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   1336484篇
  免费   100322篇
  国内免费   4275篇
耳鼻咽喉   16812篇
儿科学   43608篇
妇产科学   36375篇
基础医学   198005篇
口腔科学   35926篇
临床医学   129715篇
内科学   258397篇
皮肤病学   26387篇
神经病学   111958篇
特种医学   48255篇
外国民族医学   366篇
外科学   184221篇
综合类   28789篇
现状与发展   1篇
一般理论   460篇
预防医学   114433篇
眼科学   29003篇
药学   98912篇
  6篇
中国医学   3174篇
肿瘤学   76278篇
  2021年   10960篇
  2019年   11698篇
  2018年   16401篇
  2017年   12333篇
  2016年   13299篇
  2015年   15235篇
  2014年   20859篇
  2013年   32113篇
  2012年   44337篇
  2011年   46965篇
  2010年   27127篇
  2009年   24953篇
  2008年   42772篇
  2007年   45112篇
  2006年   45220篇
  2005年   43638篇
  2004年   41601篇
  2003年   39531篇
  2002年   38336篇
  2001年   60858篇
  2000年   62534篇
  1999年   52292篇
  1998年   14581篇
  1997年   13277篇
  1996年   13121篇
  1995年   12456篇
  1994年   11629篇
  1993年   10922篇
  1992年   41575篇
  1991年   40772篇
  1990年   39449篇
  1989年   37350篇
  1988年   34590篇
  1987年   33696篇
  1986年   32162篇
  1985年   30645篇
  1984年   23043篇
  1983年   19598篇
  1982年   11757篇
  1979年   20812篇
  1978年   14823篇
  1977年   12068篇
  1976年   11882篇
  1975年   12116篇
  1974年   14804篇
  1973年   14483篇
  1972年   13357篇
  1971年   12424篇
  1970年   11491篇
  1969年   10417篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
994.
995.
996.
997.
The present study was designed to evaluate the hypothesis that nebulised budesonide (NB) might be an alternative to systemic corticosteroids (SC) in the treatment of patients with exacerbations of chronic obstructive pulmonary disease (ECOPD). Patients hospitalised with ECOPD (n = 159) were randomised into three groups. Group 1 received only standard bronchodilator treatment (SBDT), group 2 received SC (40 mg prednisolone) plus SBDT, and group 3 received NB (1,500 microg q.i.d.) plus SBDT. Improvement during 10-day hospitalisation was compared with exacerbation and rehospitalisation rates after discharge. While mean+/-sd age was 64.1+/-8.9 yrs (female/male = 0.1), mean forced expiratory volume in one second (FEV(1)) at admission was found to be 37.2+/-12.2% predicted. Arterial blood gases and spirograms recovered faster in groups 2 and 3. While improvements in arterial oxygen tension (P(a,O(2))) and forced vital capacity (FVC) in group 2, and improvements in P(a,O(2)), FVC and FEV(1) in group 3, became significant at 24-h control, the first significant improvement in group 1 appeared in arterial oxygen saturation at 72-h control. The mean improvement of P(a,O(2)) after 10 days was 1.20 and 1.06 kPa (9 and 8 mmHg) higher in group 2 and 3, respectively, than in group 1. Blood glucose exhibited an upward trend only in group 2. The study demonstrates that nebulised budesonide may be an effective and safe alternative to systemic corticosteroids in the treatment of exacerbations of chronic obstructive pulmonary disease.  相似文献   
998.
999.
The 6-min walking distance (6MWD) test is used in clinical practice and research into patients with chronic obstructive pulmonary disease (COPD). However, little is known about natural long-term change in this parameter. The 6MWD was measured at baseline and then annually for 5 yrs in 294 patients with COPD and its annual rate of decline was determined. Forced expiratory volume in one second (FEV1) was also measured and the relationship between changes in both markers was explored. At baseline, the median 6MWD was 380 m (range 160-600 m). It declined by 19% (16 m.yr(-1)) over the 5 yrs compared with baseline in patients with American Thoracic Society/European Respiratory Society stage III COPD (FEV1 30-50% predicted) and by 26% (15 m.yr(-1)) in patients with stage IV COPD (FEV1 <30% pred). Over the 5-yr follow-up, the proportion of patients with a minimal clinically significant decline of 54 m increased with the severity of the disease. It was 24% in stage II, 45% in stage III, and 63% in stage IV disease. In contrast, the rate of decline of FEV1 was greater in patients with milder airflow obstruction and lesser in patients with lower absolute FEV1 values. In conclusion, the 6-min walking distance test provides increasingly useful information as the severity of chronic obstructive pulmonary disease increases.  相似文献   
1000.
Obstructive sleep apnoea is associated with increased blood pressure and other features of the metabolic syndrome. The aim of the present study was to determine the relative effectiveness of continuous positive airway pressure (CPAP) in modifying these outcomes. A randomised placebo-controlled blinded crossover trial comparing cardiovascular and metabolic outcomes after 6 weeks of therapeutic and sham CPAP was performed in 34 CPAP-na?ve patients (mean+/-SD body mass and respiratory disturbance indices were 36.1+/-7.6 and 39.7+/-13.8, respectively). Mean waking systolic and diastolic blood pressure fell by 6.7 and 4.9 mmHg, respectively, when compared with sham CPAP. No change was observed in glucose, lipids, insulin resistance or the proportion of patients with metabolic syndrome. In CPAP-compliant patients the fall in blood pressure was greater and the baroreceptor sensitivity improved significantly but no metabolic variable changed. In obese Caucasians with untreated obstructive sleep apnoea, continuous positive airways pressure can improve baroreceptor responsiveness and reduce waking blood pressure within 6 weeks, but this treatment period was insufficient to modify insulin resistance or change the metabolic profile. The mechanisms underlying this difference in the time course of blood pressure and metabolic response to continuous positive airway pressure in obstructive sleep apnoea requires further exploration.  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