全文获取类型
收费全文 | 973篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
航空 | 362篇 |
航天技术 | 368篇 |
综合类 | 2篇 |
航天 | 244篇 |
出版年
2022年 | 5篇 |
2021年 | 22篇 |
2019年 | 9篇 |
2018年 | 30篇 |
2017年 | 22篇 |
2016年 | 14篇 |
2015年 | 8篇 |
2014年 | 35篇 |
2013年 | 47篇 |
2012年 | 41篇 |
2011年 | 42篇 |
2010年 | 34篇 |
2009年 | 60篇 |
2008年 | 72篇 |
2007年 | 22篇 |
2006年 | 21篇 |
2005年 | 31篇 |
2004年 | 22篇 |
2003年 | 28篇 |
2002年 | 20篇 |
2001年 | 36篇 |
2000年 | 21篇 |
1999年 | 12篇 |
1998年 | 27篇 |
1997年 | 11篇 |
1996年 | 21篇 |
1995年 | 18篇 |
1994年 | 26篇 |
1993年 | 11篇 |
1992年 | 16篇 |
1991年 | 4篇 |
1989年 | 14篇 |
1988年 | 7篇 |
1987年 | 9篇 |
1986年 | 3篇 |
1985年 | 26篇 |
1984年 | 18篇 |
1983年 | 10篇 |
1982年 | 11篇 |
1981年 | 16篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1976年 | 4篇 |
1975年 | 6篇 |
1974年 | 8篇 |
1972年 | 8篇 |
1968年 | 6篇 |
1967年 | 5篇 |
1966年 | 5篇 |
排序方式: 共有976条查询结果,搜索用时 78 毫秒
861.
H. E. Spence A. W. Case M. J. Golightly T. Heine B. A. Larsen J. B. Blake P. Caranza W. R. Crain J. George M. Lalic A. Lin M. D. Looper J. E. Mazur D. Salvaggio J. C. Kasper T. J. Stubbs M. Doucette P. Ford R. Foster R. Goeke D. Gordon B. Klatt J. O’Connor M. Smith T. Onsager C. Zeitlin L. W. Townsend Y. Charara 《Space Science Reviews》2010,150(1-4):243-284
862.
This paper gives a brief outline of the progression from the first substorm model developed in Ref.[4] and[8] based on Kennel's ideas[3], to the present views about the mechanism by which solar wind kinetic energy is converted to electromagnetic energy at the Bow Shock and by which this energy is transferred to the magnetosphere in the form of current; about the transformation of the energy of this current to gas kinetic energy of convecting plasma tubes, and, finally, the back transformation of gas kinetic energy to electromagnetic energy in secondary magnetospheric MHD generators. The questions of the formation of the magnetospheric convection system, the nature of substorm break-up, and of the matching of currents in the magnetosphere-ionosphere system are discussed. 相似文献
863.
O.H.库德尔雅绍夫 《航空精密制造技术》1999,35(6)
介绍了俄罗斯大型运载火箭壳体结构的材料。装配和焊接概况.对我国同类型航天火箭的制造有参考和借鉴意义. 相似文献
864.
A. Dmitriev S. Kuznetsov P. Shavrin V. Lyagushin O. Nechaev M. Panasyuk E. Tolstaya M. Nikiforova 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1998,21(12):1797-1800
A set of instruments for measuring energetic particle fluxes, containing two neutron detectors under different plexiglas shielding thicknesses, a scintillation detector, measuring energy release >0. I MeV and 0.5 MeV and a Geiger counter were launched onboard OS ‘MIR’. The latitude dependencies of the cosmic ray measurements were obtained and studied. The distributions of primary particle fluxes (protons and electrons) as well as secondary particle fluxes (bremsstrahlung gamma-rays and neutrons) produced in interactions of radiation belt particles with the station materials were obtained. The electron belt, generated during the storm of March 24 1991, is studied. 相似文献
865.
This paper presents simulated results of the ionospheric behavior during few geomagnetic storms,which were occurred in the different seasons. The numerical model for ionosphere-plasmasphere coupling was used to interpret the observed variation of ionosphere structure. Reasons why the positive storms are dominant in the winter whereas the negative ones are dominant in the summer season present the special interest for the mid-latitude ionosphere. A theoretical analysis of the processes controlling the ionospheric response to the geomagnetic storms has showed a good agreement between the simulated results and measurements, as well as the crucial role of the neutral composition variations to fit the calculated and the observed ionospheric parameters. 相似文献
866.
Khodachenko ML Ribas I Lammer H Griessmeier JM Leitner M Selsis F Eiroa C Hanslmeier A Biernat HK Farrugia CJ Rucker HO 《Astrobiology》2007,7(1):167-184
Low mass M- and K-type stars are much more numerous in the solar neighborhood than solar-like G-type stars. Therefore, some of them may appear as interesting candidates for the target star lists of terrestrial exoplanet (i.e., planets with mass, radius, and internal parameters identical to Earth) search programs like Darwin (ESA) or the Terrestrial Planet Finder Coronagraph/Inferometer (NASA). The higher level of stellar activity of low mass M stars, as compared to solar-like G stars, as well as the closer orbital distances of their habitable zones (HZs), means that terrestrial-type exoplanets within HZs of these stars are more influenced by stellar activity than one would expect for a planet in an HZ of a solar-like star. Here we examine the influences of stellar coronal mass ejection (CME) activity on planetary environments and the role CMEs may play in the definition of habitability criterion for the terrestrial type exoplanets near M stars. We pay attention to the fact that exoplanets within HZs that are in close proximity to low mass M stars may become tidally locked, which, in turn, can result in relatively weak intrinsic planetary magnetic moments. Taking into account existing observational data and models that involve the Sun and related hypothetical parameters of extrasolar CMEs (density, velocity, size, and occurrence rate), we show that Earth-like exoplanets within close-in HZs should experience a continuous CME exposure over long periods of time. This fact, together with small magnetic moments of tidally locked exoplanets, may result in little or no magnetospheric protection of planetary atmospheres from a dense flow of CME plasma. Magnetospheric standoff distances of weakly magnetized Earth-like exoplanets at orbital distances 相似文献
867.
868.
The results of comparison of the characteristics of sharp boundaries of small-scale and medium-scale solar wind structures in the case of their simultaneous observation on widely spaced spacecraft are described. It is shown that even very sharp boundaries, with duration of several seconds or fractions of a second, retain their amplitude and remain very sharp during solar wind propagation to distances of up to a million kilometers. 相似文献
869.
N. A. Vlasova E. A. Ginzburg V. V. Kalegaev I. N. Myagkova M. I. Panasyuk I. A. Rubinshtein M. O. Riazantseva P. M. Svidsky V. I. Tulupov 《Cosmic Research》2013,51(5):319-325
Results of the comparative analysis of the dynamics of SCR fluxes with energies of 1–100 MeV in the interplanetary environment according to the data of the ACE and Wind spacecraft and within the Earth’s magnetosphere according to the data of the GOES-15 and Electro-L satellites in the region of geostationary orbits, and POES-19 and Meteor-M1 in the region of polar caps during two increases in SCR of January 19–31, 2012, are presented. It is shown that the decrease in the efficiency of SCR penetration into the Earth’s magnetosphere in the region of the orbits under study on January 28, 2012, is related to the passage of the Earth’s magnetosphere through the interplanetary environment structure with a quasi-radial interplanetary magnetic field and a small pressure of the solar wind. 相似文献
870.
Harry O. Ruppe 《Space Policy》1987,3(2)
Fearing that mistaken decisions may be made, the author offers his comments to clarify the future possibilities for Ariane, Hermes and Columbus. The decisions soon to be taken on the manned spaceflight programme will affect the future of the entire European space programme. The possibilities for air-breathing propulsion are also reviewed. 相似文献