全文获取类型
收费全文 | 3919篇 |
免费 | 270篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 35篇 |
儿科学 | 145篇 |
妇产科学 | 82篇 |
基础医学 | 537篇 |
口腔科学 | 106篇 |
临床医学 | 393篇 |
内科学 | 837篇 |
皮肤病学 | 65篇 |
神经病学 | 509篇 |
特种医学 | 117篇 |
外科学 | 394篇 |
综合类 | 10篇 |
预防医学 | 296篇 |
眼科学 | 99篇 |
药学 | 242篇 |
中国医学 | 2篇 |
肿瘤学 | 339篇 |
出版年
2023年 | 37篇 |
2022年 | 69篇 |
2021年 | 131篇 |
2020年 | 83篇 |
2019年 | 105篇 |
2018年 | 121篇 |
2017年 | 128篇 |
2016年 | 130篇 |
2015年 | 122篇 |
2014年 | 157篇 |
2013年 | 199篇 |
2012年 | 304篇 |
2011年 | 281篇 |
2010年 | 155篇 |
2009年 | 138篇 |
2008年 | 246篇 |
2007年 | 268篇 |
2006年 | 237篇 |
2005年 | 276篇 |
2004年 | 224篇 |
2003年 | 183篇 |
2002年 | 186篇 |
2001年 | 39篇 |
2000年 | 31篇 |
1999年 | 31篇 |
1998年 | 36篇 |
1997年 | 30篇 |
1996年 | 22篇 |
1995年 | 25篇 |
1994年 | 18篇 |
1993年 | 10篇 |
1992年 | 12篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 10篇 |
1988年 | 14篇 |
1987年 | 7篇 |
1986年 | 8篇 |
1985年 | 8篇 |
1984年 | 7篇 |
1983年 | 13篇 |
1982年 | 5篇 |
1979年 | 8篇 |
1978年 | 6篇 |
1972年 | 11篇 |
1971年 | 5篇 |
1970年 | 6篇 |
1969年 | 4篇 |
1961年 | 4篇 |
1956年 | 4篇 |
排序方式: 共有4208条查询结果,搜索用时 15 毫秒
51.
Short DNA sequences and bacterial DNA induce esophageal,gastric, and colorectal cancer cell invasion
Joonas H. Kauppila Tuomo J. Karttunen Juha Saarnio Pia Nyberg Tuula Salo David E. Graves Katri S. Selander 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2013,121(6):511-522
Toll‐like receptor 9 (TLR9) recognizes both bacterial and self‐DNA and it is abundantly expressed in the gastrointestinal tract. In this study, we investigated the influences of both bacterial DNA and specific short DNA sequences on TLR9‐mediated gastrointestinal cancer cell invasion. We assessed the effect of various DNA ligands on cellular invasion and on TLR9 and matrix metalloproteinase expression of three gastrointestinal cancer cell lines. DNA‐ligands described in this study include CpG‐ODN M362, 9‐mer (hairpin), human telomeric sequence h‐Tel22 G‐quadruplex, and bacterial DNAs from Escherichia coli and Helicobacter pylori. All of the DNAs studied were demonstrated to induce invasion in the studied cells. The DNA‐induced invasion was inhibited with a broad‐spectrum MMP inhibitor and partly also with chloroquine suggesting that it could be mediated via MMP activation, endosomal signaling, and TLR9. Interestingly, H. pylori DNA was shown to induce a more pronounced invasion in a gastric cancer cell line than in the other cell lines. Our results suggest that bacterial DNA as well as deoxynucleotides having stable secondary structures (i.e. hairpins or G‐quadruplex structures) may serve as endogenous, invasion‐inducing TLR9‐ligands and promote local progression and metastasis of cancers in the alimentary tract. 相似文献
52.
53.
54.
55.
56.
Kristina Kusche-Vihrog Pia Jeggle Hans Oberleithner 《Pflügers Archiv : European journal of physiology》2014,466(5):851-859
Once upon a time, the expression of the epithelial sodium channel (ENaC) was mainly assigned to the kidneys, colon and sweat glands where it was considered to be the main determinant of sodium homeostasis. Recent, though indirect, evidence for the possible existence of ENaC in a non-epithelial tissue was derived from the observation that the vascular endothelium is a target for aldosterone. Inhibitory actions of the intracellular aldosterone receptors by spironolactone and, more directly, by ENaC blockers such as amiloride supported this view. Shortly after, direct data on the expression of ENaC in vascular endothelium could be demonstrated. There, endothelial ENaC (EnNaC) could be defined as a major regulator of cellular mechanics which is a critical parameter in differentiating between vascular function and dysfunction. Foremost, the mechanical stiffness of the endothelial cell cortex, a layer 50–200 nm beneath the plasma membrane, has been shown to play a crucial role as it controls the production of the endothelium-derived vasodilator nitric oxide (NO) which directly affects the tone of the vascular smooth muscle cells. In contrast to soft endothelial cells, stiff endothelial cells release reduced amounts of NO, the hallmark of endothelial dysfunction. Thus, the combination of endothelial stiffness and myogenic tone might increase the peripheral vascular resistance. An elevation of arterial blood pressure is supposed to be the consequence of such functional changes. In this review, EnNaC is discussed as an aldosterone-regulated plasma membrane protein of the vascular endothelium that could significantly contribute to maintaining of an appropriate arterial blood pressure but, if overexpressed, could participate in the pathogenesis of arterial hypertension. 相似文献
57.
58.
59.
Maria Pia Villa Alessandra Rizzoli Silvia Miano Caterina Malagola 《Sleep & breathing》2011,15(2):179-184
Purpose
In view of the positive outcome of orthodontic treatment using rapid maxillary expansion (RME) on sleep-disordered breathing, we generated data on RME in children with obstructive sleep apnea (OSA) by evaluating objective and subjective data over a 36-month follow-up period, to determine whether RME is effective in the long-term treatment of OSA. We selected all patients with dental malocclusions and OSA syndrome (OSAS) confirmed by polysomnography. 相似文献60.