全文获取类型
收费全文 | 117684篇 |
免费 | 11140篇 |
国内免费 | 9170篇 |
专业分类
耳鼻咽喉 | 991篇 |
儿科学 | 1098篇 |
妇产科学 | 1155篇 |
基础医学 | 13922篇 |
口腔科学 | 1946篇 |
临床医学 | 15797篇 |
内科学 | 17542篇 |
皮肤病学 | 1214篇 |
神经病学 | 6243篇 |
特种医学 | 4295篇 |
外国民族医学 | 78篇 |
外科学 | 12007篇 |
综合类 | 20911篇 |
现状与发展 | 40篇 |
一般理论 | 6篇 |
预防医学 | 7959篇 |
眼科学 | 3379篇 |
药学 | 12238篇 |
96篇 | |
中国医学 | 7304篇 |
肿瘤学 | 9773篇 |
出版年
2024年 | 645篇 |
2023年 | 2045篇 |
2022年 | 5034篇 |
2021年 | 6419篇 |
2020年 | 4889篇 |
2019年 | 4081篇 |
2018年 | 4207篇 |
2017年 | 3749篇 |
2016年 | 3604篇 |
2015年 | 5448篇 |
2014年 | 6659篇 |
2013年 | 5854篇 |
2012年 | 8524篇 |
2011年 | 9413篇 |
2010年 | 5930篇 |
2009年 | 4684篇 |
2008年 | 6047篇 |
2007年 | 5988篇 |
2006年 | 5798篇 |
2005年 | 5864篇 |
2004年 | 3811篇 |
2003年 | 3491篇 |
2002年 | 3003篇 |
2001年 | 2663篇 |
2000年 | 2808篇 |
1999年 | 2998篇 |
1998年 | 1997篇 |
1997年 | 2017篇 |
1996年 | 1550篇 |
1995年 | 1471篇 |
1994年 | 1270篇 |
1993年 | 791篇 |
1992年 | 988篇 |
1991年 | 795篇 |
1990年 | 664篇 |
1989年 | 625篇 |
1988年 | 520篇 |
1987年 | 458篇 |
1986年 | 399篇 |
1985年 | 298篇 |
1984年 | 136篇 |
1983年 | 116篇 |
1982年 | 68篇 |
1981年 | 72篇 |
1980年 | 47篇 |
1979年 | 54篇 |
1974年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
PURPOSE: To examine the relationship between ametropia and optical aberrations in a population of 200 normal human eyes with refractive errors spanning the range from +5.00 to -10.00 D. METHODS: Using a reduced-eye model of ametropia, we tested the hypothesis that the optical system of the eye is uncorrelated with the degree of ametropia. These predictions were evaluated experimentally with a Shack-Hartmann aberrometer that measured the monochromatic aberrations across the central 6 mm of the dilated pupil in well-corrected, cyclopleged eyes. RESULTS: Optical theory predicted, and control experiments on a model eye verified, that Shack-Hartmann measurements of spherical aberration will vary with axial elongation of the eye even if the dioptric components of the eye are fixed. Contrary to these predictions, spherical aberration was not significantly different from emmetropic eyes. Root mean square of third-order aberrations, fourth-order aberrations, and total higher aberrations (third to 10th) in myopic and hyperopic eyes were also uncorrelated with refractive error. Astigmatic eyes tended to have larger total higher-order aberrations than nonastigmatic eyes. CONCLUSIONS: We conclude that a reduced-eye model of myopia assuming fixed optical parameters and variable axial length is not tenable. 相似文献
102.
前锯肌下部肌皮瓣移植的应用解剖 总被引:1,自引:1,他引:0
目的:为前锯肌下部肌皮瓣移植提供解剖学基础。方法:在25具(50侧)成人尸体标本上,对前锯肌下部的形态、血供和神经支配进行了应用解剖学观测。结果:前锯肌下部的血供主要来自胸背动脉的前锯肌支,外径1.3±0.2mm,伴行静脉外径1.5±0.2mm,长4.9±1.1cm;由胸长神经支配,其横径为1.7±0.4mm,神经干长7.7±1.4cm。结论:以胸背血管及前锯肌支为血管蒂和胸长神经为蒂可切取前锯肌下部12.0cm×9.0cm的肌皮瓣,修复较大创面或重建肌动力 相似文献
103.
104.
F L Rosenfeldt V Chang M Grigg S Parker R Cearns M Rabinov W G Xu 《Anaesthesia and intensive care》1986,14(2):158-162
Hypertension after cardiac surgery is common and requires accurate control by carefully regulated infusions of drugs such as sodium nitroprusside. A microprocessor-based controller has been designed to close the loop between the blood pressure response and the infusion rate of a hypotensive drug. This system has been refined by computer simulation of the blood pressure response to sodium nitroprusside and by experience gained in using the controller in eleven patients in the early recovery period after cardiac surgery. The controller was able automatically to maintain blood pressure within 10% of a specified value. Provision of sophisticated safety features in automatic drug infusion controllers is essential for patient protection. 相似文献
105.
106.
本文总结了14例应用刮治和自体骨移植术治疗大型牙源性角化囊肿的方法,14例植骨均成活,4例术后囊肿复发,再次手术,指出:与骨断切除治疗大型角化囊肿的方法比较,此法最大的优点是有利于保持患者面容和咀嚼功能,并对大型角化囊肿的手术原则,自体骨移植问题及手术注意事项进行了讨论。 相似文献
107.
108.
109.
Region-specific growth properties and trophic requirements of brain- and spinal cord-derived rat embryonic neural precursor cells 总被引:2,自引:0,他引:2
To determine whether neural precursor cells have region-specific growth properties, we compared the proliferation, mitogenicity, and differentiation of these cells isolated from the embryonic day 16 rat forebrain and spinal cord. Neural precursor cells isolated from both regions were cultured in growth medium supplemented with epidermal growth factor, basic fibroblast growth factor, or epidermal growth factor+basic fibroblast growth factor. Under all three conditions, both neural precursor cell populations proliferated for multiple passages. While spinal cord-derived neural precursor cells proliferated moderately faster in epidermal growth factor-enriched growth medium, brain-derived cells proliferated much faster in basic fibroblast growth factor-enriched growth medium. When exposed to both epidermal growth factor and basic fibroblast growth factor, the two neural precursor cell populations expanded and proliferated more rapidly than when exposed to a single factor, with brain-derived neural precursor cells expanding significantly faster than spinal cord-derived ones (P<0.0001). Differentiation studies showed that both neural precursor cell populations were multi-potent giving rise to neurons, astrocytes, and oligodendrocytes. However, neuronal differentiation from brain-derived neural precursor cells was greater than spinal cord-derived ones (11.95+/-5.00% vs 1.92+/-1.13%; passage 2). Further, the two neural precursor cell populations differentiated into a similar percentage of oligodendrocytes (brain: 8.66+/-5.85%; spinal cord: 7.69+/-3.91%; passage 2). Immunofluorescence and Western blot studies showed that neural precursor cells derived from both regions expressed receptors for basic fibroblast growth factor and epidermal growth factor. However, brain-derived neural precursor cells expressed higher levels of the two receptors than spinal cord-derived ones in growth medium containing epidermal growth factor+basic fibroblast growth factor. Thus, our results showed that neural precursor cells isolated from the two regions of the CNS have distinct properties and growth requirements. Identifying phenotypic differences between these neural precursor cell populations and their growth requirements should provide new insights into the development of cell therapies for region-specific neurological degenerative diseases. 相似文献
110.