全文获取类型
收费全文 | 4358716篇 |
免费 | 338465篇 |
国内免费 | 14735篇 |
专业分类
耳鼻咽喉 | 60304篇 |
儿科学 | 139445篇 |
妇产科学 | 114262篇 |
基础医学 | 666636篇 |
口腔科学 | 118063篇 |
临床医学 | 396973篇 |
内科学 | 790581篇 |
皮肤病学 | 107729篇 |
神经病学 | 368299篇 |
特种医学 | 169462篇 |
外国民族医学 | 753篇 |
外科学 | 656152篇 |
综合类 | 121298篇 |
现状与发展 | 24篇 |
一般理论 | 2614篇 |
预防医学 | 360306篇 |
眼科学 | 100906篇 |
药学 | 307647篇 |
26篇 | |
中国医学 | 11943篇 |
肿瘤学 | 218493篇 |
出版年
2021年 | 56175篇 |
2020年 | 35818篇 |
2019年 | 58816篇 |
2018年 | 74387篇 |
2017年 | 56985篇 |
2016年 | 63119篇 |
2015年 | 76071篇 |
2014年 | 110288篇 |
2013年 | 175840篇 |
2012年 | 124248篇 |
2011年 | 128969篇 |
2010年 | 125878篇 |
2009年 | 127608篇 |
2008年 | 115185篇 |
2007年 | 122470篇 |
2006年 | 131296篇 |
2005年 | 125367篇 |
2004年 | 126671篇 |
2003年 | 116861篇 |
2002年 | 106142篇 |
2001年 | 166944篇 |
2000年 | 162035篇 |
1999年 | 148675篇 |
1998年 | 71666篇 |
1997年 | 67608篇 |
1996年 | 65628篇 |
1995年 | 61049篇 |
1994年 | 54976篇 |
1993年 | 51019篇 |
1992年 | 106624篇 |
1991年 | 101381篇 |
1990年 | 97243篇 |
1989年 | 94818篇 |
1988年 | 87149篇 |
1987年 | 85307篇 |
1986年 | 80203篇 |
1985年 | 78359篇 |
1984年 | 65401篇 |
1983年 | 58197篇 |
1982年 | 47188篇 |
1981年 | 43855篇 |
1980年 | 41072篇 |
1979年 | 55102篇 |
1978年 | 44753篇 |
1977年 | 39978篇 |
1976年 | 36836篇 |
1975年 | 36805篇 |
1974年 | 39608篇 |
1973年 | 37752篇 |
1972年 | 35358篇 |
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
891.
In obstetrics and gynaecology, as well as in many other fields of medicine, ultrasound has become an indispensable diagnostic tool. Ultrasound training, however, still lacks proper quality assessment and control. In fact, in prenatal diagnostics most fetal anomalies requiring diagnosis during pregnancy are extremely rare. Therefore, effective training opportunities are limited to the very few medical centres which treat many such cases. Ultrasound simulator-based training, as performed with the Sonofit Sonotrainer, has been demonstrated to partly overcome this dilemma. In this article, the authors summarize their experience in using and evaluating various teaching concepts after the implementation of the ultrasound simulator under different conditions. Furthermore, an overview of the advantages of the Sonotrainer-based ultrasound training and its acceptance among trainees is provided. The authors also focus on aspects of quality assessment in gynaecological and prenatal ultrasound. 相似文献
892.
893.
For many parents stopping life-sustaining medical treatment on their dying infant is psychologically impossible. Dostoevsky's insights into human behavior, particularly the fact that individuals do not want the anxiety and guilt associated with responsibility for making difficult decisions, might change the way physicians approach parents for permission to withdraw life-prolonging medical interventions on dying infants. 相似文献
894.
N. N. Polygalova A. G. Mikhailovskii E. S. Limanskii B. Ya. Syropyatov M. I. Vakhrin 《Pharmaceutical Chemistry Journal》2006,40(3):132-134
A series of 1-alkyl-3,4-dihydroisoquinolines and the related 4-alkyl-1,2-dihydro-benzo[f]isoquinolines was synthesized using
reactions of dialkylbenzylcarbinols and their naphthyl analogs with alkylcyanides. Experiments showed that 1-alkyl-6,7-dimethoxy-3,4-dihydroisoquinolines
typically produce a hypotensive action, while the benzo-annelated structures usually exhibit a hypertensive effects. The most
active compound decreases the arterial pressure in cats by 52 Torr and the effect lasts for about 4 hours.
__________
Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 40, No. 3, pp. 15–17, March, 2006. 相似文献
895.
I. V. Shilova E. A. Krasnov E. I. Korotkova M. G. Nagaev A. N. Lukina 《Pharmaceutical Chemistry Journal》2006,40(12):660-662
Extracts of the above-ground part of meadowsweet (Filipendula ulmaria L. Maxim.) demonstrate a pronounced antioxidant activity. It is established that 70% and 95% ethanol extracts contain the
most active substances. Investigation of the chemical composition of the above-ground part of the plant and its 70% ethanol
extract by means of qualitative reactions, thin-layer chromatography, and paper chromatography showed the presence of various
phenolic compounds, including quercetin and its glycosides, dihydroquercetin, apigenin, rododendrol, esculetin, and m-hydroxybenzoic, salicylic, anisic, gallic, gentisic, ferulic, chlorogenic, and caffeic acids.
__________
Translated From Khimiko-Farmatsevticheskii Zhurnal, Vol. 40, No. 12, Pp. 22–24, December, 2006. 相似文献
896.
897.
Pankaj Dabir Snehal Dabir B V Siva Prasad M V R Reddy 《Infection, genetics and evolution》2006,6(4):287-291
Molecular characterization of Wuchereria bancrofti is essential to develop suitable anti-filarial drugs and vaccines. We describe here isolation, sequence analysis and cloning of a partial cDNA of an enzyme superoxide dismutase from this parasite. The immunoscreening of a lambda zap W. bancrofti microfilarial (Mf) cDNA library with microfilaremic sera had resulted in the isolation of several seroreactive clones including, WbSOD. This clone contained a 309 bp insert and showed significant nucleotide and deduced amino acid sequence homologies to the superoxide dismutases of other nematode parasites. The antioxidant property of this enzyme may have important contribution in the defense mechanism of the parasite against host immune response. 相似文献
898.
Steven M Shechter Andrew J Schaefer R Scott Braithwaite Mark S Roberts 《Medical decision making》2006,26(5):550-553
The authors discuss techniques for Monte Carlo (MC) cohort simulations that reduce the number of simulation replications required to achieve a given degree of precision for various output measures. Known as variance reduction techniques, they are often used in industrial engineering and operations research models, but they are seldom used in medical models. However, most MC cohort simulations are well suited to the implementation of these techniques. The authors discuss the cost of implementation versus the benefit of reduced replications. 相似文献
899.
900.