全文获取类型
收费全文 | 727篇 |
免费 | 62篇 |
国内免费 | 8篇 |
专业分类
儿科学 | 56篇 |
妇产科学 | 5篇 |
基础医学 | 86篇 |
口腔科学 | 11篇 |
临床医学 | 101篇 |
内科学 | 162篇 |
皮肤病学 | 6篇 |
神经病学 | 38篇 |
特种医学 | 153篇 |
外科学 | 41篇 |
综合类 | 8篇 |
预防医学 | 47篇 |
眼科学 | 8篇 |
药学 | 34篇 |
中国医学 | 2篇 |
肿瘤学 | 39篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 9篇 |
2020年 | 10篇 |
2019年 | 3篇 |
2018年 | 15篇 |
2017年 | 10篇 |
2016年 | 9篇 |
2015年 | 14篇 |
2014年 | 21篇 |
2013年 | 29篇 |
2012年 | 26篇 |
2011年 | 21篇 |
2010年 | 17篇 |
2009年 | 25篇 |
2008年 | 15篇 |
2007年 | 12篇 |
2006年 | 19篇 |
2005年 | 25篇 |
2004年 | 12篇 |
2003年 | 14篇 |
2002年 | 15篇 |
2001年 | 18篇 |
2000年 | 11篇 |
1999年 | 17篇 |
1998年 | 41篇 |
1997年 | 60篇 |
1996年 | 42篇 |
1995年 | 33篇 |
1994年 | 34篇 |
1993年 | 27篇 |
1992年 | 15篇 |
1991年 | 12篇 |
1990年 | 4篇 |
1989年 | 17篇 |
1988年 | 19篇 |
1987年 | 17篇 |
1986年 | 21篇 |
1985年 | 19篇 |
1984年 | 9篇 |
1983年 | 6篇 |
1982年 | 11篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1978年 | 6篇 |
1977年 | 8篇 |
1976年 | 4篇 |
1975年 | 5篇 |
1969年 | 1篇 |
排序方式: 共有797条查询结果,搜索用时 15 毫秒
1.
Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography 总被引:2,自引:0,他引:2
The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study. 相似文献
2.
Paediatric dacryocystorhinostomy 总被引:1,自引:0,他引:1
KN Hakin FRCS FRCOphth TJ Sullivan FRACO FRACS A Sharma FCOphth † RAN Welham FRCS FCOphth † 《Clinical & experimental ophthalmology》1994,22(4):231-235
Of 258 cases of dacryocystorhinostomy performed on children in the period September 1981 to September 1991, 130 were for simple, unresolved congenital nasolacrimal duct obstruction. Other indications for surgery included punctal agenesis, lacrimal fistula, post-traumatic and post-inflammatory canalicular obstruction. Of 177 children without canalicular pathology, 171 (96%) were relieved of symptoms with one operation, without canalicular intubation. Of 81 cases with canalicular disease, 55 of 70 (79%) who underwent DCR plus canalicular intubation, and 10 of 11 who underwent DCR plus Lester-Jones tube, were substantially improved with one operation. No child required peroperative or postoperative blood transfusion. Dacryocystorhinostomy in childhood, in experienced surgical hands, is a safe procedure, achieving relief of symptoms in most cases, particularly in the absence of canalicular disease. 相似文献
3.
4.
5.
Factors influencing women to undergo screening mammography 总被引:2,自引:0,他引:2
6.
7.
8.
9.
The effect of surface chemistry modification of titanium alloy on signalling pathways in human osteoblasts 总被引:2,自引:0,他引:2
Zreiqat H Valenzuela SM Nissan BB Roest R Knabe C Radlanski RJ Renz H Evans PJ 《Biomaterials》2005,26(36):7579-7586
Establishing and maintaining mature bone at the bone–device interface is critical to the long-term success of prosthesis. Poor cell adhesion to orthopaedic and dental implants results in implant failure. Considerable effort has been devoted to alter the surface characteristics of these biomaterials in order to improve the initial interlocking of the device and skeleton. We investigated the effect of surface chemistry modification of titanium alloy (Ti–6Al–4V) with zinc, magnesium or alkoxide-derived hydroxy carbonate apatite (CHAP) on the regulation of key intracellular signalling proteins in human bone-derived cells (HBDC) cultured on these modified Ti–6Al–4V surfaces. Western blotting demonstrated that modifying Ti–6Al–4V with CHAP or Mg results in modulation of key intracellular signalling proteins. We showed an enhanced activation of Shc, a common point of integration between integrins and the Ras/Mapkinase pathway. Mapkinase pathway was also upregulated, suggesting its role in mediating osteoblastic cell interactions with biomaterials. The signalling pathway involving c-fos (member of the activated protein-1) was also shown to be upregulated in osteoblasts cultured on the Mg and CHAP modified Ti–6Al–4V. Thus surface modification with CHAP or Mg may contribute to successful osteoblast function and differentiation at the skeletal tissue–device interface. 相似文献
10.