全文获取类型
| 收费全文 | 1354篇 |
| 免费 | 169篇 |
| 国内免费 | 43篇 |
专业分类
| 电工技术 | 156篇 |
| 综合类 | 129篇 |
| 化学工业 | 57篇 |
| 金属工艺 | 31篇 |
| 机械仪表 | 89篇 |
| 建筑科学 | 60篇 |
| 矿业工程 | 9篇 |
| 能源动力 | 53篇 |
| 轻工业 | 11篇 |
| 水利工程 | 27篇 |
| 石油天然气 | 26篇 |
| 武器工业 | 12篇 |
| 无线电 | 108篇 |
| 一般工业技术 | 110篇 |
| 冶金工业 | 24篇 |
| 原子能技术 | 2篇 |
| 自动化技术 | 662篇 |
出版年
| 2025年 | 6篇 |
| 2024年 | 11篇 |
| 2023年 | 12篇 |
| 2022年 | 21篇 |
| 2021年 | 24篇 |
| 2020年 | 77篇 |
| 2019年 | 69篇 |
| 2018年 | 72篇 |
| 2017年 | 80篇 |
| 2016年 | 68篇 |
| 2015年 | 69篇 |
| 2014年 | 81篇 |
| 2013年 | 93篇 |
| 2012年 | 69篇 |
| 2011年 | 82篇 |
| 2010年 | 74篇 |
| 2009年 | 61篇 |
| 2008年 | 60篇 |
| 2007年 | 72篇 |
| 2006年 | 63篇 |
| 2005年 | 37篇 |
| 2004年 | 42篇 |
| 2003年 | 48篇 |
| 2002年 | 43篇 |
| 2001年 | 44篇 |
| 2000年 | 39篇 |
| 1999年 | 32篇 |
| 1998年 | 27篇 |
| 1997年 | 18篇 |
| 1996年 | 14篇 |
| 1995年 | 8篇 |
| 1994年 | 15篇 |
| 1993年 | 3篇 |
| 1992年 | 5篇 |
| 1991年 | 6篇 |
| 1990年 | 6篇 |
| 1989年 | 1篇 |
| 1988年 | 5篇 |
| 1986年 | 3篇 |
| 1985年 | 2篇 |
| 1984年 | 1篇 |
| 1982年 | 1篇 |
| 1981年 | 1篇 |
| 1979年 | 1篇 |
排序方式： 共有1566条查询结果，搜索用时 0 毫秒
81.
研究了用Toylor级数对多延时时变系统的近似求解。通过使用延时、乘积及积分运算矩阵,将系统求解简化为解一组联立方程组,为多延时时变系统的分析与设计提供了又一条途径。所给出的算法适合计算机实现。文中的算例验证了本文方法的有效性。 相似文献
82.
Abstract The effects of buoyancy forces on the laminar boundary layer flow and heat transfer along vertically moving cylinders are analyzed for the cases of prescribed surface temperature and prescribed wall heat flux in power of streamwise distance. Local similarity solutions are obtained to show the effects of buoyancy parameters and the transverse curvature of the cylinder on the surface friction and heat transfer rate. 相似文献
83.
Traditional principles of mechanics are primarily conceived for constant mass systems, which are only valid if mass is gained or lost at null velocity with respect to an inertial reference frame for variable mass systems, thus the numerical algorithms for time‐varying structures based on these principles are only suitable for this special case. In this paper, Hamilton's law of variable mass system is derived based on Meshchersky's fundamental equation, and two classes of novel time finite element formulations for linear systems with arbitrary continuous time‐varying parameters are developed based on the previous law. The formulations are verified extensively through numerical examples in which the convergence and effectiveness of algorithms are evaluated. Numerical examples demonstrate that compared with the algorithms for time‐varying structures that developed based on traditional principles of mechanics, the proposed algorithms provide extended capabilities in both time‐varying mass problems that mass is gained or lost at any velocity (such as rocket problem) and moving‐mass problems (such as vehicle‐bridge interaction problem) besides the time‐varying stiffness and damping problems, the proposed algorithms have a wider range of application. In particular, Hamilton's law of variable mass system provides a solid theoretical foundation for further research on the algorithm design for time‐varying structures. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
84.
Periodic feedback is a control strategy implemented by fast zero-average oscillations in the parameters of the control law. It is well known that time invariant feedback control offers no means for zeros relocation. Periodic feedback allows zeros relocation in an asymptotic sense, resulting in improved closed loop characteristics, such as increased gain margins. 相似文献
85.
J. Maity S. A. Rahman S. Alam K. K. Singh P. Kumar S. Hembram 《Materialwissenschaft und Werkstofftechnik》2023,54(3):335-344
Plain carbon steels of five different carbon contents up to eutectoid composition have been provided with the conventional full annealing treatment. Qualitative and quantitative studies of the microstructure are carried out using optical microscopy and field emission scanning electron microscopy techniques. Even under similar cooling rate pertaining to the full annealing treatment (furnace cooling); microstructural modifications of individual microconstituents are feasible with varying chemistry (carbon content) of plain carbon steel. The refinement of microstructure for both proeutectoid α-ferrite and pearlite is found to be accentuated with increasing carbon content of annealed steels till eutectoid composition. Hall-Petch type relationship explains adequately the relationship between hardness and the size of the microconstituent both in terms of the grain size of proeutectoid α-ferrite and the interlamellar spacing of pearlite. Henceforth an empirical relationship is developed for the first time taking into account the rule of mixture to correlate overall hardness, carbon content, grain size of proeutectoid α-ferrite and interlamellar spacing of pearlite. The empirical relationship originated thereby is found to closely match the experimental results. 相似文献
86.
Aiqing Chen Li Tang Yan‐Jun Liu Ying Gao 《International Journal of Adaptive Control and Signal Processing》2019,33(9):1344-1358
This paper is concerned with adaptive tracking control for switched uncertain nonlinear systems, which contain the time‐varying output constraint (TVOC) and input asymmetric saturation characteristic. In response to the unknown functions, the fuzzy logic systems are adopted. The controller is constructed by the backstepping technique. Based on the Tangent Barrier Lyapunov Function (BLF‐Tan), an adaptive switched control scheme is designed. It is demonstrated that all signals in the resulted system are semiglobally uniformly ultimately bounded with TVOC under arbitrary switchings. Furthermore, the effectiveness of presented control method is validated via the simulation example. 相似文献
87.
This paper is devoted to investigating the exponential synchronization of coupled Lur'e dynamical networks with multiple time‐varying delays and stochastic disturbance. The problem studied in this paper could be regarded as a kind of leader‐following synchronization issue. As the networks may suffer from certain impulsive disturbance, an effective distributed impulsive control protocol is proposed to synchronize the stochastic Lur'e dynamical networks. According to the comparison principle, the average impulsive interval, and the extended formula for the variation of parameters, sufficient conditions are derived for successful achievement of the network synchronization with consideration to different functions of impulsive effects. Furthermore, the exponential convergence rate is obtained based on the impulsive solution equation. In addition, finally, some numerical simulations are given to illustrate the validity of the control scheme and the theoretical analysis. 相似文献
88.
In this paper, we present a robust fault‐tolerant control scheme for constrained multisensor linear parameter‐varying systems, subject to bounded disturbances, that utilises multiple sensor fusion. The closed‐loop scheme consists of a tube model predictive control‐based feedback tracking controller and sensor‐estimate fusion strategy, which allows for the reintegration of previously faulty sensors. The active fault‐tolerant fusion‐based mechanism tracks the healthy‐faulty transitions of suitable residual variables by means of set separation and precomputed transition times. The sensor‐estimate pairings are then reconfigured based on available healthy sensors. Under the proposed scheme, robust preservation of closed‐loop system boundedness is guaranteed for a wide range of sensor fault situations. An example is presented to illustrate the performance of the fault‐tolerant control strategy. 相似文献
89.
Without any prior knowledge of the physical bounds of unknown parameters and uncertain nonlinearities, an indirect adaptive robust controller is constructed for uncertain nonlinear time‐varying systems in a strict‐feedback form. Firstly, an adaptive strong robust controller is derived based on the command filtered adaptive backstepping approach. This controller not only can guarantee the boundedness of the closed‐loop system signals in the presence of time‐varying (TV) parameters and uncertain nonlinearities but also obviate the need to compute analytic derivatives of virtual control functions. Thus, the problem of “explosion of terms” in the standard adaptive backstepping technique is avoided. Through introduction of a simple adaptation law on the upper bound of uncertainties, a smooth robust control term is used to realize the disturbance attenuation. Afterwards, based on the nonlinear X‐swapping techniques, a modular approach in which the controller and the identifier can be designed separately is exploited. A novel algorithm is proposed to estimate the TV parameters accurately. By adopting the variation trend of the covariance matrix as an indicator of the driving signals' persistent excitation level, this online parameter estimation law is switched between a modified least‐squares algorithm and a gradient algorithm based on fixed σ‐modification. Finally, a series of properties on the asymptotic stability and the global uniform ultimate boundedness of the closed‐loop system is established. Simulation results verify the effectiveness of the suggested method. 相似文献
90.
Milad Shahvali Javad Askari 《International Journal of Adaptive Control and Signal Processing》2017,31(1):97-121
In this paper, an adaptive neural output‐feedback control approach is considered for a class of uncertain multi‐input and multi‐output (MIMO) stochastic nonlinear systems with unknown control directions. Neural networks (NNs) are applied to approximate unknown nonlinearities, and K‐filter observer is designed to estimate unavailable system's states. Due to utilization of Nussbaum gain function technique in the proposed approach, the singularity problem and requirement to prior knowledge about signs of high‐frequency gains are removed, simultaneously. Razumikhin functional method is employed to deal with unknown state time‐varying delays, so that the offered control approach is free of common assumptions on derivative of time‐varying delays. Also, an adaptive neural dynamic surface control is developed; hence, explosion of complexity in conventional backstepping method is eliminated, effectively. The boundedness of all the resulting closed‐loop signals is guaranteed in probability; meanwhile, convergence of the tracking errors to adjustable compact set in the sense of mean quartic value is also proved. Finally, simulation results are shown to verify and clarify efficiency of the offered approach. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献