全文获取类型
收费全文 | 12380篇 |
免费 | 772篇 |
国内免费 | 616篇 |
专业分类
电工技术 | 330篇 |
综合类 | 476篇 |
化学工业 | 619篇 |
金属工艺 | 214篇 |
机械仪表 | 1243篇 |
建筑科学 | 343篇 |
矿业工程 | 29篇 |
能源动力 | 158篇 |
轻工业 | 36篇 |
水利工程 | 17篇 |
石油天然气 | 49篇 |
武器工业 | 123篇 |
无线电 | 4701篇 |
一般工业技术 | 1528篇 |
冶金工业 | 259篇 |
原子能技术 | 85篇 |
自动化技术 | 3558篇 |
出版年
2024年 | 15篇 |
2023年 | 81篇 |
2022年 | 101篇 |
2021年 | 143篇 |
2020年 | 166篇 |
2019年 | 205篇 |
2018年 | 217篇 |
2017年 | 358篇 |
2016年 | 365篇 |
2015年 | 378篇 |
2014年 | 686篇 |
2013年 | 717篇 |
2012年 | 794篇 |
2011年 | 957篇 |
2010年 | 673篇 |
2009年 | 718篇 |
2008年 | 947篇 |
2007年 | 846篇 |
2006年 | 875篇 |
2005年 | 752篇 |
2004年 | 679篇 |
2003年 | 487篇 |
2002年 | 382篇 |
2001年 | 285篇 |
2000年 | 245篇 |
1999年 | 267篇 |
1998年 | 229篇 |
1997年 | 150篇 |
1996年 | 158篇 |
1995年 | 140篇 |
1994年 | 122篇 |
1993年 | 107篇 |
1992年 | 89篇 |
1991年 | 89篇 |
1990年 | 77篇 |
1989年 | 68篇 |
1988年 | 47篇 |
1987年 | 24篇 |
1986年 | 31篇 |
1985年 | 17篇 |
1984年 | 20篇 |
1983年 | 17篇 |
1982年 | 21篇 |
1981年 | 11篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1974年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
本文给出一种简单非线性PID控制器的设计方法。该控制器设计简单.有较好的适应性、鲁棒性和抗干扰性,通过其在电液伺服系统中的应用表明该方法的有效性和可行性,该控制方案能用于机器人等复杂的控制系统中,有较好的应用前景。 相似文献
52.
非线性滤波在射线图像降噪增强中的应用 总被引:1,自引:2,他引:1
射线数字成像是当前射线检测与诊断技术发展的方向,图像降噪增强是提高射线成像检测灵敏度和分辨力的关键。重点探讨以排序滤波为代表的非线性滤波图像降噪增强方法,对射线图像的处理表明,线性滤波在降噪的同时会引起较大的边级模糊,而排序滤波不仅降低噪声且能保持图像细节,提高图像质量效果明显。 相似文献
53.
54.
David O. Cooney 《Chemical Engineering Communications》1990,91(1):1-9
A simple method is presented for determining fluid-phase and solid-phase solute concentration profiles, and solute breakthrough curves, for fixed bed adsorbers when both the fluid-phase and solid-phase mass transfer resistances are important. The method applies to any nonlinear isotherm of the “favorable” type. Freundlich and Langmuir isotherms are used as specific examples in the present paper. Constant-pattern behavior and linear-driving-force rate laws are assumed. 相似文献
55.
This paper studies the robust distributed receding horizon control (DRHC) problem for large-scale continuous-time nonlinear systems subject to communication delays and external disturbances. A dual-mode robust DRHC strategy is designed to deal with the communication delays and the external disturbances simultaneously. The feasibility of the proposed DRHC and the stability of the closed-loop system are analyzed, and the sufficient conditions for ensuring the feasibility and stability are developed, respectively. We show that: (1) the feasibility is affected by the bounds of external disturbances, the sampling period and the bound of communication delays; (2) the stability is related to the bounds of external disturbances, the sampling period, the bound of communication delays and the minimum eigenvalues of the cooperation matrices; (3) the closed-loop system is stabilized into a robust invariant set under the proposed conditions. A simulation study is conducted to verify the theoretical results. 相似文献
56.
This paper presents a multivehicle sampling algorithm to generate trajectories for nonuniform coverage of a nonstationary spatiotemporal field characterized by spatial and temporal decorrelation scales that vary in space and time, respectively. The sampling algorithm described in this paper uses a nonlinear coordinate transformation that renders the field locally stationary so that existing multivehicle control algorithms can be used to provide uniform coverage. When transformed back to the original coordinates, the sampling trajectories are concentrated in regions of short spatial and temporal decorrelation scales. For fields with coupled spatial statistics, i.e., the spatial decorrelation scales are functions of both spatial dimensions, the coordinate transformation is implemented numerically, whereas for decoupled spatial statistics, the transformation is expressed analytically. We show that the analytical transformation results in vehicle motion that preserves the vehicle sampling speed (which is a measure of vehicle speed scaled by the ratio of the spatial and temporal decorrelation scales), in the original domain; the sampling speed determines the minimum number of vehicles needed to cover a spatiotemporal domain. Theoretical results are illustrated by numerical simulations. 相似文献
57.
The emergence of synchronization in a network of coupled oscillators is a fascinating subject of multidisciplinary research. This survey reviews the vast literature on the theory and the applications of complex oscillator networks. We focus on phase oscillator models that are widespread in real-world synchronization phenomena, that generalize the celebrated Kuramoto model, and that feature a rich phenomenology. We review the history and the countless applications of this model throughout science and engineering. We justify the importance of the widespread coupled oscillator model as a locally canonical model and describe some selected applications relevant to control scientists, including vehicle coordination, electric power networks, and clock synchronization. We introduce the reader to several synchronization notions and performance estimates. We propose analysis approaches to phase and frequency synchronization, phase balancing, pattern formation, and partial synchronization. We present the sharpest known results about synchronization in networks of homogeneous and heterogeneous oscillators, with complete or sparse interconnection topologies, and in finite-dimensional and infinite-dimensional settings. We conclude by summarizing the limitations of existing analysis methods and by highlighting some directions for future research. 相似文献
58.
The paper deals with state estimation of the nonlinear stochastic systems by means of the unscented Kalman filter with a focus on specification of the σ-points. Their position is influenced by two design parameters—the scaling parameter determining the spread of the σ-points and a covariance matrix decomposition determining rotation of the σ-points. In this paper, a choice of the scaling parameter is analyzed. It is shown that considering other values than the standard choice may lead to increased quality of the estimate, especially if the scaling parameter is adapted. Several different criteria for the adaptation are proposed and techniques to reduce computational costs of the adaptation are developed. The proposed algorithm of the unscented Kalman filter with advanced adaptation of the scaling parameter is illustrated in a numerical example. 相似文献
59.
《自动化学报》2014,(11)
A nonlinear control is proposed for trajectory tracking of a 6-DOF model-scaled helicopter with constraints on main rotor thrust and fuselage attitude. In the procedure of control design, the mathematical model of helicopter is simplified into three subsystems: altitude subsystem, longitudinal-lateral subsystem and attitude subsystem. The proposed control is developed by combining the sub-controls for the corresponding subsystems. The sub-controls for altitude subsystem and longitudinal-lateral subsystem are designed with hyperbolic tangent functions to satisfy the constraints; the sub-control for attitude subsystem is based on backstepping technique such that fuselage attitude tracks the virtual control for longitudinallateral subsystem. It is proved theoretically that tracking errors are ultimately bounded, and control constraints are satisfied.Performances of the proposed controller are demonstrated by simulation results. 相似文献
60.
《Automatica》2014,50(11):2918-2923
In this paper we consider the problem of global asymptotic stabilization with prescribed local behavior. We show that this problem can be formulated in terms of control Lyapunov functions. Moreover, we show that if the local control law has been synthesized employing an LQ approach, then the associated Lyapunov function can be seen as the value function of an optimal problem with some specific local properties. We illustrate these results on two specific classes of systems: backstepping and feedforward systems. Finally, we show how this framework can be employed when considering the orbital transfer problem. 相似文献