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   392篇
  免费   14篇
  国内免费   4篇
耳鼻咽喉   4篇
儿科学   24篇
妇产科学   3篇
基础医学   28篇
口腔科学   2篇
临床医学   26篇
内科学   118篇
皮肤病学   2篇
神经病学   19篇
特种医学   100篇
外科学   56篇
综合类   3篇
预防医学   3篇
眼科学   1篇
药学   13篇
肿瘤学   8篇
  2022年   1篇
  2021年   3篇
  2020年   1篇
  2019年   6篇
  2018年   3篇
  2017年   1篇
  2016年   3篇
  2015年   3篇
  2014年   7篇
  2013年   16篇
  2012年   18篇
  2011年   10篇
  2010年   11篇
  2009年   15篇
  2008年   14篇
  2007年   16篇
  2006年   20篇
  2005年   6篇
  2004年   14篇
  2003年   6篇
  2002年   5篇
  2001年   9篇
  2000年   8篇
  1999年   6篇
  1998年   16篇
  1997年   17篇
  1996年   16篇
  1995年   6篇
  1994年   11篇
  1993年   12篇
  1992年   3篇
  1991年   1篇
  1990年   7篇
  1989年   14篇
  1988年   11篇
  1987年   18篇
  1986年   12篇
  1985年   14篇
  1984年   6篇
  1983年   10篇
  1982年   9篇
  1981年   2篇
  1980年   4篇
  1979年   4篇
  1978年   6篇
  1977年   4篇
  1976年   2篇
  1975年   3篇
排序方式: 共有410条查询结果,搜索用时 15 毫秒
61.
62.
63.
64.
65.
66.
STUDY OBJECTIVES: To investigate the technical properties and user friendliness of 10 office spirometers devoted for use in general practice, and to compare the results with standard diagnostic spirometers. DESIGN: Multicenter study. SETTING: Ten spirometer models were tested independently in three pulmonary function laboratories and by three general practitioners (GPs). MEASUREMENTS: The laboratories studied the technical quality of the office spirometers in terms of precision and agreement with standard spirometers, whereas the three GPs assessed their user friendliness. The spirometers tested were as follows: Spirobank (Medical International Research; Rome, Italy); Simplicity (Puritan Bennett; Pleasanton, CA); OneFlow (Clement Clarke International; Harlow, Essex, UK); Datospir 70 (Sibelmed; Barcelona, Spain); Datospir 120 (Sibelmed); SpiroPro (SensorMedics; Yorba Linda, CA); EasyOne (NDD; Zurich, Switzerland); MicroLoop (Micro Medical; Chatham, Kent, UK); SpiroStar (Medikro; Kuopio, Finland); and Pneumotrac (Vitalograph; Maids Moreton, Buckingham, UK). FVC and FEV1 were measured in 399 subjects. User friendliness was assessed by the three GPs using a questionnaire. RESULTS: The precision of FEV1 of the office and standard spirometers was comparable, but three office spirometers had > 200 mL limits of precision for FVC. Some devices presented a proportional difference on the FEV1 with standard spirometers, underestimating the small values. The limits of agreements between standard and some office spirometers for FEV1/FVC ratio was > 10%. The overall user friendliness was estimated as good. CONCLUSIONS: The global quality and user friendliness of several office spirometers make them acceptable for the detection of COPD, although differences between the laboratory and some of the office spirometers values suggest that the misclassification rates may be increased when using some models of office spirometers.  相似文献   
67.
High levels of angiotensin-converting-enzyme (ACE) may increase the risk of dementia through blood pressure elevation and subsequent development of cerebral small-vessel disease. However, high ACE levels may also decrease this risk through amyloid degradation which prevents brain atrophy. Within the SMART-MR study, a prospective cohort study among patients with symptomatic atherosclerotic disease, serum ACE levels were measured at baseline and a 1.5 Tesla brain MRI was performed at baseline and after on average (range) 3.9 (3.0-5.8) years of follow-up in 682 persons (mean age 58 ± 10 years). Brain segmentation was used to quantify total, deep, and periventricular white matter lesion (WML) volume, and total brain, cortical gray matter and ventricular volume (%ICV). Lacunar infarcts were rated visually. Regression analyses were used to examine the prospective associations between serum ACE and brain measures. Patients with the highest serum ACE levels (>43.3 U/L) had borderline significantly more progression of deep WML volumes than patients with the lowest ACE levels (<21.8 U/L); mean difference (95% CI) in change was 0.20 (-0.02; 0.43) %ICV. On the contrary, patients with the highest serum ACE levels had significantly less progression of cortical brain atrophy than patients with the lowest ACE levels; mean difference (95% CI) in change was 0.78 (0.21; 1.36) %ICV. Serum ACE was not associated with subcortical atrophy, periventricular WML, or lacunar infarcts. Our results show that higher ACE activity is associated with somewhat more progression of deep WML volume, but with less progression of cortical brain atrophy. This suggests both detrimental and beneficial effects of high ACE levels on the brain.  相似文献   
68.
We describe two Turner patients suffering from severe essential hyperhidrosis. Since both disorders are rare (1 in 5000 live female births for Turner syndrome and approximately 1 in 1000 persons for essential hyperhidrosis), our finding of two patients with these disorders in a total of 150 essential hyperhidrosis patients may suggest that this association is more frequent in Turner syndrome than previously thought.  相似文献   
69.
70.
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