全文获取类型
收费全文 | 29772篇 |
免费 | 3092篇 |
国内免费 | 2813篇 |
专业分类
电工技术 | 2356篇 |
综合类 | 4735篇 |
化学工业 | 1260篇 |
金属工艺 | 736篇 |
机械仪表 | 2465篇 |
建筑科学 | 1672篇 |
矿业工程 | 897篇 |
能源动力 | 458篇 |
轻工业 | 980篇 |
水利工程 | 913篇 |
石油天然气 | 1014篇 |
武器工业 | 562篇 |
无线电 | 6812篇 |
一般工业技术 | 2262篇 |
冶金工业 | 380篇 |
原子能技术 | 367篇 |
自动化技术 | 7808篇 |
出版年
2024年 | 224篇 |
2023年 | 815篇 |
2022年 | 858篇 |
2021年 | 998篇 |
2020年 | 937篇 |
2019年 | 1115篇 |
2018年 | 633篇 |
2017年 | 888篇 |
2016年 | 1004篇 |
2015年 | 1157篇 |
2014年 | 1783篇 |
2013年 | 1612篇 |
2012年 | 1798篇 |
2011年 | 1911篇 |
2010年 | 1910篇 |
2009年 | 2107篇 |
2008年 | 2463篇 |
2007年 | 2101篇 |
2006年 | 1528篇 |
2005年 | 1484篇 |
2004年 | 1265篇 |
2003年 | 1085篇 |
2002年 | 813篇 |
2001年 | 682篇 |
2000年 | 610篇 |
1999年 | 543篇 |
1998年 | 427篇 |
1997年 | 409篇 |
1996年 | 410篇 |
1995年 | 394篇 |
1994年 | 329篇 |
1993年 | 290篇 |
1992年 | 245篇 |
1991年 | 237篇 |
1990年 | 222篇 |
1989年 | 231篇 |
1988年 | 60篇 |
1987年 | 24篇 |
1986年 | 19篇 |
1985年 | 15篇 |
1984年 | 21篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1959年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
This paper investigates the problem of robust exponential stability for neutral systems with time-varying delays and nonlinear perturbations. Based on a novel Lyapunov functional approach and linear matrix inequality technique, a new delay-dependent stability condition is derived. Since the model transformation and bounding techniques for cross terms are avoided, the criteria proposed in this paper are less conservative than some previous approaches by using the free-weighting matrices. One numerical example is presented to illustrate the effectiveness of the proposed results. 相似文献
992.
993.
This paper presents an approach in designing a robust controller for vehicle suspensions considering changes in vehicle inertial properties. A four-degree-of-freedom half-car model with active suspension is studied in this paper, and three main performance requirements are considered. Among these requirements, the ride comfort performance is optimized by minimizing the H∞ norm of the transfer function from the road disturbance to the sprung mass acceleration, while the road holding performance and the suspension deflection limitation are guaranteed by constraining the generalized H2 (GH2) norms of the transfer functions from the road disturbance to the dynamic tyre load and the suspension deflection to be less than their hard limits, respectively. At the same time, the controller saturation problem is considered by constraining its peak response output to be less than a given limit using the GH2 norm as well. By solving the finite number of linear matrix inequalities (LMIs) with the minimization optimization procedure, the controller gains, which are dependent on the time-varying inertial parameters, can be obtained. Numerical simulations on both frequency and bump responses show that the designed parameter-dependent controller can achieve better active suspension performance compared with the passive suspension in spite of the variations of inertial parameters. 相似文献
994.
Delay-dependent stability analysis for Markovian jump systems with interval time-varying-delays 总被引:1,自引:0,他引:1
This paper proposes improved stochastic stability conditions for Markovian jump systems with interval time-varying delays. In terms of linear matrix inequalities (LMIs), less conservative delay-range-dependent stability conditions for Markovian jump systems are proposed by constructing a different Lyapunov-Krasovskii function. The resulting criteria have advantages over some previous ones in that they involve fewer matrix variables but have less conservatism. Numerical examples are provided to demonstrate the efficiency and reduced conservatism of the results in this paper. 相似文献
995.
996.
考虑直升机在飞行包线内模型参数的变化及不确定性影响,设计了鲁棒保性能控制律;根据直升机一个标称状态点构造出了参数不确定性矩阵,利用Lyapunov稳定性定理和线性矩阵不等式方法给出了控制器存在的充分条件及参数化设计方法,进行直升机三轴姿态稳定保性能控制律的设计;仿真结果表明,所设计的控制器满足三轴姿态稳定要求且具有很好的鲁棒性。 相似文献
997.
考虑系统外界干扰、系统参数摄动等非线性扰动环节对中立型时滞系统的H∞影响,提出基于Lyapunov稳定性理论的鲁棒H∞控制器的设计思想.利用线性矩阵不等式(LMI)方法,给出了该类具有状态非线性不确定性中立型时滞系统的鲁棒∞控制器的设计实例.在非线性不确定函数满足增益有界的条件下,得到了该类时滞系统满足鲁棒∞性能的一个充分条件.通过求解一个线性矩阵不等式LMI,即可获得鲁棒∞控制器.仿真结果表明了基于Lyapunov稳定性理论,LMI技术设计的控制器克服了系统外界非线性干扰或系统本身非线性参数摄动的影响,实现了闭环系统的H∞性能条件下的渐近稳定,满足了该系统鲁棒H∞控制的要求. 相似文献
998.
In many real-world applications of evolutionary algorithms, the fitness of an individual requires a quantitative measure. This paper proposes a self-adaptive linear evolutionary algorithm (ALEA) in which we introduce a novel strategy for evaluating individual’s relative strengths and weaknesses. Based on this strategy, searching space of constrained optimization problems with high dimensions for design variables is compressed into two-dimensional performance space in which it is possible to quickly identify ‘good’ individuals of the performance for a multiobjective optimization application, regardless of original space complexity. This is considered as our main contribution. In addition, the proposed new evolutionary algorithm combines two basic operators with modification in reproduction phase, namely, crossover and mutation. Simulation results over a comprehensive set of benchmark functions show that the proposed strategy is feasible and effective, and provides good performance in terms of uniformity and diversity of solutions. 相似文献
999.
In this paper, indirect adaptive state feedback control schemes are developed to solve the robust faulttolerant control (FTC) design problem of actuator fault and perturbation compensations for linear time-invariant systems. A more general and practical model of actuator faults is presented. While both eventual faults on actuators and perturbations are unknown, the adaptive schemes are addressed to estimate the lower and upper bounds of actuator-stuck faults and perturbations online, as well as to estimate control effectiveness on actuators. Thus, on the basis of the information from adaptive schemes, an adaptive robust state feed-back controller is designed to compensate the effects of faults and perturbations automatically. According to Lyapunov stability theory, it is shown that the robust adaptive closed-loop systems can be ensured to be asymptotically stable under the influence of actuator faults and bounded perturbations. An example is provided to further illustrate the fault compensation effectiveness. 相似文献
1000.
王谨 《数码设计:surface》2010,(12):166-168
数字化博物馆设计基于现代电子技术的发展,作为一种视听艺术,在二维的界面载体上构建出多维的视听虚拟空间的几种空间艺术形态的探讨。数字化博物馆的空间艺术形态表现形式本身就具有鲜明的空间性。设计师对虚拟空间形态的运用,会给观众带来更多趣味性和艺术性。对于设计师而言,设计创作的关键是从二维到多维空间思考角度的转变,并赋予其全新的审美趣味交流。 相似文献