全文获取类型
收费全文 | 640篇 |
免费 | 41篇 |
国内免费 | 16篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 42篇 |
妇产科学 | 3篇 |
基础医学 | 50篇 |
口腔科学 | 8篇 |
临床医学 | 63篇 |
内科学 | 139篇 |
皮肤病学 | 6篇 |
神经病学 | 13篇 |
特种医学 | 228篇 |
外科学 | 43篇 |
综合类 | 33篇 |
预防医学 | 23篇 |
眼科学 | 4篇 |
药学 | 17篇 |
中国医学 | 1篇 |
肿瘤学 | 22篇 |
出版年
2021年 | 7篇 |
2020年 | 7篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 8篇 |
2015年 | 9篇 |
2014年 | 5篇 |
2013年 | 12篇 |
2012年 | 5篇 |
2011年 | 8篇 |
2010年 | 18篇 |
2009年 | 26篇 |
2008年 | 9篇 |
2007年 | 16篇 |
2006年 | 11篇 |
2005年 | 12篇 |
2004年 | 6篇 |
2003年 | 17篇 |
2002年 | 9篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 11篇 |
1998年 | 46篇 |
1997年 | 50篇 |
1996年 | 39篇 |
1995年 | 22篇 |
1994年 | 40篇 |
1993年 | 25篇 |
1992年 | 6篇 |
1991年 | 12篇 |
1990年 | 9篇 |
1989年 | 28篇 |
1988年 | 20篇 |
1987年 | 18篇 |
1986年 | 25篇 |
1985年 | 15篇 |
1984年 | 17篇 |
1983年 | 14篇 |
1982年 | 14篇 |
1981年 | 24篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 10篇 |
1977年 | 10篇 |
1976年 | 11篇 |
1975年 | 10篇 |
1965年 | 3篇 |
1964年 | 2篇 |
1958年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有697条查询结果,搜索用时 15 毫秒
691.
692.
693.
José Alcides A de Arruda Lauren F Schuch Lucas G Abreu Leni Verônica O Silva João Luiz GC Monteiro Rodrigo FC Pinho Leorik P Silva Suzana COM de Sousa Bruno Augusto B de Andrade Mario José Romañach Simone de QC Lourenço Aline C Batista Elismauro Francisco de Mendonça Manoela D Martins Pantelis V Rados Elena RC Rivero Lélia B de Souza Maria das GR Pinheiro Ana Paula N Gomes Ana Carolina U Vasconcelos Ana Paula V Sobral Ricardo A Mesquita 《Oral diseases》2018,24(7):1282-1293
694.
Surbhi Sidana Jugal Kishore Vidya Ghosh Divyansh Gulati RC Jiloha Tanu Anand 《The Australasian medical journal》2012,5(5):247-250
Background
Medical education is associated with various pressures and stresses which can lead to depression. This study was undertaken to discover the prevalence of depression in medical students and various factors contributing to depression.Method
This is a cross-sectional, questionnaire-based study. Using stratified random sampling, 237 students were selected according to year of study. Patient Health Questionnaire (PHQ-9), based on PRIME-MD Today, was used to make a provisional diagnosis of depression.Results
The overall prevalence of provisionally diagnosed depressive and major depressive disorder using PHQ-9 was 21.5% and 7.6%, respectively. Year of study and academic performance of students had a statistically significant association with depression. Other factors, including gender, self-reported past history of depression, family history of psychiatric disorders, type of social support, family structure, number of siblings and education of parents were not found to have any significant association with prevalence of depression in the study. It was also observed that students were reluctant to seek help for depressive symptoms. 相似文献695.
696.
CR de Andrade PF Leite AC Montezano DA Casolari A Yogi RC Tostes R Haddad MN Eberlin FRM Laurindo HP de Souza FMA Corr��a AM de Oliveira 《British journal of pharmacology》2009,157(4):568-580
Background and purpose:
There are interactions between endothelin-1 (ET-1) and endothelial vascular injury in hyperhomocysteinemia (HHcy), but the underlying mechanisms are poorly understood. Here we evaluated the effects of HHcy on the endothelin system in rat carotid arteries.Experimental approach:
Vascular reactivity to ET-1 and ETA and ETB receptor antagonists was assessed in rings of carotid arteries from normal rats and those with HHcy. ETA and ETB receptor expression was assessed by mRNA (RT-PCR), immunohistochemistry and binding of [125I]-ET-1.Key results:
HHcy enhanced ET-1-induced contractions of carotid rings with intact endothelium. Selective antagonism of ETA or ETB receptors produced concentration-dependent rightward displacements of ET-1 concentration response curves. Antagonism of ETA but not of ETB receptors abolished enhancement in HHcy tissues. ETA and ETB receptor gene expressions were not up-regulated. ETA receptor expression in the arterial media was higher in HHcy arteries. Contractions to big ET-1 served as indicators of endothelin-converting enzyme activity, which was decreased by HHcy, without reduction of ET-1 levels. ET-1-induced Rho-kinase activity, calcium release and influx were increased by HHcy. Pre-treatment with indomethacin reversed enhanced responses to ET-1 in HHcy tissues, which were reduced also by a thromboxane A2 receptor antagonist. Induced relaxation was reduced by BQ788, absent in endothelium-denuded arteries and was decreased in HHcy due to reduced bioavailability of NO.Conclusions and implications:
Increased ETA receptor density plays a fundamental role in endothelial injury induced by HHcy. ET-1 activation of ETA receptors in HHcy changed the balance between endothelium-derived relaxing and contracting factors, favouring enhanced contractility.British Journal of Pharmacology (2009) 157, 568–580; doi:10.1111/j.1476-5381.2009.00165.x; published online 9 April 2009This article is part of a themed section on Endothelium in Pharmacology. For a list of all articles in this section see the end of this paper, or visit: http://www3.interscience.wiley.com/journal/121548564/issueyear?year=2009 相似文献697.
目的:近年来,树突状细胞参与调节作用的研究较多。实验拟验证重组腺相关病毒(rAAV)介导癌胚抗原基因转染树突状细胞后其的免疫调节作用的变化。方法:实验于2006-06/2006-11在美国阿肯色大学医学院基因治疗中心完成。①实验方法:取健康人外周血(自愿捐献),采用改良Ficoll密度梯度离心的方法分离外周血单个核细胞,取贴壁细胞,分为rAAV/CEA转染组和空白对照组,均采用重组人粒细胞巨噬细胞集落刺激因子、白细胞介素4、肿瘤坏死因子-α诱导树突状细胞前体细胞成熟,将成熟树突状细胞与末梢血淋巴细胞按比例混合培养,可得到激活的细胞毒性T淋巴细胞。②实验评估:采用流式细胞仪检测树突状细胞表面标志表达,细胞毒性T淋巴细胞的免疫表型变化,细胞毒性T淋巴细胞γ-干扰素表达。采用酶联免疫吸附法(ELISA法)检测树突状细胞的白细胞介素12和白细胞介素10表达。结果:①rAAV/CEA转染树突状细胞的CD14较空白对照组降低,共刺激分子CD40、CD80、CD83、CD86表达均较空白对照组高。②成熟树突状细胞细胞因子表达中,rAAV/CEA转染组的白细胞介素12较空白对照组升高,白细胞介素10降低。③与空白对照组比较,rAAV/CEA转染组能高表达CD8 T细胞和其表型CD69,CD8/CD56的T细胞比例上调,CD25 CD4 的T细胞减少。④rAAV/CEA转染的细胞毒性T淋巴细胞表达相对较高水平的γ-干扰素,与杀伤实验结果相吻合。结论:rAAV/CEA转染树突状细胞能够激活细胞毒性T淋巴细胞的特异性杀伤作用,与树突状细胞和细胞毒性T淋巴细胞等免疫细胞表面标志变化和细胞内细胞因子水平变化相关。 相似文献