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571.
C. E. Fichtel D. L. Bertsch B. Dingus R. C. Hartman S. D. Hunter G. Kanbach D. A. Kniffen P. W. Kwok Y. C. Lin J. R. Mattox H. A. Mayer-Hasselwander P. F. Michelson C. von Montigny P. L. Nolan K. Pinkau H. Rothermel E. J. Schneid M. Sommer P. Sreekumar D. J. Thompson 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1993,13(12):637-646
The Energetic Gamma-Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory covers the high energy gamma ray energy range, approximately 30 MeV to 30 GeV, with a sensitivity considerably greater than earlier high energy gamma-ray satellites. Thus far, 4 pulsars have been detected and their properties measured, including in 3 cases the energy spectrum as a function of phase. The details of the galactic plane are being mapped and a spectra of the center region has been obtained in good agreement with that expected from cosmic ray interactions. The Magellanic clouds have been examined with the Large Magellanic Cloud having been detected at a level consistent with it having a cosmic ray density compatible with quasi-stable equilibrium. Sixteen Active Galactic Nuclei (AGN's) have been seen thus far with a high degree of certainty including 12 quasars and 4 BL Lac objects, but no Seyferts. Time variation has been detected in some of these AGN's. 相似文献
572.
Liu R. Lee C.Q. Upadhyay A.K. 《IEEE transactions on aerospace and electronic systems》1992,28(3):697-707
When an LLC-type parallel resonant converter (LLC-PRC) operates above resonant frequency, the switching transistors can be turned off at zero voltage. Further study reveals that the LLC-PRC possesses the advantage of lower converter voltage gain as compared with the conventional PRC. Based on the analytic results derived, a complete set of design curves from which a systematic design procedure is developed is obtained. Experimental results from a 150-W, 150-kHz, multioutput LLC-type PRC power supply are presented 相似文献
573.
It is well known that passive target tracking by a single observer, commonly referred to as target motion analysis (TMA), can be done using angle and/or frequency measurements. Depending on the measurement set, different passive tracking procedures result: angle-only tracking (AOT), frequency-only tracking (FOT), and angle/frequency tracking (AFT). Whereas the two-dimensional passive tracking problem has been solved for a multitude of scenarios, thus giving a good insight into the parametric dependences, the three-dimensional problem has been discussed only in a few specific cases. To get a deeper insight into the parametric dependences of three-dimensional TMA, this work analyzes AOT and AFT in typical three-dimensional Airborne Warning and Control System (AWACS) scenarios. A Cramer Rao (CR) analysis of the problem reveals the parametric dependences of both methods and gives a clear idea of the increase in estimation accuracy by using AFT instead of AOT. The results obtained in this way are well confirmed by Monte Carlo simulations taking maximum likelihood (ML) as estimation procedure. 相似文献
574.
K.Ya. Kondratyev V.V. Kozoderov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1985,5(6):105-109
Based on the 1974–78 NOAA data, characteristic features of the variability of the Earth's radiation budget and its components over the area of the Northern Atlantic have been analyzed. Calculations of the mean square deviation for the ERB and its components have let to the conclusions that anomalous regions of maximum variability may be considered as energy-active zones. 相似文献
575.
M. K. Hudson W. Lotko C. A. Cattell R. L. Lysak I. Roth M. Temerin 《Space Science Reviews》1995,71(1-4):623-646
Intermediate or mesoscale processes mediate the transfer of mass, momentum, and energy across the dynamic solar wind-magnetosphere interface, and the propagation of this input through the system to the ionosphere and atmosphere. The Dartmouth-Berkeley-Minnesota theory team has identified a number of mesoscale phenomena to be investigated as part of the GGS program, including: (1) effects of upstream density fluctuations on magnetopause dynamics, (2) three-dimensional reconnection, (3) magnetopause depletion layer studies, (4) ring current interaction with Pc 1 and Pc 5 waves, (5) generation of ion Larmor-scale current layers in the near Earth plasmasheet, (6) test particle studies in the magnetotail, (7) simulation of magnetosphere- ionosphere coupling including effects of kinetic Alfvén waves and (8) auroral acceleration region studies of the effects of kinetic Alfvén waves on particle distribution functions. A broad range of techniques will be implemented including ideal and reduced MHD, two fluid, hybrid, particle-in-cell and test particle simulations. Detailed comparison of simulation results with GGS satellite and ground based data will be undertaken. 相似文献
576.
K. Shibasaki T. Takano S. Enome H. Nakajima M. Nishio Y. Hanaoka C. Torii H. Sekiguchi T. Bushimata S. Kawashima N. Shinohara H. Koshiishi Y. Shiomi 《Space Science Reviews》1994,68(1-4):217-224
The early phases of three flares, observed by the Nobeyama Radio Heliograph, are studied. Nonthermal and thermal radio sources are identified by comparison with soft X-ray images taken by the Soft X-ray Telescope onboard the Yohkoh satellite. Two of the flares are mainly of nonthermal origin and their location coincides with one of the footpoints of soft X-ray loops. Another flare has both thermal and nonthermal components which start to brighten simultaneously. This suggests that particle acceleration and plasma compression develop simultaneously. 相似文献
577.
P E Villeneuve K S Wenger B G Thompson T Kedar E H Dunlop 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1994,14(11):75-78
The gas exchange portion of a phase-separated loop bioreactor was tested with respect to oxygen mass transfer and micromixing in accelerations of 0.01g, 1g, and 2g. A plot of the overall mass transfer coefficient versus gravity indicates the rate of oxygen transfer does not change as a function of acceleration. Also, it was determined that the micromixing did not exhibit significant changes in the various gravitational fields. These observations indicate the loop bioreactor should function independent of acceleration. 相似文献
578.
579.
K.B. Serafimov I.S. Kutiev Ts.P. Dachev 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1985,5(10):33-36
With data of satellite INTERCOSMOS-BULGARIA-1300 northern and corresponding southern hemisphere plasma densities have been compared. Southern densities are greater in the ?90 to ?180 and +30 to +120° ranges. The opposite is true for ?60 to +30°. No asymmetry has been observed during daytime. These results are explained by the variations of the magnetic declination. 相似文献
580.
Viktor K. Decyk 《Space Science Reviews》1985,42(1-2):113-130
One important type of problem for particle simulation of plasmas, is one which is bounded and has external sources and sinks.
For example, there are problems with antennas for studying RF heating or current drive in fusion plasmas, or problems in space
simulation where particles are injected at one boundary with some specified energy or momentum distribution. In understanding
such simulation results, it is useful to know how energy and momentum are flowing inside the plasma. This can be accomplished
in electrostatic particle simulations on the basis of some theorems for energy and momentum flow. An important application
of these theorems occurs when many waves are involved in producing some effect, e.g., generating a current by RF. One can
then extract the contribution of each wave to the effect to identify which are most important. Examples of such wave-particle
diagnostics will be given. 相似文献