全文获取类型
收费全文 | 1418篇 |
免费 | 167篇 |
国内免费 | 37篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 55篇 |
妇产科学 | 21篇 |
基础医学 | 276篇 |
口腔科学 | 19篇 |
临床医学 | 149篇 |
内科学 | 347篇 |
皮肤病学 | 12篇 |
神经病学 | 92篇 |
特种医学 | 185篇 |
外科学 | 129篇 |
综合类 | 24篇 |
预防医学 | 65篇 |
眼科学 | 10篇 |
药学 | 88篇 |
中国医学 | 4篇 |
肿瘤学 | 142篇 |
出版年
2021年 | 14篇 |
2020年 | 10篇 |
2019年 | 9篇 |
2018年 | 25篇 |
2017年 | 16篇 |
2016年 | 15篇 |
2015年 | 26篇 |
2014年 | 30篇 |
2013年 | 41篇 |
2012年 | 42篇 |
2011年 | 49篇 |
2010年 | 61篇 |
2009年 | 60篇 |
2008年 | 49篇 |
2007年 | 56篇 |
2006年 | 50篇 |
2005年 | 47篇 |
2004年 | 40篇 |
2003年 | 25篇 |
2002年 | 36篇 |
2001年 | 39篇 |
2000年 | 29篇 |
1999年 | 24篇 |
1998年 | 58篇 |
1997年 | 60篇 |
1996年 | 58篇 |
1995年 | 51篇 |
1994年 | 55篇 |
1993年 | 40篇 |
1992年 | 29篇 |
1991年 | 32篇 |
1990年 | 36篇 |
1989年 | 43篇 |
1988年 | 41篇 |
1987年 | 29篇 |
1986年 | 29篇 |
1985年 | 22篇 |
1984年 | 17篇 |
1983年 | 15篇 |
1982年 | 14篇 |
1981年 | 23篇 |
1980年 | 21篇 |
1979年 | 16篇 |
1978年 | 20篇 |
1977年 | 19篇 |
1976年 | 12篇 |
1973年 | 9篇 |
1972年 | 13篇 |
1971年 | 9篇 |
1969年 | 12篇 |
排序方式: 共有1622条查询结果,搜索用时 15 毫秒
1.
2.
3.
Digital radiography of subtle pulmonary abnormalities: an ROC study of the effect of pixel size on observer performance 总被引:3,自引:0,他引:3
Forty conventional radiographs with examples of mild interstitial infiltrates and subtle pneumothoraces and 40 normal studies of the chest were selected and digitized, with pixel sizes of 1.0, 0.5, 0.2, and 0.1 mm. Observer performance tests were carried out using receiver operating characteristic analysis. Conventional radiographs and digitized images were compared. The results indicate that, in such cases, diagnostic accuracy increases significantly as the pixel size is reduced, at least to the 0.1-mm level. We conclude that, for digital systems using screen-film or similar image receptors, use of a pixel size substantially larger than 0.1 mm may result in some loss of diagnostic accuracy. 相似文献
4.
5.
B C Elson D M Ikeda I Andersson C Wattsg?rd 《AJR. American journal of roentgenology》1992,158(5):993-995
The mammographic features of fibrosarcoma of the breast, a rare malignant tumor, have not been described. Accordingly, we reviewed the mammograms, pathology reports, and medical records of five women with this tumor. All cases had surgical biopsies and a diagnosis made by histologic evaluation. The age of the patients ranged from 48 to 79 years. Histologically, three of the five fibrosarcomas were thought to have arisen from phyllodes tumor, and four were palpable. On mammograms, the tumors were dense masses with largely indistinct margins, ranging from 1.5 to 7.0 cm in diameter. One contained calcified osseous elements suggesting osseous trabeculae. Although the osseous trabeculae in that tumor strongly suggested sarcoma, most of the tumors had a nonspecific appearance on mammograms. Fibrosarcomas of the breast have a nonspecific mammographic appearance. Surgical biopsy and histologic evaluation are necessary for definitive diagnosis. 相似文献
6.
7.
PL Macken FRACO FRACS CJ Pavlin FRCS R Tuli MD GE Trope PhD FRCS 《Clinical & experimental ophthalmology》1995,23(3):217-220
Background: Spherophakia is an uncommon diagnosis. This is the first case report of spherophakia evaluated by ultrasound biomicroscopy.
Methods: Ultrasound biomicroscopy is a new diagnostic technique developed by one of the authors and provides images with microscopic resolution of the anterior segment. A patient with spherophakia was evaluated by ultrasound biomicroscopy (Zeiss-Humphrey, 50MHz) before and after YAG laser iridotomy.
Results: Ultrasound biomicroscopic assessment revealed a shallow anterior chamber, a very steep anterior lens curvature, iridolenticular contact, elongated zonules, and an increased distance between the lens equator and the ciliary processes. Angle closure glaucoma was due to a pupil block mechanism. The pupil block was relieved by YAG laser iridotomy.
Conclusions: Ultrasound biomicroscopy is a useful technique to confirm the diagnosis of spherophakia. The pupil block in spherophakia is relieved by YAG laser iridotomy. 相似文献
Methods: Ultrasound biomicroscopy is a new diagnostic technique developed by one of the authors and provides images with microscopic resolution of the anterior segment. A patient with spherophakia was evaluated by ultrasound biomicroscopy (Zeiss-Humphrey, 50MHz) before and after YAG laser iridotomy.
Results: Ultrasound biomicroscopic assessment revealed a shallow anterior chamber, a very steep anterior lens curvature, iridolenticular contact, elongated zonules, and an increased distance between the lens equator and the ciliary processes. Angle closure glaucoma was due to a pupil block mechanism. The pupil block was relieved by YAG laser iridotomy.
Conclusions: Ultrasound biomicroscopy is a useful technique to confirm the diagnosis of spherophakia. The pupil block in spherophakia is relieved by YAG laser iridotomy. 相似文献
8.
9.
10.