全文获取类型
收费全文 | 926篇 |
免费 | 62篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 40篇 |
妇产科学 | 6篇 |
基础医学 | 70篇 |
口腔科学 | 9篇 |
临床医学 | 72篇 |
内科学 | 202篇 |
皮肤病学 | 2篇 |
神经病学 | 8篇 |
特种医学 | 472篇 |
外科学 | 20篇 |
综合类 | 36篇 |
预防医学 | 20篇 |
眼科学 | 3篇 |
药学 | 35篇 |
中国医学 | 1篇 |
肿瘤学 | 14篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 13篇 |
2020年 | 5篇 |
2019年 | 3篇 |
2018年 | 13篇 |
2017年 | 7篇 |
2016年 | 10篇 |
2015年 | 11篇 |
2014年 | 10篇 |
2013年 | 15篇 |
2012年 | 14篇 |
2011年 | 19篇 |
2010年 | 17篇 |
2009年 | 25篇 |
2008年 | 15篇 |
2007年 | 29篇 |
2006年 | 19篇 |
2005年 | 12篇 |
2004年 | 12篇 |
2003年 | 11篇 |
2002年 | 15篇 |
2001年 | 17篇 |
2000年 | 15篇 |
1999年 | 14篇 |
1998年 | 48篇 |
1997年 | 39篇 |
1996年 | 65篇 |
1995年 | 50篇 |
1994年 | 34篇 |
1993年 | 42篇 |
1992年 | 18篇 |
1991年 | 18篇 |
1990年 | 16篇 |
1989年 | 34篇 |
1988年 | 38篇 |
1987年 | 30篇 |
1986年 | 30篇 |
1985年 | 45篇 |
1984年 | 24篇 |
1983年 | 24篇 |
1982年 | 26篇 |
1981年 | 24篇 |
1980年 | 12篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 26篇 |
1976年 | 18篇 |
1975年 | 14篇 |
1967年 | 1篇 |
排序方式: 共有1011条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
B C Goss K P McGee E C Ehman A Manduca R L Ehman 《Magnetic resonance in medicine》2006,56(5):1060-1066
Magnetic resonance elastography (MRE) is a phase-contrast technique that can spatially map shear stiffness within tissue-like materials. To date, however, MRE of the lung has been too technically challenging-primarily because of signal-to-noise ratio (SNR) limitations and phase instability. We describe an approach in which shear wave propagation is not encoded into the phase of the MR signal of a material, but rather from the signal arising from a polarized noble gas encapsulated within. To determine the feasibility of the approach, three experiments were performed. First, to establish whether shear wave propagation within lung parenchyma can be visualized with phase-contrast MR techniques, MRE was performed on excised porcine lungs inflated with room air. Second, a phantom consisting of open-cell foam filled with thermally polarized (3)He gas was imaged with MRE to determine whether shear wave propagation can be encoded by the gas. Third, preliminary evidence of the feasibility of MRE in vivo was obtained by using a longitudinal driver on the chest of a normal volunteer to generate shear waves in the lung. The results suggest that MRE in combination with hyperpolarized noble gases is potentially useful for noninvasively assessing the regional elastic properties of lung parenchyma, and merits further investigation. 相似文献
5.
6.
A randomized controlled trial of electromagnetic therapy in the primary care management of venous leg ulceration 总被引:1,自引:1,他引:0
OBJECTIVE: The aim was to establish the potential efficacy, tolerabilityand side-effect profile of electromagnetic therapy as an adjunctto conventional dressings in the treatment of venous leg ulcers. METHOD: A prospective, randomized, double blind controlled clinicaltrial was carried out in a dedicated leg ulcer clinic basedin one urban general practice. Nineteen patients with leg ulcersof confirmed venous aetiology were assessed. The main outcomemeasures were rate and scale of venous leg ulcer healing, changesin patient-reported pain levels, quality of life, degree ofmobility, side effect profile and acceptability to patientsand staff. RESULTS: Sixty-eight per cent of patients attending this dedicated clinicachieved improvements in the size of their ulcer (4, 21%, healedfully) and in reduced pain levels (P < 0.05) during the trial,despite the chronicity of ulcer histories. Patients treatedwith electromagnetic therapy at 800 Hz were found at day 50to have significantly greater healing (P < 0.05) and paincontrol (P < 0.05) than placebo therapy or treatment with600 Hz. All patients reported improved mobility at the end ofthe study. The electromagnetic therapy was well tolerated bypatients, with no differences between groups in reporting adverseevents, and proved acceptable to staff. CONCLUSION: Despite the small numbers in this pilot study, electromagnetictherapy provided significant gains in the healing of venousleg ulcers and reduction in pain. Keywords. Electromagnetic therapy, RCT, leg ulcers, primary care. 相似文献
7.
8.
9.
10.
Yu L. Liu Stephen J. Riederer Phillip J. Rossman Roger C. Grim Josef P. Debbins Richard L. Ehman 《Magnetic resonance in medicine》1993,30(4):507-511
A technique is described that provides improved reproducibility of breath-holding for MR image acquisition by monitoring the superior-inferior (S/I) position of the diaphragm. The method incorporates detection of the level of inspiration using an MR signal, rapid display to the patient of diaphragm position to enable breath-hold adjustment, and triggering of image data acquisition once appropriate position is attained. The response time of the system is short, approximately 10 ms. Studies in six volunteers using this method demonstrate a considerable decrease in the S/I range of diaphragm position over 10 consecutive periods of suspended respiration. The mean range is 1.3 mm with the system, while it is 8.3 mm without using it is expected that this method will be of assistance in many abdominal and cardiothoracic studies that use breath-hold techniques. 相似文献