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601.
602.
地震序列类型早期判断的可能性 总被引:2,自引:0,他引:2
详细讨论利用地震现场提供的1天、3天和7天观测资料,预测地震序列类型和最大强余震震级的可能性和现实性。47个M≥6.0地震的地震序列实例检验表明,利用7天内的观测资料,准确率可达到85.1%。因此,使用b值横截距法有可能在早期预测最大强余震的震级并判断地震序列的类型。 相似文献
603.
P. Vivekananda Rao M. B. K. Sarma B. V. N. S. Prakash Rao 《Journal of Astrophysics and Astronomy》1991,12(3):225-263
Results of analysis of photoelectric observations of the RS CVn eclipsing binary WY Cancri in the standard passbands ofUBV during 1973-74, 1976-79 and inUBVRI during 1984-86 are reported. A preliminary analysis of the eclipses suggested the primary eclipse to be transit. A study
of the percentage contribution of the distortion wave amplitudes in all the colours with respect to the luminosities of both
components, showed the hotter component to be the source of the distortion wave. The clean (wave removed) light curves of
different epochs have not merged, suggesting residual effects of spot activity. The reason for this is attributed to the presence
of either (1) polar spots or (2) small spots uniformly distributed all over the surface of the hotter component. This additional
variation is found to have a periodicity of about 50 years or more. The distortion waves in yellow colour are modelled according
to Budding’s (1977) method. For getting the best fit of the observations and theory, it was found necessary to assume three
or four spots on the surface of the hot component. Out of these four spot groups, three are found to have direct motion with
migration periods of 1.01, 1.01 and 2.51 years while the fourth one has a retrograde motion with a migration period of 3.01
years. From these periods and the latitudes of the spots derived from the model a co-rotating latitude of 4ℴ is obtained.
The temperatures of these spots are found to be lower than that of the photosphere by about 700ℴK to 800ℴK. Assuming the light
curve of 1985-86, which is the brightest of all the observed seasons, to be least affected by the spots, the light curves
of the other seasons are all brought up to the quadrature level of this season by applying suitable corrections. The merged
curves in theUBVRI colours are analysed for the elements by the Wilson-Devinney method. This analysis yielded the following absolute elements:
相似文献
604.
605.
606.
弹道导弹的GNSS/SST/SINS组合导航系统研究 总被引:2,自引:0,他引:2
提出一种组合导航方案,该方案在硬件上采用全捷联的结构,在算法上将捷联星光跟踪仪(strapdown startracker,SST)的姿态信息,高动态GNSS的位置、速度信息与捷联惯导进行组合滤波,全面提高导航精度。设计并实现了弹道导弹GNSS/SST/SINS组合导航系统实时仿真平台,仿真结果表明了该组合方案的稳定、可靠性。 相似文献
607.
Basílio X. Santiago Rebecca A. W. Elson Steinn Sigurdsson & Gerard F. Gilmore 《Monthly notices of the Royal Astronomical Society》1998,295(4):860-868
We present V and I photometry of two open clusters in the LMC down to V ∼26. The clusters were imaged with the Wide Field and Planetary Camera 2 (WFPC2) on board the Hubble Space Telescope ( HST ), as part of the Medium Deep Survey Key Project. Both are low-luminosity ( M
608.
Evolutionary synthesis of stellar populations: a modular tool 总被引:1,自引:0,他引:1
Claudia Maraston 《Monthly notices of the Royal Astronomical Society》1998,300(3):872-892
A new tool for the evolutionary synthesis of stellar populations is presented, which is based on three independent matrices, giving respectively (1) the fuel consumption during each evolutionary phase as a function of stellar mass, (2) the typical temperatures and gravities during such phases, and (3) the colours and bolometric corrections as functions of gravity and temperature. The modular structure of the code allows one easily to assess the impact on the synthetic spectral energy distribution of the various assumptions and model ingredients, such as, for example, uncertainties in stellar evolutionary models, the mixing length, the temperature distribution of horizontal branch stars, asymptotic giant branch mass loss, and colour–temperature transformations. The so-called 'AGB phase transition' in Magellanic Cloud clusters is used to calibrate the contribution of the thermally pulsing asymptotic giant branch phase to the synthetic integrated luminosity. As an illustrative example, solar-metallicity ( Y = 0.27, Z = 0.02) models, with ages ranging between 30 Myr and 15 Gyr and various choices for the slope of the initial mass function, are presented. Synthetic broad-band colours and the luminosity contributions of the various evolutionary stages are compared with Large Magellanic Cloud and Galactic globular cluster data. In all these cases, a good agreement is found. Finally, the evolution is presented of stellar mass-to-light ratios in the bolometric and U B V R K passbands, in which the contribution of stellar remnants is accounted for. 相似文献
609.
Pavel Kroupa 《Monthly notices of the Royal Astronomical Society》1998,300(1):200-204
Recent images taken with the Hubble Space Telescope ( HST ) of the interacting disc galaxies NGC 4038/4039 (the Antennae) reveal clusters of many dozens and possibly hundreds of young compact massive star clusters within projected regions spanning about 100 to 500 pc. It is shown here that a large fraction of the individual star clusters merge within a few tens to a hundred Myr. Bound stellar systems with radii of a few hundred parsecs, masses ≲ 10
610.
Near-infrared photometry of all 11 silicate carbon stars north of declination −10° is made. Combined with available data in the visible range and from IRAS, we discuss their distribution on the infrared two-color diagrams and their spectral distribution, and we compare with the results for normal carbons and so ascertain their evolutionary status. 相似文献
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