全文获取类型
收费全文 | 857篇 |
免费 | 43篇 |
国内免费 | 36篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 53篇 |
妇产科学 | 50篇 |
基础医学 | 64篇 |
口腔科学 | 25篇 |
临床医学 | 101篇 |
内科学 | 183篇 |
皮肤病学 | 5篇 |
神经病学 | 25篇 |
特种医学 | 165篇 |
外科学 | 62篇 |
综合类 | 13篇 |
预防医学 | 54篇 |
眼科学 | 25篇 |
药学 | 55篇 |
肿瘤学 | 53篇 |
出版年
2022年 | 4篇 |
2021年 | 11篇 |
2020年 | 5篇 |
2019年 | 10篇 |
2018年 | 16篇 |
2017年 | 9篇 |
2016年 | 6篇 |
2015年 | 9篇 |
2014年 | 13篇 |
2013年 | 22篇 |
2012年 | 28篇 |
2011年 | 30篇 |
2010年 | 52篇 |
2009年 | 46篇 |
2008年 | 20篇 |
2007年 | 35篇 |
2006年 | 14篇 |
2005年 | 24篇 |
2004年 | 10篇 |
2003年 | 9篇 |
2002年 | 14篇 |
2001年 | 15篇 |
2000年 | 8篇 |
1999年 | 9篇 |
1998年 | 52篇 |
1997年 | 47篇 |
1996年 | 47篇 |
1995年 | 44篇 |
1994年 | 42篇 |
1993年 | 26篇 |
1992年 | 5篇 |
1991年 | 14篇 |
1990年 | 13篇 |
1989年 | 26篇 |
1988年 | 24篇 |
1987年 | 13篇 |
1986年 | 15篇 |
1985年 | 10篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 12篇 |
1981年 | 11篇 |
1980年 | 11篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 10篇 |
1976年 | 6篇 |
1929年 | 4篇 |
1891年 | 3篇 |
1884年 | 5篇 |
排序方式: 共有936条查询结果,搜索用时 0 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.
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
5.
R. B. Stewart D. L. Kurtz M. Zweifel T. -K. Li J. C. Froehlich 《Psychopharmacology》1992,106(2):169-174
The duration of retention of tolerance to ethanol was tested in the alcohol-preferring (P) and alcohol-nonpreferring (NP)
rats lines, using ethanol-induced hypothermia as a measure of tolerance. Rats received two injections of ethanol (3.5 g/kg)
body wt, IP) and the time between the injections was 1, 2, or 3 days. When one day separated the two injections, tolerance
to the hypothermic effect of a second “test” injection was found in both lines. When 2 or 3 days separated the two injections,
the P line showed a loss of tolerance and the NP line showed sensitization to ethanol. Sensitization in the NP line grew stronger
when the interval between injections was increased from 2 to 3 days. The duration of retention of tolerance to ethanol-induced
hypothermia in the P line was shorter than has previously been reported for motor impairment in this line. It appears that
the duration of tolerance retention in the P line depends on the test used to measure tolerance. Sensitization to ethanol
in the NP line may be associated with low oral ethanol intake.
This research was supported, in part, by grants AA08312, AA03243, and AA07611 from the PHS 相似文献
6.
7.
8.
9.
The development of both adenocarcinoma of the jejunum and in situ squamous carcinoma of the oesophagus in an adult coeliac patient is described. Good evidence that adenocarcinoma of jejunum occurs more frequently in patients with coeliac disease has recently become available though this association has been suggested for some time. While oesophageal carcinoma has long been associated with coeliac disease, in situ carcinoma of oesophagus has not been previously described in these circumstances. We feel that the risk of this complication, as calculated from published series, warrants a screening programme for oesophageal malignancy in adult coeliacs. 相似文献
10.
The triphenyl and tributyl phosphine initiated polymerization of maleic anhydride was investigated. The structure of the macro zwitterions, formed under the given reaction conditions, depended on the initiator employed. If the polymerization was initiated by triphenyl phosphine, the macromolecules contained succinic anhydride units and cyclopentanone derivatives, formed from further rearrangement. If, however, tributyl phosphine was employed as initiator, the polymers were mostly made up of conjugated ketoolefinic units. IR, NMR and mass spectrometric measurements were carried out to determine the structure of the polymers. Existence of the macro zwitterions was proved by high voltage electrophoresis. The semi-conductor properties of the polymers containing conjugated ketoolefinic units are discussed. Spectroscopic investigation of the kinetics of the triphenyl phosphine initiated polymerization of maleic anhydride showed that the initiation reaction of the ylide, formed with the monomer, proceeded about 90 times slower than the propagation reaction due to addition of the monomer to the growing chain-end. 相似文献