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401.
402.
Sanchez-Avila C. Sanchez-Reillo R. de Martin-Roche D. 《Aerospace and Electronic Systems Magazine, IEEE》2002,17(10):3-6
A biometric identification system, based on the processing of the human iris by the dyadic wavelet transform, has been introduced. The procedure to obtain an iris signature of 256 bits has been described, as well as the feature extraction block and the verification system. The results have shown that the system can achieve high rates of security. 相似文献
403.
Between 25 and 30 years ago, the IECEC Proceedings carried a series of papers by the present authors and other members of a JPL team on the problems and the desirable design features associated with the MHW RTGs to be used to power JPL's Voyager I and II spacecraft. The Voyager I and II spacecraft successfully completed their original 12 year missions 10 years ago and are at distances of over 55 AU and 70 AU from the sun. The power systems worked almost precisely as predicted. The Voyager spacecraft seem to have several decades of life left to make measurements outside the solar system. This paper gives a technical overview of the design process and problems 相似文献
404.
M. E. Wiedenbeck W. R. Binns A. C. Cummings A. J. Davis G. A. de Nolfo M. H. Israel R. A. Leske R. A. Mewaldt E. C. Stone T. T. von Rosenvinge 《Space Science Reviews》2007,130(1-4):415-429
The galactic cosmic rays arriving near Earth, which include both stable and long-lived nuclides from throughout the periodic
table, consist of a mix of stellar nucleosynthesis products accelerated by shocks in the interstellar medium (ISM) and fragmentation
products made by high-energy collisions during propagation through the ISM. Through the study of the composition and spectra
of a variety of elements and isotopes in this diverse sample, models have been developed for the origin, acceleration, and
transport of galactic cosmic rays. We present an overview of the current understanding of these topics emphasizing the insights
that have been gained through investigations in the charge and energy ranges Z≲30 and E/M≲1 GeV/nuc, and particularly those using data obtained from the Cosmic Ray Isotope Spectrometer on NASA’s Advanced Composition
Explorer mission. 相似文献
405.
Cerqueira Adriano Hoth de Gouveia Dal Pino Elisabete M. 《Space Science Reviews》2003,107(1-2):337-340
We will summarize in this paper the effects that the presence of the magnetic field can cause to proto-stellar jet dynamics,
structure and emission line properties, and the differences between two- and three-dimensional numerical simulations will
be emphasized.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
406.
407.
Vytenis M. Vasyliūnas 《Space Science Reviews》2011,158(1):91-118
Many widely used methods for describing and understanding the magnetosphere are based on balance conditions for quasi-static
equilibrium (this is particularly true of the classical theory of magnetosphere/ionosphere coupling, which in addition presupposes
the equilibrium to be stable); they may therefore be of limited applicability for dealing with time-variable phenomena as
well as for determining cause-effect relations. The large-scale variability of the magnetosphere can be produced both by changing
external (solar-wind) conditions and by non-equilibrium internal dynamics. Its developments are governed by the basic equations
of physics, especially Maxwell’s equations combined with the unique constraints of large-scale plasma; the requirement of
charge quasi-neutrality constrains the electric field to be determined by plasma dynamics (generalized Ohm’s law) and the
electric current to match the existing curl of the magnetic field. The structure and dynamics of the ionosphere/magnetosphere/solar-wind
system can then be described in terms of three interrelated processes: (1) stress equilibrium and disequilibrium, (2) magnetic
flux transport, (3) energy conversion and dissipation. This provides a framework for a unified formulation of settled as well
as of controversial issues concerning, e.g., magnetospheric substorms and magnetic storms. 相似文献
408.
409.
T. Dudok de Wit O. Alexandrova I. Furno L. Sorriso-Valvo G. Zimbardo 《Space Science Reviews》2013,178(2-4):665-693
Advanced spectral and statistical data analysis techniques have greatly contributed to shaping our understanding of microphysical processes in plasmas. We review some of the main techniques that allow for characterising fluctuation phenomena in geospace and in laboratory plasma observations. Special emphasis is given to the commonalities between different disciplines, which have witnessed the development of similar tools, often with differing terminologies. The review is phrased in terms of few important concepts: self-similarity, deviation from self-similarity (i.e. intermittency and coherent structures), wave-turbulence, and anomalous transport. 相似文献
410.
Blanca Mendoza Salvador Sánchez de la Peña 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
The study of the possible effect of solar variability on living organisms is one of the most controversial issues of present day science. It has been firstly and mainly carried on high latitudes, while at middle and low latitudes this study is rare. In the present review we focused on the work developed at middle and low geomagnetic latitudes of America. At these geomagnetic latitudes the groups consistently dedicated to this issue are mainly two, one in Cuba and the other in Mexico. 相似文献