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341.
张国英%刘贵立%曾梅光%钱存富%耿平 《宇航材料工艺》2000,30(2):51-54
在实验数据的基础上,利用人工神经网络建立高Co-Ni二次硬化钢的力学性能与合金成分及热处理温度对应关系的模型。提出将五个材料力学性能指标及部分合金成分作为网络的输入,其它合金成分和热处理温度作为网络的输出,根据要求的力学性能设计性能设计材料的合金成分含量及热处理条件,获得了满意的结果,为高性能材料设计提供了一定的理论辅助手段。 相似文献
342.
研究了近圆轨道上两个飞行器轨道交会的控制问题。通过对最优控制理论设计最优交会轨线的研究 ,提出了利用 H∞控制理论设计实际控制器的方法 ,给出了仿真结果 ,验证了这种方法的正确性。说明了该方法具有鲁棒的控制效果以及次优的轨道特性。 相似文献
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344.
We conduct an in-depth study on the shape error of initially curved antennas to investigate errors that occur in the design and manufacturing processes. First, a numerical model is developed to simulate the actual surfaces. This model features a main advantage that it can predict the effects of cutting patterns on the shape error. The model is used to evaluate and optimize the design of cutting patterns. An error sensitivity analysis is performed to quantify and distinguish between the effects of error sources in manufacturing. The following sources are analyzed: errors in the elastic modulus of the membrane, pressure variations, and boundary deviations. The boundary deviation is found to be the most significant error source, and thus, boundary perturbation is recommended as an efficient error control measure. Finally, an inflatable antenna model is used to experimentally validate the numerical model. The experimental results display acceptable agreement with the numerical results. Thus, the developed numerical model and error control measure are shown to be feasible and efficient. 相似文献
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346.
为了研究不同的平面斜激波流场对流线追踪"咽"式进气道性能的影响规律,寻求性能最佳的进气道,对设计马赫数为7,具有不同三维基本流场的流线追踪"咽"式进气道进行了数值模拟。研究表明:选择8-7无粘流场(即俯仰平面内的斜激波由和自由来流呈8°夹角的斜压缩面产生;偏航平面内的斜激波由和自由来流呈7°夹角的斜压缩面产生)作为基本流场设计出的流线追踪进气道压缩性能、总压恢复性能及起动性能均能满足设计要求,并有较高的捕获流量;另外,通过对其进行附面层修正,设计状态下的各性能参数都较接近无粘设计参数,并且大幅度提高了进气道的流场均匀性。 相似文献
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348.
热电偶、热电阻自动检定系统的设计与实现 总被引:1,自引:0,他引:1
介绍了热电偶、热电阻系统的工作原理及其硬件组成、软件实现,并简要叙述了其自动检定的过程及方法。 相似文献
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350.
P.A. Chaizy T.G. DimbylowP.M. Allan M.A. Hapgood 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
This paper is one of the components of a larger framework of activities whose purpose is to improve the performance and productivity of space mission systems, i.e. to increase both what can be achieved and the cost effectiveness of this achievement. Some of these activities introduced the concept of Functional Architecture Module (FAM); FAMs are basic blocks used to build the functional architecture of Plan Management Systems (PMS). They also highlighted the need to involve Science Operations Planning Expertise (SOPE) during the Mission Design Phase (MDP) in order to design and implement efficiently operation planning systems. We define SOPE as the expertise held by people who have both theoretical and practical experience in operations planning, in general, and in space science operations planning in particular. Using ESA’s methodology for studying and selecting science missions we also define the MDP as the combination of the Mission Assessment and Mission Definition Phases. However, there is no generic procedure on how to use FAMs efficiently and systematically, for each new mission, in order to analyse the cost and feasibility of new missions as well as to optimise the functional design of new PMS; the purpose of such a procedure is to build more rapidly and cheaply such PMS as well as to make the latter more reliable and cheaper to run. This is why the purpose of this paper is to provide an embryo of such a generic procedure and to show that the latter needs to be applied by people with SOPE during the MDP. The procedure described here proposes some initial guidelines to identify both the various possible high level functional scenarii, for a given set of possible requirements, and the information that needs to be associated with each scenario. It also introduces the concept of catalogue of generic functional scenarii of PMS for space science missions. The information associated with each catalogued scenarii will have been identified by the above procedure and will be relevant only for some specific mission requirements. In other words, each mission that shares the same type of requirements that lead to a list of specific catalogued scenarii can use this latter list of scenarii (regardless of whether the mission is a plasma, planetary, astronomy, etc. mission). The main advantages of such a catalogue are that it speeds-up the execution of the procedure and makes the latter more reliable. Ultimately, the information associated to each relevant scenario (from the catalogue or freshly generated by the procedure) will then be used by mission designers to make informed decisions, including the modification of the mission requirements, for any missions. In addition, to illustrate the use of such a procedure, the latter is applied to a case study, i.e. the Cross-Scale mission. One of the outcomes of this study is an initial set of generic functional scenarii. Finally, although border line with the above purpose of this paper, we also discuss multi-spacecraft specific issues and issues related to the on-board execution of the plan update system (PUS). In particular, we show that the operation planning cost of N spacecraft is not equal to N times the cost of 1 spacecraft and that on-board non-synchronised operation will not require inter-spacecraft communication. We also believe that on-board PUS should be made possible for all missions as a standard. 相似文献