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171.
Sudan and the Nile Basin 总被引:1,自引:0,他引:1
172.
173.
We complete by this part II the establishment of a second order secular Jupiter-Saturn theory. This is achieved by taking into consideration the influence of the indirect part of the planetary disturbing function, and expressing the second order secular Hamiltonian in terms of Poincaré's canonical variables. 相似文献
174.
175.
Osman M. Kamel 《Earth, Moon, and Planets》1990,49(3):269-276
In this part we present the complete solution of the planetary canonical equations of motion by the method of G. Hori through successive changes of canonical variables using the Lie series. Thus, we can eliminate the long or critical terms of the planetary perturbing function, in our general planetary theory. In our formulas, we neglect perturbation terms of order higher than the third with respect to planetary masses. 相似文献
176.
The aim of the present paper will be to utilize the results obtained in the preceding papers of this series for the development of practical procedures for obtaining the elements of any eclipsing system from the observed photometric data by their analysis in the frequency-domain, for any type of eclipses, any proximity of the two components, and any degree of the law of limbdarkening of the eclipsed star.In Section 2, which follows a brief introduction to the subject, procedures will be developed which should permit us to perform such an analysis — by hand or automatic machine computation — for the case of mutual eclipses in binary systems the components of which can be regarded as spheres; and whose apparent discs are characterized by an arbitrary radially symmetrical distribution of surface brightness. In Section 3 we shall generalize these procedures to systems consisting of arbitrarily distorted stars.Paper dedicated to Professor Hannes Alfvén on the occasion of his 70th birthday, 30 May, 1978. 相似文献
177.
Osman M. Kamel 《Earth, Moon, and Planets》1989,44(3):275-289
We explain how the first step of Hori-Lie procedure is applied in general planetary theory to eliminate short-period terms. We extend the investigation to the third-order planetary theory. We solved the canonical equations of motion for secular and periodic perturbations by this method, and obtained the first integrals of the system of canonical equations. Also we showed the relation between the determining function in the sense of Hori and the determining function in the sense of Von Zeipel. 相似文献
178.
Application of Wavelet Transform to Magnetic Data Due to Ruins of the Hittite,Civilization in Turkey
A.?Muhittin AlboraEmail author Z.?Mümtaz Hisarli Osman N.?Ucan 《Pure and Applied Geophysics》2004,161(4):907-930
— In the recent years, geophysical methods have been applied successfully in archaeological studies. In this article we have studied the application of wavelet transform to magnetic data in order to estimate boundaries of various synthetic examples and real data. Enhanced Horizontal Derivative (EHD) method is also applied as an alternative method for boundary estimation. The performance of wavelet transform and the EHD method are evaluated using magnetic data of the Sarissa-Kusakli archaeological site. All boundary results are mutually compared. Based on these comparisons, we conclude that the wavelet transform provides reasonable results.This work was supported by the TUBITAK under Project YDABCAG-100Y021.Received: 23 October 2001 相似文献
179.
A. M. I. Osman 《Astrophysics and Space Science》1986,124(2):345-357
Detailed surface photometry for the SB(s)a galaxy NGC 7771 has been carried out in the blue spectral band. Isophotes, luminosity profiles, and photometric parameters are obtained from photographs collected with the 74 inch telescope of Kottamia Observatory, Egypt. The total apparent magnitudem
T
=13.08 with maximum dimensions 3.6±0.5×2.7±0.5 (at threshold µ
m
= 27.38 mag s–2). The absolute magnitude isM
T
=–21.70 if the distance is =90.2 Mpc. The major axis is in position angle =69°.5±1° and the mean axis ratio of the outer regionsq=b/a=0.45 corresponds to an inclinationi=66°. The equivalent effective radiusr
e
*
=0.29 and the effective surface brightness µ
e
= 22.30 mag s–2.The equivalent luminosity distribution has been decomposed into two main components, anr
1/4 spheroid and an exponential disk. The total apparent magnitudes of the spheroidal and disk components are 14.36 and 13.48, which correspond to contributions of 31 and 69% to the total blue luminosity, respectively. 相似文献
180.
TheUBV photometry of the detached F-type eclipsing binary BK Pegasi is presented. The light curve solution by a simple spherical model assumption suggests that a slightly hotter, larger and more luminous primary was eclipsed during the primary minimum. Combined with the radial velocity curves in Popper (1983), it was used to determine anew the system's parameters. The age and the metal abundance of the system were estimated as (3.3 ± 0.2) × 109 yr andz = 0.028 ± 0.003 from a comparison with the new grids of stellar models and the isochrones by Schalleret al. (1993). The distance of the system was estimated as 290 pc. 相似文献