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251.
Dehbonei H. Lee S. R. Ko S. H. 《IEEE transactions on aerospace and electronic systems》2009,45(1):46-57
This two-part paper presents a comprehensive comparative study on parallel power processing (PPP) and standard schemes in dc/dc converters for photovoltaic (PV) energy systems. It is demonstrated how PPP can improve direct energy transfer (DET), which results in PV systems operating at higher voltage and efficiency. Discussions of the concepts, hypotheses, and computer simulations are presented in Part I. Part II provides the experimental results, which confirm the validity of the analysis and simulations. 相似文献
252.
Susan Jason Alex da Silva Curiel Doug Liddle Francis Chizea Ugur Murat Leloglu Mustafa Helvaci Mohammed Bekhti Djouad Benachir Lee Boland Luis Gomes Martin Sweeting 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
This paper focuses on ways in which space is being used to build capacity in science and technology in order to: 相似文献
253.
B. Klecker H. Kunow H. V. Cane S. Dalla B. Heber K. Kecskemety K.-L. Klein J. Kota H. Kucharek D. Lario M. A. Lee M. A. Popecki A. Posner J. Rodriguez-Pacheco T. Sanderson G. M. Simnett E. C. Roelof 《Space Science Reviews》2006,123(1-3):217-250
The characteristics of solar energetic particles (SEP) as observed in interplanetary space provide fundamental information about the origin of these particles, and the acceleration and propagation processes at the Sun and in interplanetary space. Furthermore, energetic particles provide information on the development and structure of coronal mass ejections as they propagate from the solar corona into the interplanetary medium. In this paper we review the measurements of energetic particles in interplanetary space and discuss their implication for our understanding of the sources, and of acceleration and propagation processes. 相似文献
254.
Myung Soo Chung JEONG-SOO Lim Dong Chul Park 《IEEE transactions on aerospace and electronic systems》2006,42(4)
Extraction of elevation information with phased array search radar in the presence of specular reflection from sea surface is presented. Specular reflection from sea causes large peak errors in the measurement of low elevation angle. An algorithm based on complex indicated angle is derived to reduce specular reflection component. From the complex indicated angle and the exactly known or approximately known data, the authors can generate a specular reflection error finding function (SREFF). SREFF clearly indicates where the measurements are much affected by the specular reflection in the complex indicated angle data 相似文献
255.
Tatsuya Arai Kichang Lee Michael B. Stenger Steven H. Platts Janice V. Meck Richard J. Cohen 《Acta Astronautica》2011,68(7-8):770-777
Orthostatic intolerance (OI) is a significant challenge for astronauts after long-duration spaceflight. Depending on flight duration, 20–80% of astronauts suffer from post-flight OI, which is associated with reduced vascular resistance. This paper introduces a novel algorithm for continuously monitoring changes in total peripheral resistance (TPR) by processing the peripheral arterial blood pressure (ABP). To validate, we applied our novel mathematical algorithm to the pre-flight ABP data previously recorded from twelve astronauts ten days before launch. The TPR changes were calculated by our algorithm and compared with the TPR value estimated using cardiac output/heart rate before and after phenylephrine administration. The astronauts in the post-flight presyncopal group had lower pre-flight TPR changes (1.66 times) than those in the non-presyncopal group (2.15 times). The trend in TPR changes calculated with our algorithm agreed with the TPR trend calculated using measured cardiac output in the previous study. Further data collection and algorithm refinement are needed for pre-flight detection of OI and monitoring of continuous TPR by analysis of peripheral arterial blood pressure. 相似文献
256.
Hildebrand P.H. Walther C. Wen-Chau Lee 《Aerospace and Electronic Systems Magazine, IEEE》1996,11(10):34-37
The ELDORA/ASTRAIA airborne Doppler weather radar was recently placed in service by US and French atmospheric sciences research laboratories. The ELDORA/ASTRAIA radar is designed to provide high resolution measurements of the air motion and rainfall characteristics of atmospheric storms which are too large, remote or fast-moving to be adequately observed by ground-based radars. This paper discusses the measurement requirements and the design goals of the radar and presents sample measurements from a recent weather research field program 相似文献
257.
258.
The two-loop, adaptive-control strategy employed by Lee and Yu is shown to consist of adjustment of loop gains so that no output feedback occurs. This means that in so far as the adaptive feature is required, both loops could be dispensed with and feedback applied locally around the input modulator. 相似文献
259.
A first cut at the difficult problem of the identification and removal of ambiguous responses to radar burst waveforms is presented. Assuming that two bursts are used, algorithms for multitarget ambiguity removal after coincidence detection are presented and illustrated by examples. The results may have significant application in ballistic missile defense surveillance radars. 相似文献
260.
A B Cox E J Ainsworth J G Jose A C Lee J T Lett 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1983,3(8):211-219
Space radiations, especially heavy ions, constitute significant hazards to astronauts. These hazards will increase as space missions lengthen. Moreover, the dangers to astronauts will be enhanced by the persistence, or even the progression, of biological damage throughout their subsequent life spans. To assist in the assessment of risks to astronauts, we are investigating the long-term effects of heavy ions on specific animal tissues. In one study, the eyes of rabbits of various ages were exposed to a single dose of Bragg plateau 20Ne ions (LET infinity approximately equals 30 keV/micrometer). The development of cataracts has shown a pronounced age-related response during the first year after irradiation, and will be followed for two more years. In other studies, mice were exposed to single or fractionated doses of 12C ions (4-cm spread-out Bragg peak; dose-averaged LET infinity = 70-80 keV/micrometer) or 60Co gamma-photons (LET infinity = 0.3 keV/micrometer). Measurements of the frequency of posterior lens opacification have shown that the tissue sparing observed with dose fractionation of gamma-photons was absent when 12C-ion doses were fractionated. Development of posterior lens cataracts was also followed for long periods (up to 21 months) in mice exposed to single doses of Bragg plateau HZE particles (40Ar, 20Ne and 12C ions: LET infinity approximately equals 100, 30 and 10 keV/micrometer, respectively) or 225 kVp X-rays. Based on average cataract levels at the different observation times, the RBE's (RBE = relative biological effectiveness) for the ions were circa 5, 3 and 1-2, respectively, over the range of doses used (0.05-0.9 Gy). Investigations of cataractogenesis are useful for exploring the model of radiation damage proposed by Casarett and by Rubin and Casarett with a tissue not connected directly to the vasculature. 相似文献