全文获取类型
收费全文 | 32354篇 |
免费 | 2402篇 |
国内免费 | 100篇 |
专业分类
耳鼻咽喉 | 367篇 |
儿科学 | 837篇 |
妇产科学 | 424篇 |
基础医学 | 4206篇 |
口腔科学 | 661篇 |
临床医学 | 2913篇 |
内科学 | 6837篇 |
皮肤病学 | 474篇 |
神经病学 | 3633篇 |
特种医学 | 1466篇 |
外国民族医学 | 3篇 |
外科学 | 4727篇 |
综合类 | 678篇 |
一般理论 | 66篇 |
预防医学 | 2795篇 |
眼科学 | 623篇 |
药学 | 1977篇 |
中国医学 | 21篇 |
肿瘤学 | 2148篇 |
出版年
2023年 | 112篇 |
2022年 | 186篇 |
2021年 | 453篇 |
2020年 | 261篇 |
2019年 | 448篇 |
2018年 | 579篇 |
2017年 | 422篇 |
2016年 | 487篇 |
2015年 | 560篇 |
2014年 | 861篇 |
2013年 | 1345篇 |
2012年 | 2040篇 |
2011年 | 2176篇 |
2010年 | 1184篇 |
2009年 | 1136篇 |
2008年 | 2082篇 |
2007年 | 2203篇 |
2006年 | 2176篇 |
2005年 | 2371篇 |
2004年 | 2095篇 |
2003年 | 1927篇 |
2002年 | 1944篇 |
2001年 | 349篇 |
2000年 | 282篇 |
1999年 | 357篇 |
1998年 | 449篇 |
1997年 | 438篇 |
1996年 | 416篇 |
1995年 | 390篇 |
1994年 | 314篇 |
1993年 | 312篇 |
1992年 | 246篇 |
1991年 | 262篇 |
1990年 | 254篇 |
1989年 | 225篇 |
1988年 | 197篇 |
1987年 | 230篇 |
1986年 | 197篇 |
1985年 | 199篇 |
1984年 | 243篇 |
1983年 | 230篇 |
1982年 | 297篇 |
1981年 | 281篇 |
1980年 | 234篇 |
1979年 | 139篇 |
1978年 | 150篇 |
1977年 | 108篇 |
1976年 | 127篇 |
1975年 | 94篇 |
1974年 | 109篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
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
92.
93.
94.
95.
96.
97.
98.
Joel A. Black Ruth Westenbroek Bruce R. Ransom William A. Catterall Stephen G. Waxman 《Glia》1994,12(3):219-227
The expression of sodium channel α-subunit isoforms in astrocytes in adult rat spinal cord and optic nerve was examined utilizing immunocytochemical methods with antibodies generated against conserved and subtype-specific sequences of the sodium channel. In adult rat spinal cord, astrocytes within the dorsal and ventral funiculi were immunolabelled with antibody SP20, which recognizes a conserved sequence within sodium channel types I, II, and III. In addition, astrocytes within these spinal cord white matter tracts were immunostained with antibody SP11-II, which recognizes sodium channel type II. Antibodies SP11-I and SP32-III, which are directed against subtype-specific sequences in sodium channel types I and III, respectively, did not label astrocytes in the dorsal and ventral funiculi of the spinal cord. In optic nerves, astrocytes were immunostained with antibody SP20. However, no detectable labelling of cells within the optic nerve was observed with antibodies SP11-I, SP11-II, and SP32-III. These observations demonstrate that sodium channel II is expressed by astrocytes in spinal cord white matter. Moreover, these data suggest that regional factors regulate the level of sodium channel isoform expression in astrocytes. 相似文献
99.
100.