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141.
基于RBF网络的惯导系统初始对准 总被引:18,自引:2,他引:18
建立了惯导系统(INS)初始对准的线性和非线性误差模型。分析了径向基函数(RBF)网络的结构和工作原理。研究了RBF网代替初始对准中的卡尔曼滤波器的实现方法。通过仿真表明,用神经网络进行初始对准,既可获得与卡尔曼滤波相同的对准精度,又提高了系统的实时性。 相似文献
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Major X-33 flight hardware has been delivered, and assembly of the vehicle is well underway in anticipation of its flight test program commencing in the summer of 1999. Attention has now turned to the operational VentureStarTM, the first single-stage-to-orbit (SSTO) reusable launch vehicle. Activities are grouped under two broad categories: (1) vehicle development and (2) market/business planning, each of which is discussed. The mission concept is presented for direct payload delivery to the International Space Station and to low Earth orbit, as well as payload delivery with an upper stage to Geosynchronous Transfer Orbit (GTO) and other high energy orbits. System requirements include flight segment and ground segment. Vehicle system sizing and design status is provided including the application of X-33 traceability and lessons learned. Technology applications to the VentureStarTM are described including the structure, propellant tanks, thermal protection system, aerodynamics, subsystems, payload bay and propulsion. Developing a market driven low cost launch services system for the 21st Century requires traditional and non-traditional ways of being able to forecast the evolution of the potential market. The challenge is balancing both the technical and financial assumptions of the market. This involves the need to provide a capability to meet market segments that in some cases are very speculative, while at the same time providing the financial community with a credible revenue stream. Furthermore, the market derived requirements need to be assessed so as not to impose unnecessary requirements on the vehicle design that add unreasonable cost to the development of the system, yet provides the right capabilities for new markets that could be triggered by dramatically lower space transportation prices. 相似文献
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带滑移铰空间机械臂惯性空间轨迹的复合自适应跟踪控制 总被引:16,自引:6,他引:16
讨论了载体的位置与姿态均不受控制的漂浮基带滑移铰空间机械臂的控制问题。动力学分析表明,结合系统动量及动量矩守恒关系得到的运动Jacobi关系及系统动力学方程将是系统惯性参数的非线性函数,借助于增广变量法,我们得到了与惯性参数呈线性关系的系统广义Jacobi矩阵及系统控制方程,以此为基础,针对系统中存在未知惯性参数的情况,设计了一种末端抓手惯性空间期望轨迹跟踪的复合自适应控制方案,此控制方案的优点在于不需要测量空间机械臂载体的位置及移动的速度,加速度,仿真运算证实了方法的有效性。 相似文献
146.
为了解决扭转振动攻丝系统体积大、成本高、使用寿命短等关键问题,使攻丝力矩明显减小的振动攻丝技术能够得到广泛应用,提出了一种结构紧凑、压力角小、具有对称结构、制造工艺简单的斜楔式扭转振动器的传动原理,导出了该振动器的输出运动方程所要满足的必要条件,并给出了输入输出构件凸轮廓线的一般方程.最后通过一个例子证实了方程的正确性.这种扭转振动器可以广泛地应用于振动攻丝、振动铰孔加工. 相似文献
147.
XIA Lidong TU Chuanyi Schwenn Rainer Donovan Eric Marsch Eckart WANG Jingsong ZHANG Yongwei XIAO Zuo 《空间科学学报》2006,26(Z1)
The KuaFu mission-Space Storms, Aurora and Space Weather Explorer-is an "L1+Polar" triple satellite project composed of three spacecraft: KuaFu-A will be located at L1 and have instruments to observe solar EUV and FUV emissions, and white-light Coronal Mass Ejections (CMEs), and to measure radio waves, the local plasma and magnetic field,and high-energy particles. KuaFuB1 and KuaFu- B2 will bein polar orbits chosen to facilitate continuous 24 hours a day observation of the north polar Aurora Oval. The KuaFu mission is designed to observe the complete chain of disturbances from the solar atmosphere to geospace, including solar flares, CMEs, interplanetary clouds, shock waves, and their geo-effects, such as magnetospheric sub-storms and magnetic storms, and auroral activities. The mission may start at the next solar maximum (launch in about 2012), and with an initial mission lifetime of two to three years. KuaFu data will be used for the scientific study of space weather phenomena, and will be used for space weather monitoring and forecast purposes. The overall mission design, instrument complement, and incorporation of recent technologies will target new fundamental science, advance our understanding of the physical processes underlying space weather, and raise the standard of end-to-end monitoring of the Sun-Earth system. 相似文献
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简要介绍了海洋一号卫星星载GPS接收机的定位原理、流程和应用,探讨了一种在轨定位结果的确认和互验方法.借助于卫星工具包软件(STK),利用NASA网站公布的HY-1卫星两行根数(TLE)进行卫星轨道推算,生成星下点位置,并与相应时刻星载GPS接收机实测数据得到的星下点位置进行比较,由此得到两种方法定位结果之间的偏差,用实际在轨数据验证了两者的位置符合程度. 相似文献