全文获取类型
收费全文 | 445篇 |
免费 | 43篇 |
国内免费 | 63篇 |
专业分类
电工技术 | 7篇 |
综合类 | 28篇 |
化学工业 | 101篇 |
金属工艺 | 77篇 |
机械仪表 | 25篇 |
建筑科学 | 28篇 |
矿业工程 | 18篇 |
能源动力 | 3篇 |
轻工业 | 36篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
武器工业 | 1篇 |
无线电 | 34篇 |
一般工业技术 | 103篇 |
冶金工业 | 34篇 |
原子能技术 | 6篇 |
自动化技术 | 48篇 |
出版年
2024年 | 2篇 |
2023年 | 3篇 |
2022年 | 37篇 |
2021年 | 41篇 |
2020年 | 15篇 |
2019年 | 16篇 |
2018年 | 14篇 |
2017年 | 8篇 |
2016年 | 17篇 |
2015年 | 30篇 |
2014年 | 36篇 |
2013年 | 41篇 |
2012年 | 37篇 |
2011年 | 33篇 |
2010年 | 30篇 |
2009年 | 28篇 |
2008年 | 32篇 |
2007年 | 23篇 |
2006年 | 14篇 |
2005年 | 16篇 |
2004年 | 13篇 |
2003年 | 12篇 |
2002年 | 15篇 |
2001年 | 10篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1994年 | 3篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有551条查询结果,搜索用时 250 毫秒
21.
目的:研究依折麦布联合他汀对急性冠脉综合征(ACS)行急诊介入术(PCI)后患者残粒样脂蛋白-胆固醇(RLP-C)水平及主要心血管不良事件(MACE)的影响。方法:选取入院诊断ACS并行急诊PCI患者共90人,术后常规冠心病二级预防用药,将其随机分为两组,对照组48例服用阿托伐他汀,研究组42例加用依折麦布治疗,检测治疗前后RLP-C水平,并通过定期随访获取患者治疗期间MACE及药物不良反应。结果:与对照组相比,研究组治疗后RLP-C水平明显下降(P<0.05),MACE发生率明显降低(P<0.05),药物不良反应没有增加。结论:依折麦布联合他汀治疗可以降低ACS行急诊PCI术后患者RLP-C水平,减少MACE,不良反应少,值得推广应用。 相似文献
22.
23.
冠脉支架表面PLGA涂层制备及其血液相容性研究 总被引:5,自引:2,他引:3
采用静电喷涂沉积(electrospray deposition ESD)法在冠脉支架表面制备了PLGA涂层.采用OLYMPUS体式显微镜、原子力显微镜(AFM)观察了涂层宏观表面形貌及三维形貌;通过对涂层支架进行球囊扩张考察了PLGA涂层与支架的结合力;通过血小板粘附实验和动态凝血时间测定研究PLGA涂层的血液相容性.结果表明:ESD法在冠脉支架表面制备PLGA涂层,支架筋拐角处无明显的聚合物胶体缠绕、粘连且涂层表面光滑;PLGA涂层将316L不锈钢基体的微坑覆盖,基体Ra=16.174nm,PLGA涂层Ra=0.149nm,涂层表面粗糙度小;涂层支架撑开后在最大塑性变形位置无涂层撕裂、翘起等缺陷,涂层与支架有良好结合力;PLGA涂层血小板粘附量少,变形小,未引起血小板激活,动态凝血时间长,直到50min未产生凝血,PLGA涂层具有较好的血液相容性. 相似文献
24.
针对不同转速对电解抛光镍钛合金心血管支架流场分布的影响特点,利用ANSYS软件对电解抛光心血管支架过程中电解液的流速分布进行了仿真,分析了电解液速度场及涡流场对电解抛光心血管支架去除机理的影响规律,并通过试验验证了其仿真结果的正确性。结果表明:随着转速的增加,速度场分布均匀,涡流变化小,电解液更新及时,电解产物可及时排出,加工精度提高,抛光后的心血管支架表面完整性好;但当转速过高时,涡流分布区域明显增大,较多气体析出,导致速度场分布不均匀且不连续,加工精度低,抛光后的心血管支架表面完整性差。 相似文献
25.
美国食品所标示的有关膳食脂肪与冠心病关系的健康声明及对中国出口食品的指导意义 总被引:1,自引:0,他引:1
介绍了FDA关于食品健康声明的定义,膳食脂肪与冠心病关系,可以标示健康声明的食品要求以及FDA在最终通过健康声明之前须考虑的安全性问题,为国内的食品界提供一些参考信息。 相似文献
26.
Diagnostic Potential of Differentially Expressed Homer1, IL-1β, and TNF-α in Coronary Artery Disease
Xuan Jing Shan-Shan Chen Wei Jing Qian Tan Ming-Xia Yu Jian-Cheng Tu 《International journal of molecular sciences》2015,16(1):535-546
Increasing evidences suggest that inflammation plays an important role in the pathogenesis of coronary artery disease (CAD). Numerous inflammatory cytokines and related genes mediate adverse cardiovascular events in patients with CAD, such as interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and Homer in the present study. The study was carried out on 163 CAD patients at different stages and 68 controls. The gene expression of Homer1, Homer2, Homer3, IL-1β, and TNF-α in the peripheral blood leukocytes were measured by real-time polymerase chain reaction. The mRNA levels of Homer1, IL-1β, and TNF-α in CAD patients were significantly higher than those in the control group, but not Homer2 and Homer3. However, there was no considerable difference in the mRNA levels of Homer1, IL-1β, and TNF-α among AMI, UAP, and SAP three subgroups of CAD. The receiver operating characteristic (ROC) curves showed that Homer1 had a better diagnostic value for UAP patients compared with IL-1β and TNF-α. Like IL-1β and TNF-α, Homer1 may also be an important participant of atherosclerotic plaque development and eventually rupture. The results of the present study may provide an important basis for diagnosing CAD patients, and provide new therapeutic targets for CAD. 相似文献
27.
This paper studies the influence of a High-Porosity Mesh (HPM) stent on the hemodynamic characteristics in the intracranial aneurysm based on the Computational Fluid Dynamics (CFD). An idealized basilar tip aneurysm model and a HPM stent model are built. The pulsating blood flow in a cardiac cycle is computationally simulated for non-stented and stented models, to provide a wealth of information of the spatio-temporally varying blood flow field. The influence of the stent placement on the hemodynamic characteristics is analyzed in terms of distributions of velocity, pressure, Wall Shear Stress (WSS) and Energy Loss (EL), which are believed to play an important role in the development and rupture of the aneurysm. The numerical results clearly show that the velocity, pressure, WSS and EL of the blood flow in the aneurysm are reduced by 30%-40% when the HPM stent is implanted. These computational results may provide valuable hemodynamic information for clinical neurosurgeon. 相似文献
28.
29.
Dr Niels Grabow David P. Martin Klaus‐Peter Schmitz Katrin Sternberg 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2010,85(6):744-751
Stents are structural implants with widespread clinical use in vascular intervention to re‐open stenotic vessels for the treatment of coronary artery disease and peripheral arterial occlusive disease. Apart from their mechanical function, current drug‐eluting stents (DES) utilize local drug delivery from a drug‐incorporated permanent polymer coating to prevent in‐stent restenosis. This delayed closure of the stented vessel is considered one of the major limitations of conventional bare metal stents (BMS). The long‐term safety of DES, however, is still under debate, with reported cases of delayed healing, late thrombosis and hypersensitivity demanding further evolution in this field. A promising approach to circumvent the limitations of first generation DES is the application of degradable polymer coatings in second generation DES, and fully absorbable polymer stents. From a materials and engineering perspective, this paper provides a mini‐review of current clinically relevant DES technology and recent advancements in the development of stents from degradable polymeric materials as an alternative to permanent BMS and DES. This review, includes work on degradable stents and coatings based on blends of polylactic acid and the microbially‐produced poly(4‐hydroxybutyrate). Copyright © 2009 Society of Chemical Industry 相似文献
30.
D. J. Pennell H. G. Bogren J. Keegan D. N. Firmin S. R. Underwood 《Magma (New York, N.Y.)》1994,2(3):393-395
Coronary artery imaging is an important investigation for the management of coronary artery disease. Alternative noninvasive imaging would be useful, but the small caliber and tortuosity of the coronary vessels and cardiac and respiratory motion create formidable imaging problems. We first studied 21 normal subjects and 5 with coronary artery disease established by X-ray contrast angiography, of whom 2 had undergone bypass grafting. Of these, 22 were imaged successfully. Identification of the artery was possible for the left main stem, left anterior descending, right coronary, and left circumflex arteries respectively in 95%, 91%, 95%, and 76%. The arterial diameter at the origin could be measured in 77%, 77%, 81%, and 63%. The mean ±SD arterial diameter in each case (4.8±0.8, 3.7±0.5, 3.9±0.9, and 2.9±0.6 mm) was not significantly different from reference values (allp=ns). The mean length of artery visualized was 10.4±5.2,46.7±22.8,53.7±27.9, and 26.3±17.5 mm. In 12 normal males, the total coronary area was 30.9±9.2 mm2 and the ratio compared with body surface area was 16.4±4.4 mm2 m–2 (bothp=ns compared with reference values). In seven patients, with X-ray contrast coronary angiography, the proximal arterial diameter measured by magnetic resonance was 3.9±1.1 mm, and by X-ray contrast angiography 3.7±1.0 mm (p=ns). We then studied 17 patients with angina. Imaging of just the relevant artery was performed and analysis was blinded to the X-ray angiography results. Stenosis was identified on the magnetic resonance (MR) images by localized reduction in vessel signal intensity. Stenosis location by MR was assessed by measurement of its distance from a reference vessel, with correlation to the X-ray findings. X-ray coronary angiography showed 23 stenoses of which 15 (65%) were correctly located by blind assessment of the MR images. Of the eight remaining stenoses, a further 5 (63%) were correctly located on the MR images after retrospective comparison (overall sensitivity 87%). There were three lesions thought to represent stenosis by MR, which on review of the X-ray angiogram proved to be a minor stenosis <50% (two cases) or a tortuous vessel (one case). Greater signal loss was seen in the more severe stenoses. The stenosis length by MRI was greater than by X-ray (8.4 versus 5.1 mm,p<0.001). The overestimation of stenosis length may be due to turbulence. 相似文献