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991.
J. Chang J.H. Adams Jr. H.S. Ahn G.L. Bashindzhagyan K.E. Batkov M. Christl A.R. Fazely O. Ganel R.M. Gunashingha T.G. Guzik J. Isbert K.C. Kim E.N. Kouznetsov Z.W. Lin M.I. Panasyuk A.D. Panov W.K.H. Schmidt E.S. Seo N.V. Sokolskaya John W. Watts J.P. Wefel J. Wu V.I. Zatsepin 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008
The Advanced Thin Ionization Calorimeter (ATIC) experiment is designed for high energy cosmic ray ion detection. The possibility to identify high energy primary cosmic ray electrons in the presence of the ‘background’ of cosmic ray protons has been studied by simulating nuclear-electromagnetic cascade showers using the FLUKA Monte Carlo simulation code. The ATIC design, consisting of a graphite target and an energy detection device, a totally active calorimeter built up of 2.5 cm × 2.5 cm × 25.0 cm BGO scintillator bars, gives sufficient information to distinguish electrons from protons. While identifying about 80% of electrons as such, only about 2 in 10,000 protons (@ 150 GeV) will mimic electrons. In September of 1999 ATIC was exposed to high-energy electron and proton beams at the CERN H2 beam line, and this data confirmed the electron detection capabilities of ATIC. From 2000-12-28 to 2001-01-13 ATIC was flown as a long duration balloon test flight from McMurdo, Antarctica, recording over 360 h of data and allowing electron separation to be confirmed in the flight data. In addition, ATIC electron detection capabilities can be checked by atmospheric gamma-ray observations. 相似文献
992.
RFNN control for PMLSM drive via backstepping technique 总被引:2,自引:0,他引:2
Faa-Jeng Lin Po-Hung Shen Rong-Fong Fung 《IEEE transactions on aerospace and electronic systems》2005,41(2):620-644
A robust fuzzy neural network (RFNN) control system is proposed in this study to control the position of the mover of a permanent magnet linear synchronous motor (PMLSM) drive system to track periodic reference trajectories. First, an ideal feedback linearization control law is designed based on the backstepping technique. Then, a fuzzy neural network (FNN) controller is designed to be the main tracking controller of the proposed RFNN control system to mimic an ideal feedback linearization control law, and a robust controller is proposed to confront the shortcoming of the FNN controller. Moreover, to relax the requirement for the bound of uncertainty term, which comprises a minimum approximation error, optimal parameter vectors and higher order terms in Taylor series, an adaptive bound estimation is investigated where a simple adaptive algorithm is utilized to estimate the bound of uncertainty. Furthermore, the simulated and experimental results due to periodic reference trajectories demonstrate that the dynamic behaviors of the proposed control systems are robust with regard to uncertainties. 相似文献
993.
994.
电子束蒸发镀铝-铬合金涂层研究 总被引:1,自引:0,他引:1
本文研究了电子束蒸发镀铝-铬合金涂层的制备工艺,通过讨论不同的电压、束流对膜层外观、结合力、内应力的影响,确定了合适的陈镀工艺,对涂层和膜料的成分者了分析,表明涂层中铬含量与膜料中铬含量的较大差异,最后探讨了不同含铬量的涂层的耐蚀性。 相似文献
995.
J. Aarons M. Mendillo B. Lin M. Colerico T. Beach P. Kintner J. Scali B. Reinisch G. Sales E. Kudeki 《Space Science Reviews》1999,87(3-4):357-386
A large number of instruments was used in October 1996 to record activities in the equatorial ionosphere above South America.
In a month at solar minimum, data were obtained at various levels of magnetic activity and various levels of ionospheric irregularity
development. With this multi-instrumented study, it was possible to utilize optical data, radar, GPS transmissions, and ionosondes
at various sites in the equatorial region. The concept of this paper is to review the plethora of events which occurred during
this month with a view to describing the interrelationship of the wide variety of irregularity developments. Data were obtained
on nights when no irregularities were observed at any location in the equatorial region across South America. There were nights
when only localized irregularity structures with relatively narrow latitudinal and longitudinal effects were noted close to
the magnetic equator. We noted the occasional presence in the 02–06 local time period of plume structures with data available
from optical observations as well as from phase and amplitude scintillation. During a major magnetic storm on one night, October
22–23, a long lasting high altitude plume was detected by the Jicamarca radar. On this night, irregularities were noted all
across South America and even beyond the western and eastern coasts. This plume produced ionospheric effects which could be
traced to turbulence at over 2000 km above the magnetic equator. With additional data from high latitude stations and from
Guam and Kwajelein, it was possible to link and compare irregularity development in the same time period over a large portion
of the globe. The aim of this paper is to give a day-to-day picture of the occurrence and intensity of equatorial irregularity
development over a month-long period rather than a short case study or the converse, long term statistics over several seasons.
Using this database and the modeling of total electron content as a function of solar flux, we outline the possibilities and
limitations for forecasting irregularity activity in this region for a period of low solar flux. Forecasting is limited and
calls for experimental data for necessary and sufficient gradients and wind conditions for plumes to fully develop.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
996.
自适应预测控制在轮胎胎面缠绕系统的应用 总被引:1,自引:0,他引:1
论文叙述了轮胎胎面缠绕成型的基本原理,针对一类具有大滞后及模型慢时变的轮胎胎面缠绕控制系统,提出了一种自适应预测控制方案,在胎面缠绕系统的组成及控制原理进行分析的基础上,对其自适应预测控制进行了仿真研究。该方案增强了系统的跟踪性及鲁棒性。 相似文献
997.
Rong-Jong Wai Faa-Jeng Lin 《IEEE transactions on aerospace and electronic systems》2001,37(4):1176-1192
In this study an adaptive recurrent-neural-network controller (ARNNC) is proposed to control a linear induction motor (LIM) servo drive. First, the secondary flux of the LIM is estimated with an adaptive flux observer on the stationary reference frame and the feedback linearization theory is used to decouple the thrust force and the flux amplitude of the LIM. Then, an ARNNC is proposed to control the mover of the LIM for periodic motion. In the proposed controller, the LIM servo drive system is identified by a recurrent-neural-network identifier (RNNI) to provide the sensitivity information of the drive system to an adaptive controller. The backpropagation algorithm is used to train the RNNI on line. Moreover, to guarantee the convergence of identification and tracking errors, analytical methods based on a discrete-type Lyapunov function are proposed to determine the varied learning rates of the RNNI and the optimal learning rate of the adaptive controller. The effectiveness of the proposed control scheme is verified by both the simulated and experimental results. Furthermore, the advantages of the proposed control system are indicated in comparison with the sliding mode control system 相似文献
998.
根据北斗一号卫星天线在轨的实际飞行温度,反推出了SR107-ZK白漆的太阳吸收比αs退化曲线,并根据该曲线外推,得到了8年寿命末期的太阳吸收比αs,预测了卫星寿命末期天线反射面的最高温度。 相似文献
999.
1000.