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991.
992.
基于声发射的可倾瓦径向滑动轴承碰摩故障诊断 总被引:6,自引:0,他引:6
该文尝试使用声发射技术检测径向可倾瓦轴承瓦块与转轴的碰摩故障,并在600 MW汽轮机发电机组模化实验台上进行了相应的实验研究。实验结果表明,当瓦块与转轴发生碰摩时,声发射信号的时域波形中出现周期性的脉冲信号,而且脉冲周期与轴旋转周期相同。此外,通过合理布置声发射传感器在轴承座上的位置,可以根据不同位置测量到的声发射信号幅值变化,以及声发射脉冲到达2个传感器的时间差,推断出发生碰摩的瓦块位置。因此,声发射技术能够作为可倾瓦径向滑动轴承故障诊断的有益补充。 相似文献
993.
本文主要通过S7-400和WINCC60的使用介绍传动故障诊断系统的开发设计,通过系统的实际应用,使大家了解传动诊断系统的功能和作用对现代化高节奏生产企业的重要性。 相似文献
994.
Antonio J. Suárez Fábrega José Manuel Bravo Caro Pedro J. Abad Herrera Rafael M. Gasca 《International Journal of Adaptive Control and Signal Processing》2014,28(12):1299-1324
In this paper, a new data‐driven fault‐detection method is proposed. This method is based on a new nonparametric system identification approach, which constitutes the principal contribution to this work. The fault‐detection method is a parametric model‐free approach that can be applied to nonlinear systems that work at various operating points. Not only can the fault‐detection process be applied to the steady state of each operating point, but it can also be applied to the transient state resulting from a change in the operating point. In order to detect faults, the proposed method uses an interval predictor based on bounded‐error techniques. The utilization of techniques based on bounded error enables system uncertainties to be included in an explicit way. This in turn leads to the possibility of obtaining interval predictions of the behaviour of the system, which include information on the reliability of the prediction itself. In order to show the effectiveness of the fault‐detection method, two examples are presented: in the form of a simulated process (counter‐flow shell‐and‐tube heat‐exchanger system) and an example of a real application (two‐tanks system). A comparison with two fault‐detection methods has also been included. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
995.
996.
Ji Qi Yanhui Li 《International Journal of Adaptive Control and Signal Processing》2021,35(6):1062-1082
In the network environment, the single time-triggered scheme wastes limited bandwidth resources due to all the sampled data are transmitted to the networks, and the single event-triggered scheme may increase system error because of ignoring factors such as changes in network utilization. To reduce the design conservatism, this paper is concerned with the hybrid-triggered L1 fault detection filter design for a class of nonlinear networked control systems (NCSs) described by Takagi–Sugeno (T-S) fuzzy model. Taking the effects of time-triggered scheme and event-triggered scheme into consideration simultaneously, we construct a fuzzy fault detection system. New results on stability and L1 performance are proposed for fuzzy fault detection system by exploiting the Lyapunov–Krasovskii functional and by means of the integral inequality method. Specially, attention is focused on the design of fault detection filter that guarantees a prescribed L1 noise attenuation level . Finally, two examples are presented to demonstrate the effectiveness of the proposed method. 相似文献
997.
Active fault‐tolerant control for near space vehicles based on reference model adaptive sliding mode scheme 下载免费PDF全文
Jing Zhao Bin Jiang Fahmida N. Chowdhury Peng Shi 《International Journal of Adaptive Control and Signal Processing》2014,28(9):765-777
In this paper, an adaptive sliding mode (ASM) scheme is proposed for fault identification and fault‐tolerant control of near space vehicles (NSVs). First, the attitude dynamic model is introduced, and a baseline controller based on reference sliding mode scheme is designed in the case of no faults. Then fault parameterizations with actuator dynamics is presented for several classes of faults: lock‐in‐place, float, hard‐over, and loss of effectiveness. On the basis of adaptive observer design, fault parameters can be accurately estimated on‐line. Furthermore, an ASM fault‐tolerant controller is designed for both cases of actuator dynamic faults and control effector damage. Finally, simulation experiments show that the proposed ASM scheme is able to quickly and accurately identify faults and reconfigure the controller, resulting in excellent overall system performance. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
998.
Non‐minimum phase switched systems: HOSM‐based fault detection and fault identification via Volterra integral equation 下载免费PDF全文
H. Ríos J. Davila T. Raïssi L. Fridman A. Zolghadri 《International Journal of Adaptive Control and Signal Processing》2014,28(12):1372-1397
In this paper, the problem of continuous and discrete state estimation for a class of linear switched systems with additive faults is studied. The class of systems under study can contain non‐minimum phase zeroes in some of their ‘operating modes’. The conditions for exact reconstruction of the discrete state are given using structural properties of the switched system. The state space is decomposed into the strongly observable part, the non‐strongly observable part, and the unobservable part, to analyze the effect of the unknown inputs. State observers based on high‐order sliding mode to exactly estimate the strongly observable part and Luenberger‐like observers to estimate the remaining parts are proposed. For the case when the exact estimation of the state cannot be achieved, the ultimate bounds on the estimation errors are provided. The proposed strategy includes a high‐order sliding‐mode‐based fault detection and a fault identification scheme via the solution of a Volterra integral equation. The feasibility of the proposed method is illustrated by simulations. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
999.
The selective separation of carbon dioxide (CO2) from a wet gaseous mixture of CO2/H2 through facilitated transport membranes containing immobilized aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), ethylenediamine (EDA) and monoprotonated ethylenediamine (EDAH+) and their blends was experimentally investigated. The effect of CO2 partial pressure, amine concentration, feed side pressure and amine species on the CO2 and H2 permeances were studied. The CO2 permeability through amine solution membranes decreased with increasing CO2 feed partial pressure but the H2 permeance was almost independent of the H2 partial pressure. A comparison of experimental results showed that single or blended amines with low viscosity and a moderate equilibrium constant, i.e., large forward and reverse reaction rate of CO2‐amine, are suitable for effective separation of CO2. The permeability of CO2 generally increased with an increase in amine concentration, although this increase may be compromised by the salting out effect and decrease in diffusivities of species. The results obtained indicated that CO2 permeance across a variety of amines are in the order of DEA (2 M) > MD (2 M) > MD (1 M) > MEA (2 M) > MEA (4 M) > MD (4 M) > DEA (1 M) > DEA (4 M) > MEA (1 M) for various concentrations of MEA + DEA blend and are in the order of EDAH+ (2 M) > DEA (2 M) > MH (2 M) > DH (2 M) > ED (2 M) > EDA (2 M) > MEA (2 M) for various blends of amine. 相似文献
1000.
VSP技术在缅甸石油勘探区块的应用 总被引:1,自引:0,他引:1
黎玮 《勘探地球物理进展》2009,32(2):127-132
缅甸中部曼德勒市以西某石油勘探区块勘探程度低,面临许多急需解决的地质问题。A-1井是中国石化在该区块开钻的第1口探井,2008年油气测试获得了较好的油气显示。在A-1井首次采集了零偏和非零偏VSP资料,进行了初至拾取、三分量旋转、波场分离、反射波成像等处理;综合利用A-1井的测井、钻井、VSP、二维地面地震等资料,标定了该区块A-1井处地震反射波组的地质属性,确定了主断层的断点位置,建立了泊松比参数与主力含气层段、非出气层段等的特征关系。VSP技术的应用在该区块的油气勘探中发挥了积极的作用。 相似文献