首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   280篇
  免费   7篇
电工技术   2篇
综合类   3篇
化学工业   35篇
金属工艺   5篇
机械仪表   15篇
建筑科学   13篇
矿业工程   1篇
能源动力   9篇
轻工业   12篇
水利工程   5篇
石油天然气   5篇
无线电   28篇
一般工业技术   71篇
冶金工业   38篇
自动化技术   45篇
  2023年   4篇
  2022年   11篇
  2021年   17篇
  2020年   10篇
  2019年   9篇
  2018年   13篇
  2017年   15篇
  2016年   16篇
  2015年   9篇
  2014年   10篇
  2013年   21篇
  2012年   17篇
  2011年   19篇
  2010年   11篇
  2009年   10篇
  2008年   5篇
  2007年   9篇
  2006年   7篇
  2004年   4篇
  2003年   3篇
  2002年   2篇
  2001年   3篇
  2000年   4篇
  1999年   3篇
  1998年   14篇
  1997年   8篇
  1996年   5篇
  1995年   3篇
  1994年   1篇
  1993年   3篇
  1992年   5篇
  1991年   3篇
  1989年   2篇
  1987年   1篇
  1985年   3篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1980年   1篇
  1978年   3篇
排序方式: 共有287条查询结果,搜索用时 171 毫秒
51.
In the application of Z‐number, how to generate Z‐number is a significant and open issue. In this paper, we proposed a method of generating Z‐number based on the OWA weights using maximum entropy considering the attitude (preference) of the decision maker. Some numerical examples are used to illustrate the effectiveness of the proposed method. Results show that the attitude (preference) of the decision maker can give an optimal possibility distribution of the reliability for Z‐number using maximum entropy.  相似文献   
52.
The effects of bottom topography and horizontal temperature gradients on the shallow water flows are theoretically investigated. The considered systems of partial differential equations (PDEs) are non-strictly hyperbolic and non-conservative due to the presence of non-conservative differential terms on the right hand side. The solutions of these model equations are very challenging for a numerical scheme. Thus, our primary goal is to introduce an improved numerical scheme which can handle the non-conservative differential terms efficiently and accurately. In this paper, the space–time conservation element and solution element (CESE) method is extended to approximate these model equations. The proposed scheme has capability to overcome all difficulties posed by this nonlinear system of PDEs. The performance of the scheme is analyzed by considering several case studies of practical interest and the results of suggested scheme are compared with those of central NT scheme. The accuracy of the scheme is verified qualitatively and quantitatively.  相似文献   
53.
Wireless Personal Communications - Medical Body Area Networks or MBANs are gaining popularity in healthcare circles because of the convenience they provide to patients and caregivers and assist in...  相似文献   
54.
Safety assessment of oil and gas (O&G) pipelines is necessary to prevent unwanted events that may cause catastrophic accidents and heavy financial losses. This study develops a safety assessment model for O&G pipeline failure by incorporating fuzzy logic into Bayesian belief network. Proposed fuzzy Bayesian belief network (FBBN) model explicitly represents dependencies of events, updating probabilities and representation of uncertain knowledge (such as randomness, vagueness and ignorance). The study highlights the utility of FBBN in safety analysis of O&G pipeline because of its flexible structure, allowing it to fit a wide variety of accident scenarios. The sensitivity analysis of the proposed model indicates that construction defect, overload, mechanical damage, bad installation and quality of worker are the most significant causes for the O&G pipeline failures. The research results can help owners of transmission and distribution pipeline companies and professionals to prepare preventive safety measures and allocate proper resources.  相似文献   
55.
Effective inspection and monitoring practices for the condition assessment of pipes ensure better decision(s) for repair or replacement before they fail. Pipe deterioration is a physical manifestation of the aging process in which many factors can contribute to structural failure. Various technologies/ techniques have been developed during the last few years to inspect/monitor piping systems, but how to intelligently interpret the collected data remains a challenge. In this paper, a new approach based on hierarchical evidential reasoning is proposed. This approach uses Dempster–Shafer (D-S) theory to make inferences for condition assessment of buried pipes. A hierarchical evidential reasoning model can help combine different distress indicators (bodies of evidence) at different hierarchical levels using D-S rule of combination. The proposed hierarchical evidential reasoning method is demonstrated with an example of condition assessment for a large diameter pipe. Information from multiple sources is fused to obtain a more reliable assessment of pipe deterioration.  相似文献   
56.
57.
Gastroesophageal reflux disease (GERD) is caused by excessive reflux of gastric content and duodenal bile into the esophagus, and impaired clearance of refluxate from the esophagus. In this perspective, raft-forming antireflux formulations offer better alternatives to the conventional therapies for treatment of uncomplicated GERD. In addition to the alginate-based systems, various natural polysaccharides have generated interest as raft-forming agents because of their bioadhesive/mucoprotective nature. Inclination of current therapy is towards natural products for healing of the disease, which also underlines the market potential of this class, demanding for thorough investigation and development of evaluation methods with better in vitro-in vivo correlation.  相似文献   
58.
Anodic polymerization of o‐aminoazotoluene azo dye on platinum electrodes in 0.5 M HCl in 50% v/v ethanol/water and in MeCN was studied by cyclic voltammetry. The formed films, in both media, were electroactive in acidic solutions but electroinactive in neutral and alkaline solutions and aprotic MeCN. The pair of redox peaks due to the electroactivity is attributed to a 1:1 proton + electron elimination (on oxidation)/addition (on reduction) at the amino/imino linkages which connect the aromatic nuclei. Chronocoulometry showed that the kinetics of these processes were dominated by the transport of solvated protons and Cl ions through the polymer films. Reduction of the polymer films in acid solutions led to their gradual degradation due to the irreversible reduction of the azo groups in the polymer skeleton, while the reversible reduction of these groups in MeCN saved the polymer from degradation. The rate of electron transfer reactions of the redox couple [Fe(CN)6]3−/4− on polymer‐covered platinum electrodes decreased substantially with increasing the polymer film thickness.  相似文献   
59.
As of yet, III-V p-type field-effect transistors (p-FETs) on Si have not been reported, due partly to materials and processing challenges, presenting an important bottleneck in the development of complementary III-V electronics. Here, we report the first high-mobility III-V p-FET on Si, enabled by the epitaxial layer transfer of InGaSb heterostructures with nanoscale thicknesses. Importantly, the use of ultrathin (thickness, ~2.5 nm) InAs cladding layers results in drastic performance enhancements arising from (i) surface passivation of the InGaSb channel, (ii) mobility enhancement due to the confinement of holes in InGaSb, and (iii) low-resistance, dopant-free contacts due to the type III band alignment of the heterojunction. The fabricated p-FETs display a peak effective mobility of ~820 cm(2)/(V s) for holes with a subthreshold swing of ~130 mV/decade. The results present an important advance in the field of III-V electronics.  相似文献   
60.
Oil and gas (O&G) pipelines are expensive assets that cross through both the ecologically sensitive and densely populated urban areas. The pipeline failure may have potentially significant consequences for both the natural and human environments. In order to maintain the integrity of O&G pipelines, inspection and maintenance processes should be governed by efficient policies. The objective of this paper is to conduct a state-of-the-art review of maintenance policies of O&G pipelines to investigate their advantages, limitations, and associated implementation issues. Maintenance policies can be categorised into corrective, preventive, predictive and proactive. Corrective maintenance policies (1940s) were based on the ‘repair when broke’ philosophy. Economic considerations shifted practice towards preventive maintenance (1970s to 1990s); later with improved inspection techniques and environmental regulations, predictive and proactive or risk-based maintenance (RBM) policies were developed. This review explicates different methodologies for RBM and related issues, e.g. uncertainties and variability, conservative assumptions, etc. Uncertainties associated with investigation and prediction of defects have been more frequently reported in the literature so far. Moreover, existing studies primarily focused on reducing the likelihood and cost of failure, whereas consideration of environmental factors in overall risk has been a relatively less addressed issue.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号