全文获取类型
收费全文 | 10635篇 |
免费 | 682篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 106篇 |
儿科学 | 238篇 |
妇产科学 | 234篇 |
基础医学 | 1336篇 |
口腔科学 | 304篇 |
临床医学 | 856篇 |
内科学 | 3107篇 |
皮肤病学 | 219篇 |
神经病学 | 976篇 |
特种医学 | 323篇 |
外科学 | 1555篇 |
综合类 | 70篇 |
一般理论 | 1篇 |
预防医学 | 754篇 |
眼科学 | 199篇 |
药学 | 615篇 |
中国医学 | 36篇 |
肿瘤学 | 426篇 |
出版年
2023年 | 54篇 |
2022年 | 128篇 |
2021年 | 342篇 |
2020年 | 157篇 |
2019年 | 280篇 |
2018年 | 375篇 |
2017年 | 198篇 |
2016年 | 289篇 |
2015年 | 279篇 |
2014年 | 412篇 |
2013年 | 494篇 |
2012年 | 749篇 |
2011年 | 830篇 |
2010年 | 497篇 |
2009年 | 428篇 |
2008年 | 646篇 |
2007年 | 705篇 |
2006年 | 692篇 |
2005年 | 609篇 |
2004年 | 578篇 |
2003年 | 452篇 |
2002年 | 453篇 |
2001年 | 166篇 |
2000年 | 204篇 |
1999年 | 149篇 |
1998年 | 96篇 |
1997年 | 67篇 |
1996年 | 69篇 |
1995年 | 56篇 |
1994年 | 52篇 |
1993年 | 55篇 |
1992年 | 80篇 |
1991年 | 67篇 |
1990年 | 68篇 |
1989年 | 60篇 |
1988年 | 50篇 |
1987年 | 30篇 |
1986年 | 45篇 |
1985年 | 37篇 |
1984年 | 33篇 |
1983年 | 32篇 |
1982年 | 26篇 |
1981年 | 23篇 |
1980年 | 19篇 |
1979年 | 26篇 |
1978年 | 19篇 |
1977年 | 20篇 |
1976年 | 22篇 |
1974年 | 24篇 |
1969年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
Zinc sulfate addition to glass-ionomer-based cements: influence on physical and antibacterial properties, zinc and fluoride release. 总被引:5,自引:0,他引:5
Prudencio W R Osinaga Rosa Helena M Grande Rafael Y Ballester Maria Regina L Simionato Célia Regina M Delgado Rodrigues Antonio Muench 《Dental materials》2003,19(3):212-217
OBJECTIVES: The aim of this study is to evaluate the effect of ZnSO(4) addition to a conventional glass ionomer and a resin-modified glass ionomer on solubility, flexural strength, zinc and fluoride (F) release, and Streptococcus mutans growth inhibition. METHODS: 5 or 10% ZnSO(4) was added to Vitremer and Ketac-Fil powders. Solubility test was performed based on ISO 7489. Flexural strength was determined by 3-point bending test based on ISO 4049. Zn release/uptake was determined by atomic emission spectrometry; F release/uptake was measured using a F-specific electrode. Both release measurements were performed for 15 d before and 15 d after recharging. Antibacterial test was conducted according to agar plate methods against S. mutans, by measuring the inhibition halos in 1-h and 15-d specimens. Data were analyzed by ANOVA. RESULTS: Solubility increased with higher ZnSO(4) content, but remained below the ISO 7489 limit. Flexural strength was not affected by ZnSO(4) addition, and Vitremer performed better than Ketac-Fil. The control materials released no zinc. Vitremer with 10% ZnSO(4) released the highest amount of zinc. Fluoride release was similar for Ketac-Fil and Vitremer. In both cases, the highest amounts were released in the first 24 h. The growth inhibition halo of S. mutans was similar for both materials with highest content of ZnSO(4) and occurred only with 1-h specimens. SIGNIFICANCE: Zinc addition decreased microorganisms growth and improved fluoride release, without significantly affecting the materials' flexural strength and solubility. 相似文献
9.
Hugo Maia Julio Casoy Tania Correia Luís Freitas Kleber Pimentel Célia Athayde Elsimar Coutinho 《Gynecological endocrinology》2006,22(10):547-551
OBJECTIVES: To determine whether aromatase expression in the eutopic endometrium and adenomyotic foci is affected by previous use of oral contraceptives containing gestodene, and to determine whether changes in cyclooxygenase-2 (COX-2) expression occur in adenomyosis during the menstrual cycle. PATIENT AND METHODS: This was a retrospective cohort study carried out in paraffin-embedded endometrial tissue obtained from patients with a histological diagnosis of adenomyosis obtained during the proliferative (n = 25) and luteal (n = 10) phases of the menstrual cycle and following the use of continuous oral contraception with gestodene/ethinyl estradiol (n = 7). COX-2 and aromatase expression were measured in both eutopic endometrium and adenomyotic foci using immunohistochemical methods. RESULTS: Aromatase expression was detected in 80% of the endometrial slices by immunohistochemistry. In positive cases, aromatase was mainly detected in the stromal cells of the eutopic endometrium, whereas in the adenomyotic foci this expression was negative in the majority of the cases. Oral contraceptives containing gestodene, on the other hand, were effective in suppressing aromatase expression in both eutopic and ectopic endometrium. COX-2 expression was detected by immunohistochemistry in the glandular epithelium of both eutopic endometrium and adenomyotic foci and there were no significant changes in its intensity throughout the menstrual cycle. CONCLUSION: Aromatase expression in the eutopic endometrium and adenomyotic foci is suppressed by oral contraceptives containing gestodene. Increased aromatase activity may be responsible for the persistent COX-2 expression during the luteal phase. 相似文献
10.
E Gamiz G Delgado Calvo-Flores J Parraga R Delgado Calvo-Flores 《Annales pharmaceutiques fran?aises》1989,47(1):33-41
A study has been carried out on the possible pharmaceutical use of spanish talcs following the normalized assays of the main european pharmacopoeia and other quantitative methods. Only the talc nr3, not processed, meets all the assays of pharmacopoeia. The samples 2 and 4 (crushed) exceed the highest tolerated content in chlorides. The talc 1 (also crushed) only meets the loss on drying. The measures of some of these assays by using quantitative methods lead to more correct results and even sometimes in opposition with those obtained by pharmacopoeia methods. The particle size estimated by shifting and sedimentation shows that the crushed talcs are silty, whereas the only talc not processed is sandy. Considering the medium sizes estimated by scanning microscopy, it can be said that the pulverization of the talcs 1, 2 and 4 is characteristic of a micronization. 相似文献