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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
94.
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
95.
为了实现同平面气动辅助空间交会,首先分析了其必须满足的2个必要条件:轨道转移问题和调相问题。然后分析了同平面HEO-LEO霍曼轨道转移技术及其调相问题。最后通过应用最优控制理论,求解一个典型同平面高轨道向低轨道转移的最优轨迹,确定了OTV在大气作用阶段轨道相角的变化大小。进一步依据空间交会理论得到了同平面HEO-LEO气动辅助空间交会所必须满足的标准相角的计算公式,并分析了气动辅助空间交会的调相问题。最后将霍曼方法和气动辅助方法进行了比较,得出了气动辅助空间交会不但可以节省燃料,而且能够在合理的时间内实现空间交会的结论。 相似文献
96.
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
97.
G. LABEAS J. DIAMANTAKOS 《Fatigue & Fracture of Engineering Materials & Structures》2006,29(5):365-371
Prediction of the coalescence of adjacent cracks is critical for residual strength estimation of structures under multiple site damage conditions. A methodology successfully developed for the case of crack link‐up prediction of un‐stiffened plates, is extended for the case of typical cracked stiffened aircraft panels. The proposed link‐up criterion is based on the change in the magnitudes of elastic and plastic strain energies of the stiffened panel, before and after the cracks coalesce. The strain energy magnitudes of interest are calculated using non‐linear elastic–plastic finite‐element analysis. For the application and verification of the method, experimental results from the open literature are used. Residual strength values calculated by the proposed methodology are in good agreement with the experimental results. The present criterion provides superior results when compared to the existing and commonly applied link‐up criteria. 相似文献
98.
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
99.
Compression-after-impact (CAI) strength of foam-cored sandwich panels with composite face sheets is investigated experimentally. The low-velocity impact by a semi-spherical (blunt) projectile is considered, producing a damage mainly in a form of core crushing accompanied by a permanent indentation (residual dent) in the face sheet. Instrumentation of the panels by strain gauges and digital speckle photography analysis are used to study the effect of damage on failure mechanisms in the panel. Residual dent growth inwards toward the mid-plane of a sandwich panel followed by a complete separation of the face sheet is identified as the failure mode. CAI strength of sandwich panels is shown to decrease with increasing impact damage size. Destructive sectioning of sandwich panels is used to characterise damage parameters and morphology for implementation in a finite element model. The finite element model that accounts for relevant details of impact damage morphology is developed and proposed for failure analysis and CAI strength predictions of damaged panels demonstrating a good correlation with experimental results. 相似文献
100.
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