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821.
Common properties of raw wood can be determined by measuring the microwave propagation in the media. Unlike early designs from the 1970s and 1980s, simple constructions with phase and attenuation recording are now possible, if optimal frequencies are selected. At K-band, most quality impairments can be detected from basic group delay measurements, e.g., knots or insect holes smaller than 5 mm are observable. Impairments can be detected from a non-parallel viewing direction 相似文献
822.
A summary of the discussions of Working Group 1 (Rees, Reeves, Schramm, Steigman, Tammann, and TPW) on Big Bang Theory as it relates to primordial nuclei and their galactic evolution. 相似文献
823.
824.
P.L. Bernacca C. Facchinetti E. Fantino 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
Purpose of the present study is to provide algorithms for and examples of how to simulate star visibility and tracking by a Telescope attached to the main truss of the International Space Station (ISS). 相似文献
825.
A. P. Paramonov 《Russian Aeronautics (Iz VUZ)》2010,53(2):121-125
Problems of improving the efficiency of design works in the process of space-rocket complex (SRC) updating are considered.
The methodical foundation for the expert system application to form promising technical solutions in studying the flight vehicle
(FV) modification is presented. 相似文献
826.
G. Zimbardo S. Perri P. Pommois P. Veltri 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
The transport of energetic particles in the presence of magnetic turbulence can exhibit a variety of regimes different from the standard quasilinear diffusion. Here we discuss a number of solar and space problems where nonquasilinear diffusion is found, and then we illustrate anomalous transport regimes, for which the mean square deviation grows nonlinearly with time. In particular, we concentrate on superdiffusive regimes, and show what is the theoretical framework which is to be used to describe superdiffusion. We discuss the results of numerical simulations which show that superdiffusive and subdiffusive regimes are possible, and describe data analyses which allow to single out the superdiffusive transport from the observation of energetic particle profiles upstream of interplanetary shocks. The implications of superdiffusion on the efficiency of wave particle interactions are also discussed. 相似文献
827.
R. M. Millan M. P. McCarthy J. G. Sample D. M. Smith L. D. Thompson D. G. McGaw L. A. Woodger J. G. Hewitt M. D. Comess K. B. Yando A. X. Liang B. A. Anderson N. R. Knezek W. Z. Rexroad J. M. Scheiman G. S. Bowers A. J. Halford A. B. Collier M. A. Clilverd R. P. Lin M. K. Hudson 《Space Science Reviews》2013,179(1-4):503-530
BARREL is a multiple-balloon investigation designed to study electron losses from Earth’s Radiation Belts. Selected as a NASA Living with a Star Mission of Opportunity, BARREL augments the Radiation Belt Storm Probes mission by providing measurements of relativistic electron precipitation with a pair of Antarctic balloon campaigns that will be conducted during the Austral summers (January-February) of 2013 and 2014. During each campaign, a total of 20 small (~20 kg) stratospheric balloons will be successively launched to maintain an array of ~5 payloads spread across ~6 hours of magnetic local time in the region that magnetically maps to the radiation belts. Each balloon carries an X-ray spectrometer to measure the bremsstrahlung X-rays produced by precipitating relativistic electrons as they collide with neutrals in the atmosphere, and a DC magnetometer to measure ULF-timescale variations of the magnetic field. BARREL will provide the first balloon measurements of relativistic electron precipitation while comprehensive in situ measurements of both plasma waves and energetic particles are available, and will characterize the spatial scale of precipitation at relativistic energies. All data and analysis software will be made freely available to the scientific community. 相似文献
828.
An effect of the Coriolis forces on the process of gas expansion in the turbine stage is considered. Expressions for efficiency with regard for the radial flow passage are derived. The calculation results and statistical data on the geometric parameters of diagonal stages are presented. 相似文献
829.
V.P. Chuprova S.K. GerasimovaV.G. Grigoryev P.A. KrivoshapkinG.F. Krymsky V.P. MamrukovaV.M. Migunov A.N. PrikhodkoG.V. Shafer G.V. Skripin Ye.Ye. SorokinS.A. Starodubtsev V.E. Timofeev 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
Some unknown historical facts of cosmic ray studies in the north-east of the former Soviet Union related to the Yakutsk scientific group are reported for the benefit of the international scientific community. It focuses on the founders of Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy of Siberian Branch of Russian Academy of Sciences. A chronology of measurements of cosmic ray intensity variations since 1949 in Yakutia (Sakha Republic; NE Siberia) is given. In particular, for the first time the data of the first solar cosmic ray event registered at Yakutsk (GLE04), with a small ionization chamber S-2 (volume: 20 L) are presented. Moreover, the data of the large ionization chamber ASK-1 (volume: 950 L) for the 1953–2003 period useful for specialists in the field of cosmic ray variations are also shown. 相似文献
830.
The angular motion of an axisymmetrical satellite equipped with an active magnetic attitude control system is considered. The dynamics of the satellite are analytically studied on the whole control loop. The control loop is as follows: preliminary reorientation along with nutation damping, spinning about the axis of symmetry, then precise reorientation of the axis of symmetry in inertial space. Reorientation starts right after separation from the launch vehicle. Active magnetic attitude control system time-response with respect to its parameters is analyzed. It is proven that low-inclined orbit forces low control system time-response. Comparison with the common control scheme shows the time-response gain. Numerical analysis of the disturbances effect is carried out and good pointing accuracy is proved. 相似文献