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871.
T.P. Dachev 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
Comprehensive study of the dose, flux and deposited energy spectra shape data obtained by Liulin type spectrometers on spacecraft (five different experiments) and aircraft since 2001 is performed with the aim of understanding how well these parameters can characterize the type of predominant particles and their energy in the near Earth radiation environment. Three different methods for characterisation of the incoming radiation from Liulin spectrometers are described. The results revealed that the most informative one is by the shape of the deposited energy spectra. Spectra generated by Galactic Cosmic Rays (GCR) protons and their secondaries are with linear falling shape in the coordinates deposited energy/deposited per channel dose rate. The position of the maximum of the deposited energy spectra inside the South Atlantic Anomaly (SAA) region depends on the incident energy of the incoming protons. Spectra generated by relativistic electrons in the outer radiation belt have a maximum in the first channels. For higher energy depositions these spectra are similar to the GCR spectra. Mixed radiation by protons and electrons and/or bremsstrahlung is characterized by spectra with 2 maxima. All type of spectra has a knee close to 6.2 MeV deposited energy, which correspond to the stopping energy of protons in the detector. Dose to flux ratio known also as specific dose is another high information parameter, which is given by experimentally obtained formulae [Heffner, J. Nuclear radiation and safety in space. M. Atomizdat. 115, 1971 (in Russian)] connecting the dose to flux ratio and the incident energy of the particles. 相似文献
872.
V. S. Moiseev D. S. Gushchina A. N. Kozar G. E. Borzov 《Russian Aeronautics (Iz VUZ)》2009,52(3):372-375
We propose a mathematical model and the numerical method for an optimal choice of unmanned aerial vehicles (UAVs) from those
being in flight to fulfill a newly received order for monitoring (reconnaissance) of a new region. Examples of using the approach
being proposed and main lines of its realization in promising information unmanned aircraft complexes (UAC) are presented. 相似文献
873.
S. A. Mikhailov A. Yu. Onushkin Yu. P. Onushkin A. A. Safonov S. I. Kochish 《Russian Aeronautics (Iz VUZ)》2009,52(3):296-301
The algorithms for calculating available overloads and maneuvers are presented. Nesterov’s loop maneuver is analyzed. 相似文献
874.
With allowance made for thermoelasticity of working surfaces and inertia forces on the lubricant coat, a hydrodynamic problem
is solved for the noncontacting face seals with microgrooves in the high-speed rotors of FV engines. Also shown are the initiation
of surface waviness in the zone of lubricant coat fracture and the influence of its amplitude upon the seal characteristics. 相似文献
875.
V. A. Olaev 《Russian Aeronautics (Iz VUZ)》2009,52(1):88-93
A technique for the parametric synthesis of the navigation system on the basis of the magneto-inertial course transmitter is proposed; the technique makes it possible to minimize the error scatter in determining the ground speed components, to analyze a nature of the error scatter variation in determining the location coordinates in time, to simulate and further choose regular intervals of using additional data obtained from the radionavigational satellite system. 相似文献
876.
It is proposed that curves of metal creep be approximated by the time-relative linear law with the initial creep strain discontinuity; as a result, the solution of initial boundary value rheological problems is considerably simplified and is characterized by the adequate precision with a large service life. The labor intensity of computations is similar to the steady-state creep law. The introduction of functional material constants makes it possible to perform calculations of creep under the action of temperature that is different from the specified one in the basic experiments as well as calculations of nonuniformly heated structure elements. 相似文献
877.
G.C. Anagnostopoulos I. LouriP. Marhavilas E.T. Sarris 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
We analyzed data from four different instruments (HI-SCALE, URAP, SWOOPS, VHM/FGM) onboard Ulysses spacecraft (s/c) and we searched for possible evidence of Jovian emissions when the s/c approached Jupiter during the times of Halloween events (closest time approach/position to Jupiter: February 5, 2004/R = 1683 RJ,θ = ∼49°). In particular, we analyzed extensively the low energy ion measurements obtained by the HI-SCALE experiment in order to examine whether low energy ion/electron emissions show a symmetry, and whether they are observed at north high latitudes upstream from the jovian bow shock, as is known to occur in the region upstream from the south bow shock as well ( Marhavilas et al., 2001). We studied the period from October 2003 to March 2004, as Ulysses moved at distances 0.8–1.2 AU from the planet at north Jovicentric latitudes <75°, and we present here an example of characteristic Jovian periodicities in the measurements around a CIR observed by Ulysses on days ∼348–349/2003 (R = 1894 RJ,θ = 72°). We show that Ulysses observed low energy ion (∼0.055–4.7 MeV) and electron (>∼40 keV) flux and/or spectral modulation with the Jupiter rotation period (∼10 h) as well as variations with the same period in solar wind parameters, radio and magnetic field directional data. In addition, characteristic strong ∼40 min periodic variations were found superimposed on the ∼10 h ion spectral modulation. Both the ∼10 h and ∼40 min ion periodicities in HI-SCALE measurements were present in several cases during the whole period examined (October 2003 to March 2004) and were found to be more evident during some special conditions, for instance during enhanced fluxes around the start (forward shock) and the end (reverse shock) of CIRs. We infer that the Jovian magnetosphere was triggered by the impact of the CIRs, after the Halloween events, and it was (a) a principal source of forward and reverse shock-associated ion flux structures and (b) the cause of generation of ∼10 h quasi-periodic magnetic field and plasma modulation observed by Ulysses at those times. 相似文献
878.
The process of formation of a particles cloud (space debris) during breakdown of the Earth’s Artificial Satellite (EAS) is considered. A system of equations of motion is derived, and its analytical solution in the linear approximation for circular orbits is presented. The distinction between this solution and an exact numerical solution is indicated. The cases of satellite breakdown at the apogee and perigee on an elliptic orbit are also considered, and some characteristics of these processes are compared.__________Translated from Kosmicheskie Issledovaniya, Vol. 43, No. 4, 2005, pp. 269–273.Original Russian Text Copyright © 2005 by Gorelov, Zarubkin. 相似文献
879.
The regularities of propagation along the spacecraft-Martian surface-spacecraft path of a broadband Gaussian pulse in the condition of its dispersion distortions are considered in application to the problem of radiowave pulse sounding of the near-surface soil of Mars from onboard a satellite. The Martian night-side ionosphere reduces the energy considerably but does not lead to any distortion of the pulse envelope. At the sounding of a two-layer surface, the ionosphere influence, together with the signal absorption, manifests as the lower limit of the thickness of the upper layer reached for measurements in the scope of the planned experiment [1]. 相似文献
880.
T. Hanada J.-C. Liou 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008,41(7):1132-1137
This paper summarizes two new satellite impact experiments. The objective of the experiments was to investigate the outcome of low- and hyper-velocity impacts on two identical target satellites. The first experiment was performed at a low-velocity of 1.5 km/s using a 40-g aluminum alloy sphere. The second experiment was performed at a hyper-velocity of 4.4 km/s using a 4-g aluminum alloy sphere. The target satellites were 15 cm × 15 cm × 15 cm in size and 800 g in mass. The ratios of impact energy to target mass for the two experiments were approximately the same. The target satellites were completely fragmented in both experiments, although there were some differences in the characteristics of the fragments. The projectile of the low-velocity impact experiment was partially fragmented while the projectile of the hyper-velocity impact experiment was completely fragmented beyond recognition. To date, approximately 1500 fragments from each impact experiment have been collected for detailed analysis. Each piece has been weighed, measured, and analyzed based on the analytic method used in the NASA Standard Breakup Model (2000 revision). These fragments account for about 95% of the target mass for both impact experiments. Preliminary analysis results will be presented in this paper. 相似文献