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101.
B.T. Kress J.V. Rodriguez J.E. Mazur M. Engel 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
Solar energetic particle (SEP) cutoffs at geosynchronous orbit are sensitive to moderate geomagnetic activity and undergo daily variations due to the day–night asymmetry of the magnetosphere. At geosynchronous orbit, cutoff rigidity also has a large directional dependence, with the highest cutoff rigidity corresponding to ions arriving from magnetic east and lowest cutoff rigidity corresponding to ions incident from the west. Consequently, during geomagnetically quiet periods, the SEP flux observed by an eastward facing particle detector is significantly lower than observed by a westward facing particle detector. During geomagnetically disturbed periods the cutoff is suppressed allowing SEPs access well inside of geosynchronous, so that the east–west SEP flux ratio approaches unity. Variations in the east–west SEP flux ratio observed by GOES Energetic Particle Sensors (EPS) have recently been reported by Rodriguez et al. (2010). In NOAA’s operational processing of EPS count rates into differential fluxes, the differential flux is treated as isotropic and flat over the energy width of the channel. To compare modeled SEP flux with GOES EPS observations, the anisotropy of the flux over the EPS energy range and field of view must be taken into account. A technique for making direct comparisons between GOES EPS observations and SEP flux modeled using numerically computed geomagnetic cutoffs is presented. Initial results from a comparison between modeled and observed flux during the 6–11 December 2006 SEP event are also presented. The modeled cutoffs reproduce the observed flux variations well but are in general too high. 相似文献
102.
Y. Sahai R. de Jesus P.R. Fagundes C.L. Selhorst A.J. de Abreu S. Tulasi Ram A. Aragon-Angel V.G. Pillat J.R. Abalde W.L.C. Lima J.A. Bittencourt 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
The main objective of the present investigation has been to compare the ionospheric parameters (NmF2 and hmF2) observed by two ground-based ionospheric sounders (one at PALMAS- located near the magnetic equator and the other at Sao Jose dos Campos-located in the low-latitude region) in the Brazilian sector with that by the satellite FORMOSAT-3/COSMIC radio occultation (RO) measurements during two geomagnetic storms which occurred in December 2006 and July 2009. It should be pointed out that in spite of increasing the latitude (to 10°) and longitude (to 20°) around the stations; we had very few common observations. It has been observed that both the peak electron density (NmF2) and peak height (hmF2) observed by two different techniques (space-borne COSMIC and ground-based ionosondes) during both the geomagnetic storm events compares fairly well (with high correlation coefficients) at the two stations in the Brazilian sector. It should be pointed out that due to equatorial spread F (ESF) in the first storm (December 2006) and no-reflections from the ionosphere during nighttime in the second storm (July 2009), we had virtually daytime data from the two ionosondes. 相似文献
103.
A.N. Fahrutdinova S.V. Maksyutin M.V. Elakhov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
In this paper we study the influence of the interplanetary magnetic field (IMF) polarity changes caused by the Earth passing through the IMF sector boundary on the dynamic processes taking place in neutral atmosphere within the altitude interval of the upper mesosphere–lower thermosphere (83–101 km). The analysis has revealed the influence of the IMF sector structure on dynamics of the upper mesosphere–lower thermosphere. There has been a significant seasonal variation of the wind reaction to the IMF polarity changes observed. The influence of the IMF polarity changes on neutral atmosphere dynamics within the altitude range of 83–101 km is most pronounced in the zonal component of neural wind when the IMF polarity changes from negative to positive in all the seasons except for spring and when IMF polarity changes from positive to negative – in spring only. 相似文献
104.
《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2020,65(9):2158-2166
In this study, the relationship between total electron content (TEC) and solar and geomagnetic parameters for Ankara station (39.7 N, 32.76 E), Turkey located in the mid-latitude ionosphere is investigated. In this context, F10.7 solar flux and Interplanetary Magnetic Fields (IMF) from solar parameters and Kp and Dst indices from geomagnetic parameters affecting on TEC are considered. The relationship between the variables is investigated by means of the statistical multiple regression model at the universal time (UT) (Local Time = UT + 2 h) 1200 and 2400 in the years when the 24th solar cycle was minimum (2007–2009) and maximum (2015). As a result, it is found that explainable rates by solar and geomagnetic parameters of TEC changes in 2007–2009 are lower than in 2015 at daytime, while the explainable rates in the solar minimum years are higher than those the maximum year at nighttime. To be higher than the solar maximum of explainable rate in the solar minimum years at nighttime may be related to the fact that the dynamics of the ionosphere is significantly different than expected in this deep minimum period. As expected in 2015, the relationship between TEC and independent parameters is greater at daytime than at nighttime. 相似文献
105.
M.V. Stepanova E.E. Antonova O. Troshichev 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2005,36(12):2451-2454
The 15-min averaged polar cap (PC) index was used as an input parameter for the Dst variation forecasting. The PC index is known to describe well the principal features of the solar wind as well as the total energy input to the magnetosphere. This allowed us to design a neural network able to forecast the Dst variations from 1 to 4 h ahead. 1998 PC and Dst data sets were used for training and testing and 1997 data sets was used for validation proposes. From the 15 moderate and strong geomagnetic storms observed during 1997, nine were successfully forecasted. In three cases the observed minimum Dst value was less than the predicted one, and only in three cases the neural network was not able to reproduce the features of the geomagnetic storm. 相似文献
106.
Gustavo A. Mansilla 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
This paper examines the response of the high latitude ionosphere–thermosphere system during two intense geomagnetic storms. For that, data taken by instruments on board Dynamic Explorer 2 taken at heights of the F2-layer are used. These results represent a comparison of simultaneous measurements of storm disturbances in gas composition, electron density and temperature in common local time sectors. Documented are an increase in electron temperature and a decrease in electron density; increases both in electron temperature and electron density; and the correlation between electron density decreases and increases in the ratio N2/O. It is noticed that the decrease in electron density is sometimes due to an increase in the molecular nitrogen density N2 and not always is attributed both to the increase in N2 density and the simultaneous decrease in the atomic oxygen density. 相似文献
107.
空间地磁亚暴环境可以给地球同步轨道卫星带来灾难性后果。文章主要介绍了地磁亚暴环境效应及国内外的相关设备,并根据我国现状,提出进行大型地磁亚暴环境试验的必要性和可行性。 相似文献
108.
M. Hayosh Z. Nme
ek J. afrnkov G.N. Zastenker 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2005,36(12):2417-2422
The magnetosheath plays a dominant role in the Sun–Earth connection because the magnetosheath field and plasma actually interact with the magnetosphere. The interactions change the magnetospheric magnetic field from its nominal value through a long chain of different processes. The change is usually described by geomagnetic indices and thus it can be expected that these indices would reflect changes in the magnetosheath. The present paper analyzes the relation between geomagnetic activity characterized by changes of the Kp, DST and AE indices and ion flux measured in the night-side magnetosheath. The results suggest a weak dependence of the DST index on the ion flux in the inner magnetosheath that is connected with a magnetopause displacement. On the other hand, fluctuations of the ion flux in the analyzed frequency range do not correlate with any of the indices. 相似文献
109.
《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2020,65(5):1439-1446
This paper presents the first results of a new Arar-magnetometer station located (Geographic Coordinates: 30°50.2′N, 41°11.3′E) at Northern Border University in Saudi Arabia. The geomagnetic response detected by the station during a moderate magnetic storm of April 20, 2018 is examined as an initial study. The X-component of the magnetic field measured by the station showed a prompt increase coincident with the Sudden Storm Commencement (SSC) measured by the ACE satellite. The three components of the measured magnetic field were compared to the measured data from the nearest four INTERMAGNET stations as a test. The high rate of magnetic field digital data system of Arar-Magnetometer station with sampling rate of 0.1 s allowed us to study the geomagnetic pulsation at the northern region of the Arabian Peninsula for the first time, which will promote the research of space weather monitoring in that area. 相似文献
110.
Vladimir N. Melnikov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
The aim of the study is to explore whether age at death from cardiovascular diseases depends on solar and geomagnetic activities. The data were collected for 1970–1978 in Novosibirsk, West Siberia, for industrial workers of Siberian origin. The Spearman correlations are computed between linearly detrended lifespan and daily or monthly physical variables to establish immediate (lag, L = 0), delayed (L = 1–3 days) and cumulative (L = ±30 days) influences. Significant correlations ranging from r = −0.26 to r = −0.30 for L from 0 to 3, respectively, are found for men between solar radio flux at wavelength 10.7 cm and age at death from acute myocardial infarction (AMI) but not from acute heart failure, ischemic heart disease and stroke. For AMI, women’s longevity displays an opposite (direct) association with the average solar character occurred at the calendar month of death. The index of geomagnetic activity, Ap, exhibits inverse association with longevity for the AMI stratum for both sexes. GLM univariate procedure revealed higher contribution of Ap to the variance of lifespan compared to season of death. The individual age at death susceptibility to cosmic influences is found to depend upon solar activity at year of birth. It is concluded that associations between the lifespan for cardiovascular decedents and the indices of solar and geomagnetic activities at time of death and of birth are cause-of-death- and sex-specific. 相似文献