全文获取类型
收费全文 | 460篇 |
免费 | 21篇 |
国内免费 | 2篇 |
专业分类
测绘学 | 5篇 |
大气科学 | 37篇 |
地球物理 | 145篇 |
地质学 | 187篇 |
海洋学 | 24篇 |
天文学 | 69篇 |
自然地理 | 16篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 8篇 |
2020年 | 10篇 |
2018年 | 14篇 |
2017年 | 16篇 |
2016年 | 17篇 |
2015年 | 21篇 |
2014年 | 25篇 |
2013年 | 19篇 |
2012年 | 27篇 |
2011年 | 27篇 |
2010年 | 23篇 |
2009年 | 28篇 |
2008年 | 15篇 |
2007年 | 10篇 |
2006年 | 17篇 |
2005年 | 20篇 |
2004年 | 15篇 |
2003年 | 18篇 |
2002年 | 7篇 |
2001年 | 4篇 |
2000年 | 7篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 6篇 |
1995年 | 3篇 |
1994年 | 8篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1988年 | 3篇 |
1985年 | 3篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1971年 | 5篇 |
1968年 | 2篇 |
1966年 | 2篇 |
1965年 | 4篇 |
1963年 | 2篇 |
1961年 | 3篇 |
1958年 | 5篇 |
1957年 | 3篇 |
1948年 | 2篇 |
排序方式: 共有483条查询结果,搜索用时 15 毫秒
31.
The ML 5.3 Épagny (French Alps) earthquake of 1996 July 15: a long-awaited event on the Vuache Fault
32.
Vít Kárník Dana Procházková Zdeňka Schenková Julius Drimmel Dieter Mayer-Rosa Dragutin Cvijanovic Vladimir Kuk Andelka Miloševič Francesco Giorgetti Reviewer J. Janský 《Studia Geophysica et Geodaetica》1978,22(4):411-414
Summary Isoseismal maps of the three strongest Friuli aftershocks of September 1976 were compiled using the contributions from European countries within the shaken area. The characteristic features of the macroseismic fields are discussed. 相似文献
33.
Summary The paper presents a method of evaluating oscillations with a time-variable frequency using a computer. The given function is first interpolated at points which are not distributed equidistantly in time, but the digitizing step varies with time according to a known optional regularity. The spectrum of the obtained function is computed for various of these interpolations and tests are run to determine when the interpolation best compensates the time variation of the frequency. The initial and terminal frequency in the given sample is then determined. The usability of this method with respect to various types of oscillations with a variable frequency and its accuracy in comparison to sonagrams are discussed. 相似文献
34.
Dana Procházková Vít Kárník Ivan Brouček Reviewer A. Zátopek 《Studia Geophysica et Geodaetica》1980,24(1):102-103
an¶rt;u am mu 15- an 1979. a auu a mumuu auu. 相似文献
35.
Summary Three quantities M, E
1/2
and E
2/3
are used for studying the Balkan earthquake provinces. Most of them show a regular trend of activity, for some of them the observation period of 70 years is too short. Some graphs give evidence of the coincidence or migration of activity. 相似文献
36.
N. Delsate P. Robutel A. Lemaître T. Carletti 《Celestial Mechanics and Dynamical Astronomy》2010,108(3):275-300
We hereby study the stability of a massless probe orbiting around an oblate central body (planet or planetary satellite) perturbed
by a third body, assumed to lay in the equatorial plane (Sun or Jupiter for example) using a Hamiltonian formalism. We are
able to determine, in the parameters space, the location of the frozen orbits, namely orbits whose orbital elements remain
constant on average, to characterize their stability/unstability and to compute the periods of the equilibria. The proposed
theory is general enough, to be applied to a wide range of probes around planet or natural planetary satellites. The BepiColombo
mission is used to motivate our analysis and to provide specific numerical data to check our analytical results. Finally,
we also bring to the light that the coefficient J
2 is able to protect against the increasing of the eccentricity due to the Kozai-Lidov effect and the coefficient J
3 determines a shift of the equilibria. 相似文献
37.
We calculate NLTE models of stellar winds of hot compact stars (central stars of planetary nebulae and subdwarf stars). The studied range of subdwarf parameters is selected to cover a large part of these stars. The models predict the wind hydrodynamical structure and provide mass-loss rates for different abundances. Our models show that CNO elements are important drivers of subdwarf winds, especially for low-luminosity stars. We study the effect of X-rays and instabilities on these winds. Due to the line-driven wind instability, a significant part of the wind could be very hot. 相似文献
38.
Benoît Noyelles 《Icarus》2010,207(2):887-902
The saturnian coorbital satellites Janus and Epimetheus present a unique dynamical configuration in the Solar System, because of high-amplitude horseshoe orbits, due to a mass ratio of order unity. As a consequence, they swap their orbits every 4 years, while their orbital periods is about 0.695 days. Recently, Tiscareno et al. (Tiscareno, M.S., Thomas, P.C., Burns, J.A. [2009]. Icarus 204, 254-261) got observational informations on the shapes and the rotational states of these satellites. In particular, they detected an offset in the expected equilibrium position of Janus, and a large libration of Epimetheus.We here propose to give a three-dimensional theory of the rotation of these satellites in using these observed data, and to compare it to the observed rotations. We consider the two satellites as triaxial rigid bodies, and we perform numerical integrations of the system in assuming the free librations as damped.The periods of the three free librations we get, associated with the three dimensions, are respectively 1.267, 2.179 and 2.098 days for Janus, and 0.747, 1.804 and 5.542 days for Epimetheus. The proximity of 0.747 days to the orbital period causes a high sensitivity of the librations of Epimetheus to the moments of inertia. Our theory explains the amplitude of the librations of Janus and the error bars of the librations of Epimetheus, but not an observed offset in the orientation of Janus. 相似文献
39.
B. Košt’ák S. Cacoń N. D. Dobrev E. Avramova-Tačeva E. Fecker J. Kopecký L. Petro R. Schweitzer A. A. Nikonov 《Izvestiya Physics of the Solid Earth》2007,43(6):503-516
Long-term repeated measurements of microdisplacements in tectonic fault structures of various parts of Central Europe and the Balkan Mountains showed that displacement trends changed significantly at several points in the period from 1997 through 2000; afterward, long-term trends were restored. This phenomenon took place in the periods of strong (M > 7) earthquakes in Iran (1997) and in the North Anatolian fault zone in Turkey (1999). Two strong Izmit earthquakes of 1999 in Turkey at distances of 600 km from the Balkan Peninsula and 1400 km from observation points in Central Europe were the main seismic events of the period studied. Apparently, the crustal deformation due to the sources of the aforementioned earthquakes reaches the central part of the European craton. Anomalous displacements in some areas occurred due to deformation propagating for great distances in the heterogeneous block medium of the West European part of the Eurasian plate. Changes in stresses can be caused by impulsive deformations of various intensities acting on some structural units (fault segments) at various distances. 相似文献
40.
The Mississippi Valley-type (MVT) Pb–Zn ore district at Mežica is hosted by Middle to Upper Triassic platform carbonate rocks
in the Northern Karavanke/Drau Range geotectonic units of the Eastern Alps, northeastern Slovenia. The mineralization at Mežica
covers an area of 64 km2 with more than 350 orebodies and numerous galena and sphalerite occurrences, which formed epigenetically, both conformable
and discordant to bedding. While knowledge on the style of mineralization has grown considerably, the origin of discordant
mineralization is still debated. Sulfur stable isotope analyses of 149 sulfide samples from the different types of orebodies
provide new insights on the genesis of these mineralizations and their relationship. Over the whole mining district, sphalerite
and galena have δ
34
S values in the range of –24.7 to –1.5‰ VCDT (–13.5 ± 5.0‰) and –24.7 to –1.4‰ (–10.7 ± 5.9‰), respectively. These values are
in the range of the main MVT deposits of the Drau Range. All sulfide δ
34
S values are negative within a broad range, with δ
34
S
pyrite <δ
34
S
sphalerite <δ
34
S
galena for both conformable and discordant orebodies, indicating isotopically heterogeneous H2S in the ore-forming fluids and precipitation of the sulfides at thermodynamic disequilibrium. This clearly supports that
the main sulfide sulfur originates from bacterially mediated reduction (BSR) of Middle to Upper Triassic seawater sulfate
or evaporite sulfate. Thermochemical sulfate reduction (TSR) by organic compounds contributed a minor amount of 34S-enriched H2S to the ore fluid. The variations of δ
34
S values of galena and coarse-grained sphalerite at orefield scale are generally larger than the differences observed in single
hand specimens. The progressively more negative δ
34
S values with time along the different sphalerite generations are consistent with mixing of different H2S sources, with a decreasing contribution of H2S from regional TSR, and an increase from a local H2S reservoir produced by BSR (i.e., sedimentary biogenic pyrite, organo-sulfur compounds). Galena in discordant ore (–11.9
to –1.7‰; –7.0 ± 2.7‰, n = 12) tends to be depleted in 34
S compared with conformable ore (–24.7 to –2.8‰, –11.7 ± 6.2‰, n = 39). A similar trend is observed from fine-crystalline sphalerite I to coarse open-space filling sphalerite II. Some variation
of the sulfide δ
34
S values is attributed to the inherent variability of bacterial sulfate reduction, including metabolic recycling in a locally
partially closed system and contribution of H2S from hydrolysis of biogenic pyrite and thermal cracking of organo-sulfur compounds. The results suggest that the conformable
orebodies originated by mixing of hydrothermal saline metal-rich fluid with H2S-rich pore waters during late burial diagenesis, while the discordant orebodies formed by mobilization of the earlier conformable
mineralization. 相似文献