全文获取类型
收费全文 | 4023篇 |
免费 | 32篇 |
国内免费 | 17篇 |
专业分类
航空 | 1594篇 |
航天技术 | 1428篇 |
综合类 | 17篇 |
航天 | 1033篇 |
出版年
2022年 | 15篇 |
2021年 | 41篇 |
2019年 | 30篇 |
2018年 | 118篇 |
2017年 | 93篇 |
2016年 | 82篇 |
2015年 | 33篇 |
2014年 | 124篇 |
2013年 | 140篇 |
2012年 | 116篇 |
2011年 | 202篇 |
2010年 | 159篇 |
2009年 | 239篇 |
2008年 | 250篇 |
2007年 | 132篇 |
2006年 | 96篇 |
2005年 | 119篇 |
2004年 | 125篇 |
2003年 | 143篇 |
2002年 | 96篇 |
2001年 | 145篇 |
2000年 | 67篇 |
1999年 | 72篇 |
1998年 | 84篇 |
1997年 | 77篇 |
1996年 | 76篇 |
1995年 | 92篇 |
1994年 | 65篇 |
1993年 | 52篇 |
1992年 | 74篇 |
1991年 | 21篇 |
1990年 | 25篇 |
1989年 | 66篇 |
1988年 | 30篇 |
1987年 | 34篇 |
1986年 | 32篇 |
1985年 | 114篇 |
1984年 | 81篇 |
1983年 | 60篇 |
1982年 | 66篇 |
1981年 | 105篇 |
1980年 | 47篇 |
1979年 | 21篇 |
1978年 | 22篇 |
1977年 | 21篇 |
1976年 | 24篇 |
1975年 | 26篇 |
1974年 | 26篇 |
1973年 | 15篇 |
1970年 | 10篇 |
排序方式: 共有4072条查询结果,搜索用时 31 毫秒
181.
N. D. Akhmetov M. M. Gimadeev V. N. Drulis V. A. Krivosheev T. V. Rzaeva 《Russian Aeronautics (Iz VUZ)》2011,54(1):108-113
A technique for calculating the energy parameters of shock waves at electrical discharge in water is presented for the transition
region of discharge channel expansion using as the base the predetermined characteristics of discharge circuit. The technique
is based on the solution of energy transport equation that is similar in form to that of radiative transfer. The validity
of the presented approach was experimentally verified. 相似文献
182.
Systems for the indication and display of secondary information in avionics and autobasing complexes
A. A. Bagdasarov R. V. Anitropov O. V. Bagdasarova I. L. Livshits 《Russian Aeronautics (Iz VUZ)》2011,54(2):185-191
We consider the peculiarities of application for the cabin indicating systems of secondary information display, formulate
and systematize the compositional and technical requirements for display systems and their elements. The tendencies and lines
in the development of head-up displays for avionics and autobasing complexes were determined. The technique of calculating
optics of such display systems with the use of electronic distortion compensation is presented. 相似文献
183.
J. Mazur L. Friesen A. Lin D. Mabry N. Katz Y. Dotan J. George J. B. Blake M. Looper M. Redding T. P. O’Brien J. Cha A. Birkitt P. Carranza M. Lalic F. Fuentes R. Galvan M. McNab 《Space Science Reviews》2013,179(1-4):221-261
The Relativistic Proton Spectrometer (RPS) on the Radiation Belt Storm Probes spacecraft is a particle spectrometer designed to measure the flux, angular distribution, and energy spectrum of protons from ~60 MeV to ~2000 MeV. RPS will investigate decades-old questions about the inner Van Allen belt proton environment: a nearby region of space that is relatively unexplored because of the hazards of spacecraft operation there and the difficulties in obtaining accurate proton measurements in an intense penetrating background. RPS is designed to provide the accuracy needed to answer questions about the sources and losses of the inner belt protons and to obtain the measurements required for the next-generation models of trapped protons in the magnetosphere. In addition to detailed information for individual protons, RPS features count rates at a 1-second timescale, internal radiation dosimetry, and information about electrostatic discharge events on the RBSP spacecraft that together will provide new information about space environmental hazards in the Earth’s magnetosphere. 相似文献
184.
Concept of monitoring for thermostressed state and service life of aircraft gas turbine engine blades 总被引:1,自引:0,他引:1
G. G. Kulikov V. A. Trushin A. I. Abdulnagimov A. A. Ganeev 《Russian Aeronautics (Iz VUZ)》2016,59(1):77-83
A concept of monitoring for material properties with residual life estimation of rotor blades for gas turbine engines is proposed. The structure of on-board control and conditionmonitoring system based on the intelligent pyrometer module with the algorithm for calculating the residual life of turbine rotor blades is described. 相似文献
185.
R.?A.?KayumovEmail author I.?Z.?Mukhamedova E.?B.?Tuisina 《Russian Aeronautics (Iz VUZ)》2016,59(4):452-459
This paper considers a beam with a technological longitudinal section on the level of the gravity center of the cross section that is loaded by a vertical concentrated force. We study the structure durability depending on the load amplitude and the initial crack length. 相似文献
186.
187.
混合排气二元收敛喷管气动与红外隐身综合设计方法 总被引:2,自引:4,他引:2
为使混合排气二元收敛喷管的设计在满足发动机推力性能要求的同时,也具有良好的红外特征信号抑制效果,从固定式混合排气二元收敛喷管的设计要求出发,提出了一套混合排气二元收敛喷管气动与红外隐身综合设计的方法和流程.并通过算例计算验证了该设计方法的可行性.另外,计算结果表明:二元喷管的进口截面位置、喷管总长、出口面积以及出口宽高比等几何参数对实现喷管推力性能均起到关键作用;而合理确定出口宽高比,对实现喷管红外隐身性能具有重要作用. 相似文献
188.
D. Vaniman M. D. Dyar R. Wiens A. Ollila N. Lanza J. Lasue J. M. Rhodes S. Clegg H. Newsom 《Space Science Reviews》2012,170(1-4):229-255
The ChemCam instrument on the Mars Science Laboratory rover Curiosity will use laser-induced breakdown spectroscopy (LIBS) to analyze major and minor element chemistry from sub-millimeter spot sizes, at ranges of ~1.5–7?m. To interpret the emission spectra obtained, ten calibration standards will be carried on the rover deck. Graphite, Ti?metal, and four glasses of igneous composition provide primary, homogeneous calibration targets for the laser. Four granular ceramic targets have been added to provide compositions closer to soils and sedimentary materials like those expected at the Gale Crater field site on Mars. Components used in making these ceramics include basalt, evaporite, and phyllosilicate materials that approximate the chemical compositions of detrital and authigenic constituents of clastic and evaporite sediments, including the elevated sulfate contents present in many Mars sediments and soils. Powdered components were sintered at low temperature (800?°C) with a small amount (9?wt.%) of lithium tetraborate flux to produce ceramics that retain volatile sulfur yet are durable enough for the mission. The ceramic targets are more heterogeneous than the pure element and homogenous glass standards but they provide standards with compositions more similar to the sedimentary rocks that will be Curiosity’s prime targets at Gale Crater. 相似文献
189.
190.