全文获取类型
收费全文 | 83632篇 |
免费 | 6138篇 |
国内免费 | 261篇 |
专业分类
耳鼻咽喉 | 959篇 |
儿科学 | 2195篇 |
妇产科学 | 1200篇 |
基础医学 | 11211篇 |
口腔科学 | 915篇 |
临床医学 | 8987篇 |
内科学 | 17842篇 |
皮肤病学 | 910篇 |
神经病学 | 8009篇 |
特种医学 | 3231篇 |
外科学 | 13299篇 |
综合类 | 946篇 |
一般理论 | 93篇 |
预防医学 | 6398篇 |
眼科学 | 2136篇 |
药学 | 5713篇 |
中国医学 | 98篇 |
肿瘤学 | 5889篇 |
出版年
2023年 | 676篇 |
2022年 | 1059篇 |
2021年 | 2478篇 |
2020年 | 1399篇 |
2019年 | 2253篇 |
2018年 | 2580篇 |
2017年 | 1853篇 |
2016年 | 1940篇 |
2015年 | 2266篇 |
2014年 | 3296篇 |
2013年 | 4155篇 |
2012年 | 6670篇 |
2011年 | 6930篇 |
2010年 | 3793篇 |
2009年 | 3319篇 |
2008年 | 5537篇 |
2007年 | 5759篇 |
2006年 | 5357篇 |
2005年 | 5304篇 |
2004年 | 4794篇 |
2003年 | 4435篇 |
2002年 | 4020篇 |
2001年 | 733篇 |
2000年 | 529篇 |
1999年 | 673篇 |
1998年 | 827篇 |
1997年 | 615篇 |
1996年 | 514篇 |
1995年 | 461篇 |
1994年 | 436篇 |
1993年 | 429篇 |
1992年 | 340篇 |
1991年 | 326篇 |
1990年 | 284篇 |
1989年 | 279篇 |
1988年 | 236篇 |
1987年 | 225篇 |
1986年 | 217篇 |
1985年 | 232篇 |
1984年 | 230篇 |
1983年 | 197篇 |
1982年 | 283篇 |
1981年 | 261篇 |
1980年 | 193篇 |
1979年 | 156篇 |
1978年 | 164篇 |
1977年 | 133篇 |
1976年 | 98篇 |
1975年 | 94篇 |
1974年 | 89篇 |
排序方式: 共有10000条查询结果,搜索用时 7 毫秒
81.
82.
83.
84.
85.
86.
87.
88.
Andrew K. C. Lam Abby Lam Jessie Charm Kwai-mui Wong 《Ophthalmic & physiological optics》2005,25(2):162-167
PURPOSE: This study compared the near phoria measurement using the Bernell muscle balance card with and without prism neutralization, using both trial frame and phoropter correction, and compared with the conventional Maddox rod method. METHODS: Forty young normal Chinese adults had their near phoria measured with trial frame correction using the conventional muscle balance card method (method 1). Any deviation was compensated with a prism bar as an alternative approach (method 2). The conventional Maddox rod method (method 3) was also carried out for comparison. These three methods were repeated with phoropter correction and considered as methods 4, 5 and 6. RESULTS: The phorias obtained from these six methods were not significantly different from each other (repeated measures anova, p > 0.05). More than half of the subjects were exophoric. Although the difference in phoria was not significant, phoria measurement using phoropter correction yielded a greater coefficient of variation. CONCLUSIONS: Near phoria measurement using the muscle balance card conducted with trial frame correction was less variable, and was also more natural and similar to a real reading situation. The use of prism for compensation did not affect the phoria results. Exophoria seems to be more common than esophoria in young Chinese adults. 相似文献
89.
Piceatannol (3,4,3',5'-tetrahydroxy-trans-stilbene) (NSC 365798) has recently been isolated and was subsequently synthesized for NCI tumor panel testing as a new antileukemic natural product from the seeds of Euphorbia lagascae. During the synthesis, a bioactive reaction mixture of several partially O-methylated piceatannol analogues was obtained. This mixture has now been maximized and subjected to bioactivity-directed fractionation, using brine shrimp lethality, to yield 3,3',5'-tri-O-methylpiceatannol (NSC 381281); this new compound has improved stability and better bioactivity in several systems than piceatannol itself. To confirm the structure, 5 was synthesized from vanillin. In addition, the isovanillin analogue, 4,3',5'-tri-O-methylpiceatannol (NSC 381864), another new compound, was synthesized and found to be bioactive. 相似文献
90.