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31.
D. A. Gurnett R. R. Anderson F. L. Scarf R. W. Fredricks E. J. Smith 《Space Science Reviews》1979,23(1):103-122
In this paper we present an initial survey of results from the plasma wave experiments on the ISEE-1 and -2 spacecraft which are in nearly identical orbits passing through the Earth's magnetosphere at radial distances out to about 22.5R
e
. Essentially every crossing of the Earth's bow shock can be associated with an intense burst of electrostatic and whistler-mode turbulence at the shock, with substantial wave intensities in both the upstream and downstream regions. Usually the electric and magnetic field spectrum at the shock are quite similar for both spacecraft, although small differences in the detailed structure are sometimes apparent upstream and downstream of the shock, probably due to changes in the motion of the shock or propagation effects. Upstream of the shock emissions are often observed at both the fundamental, f
-
p
, and second harmonic, 2f
p
-
, of the electron plasma frequency. In the magnetosphere high resolution spectrograms of the electric field show an extremely complex distribution of plasma and radio emissions, with numerous resonance and cutoff effects. Electron density profiles can be obtained from emissions near the local electron plasma frequency. Comparisons of high resolution spectrograms of whistler-mode emissions such as chorus detected by the two spacecraft usually show a good overall similarity but marked differences in detailed structure on time scales less than one minute. Other types of locally generated waves, such as the (n+1/2)f
-
g
electron cyclotron waves, show a better correspondence between the two spacecraft. High resolution spectrograms of kilometric radio emissions are also presented which show an extremely complex frequency-time structure with many closely spaced narrow-band emissions. 相似文献
32.
J. B. Blake B. H. Mauk D. N. Baker P. Carranza J. H. Clemmons J. Craft W. R. Crain A. Crew Y. Dotan J. F. Fennell R. H. Friedel L. M. Friesen F. Fuentes R. Galvan C. Ibscher A. Jaynes N. Katz M. Lalic A. Y. Lin D. M. Mabry T. Nguyen C. Pancratz M. Redding G. D. Reeves S. Smith H. E. Spence J. Westlake 《Space Science Reviews》2016,199(1-4):309-329
33.
T. Aramaki S.E. Boggs W.W. Craig H. Fuke F. Gahbauer C.J. Hailey J.E. Koglin N. Madden K. Mori R.A. Ong T. Yoshida 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
The General AntiParticle Spectrometer (GAPS) is a novel approach for indirect dark matter searches that exploits cosmic antideuterons. GAPS complements existing and planned direct dark matter searches as well as other indirect techniques, probing a different and unique region of parameter space in a variety of proposed dark matter models. The GAPS method involves capturing antiparticles into a target material with the subsequent formation of an excited exotic atom. The exotic atom decays with the emission of atomic X-rays and pions from the nuclear annihilation, which uniquely identifies the captured antiparticle. This technique has been verified through the accelerator testing at KEK in 2004 and 2005. The prototype flight is scheduled from Hokkaido, Japan in 2011, preparatory for a long duration balloon flight from the Antarctic in 2014. 相似文献
34.
A.H. Manson C.E. Meek M. Massebeuf J.L. Fellous W.G. Elford R.A. Vincent R.L. Craig R.G. Roper S. Avery B.B. Balsley G.J. Fraser M.J. Smith R.R. Clark S. Kato T. Tsuda A. Ebel 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1985,5(7):135-144
During the last decade a large number of radars (~12) have been developed, which have produced substantial quantities of tidally-corrected mean winds data. The distribution of the radars is not global, but many areas are well covered: the Americas with Poker Flat (65°N), Saskatoon (52°N), Durham (43°N), Atlanta (34°N), Puerto Rico (18°N); Europe with Kiruna (68°), Garchy (47°N) and Monpazier (44°N); and Oceania with Christchurch (44°S), Adelaide (35°S), Townsville (20°S), and Kyoto (35°N). Zonal and meridional wind height-time cross-sections from km (MF/Meteor Radar) to ~110 km have been prepared for the last 5–6 years. They are compared with cross-sections from CIRA-72 for zonal winds, and Groves (1969) for meridional winds.It is shown that while CIRA-72 is still a useful model for many purposes, significant differences exist between it and the new radar data. The latter demonstrate important seasonal, latitudinal, longitudinal and hemispheric variations. The new meridional cross-sections are of great value. The common features with Groves (1969) are the equatorward cells in summer near 85 km; however their strength (~10 ms?1) and size are less. Systematic and somewhat different variations emerge at higher (?52°N) and middle (35–44°) latitudes. 相似文献
35.
Craig Cornelius 《Space Policy》2005,21(1):2088-48
The NASA/White House Vision for Space Exploration is primarily focused on the development of human and robotic systems that will enable ‘discovery-driven’ investigations in areas important to the scientific community: Mars, the solar system's outer moons, and planets orbiting other stars. Such a portfolio can only be realized if NASA is prepared to target investment at opportunities that are most scientifically compelling. NASA's leaders will have to make decisions in subjective and uncertain environments about the relative long-term value of different kinds of scientific discoveries seen as equally important to different groups. A management paradigm of this kind will imply assessment of heterogeneous priorities and management of interdependent and changing requirements. In order to identify the basis and implications of a ‘discovery-driven’ paradigm, this paper surveys the relationship between the Vision's principles and its programmatic content, the objectives of the Vision's scientific focus areas and their interrelationships, and the public context in which science-focused exploration will proceed. 相似文献
36.
The testing and evaluation of sophisticated security systems has remained in the domain of governments in national facilities and the commercial security industry through manufacturers and engineering consultants. As well, the production of testing protocols and industry standards has been developed by national organisations, professional security, and engineering bodies in the appropriate security fields. The Security Systems Research and Testing Laboratory in the School of Engineering and Mathematics at Edith Cowan University (ECU), Perth, Western Australia has commenced operations in research, testing, and evaluation of security systems. This paper wir describe the first year of operation of the Security Systems Research and Testing Laboratory, and will describe the role that testing and evaluation of security systems plays in the education and training of Security Science graduates, as well as the benefits that the Laboratory brings to the security industry through its testing programme. 相似文献
37.
38.
The matched filter ambiguity function is presented for a burst waveform composed of repeated subbursts, each one of which consists of N pulses in which the phase is varied quadratically from pulse to pulse. The resulting ambiguity function exhibits small residual ambiguities along the delay axis separated by the reciprocal of the pulse repetition frequency (PRF). A cross-ambiguity function is derived which reduces these ambiguities to zero amplitude. A third cross-ambiguity function is presented for a receiver matched to a generalized Hamming weighted repeated quadratic burst. The location in the delay/Doppler plane of the waveform ambiguities for these waveforms is compared with that of an uncoded pulse burst. 相似文献
39.
T.H. Vonder Haar G.G. Campbell E.A. Smith A. Arking K. Coulson J. Hickey F. House A. Ingersoll H. Jacobowitz L. Smith L. Stowe 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(4):285-297
Two special measurements of the energy exchange between earth and space were made in connection with the FGGE. A global monitoring program using wide-field-of-view and scanner detectors from NASA's NIMBUS-7 satellite successfully returned measurements during the entire FGGE. This experiment system also used a black cavity detector to measure the total energy output of the sun to very high precision. A second set of high frequency time and space estimates of the radiation budget were determined from selected geostationary satellite data. Preliminary results from both radiation budget data sets and the solar “constant” measurements will be presented. 相似文献
40.
R.B. Stoltzfus S.A. Bowhill L.G. Smith 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,4(6):143-146
The Langmuir-probe technique for measurement of electron concentration in the mesosphere is capable of excellent altitude resolution, of order 1 m. Measurements from nine rocket flights frequently show small-scale ionization structures in the altitude region 60–90 km. These are believed to be identical with regions of strong coherent backscatter seem by VHF radars at Jicamarca, Peru and Urbana, Illinois. They are believed to represent intermittent turbulence attributable to nonlinear interaction of waves in the mesosphere. Parameters of the turbulent regions are estimated. 相似文献