全文获取类型
收费全文 | 1060篇 |
免费 | 19篇 |
国内免费 | 4篇 |
专业分类
航空 | 479篇 |
航天技术 | 472篇 |
综合类 | 15篇 |
航天 | 117篇 |
出版年
2022年 | 6篇 |
2021年 | 12篇 |
2020年 | 4篇 |
2019年 | 7篇 |
2018年 | 10篇 |
2017年 | 4篇 |
2016年 | 11篇 |
2015年 | 5篇 |
2014年 | 22篇 |
2013年 | 22篇 |
2012年 | 31篇 |
2011年 | 43篇 |
2010年 | 28篇 |
2009年 | 49篇 |
2008年 | 94篇 |
2007年 | 26篇 |
2006年 | 28篇 |
2005年 | 45篇 |
2004年 | 36篇 |
2003年 | 30篇 |
2002年 | 25篇 |
2001年 | 50篇 |
2000年 | 19篇 |
1999年 | 35篇 |
1998年 | 36篇 |
1997年 | 13篇 |
1996年 | 32篇 |
1995年 | 20篇 |
1994年 | 33篇 |
1993年 | 21篇 |
1992年 | 29篇 |
1991年 | 10篇 |
1990年 | 14篇 |
1989年 | 31篇 |
1988年 | 14篇 |
1987年 | 6篇 |
1986年 | 12篇 |
1985年 | 19篇 |
1984年 | 27篇 |
1983年 | 22篇 |
1982年 | 22篇 |
1981年 | 24篇 |
1980年 | 6篇 |
1979年 | 8篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1975年 | 6篇 |
1970年 | 3篇 |
1969年 | 4篇 |
排序方式: 共有1083条查询结果,搜索用时 15 毫秒
581.
G A Bazilevskaya M B Krainev A K Stozhkov YuISvirzhevskaya N S Svirzhevsky 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1994,14(10):779-782
Balloon measurements of cosmic rays were made practically every day at several locations of the former USSR and in Antarctica over a period of more than 30 years. These measurements provide a means for assessment and control of ionizing radiation at the altitudes from ground level up to 30-35 km. 相似文献
582.
Robbins L. Vijan M. Baron A.A.Y. Cannella V. McGill J. Yaniv Z. 《Aerospace and Electronic Systems Magazine, IEEE》1990,5(9):3-6
The operation of active matrix liquid crystal displays (AMLCDs), the preferred flat-panel displays for avionic and aerospace applications, is explained. An 8-in.×8-in. full-color AMLCD designed for a military aircraft is described, as well as the principles of the p-i-n diode switch on which its design is based. The performance characteristics of the display are examined 相似文献
583.
L P Filatova E N Vaulina C Grozdova TYaPrudhommeau J Proust 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1983,3(8):143-146
Two experiments with Drosophila melanogaster males were performed aboard the Salyut 6 orbital station. Mutagenic effects of a 8 day space flight on sex chromosome nondisjunction and intergene recombination in chromosome II were studied. The space flight factors (SFF) increased the frequency of chromosome nondisjunction and recombination. The model experiments showed that the combined effects of vibration and acceleration do not cover the whole spectrum of space flight mutagenic factors. These data suggest that heavy space ions are mainly responsible for the observed effect. 相似文献
584.
J. Iisaka S. Saitoh A. Koide I. Asanuma Y. Sasaki K. Muneyama 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1982,2(8):251-255
The amount of suspended solid (S.S.) discharged from Tokyo metropolitan area is estimated by use of multi-temporal Landsat data from 1979 to 1980. The method to estimate S.S. was verified with sea truth data which was observed with Landsat passes covering Tokyo Bay. The radiometric information is normalized against seasonal change of sun illuminations and atmospheric conditions. Path radiance estimation methods were discussed, because its effects are very sensitive to the estimation of S.S. concentration by Landsat MSS data. Temporal changes of S.S. distribution was also interpreted. 相似文献
585.
586.
The multicriteria approach, by its formalised and operational character, is a methodology well adapted to take into account simultaneously costs and other criteria (time scales, political criteria) from the beginning of the design phase. 相似文献
587.
Y.T. Chiu 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(2):291-304
The theoretically expected effects of active heavy ion injections in the magnetosphere are reviewed according to their chemical state (plasma or neutral) and their kinetic state (explosion or beam injection) of release. The early-phase effects of such injections (such as ionospheric heating, wave-particle interactions, radiation belt and ring current modifications and anomalous ionization) are briefly discussed. The need for understanding the magnetospheric modification aspects of heavy ion injections becomes more acute in the next decades when the transportation and construction of large-scale space structures would inject increasing volumes of heavy ions in the magnetosphere by both chemical and ion engines. Ion engine exhaust, in the form of a dense relatively cool plasma beam of high drift speed, represents a new regime of heavy ion magnetospheric modification, the effects of which have not been thoroughly investigated either theoretically or observationally. We envisage that the ion engine can be modified into a useful tool for scientific studies of magnetospheric dynamics since it is a source of a variety of ionic species independent of the need for photoionization. 相似文献
588.
V.A. Alexandrov A.S. Loevsky G.A. Popov Y.A. Romanovsky A.G. Sobol 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(2):147-151
To study artificial disturbances in the ionosphere, caused by pulsed injection of plasma two MR-12 rockets with plasma guns were launched from Volgograd in 1978–1979. The pulsed plasma was ejected from the separated daughter payload, alternatively, along and transverse the magnetic field lines. The experimental and model data on structure and dynamics of the artificial plasma blobs in the ionosphere are discussed. 相似文献
589.
590.
An efficient scheduling algorithm (stations burst plan) for demand-assigned time-division multiple-access (TDMA) satellite network systems is introduced. The total demand for transmitting data through a transponder may exceed the available bit-rate capacity, and a scheduler of the system wishes to utilize the system with minimum changes of slot allocations while maximizing throughputs. By implementing such a burst-plan algorithm, transmission of all demanded data traffic can be completed with minimum unused resources (idle slots). The underlying ideas adopted for the algorithm are that jobs with shorter remaining processing times should have higher priorities and that as many jobs are processed at a time as possible. The algorithm is particularly useful for deriving smooth burst plans for a satellite system with a large number of ground stations 相似文献