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71.
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73.
针对某型民用飞机液压地面模拟试验中设备分散、试验过程难以控制、管理的现状,根据试验过程控制的要求,基于以太网设计开发了飞机液压地面模拟试验综合控制系统.介绍了该综合控制系统的结构、功能以及软件设计.通过实际应用表明:该综合控制系统运行平稳、安全可靠、操作方便,提高了试验人员的工作效率. 相似文献
74.
空中管制员需为到达的飞机安排跑道并计算着陆时间,以飞机空中延误最小为出发点研究了多跑道的飞机着陆调度问题,约束条件为每架飞机的着陆时间应落在规定的时间窗内及相邻两架飞机应满足最小时间间隔。针对该问题设计了一种遗传算法对问题进行求解,其中染色体由飞机排序链表和跑道链表组成,相应的交叉和变异算子也做了改进设计。仿真实验用数据库OR-Library中的实例验证了该算法的有效性。 相似文献
75.
简要回顾了遗传规划的发展,对其基本原理进行了阐述,提出了基于遗传规划的飞机维修保障费用预测模型,并依据样本数据对所建模型的有效性进行了验证。实例表明,与线性回归方法和偏最小二乘回归方法相比,遗传规划在飞机维修保障费用预测中精度更高,具有较好的应用前景和推广价值。 相似文献
76.
A particle swarm optimization (PSO) algorithm improved by immunity algorithm (IA) was presented. Memory and self-regulation
mechanisms of IA were used to avoid PSO plunging into local optima. Vaccination and immune selection mechanisms were used
to prevent the undulate phenomenon during the evolutionary process. The algorithm was introduced through an application in
the direct maintenance cost (DMC) estimation of aircraft components. Experiments results show that the algorithm can compute
simply and run quickly. It resolves the combinatorial optimization problem of component DMC estimation with simple and available
parameters. And it has higher accuracy than individual methods, such as PLS, BP and v-SVM, and also has better performance
than other combined methods, such as basic PSO and BP neural network. 相似文献
77.
The Planer vertical take-off and landing (PVTOL) aircraft is a typical example of an underactuated mechanical system and has
a nonminimum-phase nature. When considering output tracking control, the Input/Output (I/O) linearization method is not appropriate
since the stability of the internal dynamics is not guaranteed. Hauser et al. regarded this system as a slightly nonminimum-phase
system which approximates to a minimum-phase one. Their control scheme yielded good results when the coupling factor was small,
but the results were not acceptable when the coupling factor increased. In this article, we propose two approaches to improve
the control performance. First, we consider the approximation error of Hauser's scheme as uncertainty, and apply the Linear
Quadratic Regulator (LQR) method, which possesses robustness against uncertainty, to determine the stabilizing feedback coefficients.
Second, from the fact that the tracking error is unavoidable, we use the “virtual reference trajectory” to design the tracking
control law, and optimize this trajectory to reduce the tracking error between the “actual reference trajectory” and the “resulting
trajectory”. This optimization also improves the control performance by choosing a suitable performance index. By using our
approach, we achieve better performance even if the coupling factor is increased. We show these results by numerical simulation.
This work was presented, in part, at the Seventh International Symposium on Artificial Life and Robotics, Oita, Japan, January
16–18, 2002 相似文献
78.
M. A. McCarthy J. R. Xiao C. T. McCarthy A. Kamoulakos J. Ramos J. P. Gallard V. Melito 《Applied Composite Materials》2004,11(5):317-340
Fibre Metal Laminates with layers of aluminium alloy and high strength glass fibre composite have been reported to possess excellent impact properties and be suitable for aircraft parts likely to be subjected to impacts such as runway debris or bird strikes. In a collaborative research project, aircraft wing leading edge structures with a glass-based FML skin have been designed, built, and subjected to bird strike tests that have been modelled with finite element analysis. In this second part of a two-part paper, a finite element model is developed for simulating the bird strike tests, using Smooth Particle Hydrodynamics (SPH) for modelling the bird and the material model developed in Part 1 of the paper for modelling the leading edge skin. The bird parameters are obtained from a system identification analysis of strikes on flat plates. Pre-test simulations correctly predicted that the bird did not penetrate the leading edge skin, and correctly forecast that one FML lay-up would deform more than the other. Post test simulations included a model of the structure supporting the test article, and the predicted loads transferred to the supporting structure were in good agreement with the experimental values. The SPH bird model showed no signs of instability and correctly modelled the break-up of the bird into particles. The rivets connecting the skin to the ribs were found to have a profound effect on the performance of the structure. 相似文献
79.
采用液压作动器/电静液作动器(HA/EHA)非相似余度配置的混合作动系统是未来多全电飞机作动系统的发展趋势,为解决混合作动系统能耗大、发热严重的问题,首先对构成混合作动系统的EHA进行效率分析,通过对比效率特性,提出根据不同工况自动切换至高效率通道进行工作的优化方法;分析飞机飞行空气负载四象限工况特点,以负载力F和作动筒运动速度v构成的工况网络作为切入点,提出了自适应工况与能量回收的混合作动系统工作模式,相较于传统工作模式能耗降低50%以上,并通过仿真验证该方法的有效性。 相似文献
80.
An intelligent toolpath (processing sequence) planning for fabricating aircraft structural parts is developed to obtain a minimum-length toolpath while maintaining the required machining time. The problem is first solved in the following ways. Firstly, an abstraction of the machining process is proposed to pick up the feed/retract points of each feature to be machined as the toolpath calculation basis. Secondly, the chaotic simulated annealing method is improved through storing the optimal solution, adding the control condition and selecting each parameter reasonably during the iteration of the algorithm so as to enhance its performance. What’s more, three solution-generating methods are used chaotically to obtain a better result. Lastly, the verification is conducted on four different aircraft structural parts, and the results prove that the proposed algorithm performs very well in terms of toolpath quality and computation time. 相似文献