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   4606篇
  免费   468篇
  国内免费   5篇
耳鼻咽喉   5篇
儿科学   117篇
妇产科学   78篇
基础医学   338篇
口腔科学   83篇
临床医学   287篇
内科学   782篇
皮肤病学   33篇
神经病学   162篇
特种医学   257篇
外科学   269篇
综合类   27篇
一般理论   1篇
预防医学   2082篇
眼科学   74篇
药学   197篇
肿瘤学   287篇
  2023年   33篇
  2022年   56篇
  2021年   36篇
  2020年   97篇
  2019年   39篇
  2018年   114篇
  2017年   119篇
  2016年   124篇
  2015年   122篇
  2014年   133篇
  2013年   216篇
  2012年   114篇
  2011年   109篇
  2010年   173篇
  2009年   166篇
  2008年   130篇
  2007年   163篇
  2006年   161篇
  2005年   141篇
  2004年   118篇
  2003年   114篇
  2002年   153篇
  2001年   176篇
  2000年   133篇
  1999年   199篇
  1998年   189篇
  1997年   222篇
  1996年   234篇
  1995年   150篇
  1994年   74篇
  1993年   138篇
  1992年   51篇
  1991年   58篇
  1990年   55篇
  1989年   72篇
  1988年   64篇
  1987年   50篇
  1986年   53篇
  1985年   48篇
  1984年   29篇
  1983年   32篇
  1982年   21篇
  1981年   32篇
  1980年   19篇
  1979年   28篇
  1978年   25篇
  1976年   26篇
  1975年   18篇
  1974年   17篇
  1931年   22篇
排序方式: 共有5079条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
5.
6.
Objectives Compare the effect of high doses of inhaled corticosteroids on bone loss in subjects with moderate to severe asthma or mild asthma, and examine the influence of dietary intake on bone metabolism. Design A survey on the effects of corticotherapy and nutrition on bone density was conducted in 74 subjects currently being treated for asthma in the asthma clinic of Hospital Laval (Sainte-Foy, Quebec, Canada). Fifty-eight subjects completed the study (attrition RATE=15%).

Main outcome measures In all subjects expiratory volumes were determined and urinary analysis was conducted for hydroxyproline, calcium, phosphorus, and cortisol levels. Osteocalcin, calcium, phosphorus, cortisol, alkaline phosphatase, and γ-glutamyltransferase levels were measured in blood samples. Bone density of the lumbar spine was determined by means of dual-energy x-ray absorptiometry. Nutrition evaluation was based on a 3-day food diary analyzed using progiciel Nutri 91. The nutritional parameters examined were calcium; phosphorus; magnesium; zinc; vitamins A, C, and D; protein; total fiber; oxalates; energy; caffeine; and alcohol in relation to bone density.

Subjects Thirty-one patients with moderate to severe asthma who had been taking more than 1,000 μg beclomethasone per day or the equivalent for more than 2 years and 27 patients with mild asthma who were taking less than 500 μg beclomethasone per day or the equivalent.

Statistical analyses performed Four factor analysis of variance with hierarchized interactions of four levels, Duncan's test, Pearson correlation coefficients.

Results Blood levels of osteocalcin and protein intake were lower in patients with moderate to severe asthma than in those with mild asthma (P<.05). Significant correlations (P<.02) were observed between bone density and calcium intake (r=.40), phosphorus intake (r=.35), protein intake (r=.30), and serum alkaline phosphatase level (r=−.30). Bone density was not significantly different between the two groups of patients with asthma.

Applications A follow-up of patients with asthma who are taking inhaled corticosteroids is needed to assess bone density, osteocalcin levels, and dietary intakes of calcium. Verify if osteocalcin level decreases over time in patients with moderate to severe asthma, monitor possible modifications in bone density, and verify if the correlation between dietary calcium and bone density is maintained. J Am Diet Assoc. 1997;97:1401–1406.  相似文献   

7.
8.
Sonoelasticity imaging of prostate cancer: in vitro results   总被引:2,自引:0,他引:2  
  相似文献   
9.
Kaposi's sarcoma. CT-radiographic correlation   总被引:1,自引:0,他引:1  
The role of CT in the diagnosis of intrathoracic Kaposi's sarcoma (KS) was evaluated retrospectively in 24 patients, in the absence of coexistent opportunistic infections. In all cases the diagnosis of KS was initially established by histologic evaluation of extrathoracic disease: 15 patients had verified parenchymal KS and nine patients endobronchial KS. (Chest roentgenograms were analyzed separately for each group: in 14 patients serial films were available for review. The predominant radiographic findings was the presence of nonspecific, bilateral, perihilar infiltrates in 22 of 24 cases (92 percent). Corresponding CT scans documented the presence of abnormal hilar densities characteristically extending into the adjacent pulmonary parenchyma along distinctly perivascular and peribronchial pathways. Discrete, poorly marginated nodules were identified radiographically in ten cases (42 percent); these proved to be randomly distributed throughout the parenchyma on CT. Radiographic evidence of mediastinal adenopathy was distinctly unusual, seen in only two cases (8 percent). While CT typically demonstrated shotty adenopathy, significantly enlarged nodes (greater than 1 cm) were rarely identified. We concluded that CT is more specific than routine roentgenograms for identifying pulmonary KS. While not pathognomonic, peribronchial and perivascular disease is sufficiently characteristic to obviate more invasive diagnostic procedures, especially in patients with established KS.  相似文献   
10.
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