58篇
  1995年   45篇
  1994年   47篇
  1993年   44篇
  1992年   20篇
  1991年   18篇
  1990年   24篇
  1989年   26篇
  1988年   31篇
  1987年   31篇
  1986年   34篇
  1985年   16篇
  1984年   9篇
  1983年   17篇
  1982年   23篇
  1980年   10篇
  1979年   17篇
  1978年   12篇
  1977年   9篇
  1976年   10篇
  1975年   7篇
  1973年   8篇
  1971年   7篇
  1970年   7篇
  1968年   11篇
排序方式: 共有1526条查询结果,搜索用时 15 毫秒
81.
饶曼人  刘丰 《药学学报》1988,23(2):100-103
尼群的平20μg/kg iv显著降低麻醉犬血压的过程,冠状窦流量明显增加。持续3h,冠状窦氧含量增加,氧摄取率、心肌耗氧量、二氧化碳产生率降低,持续了3h以上,说明该剂适用于高血压伴心肌缺血。  相似文献   
82.
83.
84.
AimsTo determine whether palliation of chest symptoms from a 10 Gy single fraction (regimen 1) was equivalent to that from 30 Gy in 10 fractions (regimen 2).Materials and methodsPatients with cytologically proven, symptomatic lung cancer not amenable to curative therapy, with performance status 0–3, were randomised to receive either 30 Gy in 10 fractions or a 10 Gy single fraction. Local symptoms were scored on a physician-assessed, five-point categorical scale and summed to produce a total symptom score (TSS). This, performance status, Hospital Anxiety and Depression (HAD) score and Spitzer's quality-of-life index were noted before treatment, at 1 month after treatment and every 2 months thereafter. Palliation was defined as an improvement of one point or more in the categorical scale. Equivalence was defined as less than 20% difference in the number achieving an improvement in the TSS.ResultsWe randomised 149 patients and analysed 74 in each arm. According to the design criteria, palliation was equivalent between the two arms. TSS improved in 49 patients (77%) on regimen 1, and in 57 (92%) patients on regimen 2, a difference of 15% (95% confidence interval [CI] 3–28) in the proportion improving between the two regimens. A complete resolution of all symptoms was achieved in three (5%) on regimen 1, and in 14 (23%) patients on regimen 2 (P < 0.001), a difference in the proportion between the two regimens of 21% (95% CI 10–33). A significantly higher proportion of patients experienced palliation and complete resolution of chest pain and dyspnoea with regimen 2. No differences were observed in toxicity. The median survival was 22.7 weeks for regimen 1 and 28.3 weeks for regimen 2 (P = 0.197).ConclusionsAlthough this trial met the pre-determined criteria for equivalence between the two palliative regimens, significantly more patients achieved complete resolution of symptoms and palliation of chest pain and dyspnoea with the fractionated regimen.  相似文献   
85.
86.
87.
BACKGROUND: Because obesity promotes inflammation and imposes mechanical constraints to the airways, a high birth weight may be a risk factor for asthma in childhood. However, to our knowledge, few studies have examined this potential relationship. OBJECTIVE: To determine the relationship between high birth weight and risk of emergency visits for asthma during childhood. DESIGN: Population-based cohort study. SETTING: Alberta, Canada. PARTICIPANTS: All neonates born at term (> or =37 weeks) between April 1, 1985, and March 31, 1988, in Alberta (N = 83,595). We divided the cohort into birth-weight categories: low (<2.5 kg), normal (2.5-4.5 kg), or high (>4.5 kg). The cohort was observed prospectively for 10 years.Main Outcome Measure Comparison of risk of emergency visits for asthma over 10 years across the birth-weight categories. RESULTS: Neonates born with a high birth weight had a significantly increased risk of emergency visits for asthma during childhood compared with neonates born with a normal birth weight (relative risk [RR], 1.16; 95% confidence interval [CI], 1.04-1.29). The relationship between birth weight and emergency visits for asthma beyond a birth weight of 4.5 kg was linear, such that every increment of 0.10 kg in birth weight was associated with an additional 10% (95% CI, 2%-19%) increase in the risk of emergency visits for asthma. Other factors associated with an elevated risk for emergency asthma visits during childhood included male sex (RR, 1.26; 95% CI, 1.22-1.30), aboriginal status (RR, 1.20; 95% CI, 1.11-1.29), and low-income status (RR, 1.11; 95% CI, 1.06-1.16). CONCLUSIONS: A high, but not low, birth weight is a risk factor for increased emergency visits during childhood. The risk increases linearly beyond a birth weight of 4.5 kg.  相似文献   
88.
89.
Annotated references in epidemiology   总被引:1,自引:0,他引:1  
The burden that heart failure imposes on the health care systems of the developed world is substantial and increasing. This article reviews the world literature on the epidemiology of heart failure and discusses the key methodological issues for research in this field.  相似文献   
90.
The nuclear medicine bleeding scan is frequently insufficient to locate sites of bleeding precisely, in spite of its great sensitivity. A small, hand-held Geiger-Müller counter, placed directly on exposed intestine in the operating room, enables precise location of the probable bleeding site. In three patients, the technique allowed a minimal amount of intestine to be resected, distinguished between large- and small-intestinal hemorrhage, and eliminated other foci as sites of bleeding.  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