收费全文 | 2836篇 |
免费 | 392篇 |
国内免费 | 4篇 |
耳鼻咽喉 | 3篇 |
儿科学 | 107篇 |
妇产科学 | 36篇 |
基础医学 | 117篇 |
口腔科学 | 75篇 |
临床医学 | 130篇 |
内科学 | 345篇 |
皮肤病学 | 20篇 |
神经病学 | 55篇 |
特种医学 | 147篇 |
外科学 | 129篇 |
综合类 | 15篇 |
预防医学 | 1917篇 |
眼科学 | 10篇 |
药学 | 43篇 |
肿瘤学 | 83篇 |
2023年 | 31篇 |
2022年 | 52篇 |
2021年 | 29篇 |
2020年 | 92篇 |
2019年 | 27篇 |
2018年 | 95篇 |
2017年 | 98篇 |
2016年 | 100篇 |
2015年 | 91篇 |
2014年 | 89篇 |
2013年 | 166篇 |
2012年 | 44篇 |
2011年 | 49篇 |
2010年 | 108篇 |
2009年 | 132篇 |
2008年 | 73篇 |
2007年 | 69篇 |
2006年 | 89篇 |
2005年 | 60篇 |
2004年 | 57篇 |
2003年 | 37篇 |
2002年 | 91篇 |
2001年 | 94篇 |
2000年 | 65篇 |
1999年 | 141篇 |
1998年 | 160篇 |
1997年 | 198篇 |
1996年 | 207篇 |
1995年 | 130篇 |
1994年 | 56篇 |
1993年 | 122篇 |
1992年 | 20篇 |
1991年 | 15篇 |
1990年 | 18篇 |
1989年 | 30篇 |
1988年 | 32篇 |
1987年 | 25篇 |
1986年 | 31篇 |
1985年 | 24篇 |
1984年 | 13篇 |
1983年 | 19篇 |
1982年 | 18篇 |
1981年 | 15篇 |
1980年 | 13篇 |
1979年 | 13篇 |
1978年 | 10篇 |
1977年 | 12篇 |
1976年 | 18篇 |
1975年 | 10篇 |
1971年 | 6篇 |
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
Objectives. To provide a basic and useful review for the indications, advantages, disadvantages, and techniques for the use of advancement flaps in the reconstruction of defects in dermatologic surgery.
Materials and Methods. We performed a literature search for articles discussing advancement flaps and compiled a brief review of our findings.
Results. The movement of the advancement flap must be balanced by the blood supply of the flap. The excision of Burow's triangles along various aspects of the advancement flap can increase movement and improve cosmesis of the flap. The types of advancement flaps discussed include the single advancement flap, double advancement flap, A-T flap (O-T flap), Burow's triangle flap (Burow's wedge flap), crescenteric advancement flap, island pedicle flap (V-Y flap), helical rim advancement flap, and facelift flap.
Conclusion. Advancement flaps are versatile and useful basic flaps for repairing defects. 相似文献