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81.
相变光盘多层膜系结构的最佳光匹配研究 总被引:2,自引:0,他引:2
论述了相变光盘最佳膜系结构的设计。采用导纳矩阵法计算膜系的能量反射率,用量优化计算方法编程计算,提出了第二大极值解作为在工艺上可行的实用光盘的膜系结构,并按这种膜系结构制作样品,其擦写循环数达100万次上。 相似文献
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ECSS通信标准E-50发展现状简介 总被引:1,自引:1,他引:0
对ECSS通信标准E-50的组成、通信协议及其与CCSDS系列标准的差异和关系进行分析,并结合空间数据通信参考模型的具体应用,介绍该标准的使用方法,提出我国应用与借鉴国际空间数据传输标准的建议。 相似文献
84.
使用multisim软件对普通调幅和抑制载波的双边带调幅电路制作和仿真,阐述multisim软件对学习和理解高频电子技术课程有很大的帮助。 相似文献
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Dynamic characteristics analysis of deployable space structures considering joint clearance 总被引:1,自引:0,他引:1
The clearance in joints influences the dynamic stability and the performance of deployable space structures (DSS). A virtual experimental modal analysis (VEMA) method is proposed to deal with the effects of joint clearance and link flexibility on the dynamic characteristics of the DSS in this paper. The focus is on the finite element modeling of the clearance joint, VEMA and the modal parameters identification of the DSS. The finite element models (FEM) of the clearance joint and the deployable structure are established in ANSYS. The transient dynamic analysis is conducted to provide the time history data of excitation and response for the VEMA. The fast Fourier transform (FFT) technique is used to transform the data from time domain to frequency domain. The frequency response function is calculated to identify the modal parameters of the deployable structure. Experimental verification is provided to indicate the VEMA method is both a cost and time efficient approach to obtain the dynamic characteristics of the DSS. Finally, we analyze the effects of clearance size and gravity on the dynamic characteristics of the DSS. The analysis results indicate that the joint clearance and gravity strongly influence the dynamic characteristics of the DSS. 相似文献
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本文介绍了配料生产过程中单片机控制系统的硬件结构及软件流程。由于硬件和软件设计上都采用了模块化的结构,所以便于安装调试,整个系统可推广到诸如水泥、矿产、食品加工等生产中。 相似文献
89.
论文从高校新校区校园文化匮乏入手,阐述了校园文化建设是高校新校区建设的关键问题,并从德育角度探寻校园文化建设的方法和途径。 相似文献
90.
New Horizons Mission Design 总被引:1,自引:0,他引:1
In the first mission to Pluto, the New Horizons spacecraft was launched on January 19, 2006, and flew by Jupiter on February 28, 2007, gaining a significant speed boost from Jupiter’s gravity assist. After a 9.5-year journey, the spacecraft will encounter Pluto on July 14, 2015, followed by an extended mission to the Kuiper Belt objects for the first time. The mission design for New Horizons went through more than five years of numerous revisions and updates, as various mission scenarios regarding routes to Pluto and launch opportunities were investigated in order to meet the New Horizons mission’s objectives, requirements, and goals. Great efforts have been made to optimize the mission design under various constraints in each of the key aspects, including launch window, interplanetary trajectory, Jupiter gravity-assist flyby, Pluto–Charon encounter with science measurement requirements, and extended mission to the Kuiper Belt and beyond. Favorable encounter geometry, flyby trajectory, and arrival time for the Pluto–Charon encounter were found in the baseline design to enable all of the desired science measurements for the mission. The New Horizons mission trajectory was designed as a ballistic flight from Earth to Pluto, and all energy and the associated orbit state required for arriving at Pluto at the desired time and encounter geometry were computed and specified in the launch targets. The spacecraft’s flight thus far has been extremely efficient, with the actual trajectory error correction ΔV being much less than the budgeted amount. 相似文献