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21.
Taner Ekici Musa Alpaslan Osman Parlak Abidin Temel 《Chemie der Erde / Geochemistry》2007,67(3):201-212
The study area is located on the middle sector of the Malatya-Ovacık Fault Zone (MOFZ) in the eastern Anatolia. Four basaltic flows from bottom to top, which are tholeiitic in character and intercalated with Pliocene sedimentary rocks, were erupted along this fault zone. Chemical compositions of these flows reveal some differences between the first flow and others in terms of high-field strength elements (HFSEs) (e.g. Ti, Zr, Nb). Limited variations in compositions within the first flow and upper flows suggest a limited fractionation range. Trace-element patterns exhibit that all the flows have similar and OIB-like patterns without positive peak at Pb and a trough at Nb—Ta, indicating minimal or no crustal contribution. Rare-earth element (REE) patterns indicate that the first flow has flat patterns with negative Eu anomaly, whereas the upper flows have variable enrichments in LREE and depletions in HREE. La/SmN, Dy/YbN and Zr/Y ratios exhibit that the degree of partial melting decreases from the first flow to upper flows. Higher values of La/YbN ratio for the upper flows and depletions at Y and Yb on the trace-element patterns suggest the presence of garnet as a residual phase, which imply that the depth of partial melting took place solely in the garnet-stability field. OIB-like trace-element patterns and trace-element ratios (e.g. La/Nb, Ce/Y and Zr/Nb) emphasize that the melts forming the Arguvan basalt were originated from the asthenospheric mantle rather than the lithospheric mantle. 相似文献
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23.
In this part we expand the indirect part of the planetary perturbing function by Smart's method, via Taylor's theorem. We neglect, in our expansion, terms of degree higher than the fourth with regard to the eccentricities and tangents of the inclinations. 相似文献
24.
Abdel-Fattah Attia H. A. Ismail I. M. Selim A. M. Osman I. A. Isaa M. A. Marie A. A. Shaker 《中国天文和天体物理学报》2005,5(4):347-355
We present a new method for determining the age and relative contribution of different stellar populations in galaxies based on the genetic algorithm. We apply this method to the barred spiral galaxy NGC 3384, using CCD images in U, B, V, R and I bands. This analysis indicates that the galaxy NGC 3384 is mainly inhabited by old stellar population (age >109yr). Some problems were encountered when numerical simulations are used for determining the contribution of different stellar populations in the integrated color of a galaxy. The results show that the proposed genetic algorithm can search efficiently through the very large space of the possible ages. 相似文献
25.
This paper presents a three‐dimensional energy‐based solution for the time‐dependent response of a deeply embedded and unsupported semi‐infinite tunnel of circular cross‐section. The tunnel is taken to be excavated quasi‐instantaneously from an infinite rock body that initially exhibits an isotropic stress state and that is made up of a homogeneous, isotropic and viscoelastic material. The viscoelastic behaviour is modelled by means of Burger's model, and the rock is taken to behave volumetrically linear elastic and to exhibit exclusively deviatoric creep. This viscoelastic problem is transformed into the Laplace domain, where it represents a quasi‐elastic problem. The displacement fields in the new solution are taken to be the products of independent functions that vary in the radial and longitudinal directions. The differential equations governing the displacements of the system and appropriate boundary conditions are obtained using the principle of minimum potential energy. The solutions for these governing equations in the Laplace domain are then obtained analytically and numerically using a one‐dimensional finite difference technique. The results are then transformed back into the time domain using an efficient numerical scheme. The accuracy of the new solution is comparable with that of a finite element analysis but requires much less computation effort. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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28.
Osman Demircan 《Astrophysics and Space Science》1978,56(2):453-472
The practical procedures for the solutions of the elements of any eclipsing system in the frequency-domain have been described in a previous paper of this series (Kopal and Demircan, 1978, Paper XIV). The fundamental quantities from which we depart in quest of our solution are twog-functions defining by the momentsA
2m (see Equations (2.13)–(2.16) in Paper XIV, or Equations (3.2)–(3.6) in Paper XV: Demircan, 1978b). If we establish the observational values for these functions, they constitute two independent relations between the unknown parametersa andc
o, and can be numerically solved for them with the aid of the general expressions for the respective moments. However, the determinacy of these parameters depends on not only the accuracy of observations but also the employedg-functions. For better understanding of the geometrical determinacy of the eclipse parametersa andc
o, different combinations of the momentsA
2m have been worked out asg-functions. For the index 2m, the values between 0 and 6 were applied. It has been noted that the behaviour of these functions vary but very little with applied different combinations of the moments. A choice of the most convenient moments to obtain a good determinacy for the eclipse elements were discussed. In this connection, (i) them-dependence of the moments, and the errors in their observational values have been considered, (ii) different practical procedures for the solution of eclipse elements were introduced, and (iii) different type of moments were tested. 相似文献
29.
Osman M. Kamel 《Earth, Moon, and Planets》1988,40(2):119-147
We shall establish a second order - with respect to a small parameter which is of the order of planetary masses - Uranus-Neptune canonical planetary theory. The construction will be through the Hori-Lie perturbation theory. We perform the elliptic expansions by hand, taking into account powers 0, 1, 2 of the eccentricity-inclination. Only the principal part of the planetary Hamiltonian will be taken into consideration. Our theory will be expressed in terms of the canonical variables of Henri Poincaré, referring the planetary coordinates to the Jacobi-Radau system of origin. Only U- N critical terms will be assumed as the periodic terms. 相似文献
30.
We present a second order secular Jupiter-Saturn planetary theory through Poincaré canonical variables, von Zeipel's method and Jacobi-Radau referential. We neglect in our expansions terms of power higher than the fourth with respect to eccentricities and sines of inclinations. We assume that the disturbing function is composed of secular and critical terms only. We shall deriveF
2si
and writeF
2s
in terms of Poincaré canonical variables in Part II of this problem. 相似文献