收费全文 | 10231篇 |
免费 | 788篇 |
国内免费 | 17篇 |
耳鼻咽喉 | 108篇 |
儿科学 | 406篇 |
妇产科学 | 373篇 |
基础医学 | 1101篇 |
口腔科学 | 196篇 |
临床医学 | 656篇 |
内科学 | 2148篇 |
皮肤病学 | 145篇 |
神经病学 | 686篇 |
特种医学 | 324篇 |
外科学 | 1281篇 |
综合类 | 32篇 |
预防医学 | 2403篇 |
眼科学 | 165篇 |
药学 | 504篇 |
中国医学 | 34篇 |
肿瘤学 | 474篇 |
2023年 | 51篇 |
2022年 | 95篇 |
2021年 | 122篇 |
2020年 | 156篇 |
2019年 | 141篇 |
2018年 | 218篇 |
2017年 | 185篇 |
2016年 | 186篇 |
2015年 | 228篇 |
2014年 | 277篇 |
2013年 | 387篇 |
2012年 | 362篇 |
2011年 | 388篇 |
2010年 | 299篇 |
2009年 | 291篇 |
2008年 | 461篇 |
2007年 | 519篇 |
2006年 | 530篇 |
2005年 | 490篇 |
2004年 | 471篇 |
2003年 | 409篇 |
2002年 | 495篇 |
2001年 | 423篇 |
2000年 | 419篇 |
1999年 | 415篇 |
1998年 | 243篇 |
1997年 | 261篇 |
1996年 | 278篇 |
1995年 | 194篇 |
1994年 | 110篇 |
1993年 | 181篇 |
1992年 | 189篇 |
1991年 | 162篇 |
1990年 | 137篇 |
1989年 | 127篇 |
1988年 | 133篇 |
1987年 | 129篇 |
1986年 | 99篇 |
1985年 | 88篇 |
1984年 | 59篇 |
1983年 | 54篇 |
1982年 | 41篇 |
1981年 | 44篇 |
1979年 | 39篇 |
1978年 | 26篇 |
1977年 | 25篇 |
1976年 | 32篇 |
1973年 | 25篇 |
1970年 | 32篇 |
1968年 | 35篇 |
Subjects Children were separated into three groups: (a) HIV-infected with growth retardation (HIV+Gr); (b) HIV-infected with normal growth (HIV+); (c) HIV-uninfected with normal growth (HIV-). All children were afebrile and free of acute infection at the time of study. During a 24-hour stay in the Pediatric Clinical Research Unit, blood was drawn for analysis of total protein, albumin, zinc, selenium, and vitamin A levels; growth measurements were obtained; and dietary intake was assessed by 24-hour weighed food intake and 24-hour dietary recall.
Statistical analysis Mean differences between groups were assessed by analysis of variance, and differences in the frequency of nutrient deficiency were determined by χ2 analysis.
Results Thirty-eight children between 2 and 11 years of age were studied: 10 HIV+Gr, 18 HIV+, and 10 HIV-. No statistically significantly differences were noted in mean levels of albumin, prealbumin, zinc, and selenium. Mean serum level of vitamin A was significantly higher in the HIV+Gr group than in the other two groups. There were no significant differences between groups in the frequency of deficiency for any nutrient studied. Mean energy and nutrient intake was similar among groups.
Applications/conclusions Abnormal serum or plasma protein or micronutrient levels were uncommon in this cohort of HIV-infected children, even in children with growth retardation. Routine monitoring of the level of proteins and micronutrients studied is unnecessary in the absence of specific clinical indicators of deficiency. J Am Diet Assoc. 1997-97:1377-1381. 相似文献