全文获取类型
收费全文 | 960篇 |
免费 | 61篇 |
国内免费 | 40篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 45篇 |
妇产科学 | 20篇 |
基础医学 | 98篇 |
口腔科学 | 24篇 |
临床医学 | 113篇 |
内科学 | 244篇 |
皮肤病学 | 17篇 |
神经病学 | 31篇 |
特种医学 | 195篇 |
外科学 | 92篇 |
综合类 | 19篇 |
预防医学 | 46篇 |
眼科学 | 12篇 |
药学 | 70篇 |
肿瘤学 | 34篇 |
出版年
2023年 | 5篇 |
2022年 | 7篇 |
2021年 | 18篇 |
2020年 | 7篇 |
2019年 | 11篇 |
2018年 | 24篇 |
2017年 | 20篇 |
2016年 | 16篇 |
2015年 | 23篇 |
2014年 | 24篇 |
2013年 | 26篇 |
2012年 | 35篇 |
2011年 | 32篇 |
2010年 | 25篇 |
2009年 | 34篇 |
2008年 | 19篇 |
2007年 | 40篇 |
2006年 | 31篇 |
2005年 | 26篇 |
2004年 | 24篇 |
2003年 | 23篇 |
2002年 | 26篇 |
2001年 | 27篇 |
2000年 | 19篇 |
1999年 | 20篇 |
1998年 | 52篇 |
1997年 | 45篇 |
1996年 | 40篇 |
1995年 | 30篇 |
1994年 | 23篇 |
1993年 | 33篇 |
1992年 | 15篇 |
1991年 | 16篇 |
1990年 | 15篇 |
1989年 | 28篇 |
1988年 | 21篇 |
1987年 | 25篇 |
1986年 | 13篇 |
1985年 | 21篇 |
1984年 | 15篇 |
1983年 | 18篇 |
1982年 | 14篇 |
1981年 | 16篇 |
1980年 | 18篇 |
1979年 | 4篇 |
1978年 | 8篇 |
1977年 | 9篇 |
1976年 | 8篇 |
1975年 | 4篇 |
1973年 | 2篇 |
排序方式: 共有1061条查询结果,搜索用时 0 毫秒
1.
2.
Marcela Hernández Hoyos Piotr Orłowski Ewa Piątkowska-Janko Piotr Bogorodzki Maciej Orkisz 《International journal of computer assisted radiology and surgery》2006,1(1):51-61
The accuracy of 2D phase contrast (PC) magnetic resonance angiography (MRA) depends on the alignment between the vessels and
the imaging plane. PC MRA imaging of blood flow is challenging when the flow in several vessels is to be evaluated with one
acquisition. For this purpose, semi-automatic determination of the plane most perpendicular to several vessels is proposed
based on centerlines extracted from 3D MRA. Arterial centerlines are extracted from 3D MRA based on iterative estimation-prediction,
multi-scale analysis of image moments, and a second-order shape model. The optimal plane is determined by minimizing misalignment
between its normal vector and the centerlines’ tangent vectors. The method was evaluated on a phantom and on 35 patients,
by seeking the optimal plane for cerebral blood flow quantification simultaneously in internal carotids and vertebral arteries.
In the phantom, difference of orientation and of height between known and calculated planes was 1.2° and 2.5 mm, respectively.
In the patients, all but one centerline were correctly extracted and the misalignment of the plane was within 12° per artery.
Semi-automatic centerline extraction simplifies and automates determination of the plane orthogonal to one vessel, thereby
permitting automatic simultaneous minimization of the misalignment with several vessels in PC MRA. 相似文献
3.
4.
5.
Normal and diseased isolated lungs: high-resolution CT 总被引:8,自引:0,他引:8
6.
The aim of this study was to determine if the effect of psychosocial work environment on psychological well‐being was different for doctors and nurses who work in emergency departments in Spain. A cross‐sectional survey was carried out among 945 emergency doctors and nurses staff from Spain. The outcome variable was the psychological well‐being measured by two dimensions of SF‐36 Health Survey (SF‐36) (mental health, vitality) and one dimension of Maslach's Burnout Inventory (emotional exhaustion). The explanatory variable was the psychosocial work environment evaluated according to Karasek and Johnson's demand‐control model that includes the dimensions of psychological demands, job control, supervisor social support and co‐workers' social support. The adjusted odds ratios and their 95 per cent confidence intervals were calculated by logistic regression. The prevalence of low vitality, bad mental health and high emotional exhaustion was higher among doctors than nurses. Exposure to high psychological demands increased the probability of low vitality, bad mental health and high emotional exhaustion among doctors and nurses. Low job control and low co‐workers' social support at work were associated with poor psychological well‐being only among doctors. Low job supervisors' social support increased the risk of bad mental health among doctors and of high emotional exhaustion among nurses. There is a different effect of psychosocial work environment on psychological well‐being between doctors and nurses. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
7.
8.
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
9.
10.