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   1502684篇
  免费   113370篇
  国内免费   6371篇
耳鼻咽喉   17789篇
儿科学   49343篇
妇产科学   39443篇
基础医学   199083篇
口腔科学   37745篇
临床医学   132034篇
内科学   307055篇
皮肤病学   32516篇
神经病学   125801篇
特种医学   63998篇
外国民族医学   274篇
外科学   237338篇
综合类   33775篇
现状与发展   2篇
一般理论   414篇
预防医学   123499篇
眼科学   30755篇
药学   102563篇
  5篇
中国医学   2850篇
肿瘤学   86143篇
  2018年   33933篇
  2017年   26880篇
  2016年   31078篇
  2015年   15133篇
  2014年   20650篇
  2013年   30409篇
  2012年   42690篇
  2011年   58676篇
  2010年   42068篇
  2009年   34711篇
  2008年   54734篇
  2007年   59189篇
  2006年   40319篇
  2005年   40407篇
  2004年   39868篇
  2003年   39868篇
  2002年   36124篇
  2001年   66295篇
  2000年   68292篇
  1999年   56730篇
  1998年   16904篇
  1997年   15201篇
  1996年   16077篇
  1995年   16321篇
  1994年   15186篇
  1993年   14205篇
  1992年   47122篇
  1991年   45822篇
  1990年   44085篇
  1989年   41889篇
  1988年   38802篇
  1987年   38117篇
  1986年   35877篇
  1985年   34661篇
  1984年   26373篇
  1983年   22128篇
  1982年   13871篇
  1981年   12447篇
  1980年   11751篇
  1979年   23548篇
  1978年   17081篇
  1977年   14387篇
  1976年   13190篇
  1975年   13729篇
  1974年   16112篇
  1973年   15401篇
  1972年   14176篇
  1971年   13037篇
  1970年   11898篇
  1969年   11123篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
The aim of this study was to determine whether patients with sickle cell disease (SCD) in steady state had pulmonary abnormalities seen on high-resolution computed tomography (HRCT) and whether any abnormalities correlated with contemporaneously diagnosed lung function abnormalities. A subsidiary question was whether the results of a noninvasive measure of haemolysis (end-tidal carbon monoxide (ETCO) levels) correlated with pulmonary function abnormalities. Thirty three patients with SCD, median (range) age 36 yrs (17-67 yrs) were examined. The degree of lobar volume loss and ground-glass opacification and prominence of central vessels on HRCT were quantitatively assessed. Pulmonary function was assessed by measurements of lung volumes, spirometry, gas transfer and oxygen saturation. ETCO levels were measured using an end-tidal CO monitor. Forced expiratory volume in one second (FEV1), forced vital capacity and total lung capacity significantly correlated with HRCT findings, particularly lobar volume loss. ETCO levels significantly negatively correlated with FEV1, vital capacity measured using a plethysmograph, specific airway conductance and arterial oxygen saturation measured by pulse oxymetry. In conclusion, the present results suggest that high-resolution computed tomography noninvasive assessment of haemolysis might be useful to identify sickle cell disease patients with respiratory function impairment.  相似文献   
52.
There is increasing evidence that the assessment of eosinophilic airway inflammation using induced sputum and measurement of airway hyperresponsiveness provides additional, clinically important information concerning asthma control. The aim of this study was to directly compare the effects of different treatments on these markers in patients with asthma and persistent symptoms, despite the use of low-dose inhaled corticosteroids. A double-blind four-way crossover study was performed, which compared a 1-month treatment with budesonide 400 mug b.i.d., additional formoterol, additional montelukast and placebo in 49 patients with uncontrolled asthma despite budesonide 100 mug b.i.d., with each treatment separated by a 4-week washout period. The change in sputum eosinophil count with formoterol (2.4 to 3.8% change, 0.6-fold reduction, 95% confidence interval (CI) 0.5-0.9) differed significantly from placebo (2.8 to 2.5% change, 1.1-fold reduction, 95% CI 0.7-1.6) and high-dose budesonide (2.7 to 1.6% change, 1.6-fold reduction, 95% CI 1.2-2.2). The effects of montelukast did not differ from placebo. The changes in methacholine airway responsiveness were small and did not differ between treatments. High-dose budesonide had the broadest range of beneficial effects on other outcomes, including symptom scores, morning peak expiratory flow and forced expiratory volume in one second. In conclusion, treatment given in addition to low-dose inhaled corticosteroids results in modest benefits. Formoterol and high-dose budesonide have contrasting effects on eosinophilic airway inflammation.  相似文献   
53.
54.
55.
56.
57.
58.
The aim of the present study was to explore differences in the clinical expression, clinical diagnoses and management of airway diseases in a primary-care setting. Patients aged >or=35 yrs who had ever smoked were enrolled when they presented for any reason to one of eight rural primary-care practices. Respiratory symptom questionnaires and spirometry were administered. In total, 1,034 patients had acceptable and reproducible spirometry, of whom 550 (53%) were males and 484 (47%) were females. Males smoked more than females (41.2 versus 29.2 pack-yrs) respectively, and were more likely to have a pre-bronchodilator forced expiratory volume in one second/forced vital capacity <0.70 at 22.4 versus 11.8%, respectively. However, more females than males reported breathlessness (51.0 versus 42.8%, respectively), a prior diagnosis compatible with airflow obstruction and taking respiratory medications (23.4 versus 14.9%, respectively). In conclusion, the current results suggest that females are more likely than males to report breathlessness and be prescribed respiratory medications independent of differences in the severity of airflow obstruction.  相似文献   
59.
60.
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