全文获取类型
收费全文 | 2043篇 |
免费 | 96篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 17篇 |
儿科学 | 69篇 |
妇产科学 | 105篇 |
基础医学 | 165篇 |
口腔科学 | 58篇 |
临床医学 | 188篇 |
内科学 | 469篇 |
皮肤病学 | 29篇 |
神经病学 | 105篇 |
特种医学 | 42篇 |
外科学 | 328篇 |
综合类 | 32篇 |
预防医学 | 251篇 |
眼科学 | 31篇 |
药学 | 195篇 |
中国医学 | 12篇 |
肿瘤学 | 48篇 |
出版年
2023年 | 22篇 |
2022年 | 46篇 |
2021年 | 88篇 |
2020年 | 48篇 |
2019年 | 82篇 |
2018年 | 80篇 |
2017年 | 64篇 |
2016年 | 60篇 |
2015年 | 71篇 |
2014年 | 111篇 |
2013年 | 109篇 |
2012年 | 155篇 |
2011年 | 141篇 |
2010年 | 89篇 |
2009年 | 76篇 |
2008年 | 124篇 |
2007年 | 100篇 |
2006年 | 79篇 |
2005年 | 87篇 |
2004年 | 83篇 |
2003年 | 89篇 |
2002年 | 61篇 |
2001年 | 24篇 |
2000年 | 35篇 |
1999年 | 26篇 |
1998年 | 16篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1994年 | 5篇 |
1992年 | 11篇 |
1991年 | 13篇 |
1990年 | 10篇 |
1989年 | 5篇 |
1988年 | 11篇 |
1987年 | 6篇 |
1986年 | 10篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1979年 | 7篇 |
1977年 | 4篇 |
1976年 | 7篇 |
1975年 | 8篇 |
1974年 | 6篇 |
1973年 | 10篇 |
1971年 | 4篇 |
1970年 | 3篇 |
1967年 | 3篇 |
1966年 | 3篇 |
1965年 | 4篇 |
排序方式: 共有2144条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
Maternal and fetal plasma vitamin E to total lipid ratio and fetal RBC antioxidant function during gestational development 总被引:1,自引:0,他引:1
S Abbasi A Ludomirski V K Bhutani S Weiner L Johnson 《Journal of the American College of Nutrition》1990,9(4):314-319
Placental transfer of vitamin E was investigated from 19 to 35 weeks of gestation by analysis of fetal and maternal blood samples for total tocopherol, total lipids, and fetal red blood cell antioxidant reserves. Fifty-two fetal blood samples were obtained under ultrasonographic guide by percutaneous umbilical blood sampling. Thirteen were from fetuses with gestational age less than or equal to 22 weeks (x serum vitamin E = 0.4 +/- 0.14 mg/dl), 12 were from fetuses at 23-27 weeks gestation (x serum vitamin E = 0.4 +/- 0.21 mg/dl), and 27 were from fetuses with gestational age 28-38 weeks (x serum level = 0.37 +/- 0.18). Total lipid levels ranged from 140 to 216 mg/dl. Maternal plasma vitamin E concentrations correlated significantly with concurrent values in the fetus. There were no significant differences in serum vitamin E levels or vitamin E to total lipid ratio in samples from early, mid, or late gestation in either the mother or fetus. Red blood cell antioxidant reserve on samples from 18 fetuses were grossly abnormal by three different functional assays. On the basis of these data, placental transfer of vitamin E appears to be relatively constant through advancing gestation. Red blood cell antioxidant reserve is uniformly low. 相似文献
6.
7.
8.
Approximately 5% of Americans over age 65, or 1.5 million individuals, currently reside in the nations's 20,000 nursing homes. The authors present material that lead to three conclusions about this population. First, nutritional deficiencies are common underlying causes of adverse clinical outcomes. Second, nutritional deficiencies are frequently not recognized. Third, opportunities for preventing or correcting undernutrition exist, provided that the significant and reversible nature of the nutrient deficiencies are identified. 相似文献
9.
Lipid peroxidation, erythrocyte superoxide-dismutase activity and trace metals in young male footballers 总被引:6,自引:0,他引:6
Metin G Atukeren P Alturfan AA Gulyasar T Kaya M Gumustas MK 《Yonsei medical journal》2003,44(6):979-986
Physical training is known to induce oxidative stress in individuals subjected to intense exercise. In this study, we investigated plasma malondialdehyde (MDA) levels and erythrocyte superoxide dismutase (SOD) activity of 25 young male footballers and a control group of similar age. Red blood cell (RBC) count, haemoglobin (Hb) and haematocrit (Hct) values, and copper (Cu) and zinc (Zn) levels were also examined. The maximal oxygen uptake (VO2max) of all subjects was determined in order to establish their functional capacity. The main finding of the present study was that plasma MDA levels, one of the most commonly used markers of lipid peroxidation, of this group of footballers aged under 21 decreased slightly when compared with those of the control group (p < 0.001). In contrast, erythrocyte SOD activity was higher in the footballer group than in the controls (p < 0.001). Footballers who are under regular training showed an improved antioxidant activity in comparison to sedentary controls. Plasma copper concentration, RBC count and Hb concentration of the footballer group were all significantly lower than those of the control group, (p < 0.001, p < 0.01, p < 0.01, respectively). Investigating the footballers' data with Spearman's correlation analyses, the correlation coefficients (r) between Zn/Cu ratio and SOD was positive (r=0.44; p < 0.05); and between VO2max and SOD (r=0.42; p < 0.05) were both positive. On the basis of statistical analysis, we suggest that regular exercise may be beneficial in cases of oxidative damage by reducing the amount of lipid peroxidation and increasing the activity of the antioxidant enzyme SOD. 相似文献
10.
Wajid M Abbasi AA Ansar M Pham TL Yan K Haque S Ahmad W Leal SM 《European journal of human genetics : EJHG》2003,11(10):812-815
This article describes the identification of a novel locus (DFNB39) responsible for an autosomal recessive form of hearing loss segregating in a Pakistani consanguineous family. The hearing impaired members of this family present with profound prelingual sensorineural hearing impairment and use sign language for communications. Linkage was established to microsatellite markers located on chromosome 7q with a maximum multipoint lod score of 3.8. The region of homozygosity spans a 19 cM region that is bounded by markers D7S3046 and D7S644. 相似文献