全文获取类型
收费全文 | 924篇 |
免费 | 46篇 |
国内免费 | 39篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 37篇 |
妇产科学 | 7篇 |
基础医学 | 85篇 |
口腔科学 | 19篇 |
临床医学 | 95篇 |
内科学 | 242篇 |
皮肤病学 | 6篇 |
神经病学 | 62篇 |
特种医学 | 204篇 |
外科学 | 71篇 |
综合类 | 26篇 |
预防医学 | 26篇 |
眼科学 | 18篇 |
药学 | 76篇 |
肿瘤学 | 33篇 |
出版年
2022年 | 4篇 |
2021年 | 8篇 |
2020年 | 4篇 |
2019年 | 9篇 |
2018年 | 16篇 |
2017年 | 10篇 |
2016年 | 9篇 |
2015年 | 15篇 |
2014年 | 20篇 |
2013年 | 27篇 |
2012年 | 29篇 |
2011年 | 22篇 |
2010年 | 25篇 |
2009年 | 40篇 |
2008年 | 19篇 |
2007年 | 42篇 |
2006年 | 21篇 |
2005年 | 22篇 |
2004年 | 14篇 |
2003年 | 24篇 |
2002年 | 16篇 |
2001年 | 13篇 |
2000年 | 13篇 |
1999年 | 20篇 |
1998年 | 52篇 |
1997年 | 45篇 |
1996年 | 42篇 |
1995年 | 31篇 |
1994年 | 27篇 |
1993年 | 36篇 |
1992年 | 9篇 |
1991年 | 19篇 |
1990年 | 18篇 |
1989年 | 35篇 |
1988年 | 29篇 |
1987年 | 32篇 |
1986年 | 18篇 |
1985年 | 25篇 |
1984年 | 15篇 |
1983年 | 19篇 |
1982年 | 16篇 |
1981年 | 20篇 |
1980年 | 20篇 |
1979年 | 4篇 |
1978年 | 17篇 |
1977年 | 10篇 |
1976年 | 7篇 |
1975年 | 4篇 |
1973年 | 4篇 |
1970年 | 4篇 |
排序方式: 共有1009条查询结果,搜索用时 453 毫秒
1.
2.
3.
Rat hemoglobins are unusually heterogeneous among mammals. This heterogeneity provides multiple opportunities for asynchronies in synthesis and degradation. We have examined rat hemoglobin turnover after an intravenous injection of 2-14C-glycine. After analyzing incorporation into the seven nonallelic globin chains of adult rats, we found the percentage of the major beta chain decreases over the red cell lifespan while the percentage of one of the minor beta chains increases. This suggests that a post-synthetic modification event converts a portion of the latter into the former. 相似文献
4.
Plasma amine oxidase activities in Norrie disease patients with an X-chromosomal deletion affecting monoamine oxidase 总被引:2,自引:0,他引:2
D. L. Murphy K. B. Sims F. Karoum N. A. Garrick A. de la Chapelle E. M. Sankila R. Norio X. O. Breakefield 《Journal of neural transmission (Vienna, Austria : 1996)》1991,83(1-2):1-12
Summary Two individuals with an X-chromosomal deletion were recently found to lack the genes encoding monoamine oxidase type A (MAO-A) and MAO-B. This abnormality was associated with almost total (90%) reductions in the oxidatively deaminated urinary metabolites of the MAO-A substrate, norepinephrine, and with marked (100-fold) increases in an MAO-B substrate, phenylethylamine, confirming systemic functional consequences of the genetic enzyme deficiency. However, urinary concentrations of the deaminated metabolites of dopamine and serotonin (5-HT) were essentially normal. To investigate other deaminating systems besides MAO-A and MAO-B that might produce these metabolites of dopamine and 5-HT, we examined plasma amine oxidase (AO) activity in these two patients and two additional patients with the same X-chromosomal deletion. Normal plasma AO activity was found in all four Norrie disease-deletion patients, in four patients with classic Norrie disease without a chromosomal deletion, and in family members of patients from both groups. Marked plasma amine metabolite abnormalities and essentially absent platelet MAO-B activity were found in all four Norrie disease-deletion patients, but in none of the other subjects in the two comparison groups. These results indicate that plasma AO is encoded by gene(s) independent of those for MAO-A and MAO-B, and raise the possibility that plasma AO, and perhaps the closely related tissue AO, benzylamine oxidase, as well as other atypical AOs or MAOs encoded independently from MAO-A and MAO-B may contribute to the oxidative deamination of dopamine and 5-HT in humans. 相似文献
5.
6.
Normal and diseased isolated lungs: high-resolution CT 总被引:8,自引:0,他引:8
7.
8.
9.
The adhesion of hematopoietic progenitor cells to bone marrow stromal cells is critical to hematopoiesis and involves multiple effector molecules. Stromal cell molecules that participate in this interaction were sought by analyzing the detergent-soluble membrane proteins of GBI/6 stromal cells that could be adsorbed by intact FDCP-1 progenitor cells. A single-chain protein from GBI/6 cells having an apparent molecular weight of 37 Kd was selectively adsorbed by FDCP-1 cells. This protein, designated p37, could be surface-radiolabeled and thus appeared to be exposed on the cell membrane. An apparently identical 37- Kd protein was expressed by three stromal cell lines, by Swiss 3T3 fibroblastic cells, and by FDCP-1 and FDCP-2 progenitor cells. p37 was selectively adsorbed from membrane lysates by a variety of murine hematopoietic cells, including erythrocytes, but not by human erythrocytes. Binding of p37 to cells was calcium-dependent, and was not affected by inhibitors of the hematopoietic homing receptor or the cell-binding or heparin-binding functions of fibronectin. It is proposed that p37 may be a novel adhesive molecule expressed on the surface of a variety of hematopoietic cells that could participate in both homotypic and heterotypic interactions of stromal and progenitor cells. 相似文献
10.