全文获取类型
收费全文 | 642篇 |
免费 | 30篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 6篇 |
综合类 | 13篇 |
化学工业 | 20篇 |
金属工艺 | 101篇 |
机械仪表 | 112篇 |
建筑科学 | 40篇 |
能源动力 | 20篇 |
轻工业 | 1篇 |
水利工程 | 2篇 |
武器工业 | 17篇 |
无线电 | 29篇 |
一般工业技术 | 66篇 |
冶金工业 | 57篇 |
原子能技术 | 2篇 |
自动化技术 | 193篇 |
出版年
2024年 | 2篇 |
2023年 | 9篇 |
2022年 | 12篇 |
2021年 | 15篇 |
2020年 | 21篇 |
2019年 | 17篇 |
2018年 | 7篇 |
2017年 | 24篇 |
2016年 | 20篇 |
2015年 | 27篇 |
2014年 | 40篇 |
2013年 | 48篇 |
2012年 | 38篇 |
2011年 | 49篇 |
2010年 | 41篇 |
2009年 | 37篇 |
2008年 | 26篇 |
2007年 | 37篇 |
2006年 | 36篇 |
2005年 | 28篇 |
2004年 | 26篇 |
2003年 | 27篇 |
2002年 | 19篇 |
2001年 | 13篇 |
2000年 | 14篇 |
1999年 | 6篇 |
1998年 | 8篇 |
1997年 | 5篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 7篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1984年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有679条查询结果,搜索用时 15 毫秒
1.
针对自动飞行控制系统结构复杂、关联部件众多,发生故障时诊断时间长,从而影响飞机运行效率的问题,提出一种基于飞机通信寻址报告系统(ACARS)的远程实时故障诊断方案。首先,分析自动飞行控制系统的故障特点,设计搭建检测滤波器;然后,利用ACARS数据链实时发送的自动飞行控制系统的关键信息进行相关部件的残差计算,并根据残差决策算法进行故障诊断及定位;最后,针对不同故障部件残差间的差异大、决策门限无法统一的缺点,提出基于二次差值的残差决策改进算法,减缓了检测对象的整体变化趋势,降低了随机噪声和干扰的影响,避免了将瞬态故障诊断为系统故障的情况。实验仿真结果表明,基于二次差值的改进残差决策算法避免了多决策门限的复杂性,在采样时间为0.1 s的情况下,故障检测所需时间大约为2 s,故障检测时间大幅降低,有效故障检测率大于90%。 相似文献
2.
Aircraft maintenance organisation is a complex socio-technical setup, where human factors influence the quality of aircraft maintenance service. Maintenance service quality is assessed based on the commitment of management and its ability to provide suitable facility, tools, spares and manpower supported with comfortable environment and maintenance procedures. Assessment of the service quality of the aircraft maintenance organisation is a complex process. Airlines, regulators, insurance companies and other agencies need decision support system, to assess the performance of a maintenance organisation. This paper provides criteria and scientific approach for assessing the maintenance organisation; it presents a methodology of applying Analytical Hierarchy Process to prioritise the key functions and to rank the maintenance organisations under study. The study has established that maintenance service quality in airline is directly correlated to its fleet size. 相似文献
3.
飞机液压系统污染及控制 总被引:2,自引:2,他引:0
本文全面分析了收音机液压系统污染的危害和主要原因,并在此基础上有针对性地提出了预防措施。 相似文献
4.
This letter investigates the scattering characteristic of the rivets on aircraft.The electric Field Integral Equation (EFIE)is used with the moment to calculate the current distribution on the surface of the rivet.With the application of Gaussian integral corresponding triangular cell,the time to fill the Z matrix is greatly reduced.Finally,the RCS of a type of rivet on aircraft is analyzed. 相似文献
5.
6.
Neural Nets Successfully Solve Complex Fluid Flow Problem. Much research is being done in the area of neural networks, and industry is actively seeking successful application to real world problems. We describe here a successful application. We have used neural networks to model complex coolant flow patterns, such as those encountered in design of hypersonic aircraft. Previous calculation methods, while reasonably accurate, are iterative and extremely time consuming. Our new approach uses a hierarchical neural network architecture to model coolant flow distribution in multiple heat exchanger panels. This method is direct, fast, and accurate. 相似文献
7.
The European Commission has been requested by member states to study the incorporation of air transport into their existing emissions trading scheme (ETS). Only CO2 is to be included, at least initially. 相似文献
8.
研究优化飞机地面空调车温控制问题,由于飞机地面空调车温度控制是非线性、时变性强的系统,工作环境不确定性,面对复杂系统温控模型不准确,传统的PID控制存在超调量大、响应速度慢、抗干扰能力弱等缺点。为提高温度控制精度,提出了一种新的稳定性好、精度高、抗干扰能力强的遗传-粒子群PID控制方法。结合传统的PID方法,遗传算法和粒子群算法的各自优点,实现了PID参数的在线整定。通过在matlab上进行仿真,实验结果证明算法具有超调量小、响应速度快、精度高、抗干扰能力强等优点,PID控制性能有显著提高,为飞机地面空调车的温度控制设计提供了依据。 相似文献
9.
Preliminary evaluation of the anticorrosive properties of aircraft coatings by electrochemical methods 总被引:5,自引:0,他引:5
L. B. Reynolds R. Twite M. Khobaib M. S. Donley G. P. Bierwagen 《Progress in Organic Coatings》1997,32(1-4):31-34
Strict regulations concerning the content of volatile organic compounds (VOCs) and heavy metals (Cr6+) in aircraft coating systems have increased the economic burden of the United States Air Force (USAF) in the area of coating maintenance. To this end, it is critical to have methods to characterize new coating systems in such a manner that the data can be used to predict accurately and reliably the expected lifetime of the coatings in service. Electrochemical noise method (ENM) and electrochemical impedance spectroscopy (EIS) are two techniques used to monitor extent and rate of corrosion. The USAF is currently employing these methods in order to supplement data acquired from traditional salt-spray methods. ENM and EIS are used to evaluate each component of the coating system and its contribution to corrosion prevention. Preliminary evaluations of an aircraft coating system on aluminum substrate (Al 2024-T3) produces resistance noise values of 106 to 107 Ω/cm2. It is hoped that these results will form the basis of coatings that give increased USAF fleet service life and reduction in maintenance manpower and materials costs. 相似文献
10.
This work shows how to use a differential geometry tool to design a novel nonlinear active fault tolerant flight control system for aircraft. The proposed control scheme consists of two main subsystems: a controller, which is designed for the nominal plant, and a fault detection and diagnosis module, which provides fault estimation. A further feedback loop exploits the fault estimation to accommodate faults affecting the system. The estimate convergence and the stability of the active fault tolerant flight controller are theoretically proved. Finally, high fidelity simulations show the effectiveness of the scheme. 相似文献