全文获取类型
收费全文 | 106353篇 |
免费 | 9030篇 |
国内免费 | 4251篇 |
专业分类
耳鼻咽喉 | 1091篇 |
儿科学 | 1615篇 |
妇产科学 | 1662篇 |
基础医学 | 13449篇 |
口腔科学 | 2117篇 |
临床医学 | 12660篇 |
内科学 | 18060篇 |
皮肤病学 | 1699篇 |
神经病学 | 7550篇 |
特种医学 | 4302篇 |
外国民族医学 | 44篇 |
外科学 | 14560篇 |
综合类 | 10809篇 |
现状与发展 | 19篇 |
一般理论 | 77篇 |
预防医学 | 6512篇 |
眼科学 | 2831篇 |
药学 | 9073篇 |
37篇 | |
中国医学 | 3554篇 |
肿瘤学 | 7913篇 |
出版年
2024年 | 225篇 |
2023年 | 1368篇 |
2022年 | 2937篇 |
2021年 | 4952篇 |
2020年 | 3364篇 |
2019年 | 3263篇 |
2018年 | 3717篇 |
2017年 | 2884篇 |
2016年 | 3085篇 |
2015年 | 4234篇 |
2014年 | 5332篇 |
2013年 | 5094篇 |
2012年 | 7791篇 |
2011年 | 8200篇 |
2010年 | 4758篇 |
2009年 | 4063篇 |
2008年 | 5650篇 |
2007年 | 5700篇 |
2006年 | 5521篇 |
2005年 | 5314篇 |
2004年 | 4173篇 |
2003年 | 3821篇 |
2002年 | 3413篇 |
2001年 | 1808篇 |
2000年 | 1881篇 |
1999年 | 1982篇 |
1998年 | 1418篇 |
1997年 | 1253篇 |
1996年 | 955篇 |
1995年 | 891篇 |
1994年 | 753篇 |
1993年 | 565篇 |
1992年 | 790篇 |
1991年 | 678篇 |
1990年 | 623篇 |
1989年 | 549篇 |
1988年 | 522篇 |
1987年 | 439篇 |
1986年 | 405篇 |
1985年 | 396篇 |
1984年 | 293篇 |
1983年 | 282篇 |
1982年 | 215篇 |
1981年 | 216篇 |
1980年 | 201篇 |
1979年 | 222篇 |
1978年 | 179篇 |
1977年 | 156篇 |
1976年 | 153篇 |
1974年 | 173篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Alexander Rodewald Rainer Pankau Angela Gosch Armin Wessel 《American journal of medical genetics. Part A》1994,53(3):227-235
The dermatoglyphic patterns of fingertips and palms of 115 patients with Williams-Beuren syndrome (WBS) were analysed and compared with the data from 199 control individuals from Germany. The following combination of dermatoglyphic patterns appears to be characteristic to WBS: an excess of whorls on all fingertips; high termination values of the main lines D, B, and A; frequent absence of C triradius (C°); high frequencies of ulnar loops on the hypothenar and distal loops on the 2nd, 3rd, and 4th inter digital areas, of distal axial triradii t", and of abnormal palmar creases such as simian crease and Sydney lines. The combination of fingertip and palmar patterns expressed by a “Log.Score-Index,” provides a high degree of discrimination between the WBS patients (92%) and the control group (88%). A “phantom picture” for WBS was constructed, which can be used for its diagnosis. © 1994 Wiley-Liss, Inc. 相似文献
992.
综述了一种快速成形技术在医学物理模型、可植入假体和组织工程人工器官制造中的应用,并比较了各种快速成形技术在人工器官制造中的优缺点,探讨了人工器官快速成形制造的发展方向。 相似文献
993.
为在纳米尺度对 NMDA受体蛋白分子进行神经细胞膜表面原位定位和探讨原子力显微镜在生物单分子操纵和调控中的应用 ,本研究应用原子力显微镜分别对分布在云母表面的膜 NMDA受体蛋白分子标记物抗 NMDAR1Ig G-葡萄球菌蛋白 A-胶体金复合物分子和结合标记物分子后的神经元膜进行扫描 ,三维形貌测定 ,通过颗粒度分析结果 ,明确标记物分子的特征性三维形貌 ,对比确定经过免疫胶体金结合后的 NMDA受体蛋白单分子在神经元膜表面的定位。结果显示 ,空白云母表面标记物分子为分散均匀的平均粒径为 49nm的球形颗粒 ,在神经元膜表面结合 NMDA目的受体蛋白分子后 ,免疫复合物分子呈现出粒径为 5 3 nm的散在分布球形或短棒状颗粒 ,长径约为宽径的 2倍 ,长轴截面可见典型的双峰三维结构。上述结果表明 ,NMDA受体蛋白单分子可以结合 1个或 1个以上的胶体金标记物分子 ;原子力显微镜可以在纳米尺度对神经元膜 NMDA受体蛋白进行标记和其免疫复合物的三维形貌测定。胶体金颗粒标记 ,原子力显微镜测定是免疫细胞化学新方法。 相似文献
994.
首先简要回顾了微电子机械系统技术研究进展,然后介绍了一种基于微处理器的消化道内按摩装置的基本结构,工作原理和特点。尤其详细介绍了采用MSP430F123微处理器产生周期脉冲,来控制整个按摩胶囊的供电。总的说来,消化道内按摩装置具有重要的临床应用价值和商业价值,开发消化道内按摩装置对我国生物医学工程产业和微电子机械系统产业的发展都有着积极和深远的意义。 相似文献
995.
Characterization of a Novel Anti-DR5 Monoclonal Antibody WD1 with the Potential to Induce Tumor Cell Apoptosis 总被引:2,自引:0,他引:2
996.
Integrin-linked kinase (ILK) is required for polarizing the epiblast,cell adhesion,and controlling actin accumulation 总被引:15,自引:0,他引:15
下载免费PDF全文
![点击此处可从《Genes & development》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Sakai T Li S Docheva D Grashoff C Sakai K Kostka G Braun A Pfeifer A Yurchenco PD Fässler R 《Genes & development》2003,17(7):926-940
Integrin-mediated cell-matrix interactions are essential for development, tissue homeostasis, and repair. Upon ligand binding, integrins are recruited into focal adhesions (FAs). Integrin-linked kinase (ILK) is an FA component that interacts with the cytoplasmic domains of integrins, recruits adaptor proteins that link integrins to the actin cytoskeleton, and phosphorylates the serine/threonine kinases PKB/Akt and GSK-3beta. Here we show that mice lacking ILK expression die at the peri-implantation stage because they fail to polarize their epiblast and to cavitate. The impaired epiblast polarization is associated with abnormal F-actin accumulation at sites of integrin attachments to the basement membrane (BM) zone. Likewise, ILK-deficient fibroblasts showed abnormal F-actin aggregates associated with impaired cell spreading and delayed formation of stress fibers and FAs. Finally, ILK-deficient fibroblasts have diminished proliferation rates. However, insulin or PDGF treatment did not impair phosphorylation of PKB/Akt and GSK-3beta, indicating that the proliferation defect is not due to absent or reduced ILK-mediated phosphorylation of these substrates in vivo. Furthermore, expression of a mutant ILK lacking kinase activity and/or paxillin binding in ILK-deficient fibroblasts can rescue cell spreading, F-actin organization, FA formation, and proliferation. Altogether these data show that mammalian ILK modulates actin rearrangements at integrin-adhesion sites. 相似文献
997.
The role of the microtubules in tumor necrosis factor-alpha-induced endothelial cell permeability 总被引:8,自引:0,他引:8
Petrache I Birukova A Ramirez SI Garcia JG Verin AD 《American journal of respiratory cell and molecular biology》2003,28(5):574-581
Tumor necrosis factor (TNF)-alpha, a major proinflammatory cytokine, triggers endothelial cell activation and barrier dysfunction which are implicated in the pathogenesis of pulmonary edema associated with acute lung injury syndromes. The mechanisms of TNF-alpha-induced vascular permeability are not completely understood. Our initial experiments demonstrated that TNF-alpha-induced decreases in transendothelial electrical resistance across human pulmonary artery endothelial cells are independent of myosin light chain phosphorylation catalyzed by either myosin light chain kinase or Rho kinase. We next assessed the involvement of another cytoskeletal component, the tubulin-based microtubule network, and found TNF-alpha to induce a decrease in stable tubulin content and partial dissolution of peripheral microtubule network as evidenced by anti-acetylated tubulin and anti-beta-tubulin immunofluorescent staining, respectively. Microtubule-stabilizing agents, paclitaxel and epothilone B, significantly attenuated TNF-alpha-induced decreases in transendothelial electrical resistance, inhibited the cytokine-induced increases in actin stress fibers, formation of intercellular gap, and restored the TNF-alpha-compromised vascular endothelial (VE)-cadherin-based cell-cell junctions. Importantly, neither TNF-alpha nor paclitaxel treatment was associated with endothelial cell apoptosis. Inhibition of p38 mitogen-activated protein kinase by SB203580 significantly attenuated TNF-alpha-induced microtubule destabilization, actin rearrangement, and endothelial barrier dysfunction. These results strongly suggest the involvement of microtubule rearrangement in TNF-alpha-induced endothelial cell permeability via p38 mitogen-activated protein kinase activation. 相似文献
998.
caspase-3、bcl-2蛋白在非霍奇金淋巴瘤组织的表达及其与细胞凋亡和增殖的关系 总被引:8,自引:0,他引:8
目的探讨caspase-3、bcl-2蛋白在非霍奇金淋巴瘤(NHL)发生、发展中的可能作用及相互关系.方法应用TdT介导的dUTP缺口末端标记(TUNEL)技术和免疫组织化学链霉素抗生物素-过氧化酶(SP)法,检测5例反应性增生淋巴组织和119例NHL组织中的细胞凋亡和增殖细胞核抗原(PCNA)、caspase-3、bcl-2蛋白的表达水平.结果 caspase-3和bcl-2在119例NHL中表达的阳性率分别为86.6%(103例)和53.8%(64例).二者在良、恶性淋巴组织中的表达方式相反在反应性增生淋巴滤泡中心caspase-3高表达而bcl-2阴性表达,滤泡套区caspase-3阴性表达而bcl-2高表达;在肿瘤性滤泡中心bcl-2常高表达而caspase-3常表达减弱或不表达;在NHL中二者的表达与肿瘤恶性度呈相反关系,高度恶性组中caspase-3的表达(44.4%)高于低度恶性组(23.7%,P<0.01),而B细胞性淋巴瘤中bcl-2的表达(42.6%)低于低度恶性组(75.5%,P<0.01);caspase-3的表达与凋亡指数呈正相关(r=0.512, P <0.01)),bcl-2的表达与凋亡指数呈负相关(r=-0.436, P<0.01).此外,NHL的凋亡指数与增殖指数呈显著正相关(r=0.710, P<0.01).结论 caspase-3可能参与了NHL的凋亡调节机制.caspase-3和bcl-2蛋白在良、恶性淋巴组织中常呈现相反的表达方式,提示二者在淋巴细胞增殖动力学调节中可能存在着密切联系. 相似文献
999.
During 1988, 108 samples were received from game birds (78 from pheasants, 28 from partridges and two from quail) for virus isolation or detection; 89 being received during the June to August rearing period. The most common clinical signs resulting in the submissions were death, scour and stunting. Virus or virus-like particles were detected in 51 cases, 43 as a result of direct electron microscopy of gut contents, seven by agar gel precipitin test for the presence of Marble spleen disease antigen and one by isolation, of a rotavirus. Particles observed by electron microscopy were: rotavirus - 15, adenovirus - 1, reovirus - 1, enterovirus - 1, 'fimbriated' virus-like particles - 10, rod-shaped virus-like particles - 19, On three occasions more than one type of particle was seen in the same sample. 相似文献
1000.
D J Alexander 《Avian pathology》1987,16(4):547-552