全文获取类型
收费全文 | 1035116篇 |
免费 | 88438篇 |
国内免费 | 13341篇 |
专业分类
耳鼻咽喉 | 14366篇 |
儿科学 | 26473篇 |
妇产科学 | 27419篇 |
基础医学 | 144939篇 |
口腔科学 | 28624篇 |
临床医学 | 98419篇 |
内科学 | 189363篇 |
皮肤病学 | 19053篇 |
神经病学 | 79109篇 |
特种医学 | 41407篇 |
外国民族医学 | 268篇 |
外科学 | 153664篇 |
综合类 | 53844篇 |
现状与发展 | 41篇 |
一般理论 | 284篇 |
预防医学 | 78439篇 |
眼科学 | 25127篇 |
药学 | 83738篇 |
186篇 | |
中国医学 | 12447篇 |
肿瘤学 | 59685篇 |
出版年
2021年 | 14595篇 |
2020年 | 10457篇 |
2019年 | 11380篇 |
2018年 | 13758篇 |
2017年 | 11720篇 |
2016年 | 12077篇 |
2015年 | 16231篇 |
2014年 | 21461篇 |
2013年 | 26305篇 |
2012年 | 36577篇 |
2011年 | 38856篇 |
2010年 | 23472篇 |
2009年 | 20450篇 |
2008年 | 32285篇 |
2007年 | 33834篇 |
2006年 | 33342篇 |
2005年 | 32757篇 |
2004年 | 29202篇 |
2003年 | 27811篇 |
2002年 | 26023篇 |
2001年 | 38963篇 |
2000年 | 39829篇 |
1999年 | 34413篇 |
1998年 | 11395篇 |
1997年 | 10799篇 |
1996年 | 10209篇 |
1995年 | 9696篇 |
1994年 | 9193篇 |
1992年 | 27808篇 |
1991年 | 27087篇 |
1990年 | 26423篇 |
1989年 | 25423篇 |
1988年 | 23898篇 |
1987年 | 23409篇 |
1986年 | 22147篇 |
1985年 | 21445篇 |
1984年 | 16543篇 |
1983年 | 14135篇 |
1982年 | 8937篇 |
1979年 | 16827篇 |
1978年 | 12153篇 |
1977年 | 10227篇 |
1976年 | 9365篇 |
1975年 | 10169篇 |
1974年 | 12677篇 |
1973年 | 12159篇 |
1972年 | 11556篇 |
1971年 | 10699篇 |
1970年 | 10233篇 |
1969年 | 9924篇 |
排序方式: 共有10000条查询结果,搜索用时 343 毫秒
71.
72.
Benyam Kinde Harrison W. Gabel Caitlin S. Gilbert Eric C. Griffith Michael E. Greenberg 《Proceedings of the National Academy of Sciences of the United States of America》2015,112(22):6800-6806
DNA methylation at CpG dinucleotides is an important epigenetic regulator common to virtually all mammalian cell types, but recent evidence indicates that during early postnatal development neuronal genomes also accumulate uniquely high levels of two alternative forms of methylation, non-CpG methylation and hydroxymethylation. Here we discuss the distinct landscape of DNA methylation in neurons, how it is established, and how it might affect the binding and function of protein readers of DNA methylation. We review studies of one critical reader of DNA methylation in the brain, the Rett syndrome protein methyl CpG-binding protein 2 (MeCP2), and discuss how differential binding affinity of MeCP2 for non-CpG and hydroxymethylation may affect the function of this methyl-binding protein in the nervous system. 相似文献
73.
Dynamic LVOT Obstruction and Aortic Stenosis in the Same Patient: A Case of Challenging Doppler Hemodynamics 下载免费PDF全文
Matthew W. Parker M.D. Francis J. Kiernan M.D. 《Echocardiography (Mount Kisco, N.Y.)》2015,32(6):1030-1032
We present a patient with both dynamic left ventricular outflow tract obstruction and valvular aortic stenosis. The aortic valve was calcified, and velocities and gradients measured by continuous‐wave Doppler met standard criteria for severe aortic stenosis. The increased subvalvular velocities invalidated assumptions of the simplified Bernoulli equation; correction using the longer form of the Bernoulli equation suggested a lower but still significant gradient. The complex shape of the subvalvular spectral Doppler envelope indicated supranormal systolic function and dynamic left ventricular outflow obstruction. Left heart catheterization with an end‐hole catheter was required to determine the subvalvular and valvular components of the obstruction. 相似文献
74.
75.
Tianying Yang Jiawei Li Yichen Jia Chunchen Yang Ruirui Sang Tongyu Zhu Ming Xu Ruiming Rong Cheng Yang 《Translational andrology and urology》2021,10(1):204
BackgroundIn the field of transplantation, inducing immune tolerance in recipients is of great importance. Blocking co-stimulatory molecule using anti-CD28 antibody could induce tolerance in a rat kidney transplantation model. Myeloid-derived suppressor cells (MDSCs) reveals strong immune suppressive abilities in kidney transplantation. Here we analyzed key genes of MDSCs leading to transplant tolerance in this model.MethodsMicroarray data of rat gene expression profiles under accession number in the Gene Expression Omnibus (GEO) database were analyzed. Running the LIMMA package in R language, the differentially expressed genes (DEGs) were found. Enrichment analysis of the DEGs was conducted in the Database for Annotation, Visualization and Integrated Discovery (DAVID) database to explore gene ontology (GO) annotation and their Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Their protein-protein interactions (PPIs) were provided by STRING database and was visualized in Cytoscape. Hub genes were carried out by CytoHubba.ResultsThree hundred and thirty-eight DEGs were exported, including 27 upregulated and 311 downregulated genes. The functions and KEGG pathways of the DEGs were assessed and the PPI network was constructed based on the string interactions of the DEGs. The network was visualized in Cytoscape; the entire PPI network consisted of 192 nodes and 469 edges. Zap70, Cdc42, Stat1, Stat4, Ccl5 and Cxcr3 were among the hub genes.ConclusionsThese key genes, corresponding proteins and their functions may provide valuable background for both basic and clinical research and could be the direction of future studies in immune tolerance, especially those examining immunocyte-induced tolerance. GSE28545相似文献
76.
由于骨盆的特殊结构,其内侧的血管网损伤导致不可压迫性出血。即使创伤中心和救治体系的建设,以及损害控制技术等发展,病死率仍然高达30%~60%。损害控制性复苏、骨盆带、外固定支架、复苏性腹主动脉内球囊阻断(REBOA)、动脉栓塞和腹膜外填塞等技术不断发展,部分已经得到普及,但迄今仍没有公认的确定性止血流程。我国正在普遍建设创伤中心,亟待制订适合我国的骨盆骨折大出血患者的救治流程,以提高救治成功率。本文阐述控制骨盆骨折大出血的外科技术和流程进展供同道参考。 相似文献
77.
目的探讨酪氨酸激酶受体RON及上皮型钙粘蛋白(E-cadherin)在子宫内膜异位症(endometriosis,EMs)上的表达及意义。方法选择2017年7~12月深圳市龙岗区人民医院收治的42例EMs患者,术中分别留取新鲜异位内膜组织和在位内膜组织,随机选取子宫切除或诊断性刮宫治疗的非EMs患者42例,术中留取其正常子宫内膜组织。采用逆转录聚合酶链反应(RT-PCR)检测子宫内膜组织中RON mRNA的表达,采用免疫组织化学方法检测对应42例石蜡组织中RON蛋白和E-cadherin的表达,并分析RON蛋白和E-cadherin的相关性。结果EMs异位内膜组织RON mRNA及RON蛋白阳性表达率显著高于在位内膜组织及正常子宫内膜组织(P<0.001),在位内膜组织及正常内膜组织中E-cadherin阳性表达率显著高于异位内膜组织(P<0.001),且异位内膜组织中RON mRNA及RON蛋白的表达与临床分期有关(P<0.001)。在同一标本中RON蛋白和E-cadherin表达呈负相关关系(r=-0.497,P<0.05)。结论RON的过度表达与EMs的发生发展密切相关,联合检测RON和E-cadherin的异常对判断EMs的发生发展有一定的参考价值,RON可能成为诊断治疗EMs的新靶点。 相似文献
78.
79.
80.