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   4505篇
  免费   542篇
  国内免费   9篇
耳鼻咽喉   16篇
儿科学   150篇
妇产科学   56篇
基础医学   322篇
口腔科学   199篇
临床医学   304篇
内科学   733篇
皮肤病学   47篇
神经病学   228篇
特种医学   189篇
外科学   331篇
综合类   54篇
预防医学   2015篇
眼科学   46篇
药学   207篇
中国医学   5篇
肿瘤学   154篇
  2023年   39篇
  2022年   60篇
  2021年   50篇
  2020年   111篇
  2019年   54篇
  2018年   122篇
  2017年   118篇
  2016年   119篇
  2015年   122篇
  2014年   128篇
  2013年   223篇
  2012年   116篇
  2011年   105篇
  2010年   166篇
  2009年   168篇
  2008年   127篇
  2007年   156篇
  2006年   159篇
  2005年   140篇
  2004年   121篇
  2003年   113篇
  2002年   154篇
  2001年   161篇
  2000年   117篇
  1999年   195篇
  1998年   180篇
  1997年   214篇
  1996年   218篇
  1995年   149篇
  1994年   76篇
  1993年   142篇
  1992年   56篇
  1991年   66篇
  1990年   50篇
  1989年   85篇
  1988年   66篇
  1987年   56篇
  1986年   66篇
  1985年   55篇
  1984年   45篇
  1983年   46篇
  1982年   24篇
  1981年   34篇
  1980年   30篇
  1979年   36篇
  1978年   28篇
  1977年   24篇
  1976年   26篇
  1974年   16篇
  1973年   20篇
排序方式: 共有5056条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
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   

5.
6.
Sonoelasticity imaging of prostate cancer: in vitro results   总被引:2,自引:0,他引:2  
  相似文献   
7.
8.
A 4.5-year follow-up retrospective study on the use of epiphysiodesis procedure for juvenile hallux valgus deformity and metatarsus primus adductus deformity shows a good reduction of deformity in nine patients with minimal change in one patient that can be explained due to the timing of the procedure. This is a minor operation for juvenile bunion deformities, using epiphyseal arrest techniques. The only complication to this procedure was one case with a noted metatarsus primus elevatus due to incomplete epiphyseal arrest from dorsal to plantar. This procedure has been found to be a safe and effective way of dealing with juvenile hallux valgus deformity when metatarsus primus adductus is the deforming force. It should be stated that in all cases a follow-up biomechanical examination and casting for orthotics took place and to date no complications, other than what has been previously mentioned, has occurred. I shall continue to perform this procedure where indicated and shall report my findings as they become available.  相似文献   
9.
BACKGROUND: Previously, complement activation has been associated with decompression sickness (DCS). However data, both in humans and in animals, are controversial. Hypothesis: Complement activation and depletion occurs after exposure to the hyperbaric environment and is associated with increasing risk of DCS. METHODS: We obtained serological samples from 102 dives (120-300 feet of seawater) with a constant partial pressure of O2 set at 1.3 ATA in thirty-five U.S. Navy diver volunteers. Blood was obtained within one hour of diving and within one hour of surfacing. Plasma was extracted and analyzed for complement depletion. The risk of DCS was estimated using a validated model of DCS risk. RESULTS: Pre-post dive concentrations of C3a were significantly related to estimated risk of DCS (Figure 1), but the variation in predicted DCS explained by C3a was small (correlation co-efficient (r2 = 0.19, p < 0.0001). CONCLUSIONS: There was a reduction in total Ca3 levels in divers after exposure to dives with a high estimated risk of DCS. This decomplementation appeared to increase as the estimated risk of DCS increased.  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