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211.
212.
John F. Arens 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1982,2(4):69-72
Arrays of detectors sensitive to infrared radiation will enable astronomical observations to be made with shorter observing times than with discrete detectors and with good relative spatial accuracy. Systems using such arrays are being developed for astronomy in several regions of the electromagnetic spectrum. An example of an infrared system is given here consisting of a 32×32 element bismuth doped silicon charge injection device array that has been used in an astronomical camera. 相似文献
213.
Forbush decreases in the cosmic radiation 总被引:1,自引:0,他引:1
John A. Lockwood 《Space Science Reviews》1971,12(5):658-715
The experimental observations of Forbush decreases in recent years are reviewed and related to different theoretical models which have been proposed. The observational data from both ground-based and spacecraft experiments were selected to illustrate the important characteristics of Forbush decreases. The form of the rigidity dependence of the cosmic-ray modulation during the decreases and effects of the geomagnetic field upon the magnitude of the decreases are discussed. Recent results to deduce the cosmic-ray flow patterns from the observed anisotropies during the decreases are presented. Other features such as differences in onset times, recovery times, precursory increases are discussed. In considering the theoretical models particular emphasis is placed upon the agreement of the predictions of the model with the experimental observations. A theoretical model is suggested which is not original but represents a synthesis of several models previously proposed. Future important measurements and analyses necessary to an understanding of Forbush decreases are outlined. 相似文献
214.
Unique springs, discharging from the surface of an arctic glacier, release H(2)S and deposit native sulfur, gypsum, and calcite. The presence of sulfur in three oxidation states indicates a complex series of redox reactions. Physical and chemical conditions of the spring water and surrounding environment, as well as mineralogical and isotopic signatures, suggest biologically mediated reactions. Cell counts and DNA analyses confirm bacteria are present in the spring system, and a limited number of sequenced isolates suggests that complex communities of bacteria live within the glacial system. 相似文献
215.
Macromolecules derived from hydrogen cyanide (HCN) may be major components of the dark matter observed in bodies in the outer Solar System, which include comets and asteroids. HCN oligomers and polymers are readily formed at room temperature and react with water to produce polypeptides and alpha-amino acids or undergo pyrolysis to produce nitrogen heterocycles. Electron spin resonance (ESR) spectroscopy shows that HCN polymer mixtures contain a significant amount of long-lived organic free radicals that are primarily carbon-based. For comparison, we have also examined samples of tholins produced from experimental analogs of Titan aerosols, which has been shown by trace organic analysis to consist partly of HCN polymer. The "Titan tholin" exhibits at least two ESR signals that can be assigned to nitrogen- and carbon-centered radicals, although heating the sample eliminates the nitrogen centers and increases the signal from the carbon centers. This result suggests that the nitrogen-centered radicals may be thermodynamically less stable, but are kinetically trapped during the spark-discharge reactions that produce tholins from mixtures of gases such as methane and nitrogen. The results strongly support previous proposals of free radical mechanisms for HCN polymerization. 相似文献
216.
Since 1972, nearly continuous observations of coronal holes and their associated photospheric magnetic fields have been made using a variety of satellite and ground-based equipment. The results of comparisons of these observations are reviewed and it is demonstrated that the structure and evolution of coronal holes is basically governed by the large-scale distribution of photospheric magnetic flux. Non-polar holes form in the decaying remnants of bipolar magnetic regions in areas with a large-scale flux imbalance. There is strong indirect evidence that the magnetic field in coronal holes is always open to interplanetary space but not all open-field regions have associated coronal holes. The well-observed declining phase of the last solar cycle was characterized by stable magnetic field and coronal hole patterns which were associated with recurrent, high-speed wind streams and interplanetary magnetic field patterns at the Earth. The ascending phase of the current cycle has been characterized by transient magnetic field and coronal hole patterns which tend to occur at high solar latitudes. This shift in magnetic field and coronal hole patterns has resulted in a less obvious and more complicated association with high-speed wind streams at the Earth.Proceedings of the Symposium on Solar Terrestrial Physics held in Innsbruck, May–June 1978.Operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.Visiting Scientist, Kitt Peak National Observatory. 相似文献
217.
Space Science Reviews - Many theories of the solar flare process invoke storage of energy in the active region magnetic field above the solar photosphere. Observational evidence relating to such... 相似文献
218.
219.
John Caldwell 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1985,5(3):195-199
Stellar occultations provide a useful means of measuring the trace gas composition of the Earth's mesosphere with a sensitivity of order one part per billion. The operational details will differ from those of other astronomical observations by ST, because of the difficulties in guiding near the Earth's limb. Two specific trace gases of interest to atmospheric studies, C and CO, are discussed in this paper. 相似文献
220.