全文获取类型
收费全文 | 145篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
大气科学 | 8篇 |
地球物理 | 39篇 |
地质学 | 71篇 |
海洋学 | 6篇 |
天文学 | 19篇 |
自然地理 | 3篇 |
出版年
2022年 | 1篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 2篇 |
2014年 | 4篇 |
2013年 | 12篇 |
2012年 | 6篇 |
2011年 | 7篇 |
2010年 | 16篇 |
2009年 | 4篇 |
2008年 | 18篇 |
2007年 | 5篇 |
2006年 | 10篇 |
2005年 | 7篇 |
2004年 | 5篇 |
2003年 | 6篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
排序方式: 共有146条查询结果,搜索用时 31 毫秒
71.
Noureddine Beghoul Jean-Luc Chatelain Mohamed-Salah Boughacha Hadj Benhallou Rida Dadou Amira Mezioud-Saïch 《Pure and Applied Geophysics》2010,167(3):277-321
Seismic events that occurred during the past half century in the Tellian Atlas, North Africa, are used to establish fundamental seismic empirical relations, tying earthquake magnitude to source parameters (seismic moment, fault plane area, maximal displacement along the fault, and fault plane length). Those empirical relations applied to the overall seismicity from 1716 to present are used to transform the magnitude (or intensity) versus time distribution into (1) cumulative seismic moment versus time, and (2) cumulative displacements versus time. Both of those parameters as well as the computed seismic moment rate, the strain rate along the Tellian Atlas strike, and various other geological observations are consistent with the existence, in the Tellian Atlas, of three distinct active tectonic blocks. These blocks are seismically decoupled from each other, thus allowing consideration of the seismicity as occurring in three different distinct seismotectonic blocks. The cumulative displacement versus time from 1900 to present for each of these tectonic blocks presents a remarkable pattern of recurrence time intervals and precursors associated with major earthquakes. Indeed, most major earthquakes that occurred in these three blocks might have been predicted in time. The Tellian Atlas historical seismicity from the year 881 to the present more substantially confirms these observations, in particular for the western block of the Tellian Atlas. Theoretical determination of recurrence time intervals for the Tellian Atlas large earthquakes using Molnar and Kostrov formalisms is also consistent with these observations. Substantial observations support the fact that the western and central Tellian Atlas are currently at very high seismic risk, in particular the central part. Indeed, most of the accumulated seismic energy in the central Tellian Atlas crust has yet to be released, despite the occurrence of the recent destructive May 2003 Boumerdes earthquake (M w = 6.8). The accumulated seismic energy is equivalent to a magnitude 7.6 earthquake. In situ stress and geodetic measurements, as well as other geophysical field data measurements, are now required to practically check the validity of those observations. 相似文献
72.
The shaking of Mercury’s orbit by the planets forces librations in longitude in addition to those at harmonics of the orbital period that have been used to detect Mercury’s molten core. We extend the analytical formulation of Peale et al. (Peale, S.J., Margot, J.L., Yseboodt, M. [2009]. Icarus 199, 1-8) in order to provide a convenient means of determining the amplitudes and phases of the forced librations without resorting to numerical calculations. We derive an explicit relation between the amplitude of each forced libration and the moment of inertia parameter (B-A)/Cm. Far from resonance with the free libration period, the libration amplitudes are directly proportional to (B-A)/Cm. Librations with periods close to the free libration period of ∼12 years may have measurable (∼arcsec) amplitudes. If the free libration period is sufficiently close to Jupiter’s orbital period of 11.86 years, the amplitude of the forced libration at Jupiter’s period could exceed the 35 arcsec amplitude of the 88-day forced libration. We also show that the planetary perturbations of the mean anomaly and the longitude of pericenter of Mercury’s orbit completely determine the libration amplitudes.While these signatures do not affect spin rate at a detectable level (as currently measured by Earth-based radar), they have a much larger impact on rotational phase (affecting imaging, altimetry, and gravity sensors). Therefore, it may be important to consider planetary perturbations when interpreting future spacecraft observations of the librations. 相似文献
73.
New experimental determination of Li and B partition coefficients during upper mantle partial melting 总被引:1,自引:1,他引:0
Luisa Ottolini Didier Laporte Nicola Raffone Jean-Luc Devidal Brieuc Le Fèvre 《Contributions to Mineralogy and Petrology》2009,157(3):313-325
Despite the growing interest for Li and B as geochemical tracers, especially for material transfer from subducting slabs to
overlying peridotites, little is known about the behaviour of these two elements during partial melting of mantle sources.
In particular, mineral/melt partition coefficients for B and to a lesser extent Li are still a matter of debate. In this work,
we re-equilibrated a synthetic basalt doped with ~10 ppm B and ~6 ppm Li with an olivine powder from a spinel lherzolite xenolith
at 1 GPa–1,330°C, and we analyzed Li and B in the run products by secondary ion mass spectrometry (SIMS). In our experiment,
B behaved as a highly incompatible element with mineral/melt partition coefficients of the order of 10−2 (D
ol/melt = 0.008 (0.004–0.013); D
opx/melt = 0.024 (0.015–0.033); D
cpx/melt = 0.041 (0.021–0.061)), and Li as a moderately incompatible element (D
ol/melt = 0.427 (0.418–0.436); D
opx/melt = 0.211 (0.167–0.256); D
cpx/melt = 0.246 (0.229–0.264)). Our partition coefficients for Li are in good agreement with previous determinations. In the case
of B, our partition coefficients are equal within error to those reported by Brenan et al. (1998) for all the mineral phases analyzed, but are lower than other coefficients from literature for some of the phases (up to
5 times for cpx). Our measurements complement the data set of Ds for modelling partial melting of the upper mantle and basalt generation, and confirm that, in this context, B is more incompatible
than previously anticipated. 相似文献
74.
Philippe A. Pezard Stéphanie Gautier Tanguy Le Borgne Bruno Legros Jean-Luc Deltombe 《Comptes Rendus Geoscience》2009,341(10-11):957-964
On the basis of an existing multiparameter borehole fluid sensor (p, T, Cw, pH, Eh), a new downhole tool designed for 200 bars and 75 °C was developed to measure the spontaneous electrical potential in situ with great precision (better than a μV). To this end, the new sensor is based on the use of unpolarizable Pb/PbCl2 electrodes either at the surface or downhole. In situ testing has demonstrated a capacity to identify several subsurface sources of natural electrical potential such as diffusion ones (membrane potential in the presence of clays, Fickian processes due to pore fluid salinity gradients), or else the electrokinetic mechanisms with gradients in pore fluid pressure. As a consequence, Multi-Sensors Electrical Tool (MuSET) might be used as an “electrical flowmeter” sensitive to both horizontal and vertical fluid flow in a vertical borehole. 相似文献
75.
76.
Jean-Luc Piveteau 《Geoforum》1975,6(2)
The lack of any unified view amongst geographers in their conceptions of the articulation of Swiss space is evidence, in the dialectical sense, of the complexity of the reality. It is also, however, a sympton of methodological uncertainty. The purpose of this article is an analysis of this malaise, usually passed over in silence.The evolution of geography during the last hundred years cannot be easily defined, but against a general trend opposed approaches have always been present.The manner of conceiving Swiss space is still affected by the changes in the physiognomy of the country, but the analysis of reality and reality itself are out of phase.It appears possible that the presuppositions admitted by authors or the intellectual paths followed by them in regionalisation should be considered and treated as one of the fundamentals of all studies concerned with the organisation of space. 相似文献
77.
Houssa Ouali Bernard Briand Jean-Luc Bouchardon Paul Capiez 《Comptes Rendus Geoscience》2003,335(5):425-433
In southeastern Central Morocco, the Bou-Acila volcanic complex is considered of Cambrian age. In spite of low-grade metamorphic effect, initial volcanic texture and mineralogy can be recognized and volcanic rocks are dominated by dolerites and porphyric dolerites. The initial mineralogy is composed of plagioclases, pyroxenes and dark minerals. A secondary mineral assemblage is composed of albite, epidote, chlorite and calcite. According to their immobile elements compositions, the southeastern central Morocco metavolcanites are of within-plate continental tholeiites. This volcanism and those recognized in many other areas in Morocco confirm a Cambrian extensive episode within the Gondwana supercontinent. To cite this article: H. Ouali et al., C. R. Geoscience 335 (2003).To cite this article: H. Ouali et al., C. R. Geoscience 335 (2003). 相似文献
78.
Jeffrey L Bada Mark A Sephton Pascale Ehrenfreund Richard A Mathies Allison M Skelley Frank J Grunthaner Aaron P Zent Richard C Quinn Jean-Luc Josset François Robert Oliver Botta Daniel P Glavin 《Astronomy& Geophysics》2005,46(6):6.26-6.27
If we are to find unequivocal evidence for life on Mars, we will need new ways to search for it. Jeff L Bada and the MOD team describe the innovative strategy developed for the ExoMars mission. 相似文献
79.
Florent Dominé Emmanuel Thibert Eric Silvente Michel Legrand Jean-Luc Jaffrezo 《Journal of Atmospheric Chemistry》1995,21(2):165-186
Laboratory and field measurements have been performed in order to improve our understanding of the HCl air-snow transfer function. The solubility and diffusion of HCl in laboratory grown single crystals of ice have been measured as a function of HCl partial pressure,P
HCl, between –8 and –25 °C. Measurements ofP
HCl and of the mole fraction of HCl in snow,X'HCl, have been measured at Summit, Greenland. Comparison of the field and laboratory measurements show that theX'HCl values are well below equilibrium values. The major processes involved in the formation of snow crystals and in their evolution after deposition are discussed in order to attempt to understand theX'HCl values and their variations. The discussion is focussed on a few well identified snow layers. It is concluded that sublimation and recrystallization of snow probably play a major role in the evolution ofX'HCl, but that our understanding of the HCl transfer function is very incomplete. Laboratory and field measurements are suggested to improve this situation. 相似文献
80.
Marine circulation above the northern Brazilian continental shelf is subject to energetic forcing factors of various origins: high water buoyancy fluxes induced by the Amazon River freshwater discharge, a strong coastal current associated with a mesoscale current (North Brazil Current (NBC)), a forcing by semidiurnal tide and by Northeast or Southeast trade winds according to the season. Using a three-dimensional (3-D) hydrodynamic numerical model (MOBEEHDYCS), and realistic bathymetry and coastline of the northern Brazilian shelf, this paper aims at studying the influence of some specific physical processes on the morphology of the Amazon plume. The very large volume discharge (180 000 m3/s on average) and the weak effect of Coriolis force are additional characteristics of the studied system, which induce a particular dynamics. The various forcing factors are successively introduced into the model in order to simulate and to determine their respective influences upon the plume extent and the hydrodynamics at the shelf scale. Simulation reveal that the coastal current is at the origin of the permanent northwestward Amazon plume extension while wind effect can either reinforce or moderate this situation. The tide intervenes also to modify the position of the salinity front: a horizontal migration of salinity front is observed under its action. 相似文献