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831.
Effects of X2-class solar flare events on ionospheric GPS-TEC and radio waves over Brazilian sector 总被引:1,自引:0,他引:1
A.J. de Abreu M. Roberto M.A. Alves J.R. Abalde P.A.B. Nogueira K. Venkatesh P.R. Fagundes R. de Jesus M. Gende I.M. Martin 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2019,63(11):3586-3605
In this investigation, we present and discuss the effects of 6 X2-class solar flare events in the ionospheric F region over Brazilian sector that occurred during 2013 to 2015. For this investigation, we present the vertical total electron content (VTEC) observations from nearly 120 Global Positioning System (GPS) receivers all over the Brazilian sector for each event. Also, ionospheric sounding observations obtained in São José dos Campos (23.2°S, 45.9°W, dip latitude 17.6°S; hereafter referred to as SJC), under the southern crest of the equatorial ionospheric anomaly (EIA), Brazil, are presented. The observations show that the greatest TEC impact occurs with the EUV fluxes increases lasting for more than one hour and when the solar active region is located close to the solar disc center. We present a detailed study of the efficiency of the EUV flux with wavelengths ranging from 0.1 to 190?nm for the F region ionization. The largest increase of ΔTEC occurs below the magnetic equator line, covering mainly the central, northeast, southeast and south regions, which includes the equatorial ionospheric anomaly (EIA) region. The ionograms show partial or total fade out in the echoes traces observed causing blackouts of radio signals of up to 60?min, which can have serious consequences to technological systems of public and private agencies around Brazilian sector. This study can help to better understand the effects of solar flares in the ionospheric F region. 相似文献
832.
I. Braun J. Engler J.R. Hörandel J. Milke 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
Since 1993, a muon telescope located at Forschungszentrum Karlsruhe (Karlsruhe Muon Telescope) has been recording the flux of single muons mostly originating from primary cosmic-ray protons with dominant energies in the 10–20 GeV range. The data are used to investigate the influence of solar effects on the flux of cosmic rays measured at Earth. Non-periodic events like Forbush decreases and ground level enhancements are detected in the registered muon flux. A selection of recent events will be presented and compared to data from the Jungfraujoch neutron monitor. The data of the Karlsruhe Muon Telescope help to extend the knowledge about Forbush decreases and ground level enhancements to energies beyond the neutron monitor regime. 相似文献
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834.
Xuemin Zhang Xuhui ShenJing Liu Zhima ZerenLu Yao Xinyan OuyangShufan Zhao Guiping YuanJiadong Qian 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
Based on the ISL data detected by DEMETER satellite, the solar cycle variation in electron density (Ne) and electron temperature (Te) were studied separately in local daytime 10:30 and nighttime 22:30 during 2005–2010 in the 23rd/24th solar cycles. The semi-annual, annual periods and decreasing trend with the descending solar activity were clearly revealed in Ne. At middle and high latitudes, there exhibited phase shift and even reversed annual variation over Southern and Northern hemisphere, and the annual variation amplitudes were asymmetrical at both hemispheres in local daytime. In local nighttime, the annual variations of Ne at south and north hemispheres were symmetrical at same latitudes, but the annual variation amplitudes at different latitudes differed largely, showing obviously zonal features. As for Te, the phase shift in annual variations was not as apparent as Ne with the increase of latitudes at Southern and Northern hemisphere in local daytime. While in local nighttime the reversed annual variations of Te were shown at low latitudinal areas, not at high latitudes as those in Ne. The correlation study on Ne and Te illustrated that, in local daytime, Ne and Te showed strong negative correlation at equator and low latitudes, but during the solar minimum years the correlation between Ne and Te changed to be positive at 25–30° latitudes in March 2009. The correlation coefficient R between Ne and Te also showed semi-annual periodical variations during 2005–2010. While in local nighttime, Ne and Te exhibited relatively weak positive correlation with R being about 0.6 at low latitudes, however no correlation beyond latitudes of 25° was obtained. 相似文献
835.
为有效解决在日蚀区太阳能热推进器推力失效、电力中断的问题,提出了蓄热式太阳能热光伏-热推进双模系统结构,并对系统各部件建立相关物理数学模型,分析了工质种类、工质流量等因素对推进性能的影响。结果表明,为保证推进器在日蚀区30min内持续提供推力和电力供应,砷化镓热光伏电池在无工质工况下能提供10W左右的低功率电力供应,在设计工况下能提供50W~110W的电力供应;液氢作为工质时,最大比冲将达到806s,随着工质流量的持续增加,比冲损失速率呈现先加快后减慢的变化趋势;液氨作为替代工质具有更快的加热速率,其比冲为240s~300s远低于氢工质比冲,其推力系数1.77要略高于氢工质推力系数1.7。通过本文研究,蓄热式太阳能双模推进系统具有较好的可行性,且推力及比冲适中,有望弥补低比冲化学推进和小推力电推进技术的不足。 相似文献
836.
邱家稳 《中国空间科学技术》1993,13(5):15-20
详细地分析了工程上应用的太阳吸收率计算公式的截断误差;从数学上推导了截断误差的计算公式;并给出了计算实例。所得结果对卫星热控材料及太阳光谱利用涂层材料的光热学性能的测量具有一定的参考价值。 相似文献
837.
本文根据Ⅰ型彗尾的背景材料,分析了MHD波的色散关系,探讨了螺旋波的稳定性及其演变的特征.根据初始条件的不同,有的彗尾中可以产生稳定的螺旋波,有的则不然,只能是浑云状态.文章给出了理论推演,列出了观测结果,理论和观测能较好地符合.可进一步结合Hale-Bopp彗星的观测,进行对比和检验. 相似文献
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