全文获取类型
收费全文 | 445篇 |
免费 | 29篇 |
国内免费 | 7篇 |
专业分类
测绘学 | 5篇 |
大气科学 | 30篇 |
地球物理 | 86篇 |
地质学 | 204篇 |
海洋学 | 28篇 |
天文学 | 59篇 |
综合类 | 2篇 |
自然地理 | 67篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 12篇 |
2021年 | 14篇 |
2020年 | 19篇 |
2019年 | 14篇 |
2018年 | 12篇 |
2017年 | 19篇 |
2016年 | 22篇 |
2015年 | 17篇 |
2014年 | 16篇 |
2013年 | 33篇 |
2012年 | 26篇 |
2011年 | 44篇 |
2010年 | 29篇 |
2009年 | 23篇 |
2008年 | 35篇 |
2007年 | 14篇 |
2006年 | 19篇 |
2005年 | 15篇 |
2004年 | 15篇 |
2003年 | 9篇 |
2002年 | 12篇 |
2001年 | 12篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1980年 | 1篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1973年 | 3篇 |
1969年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有481条查询结果,搜索用时 125 毫秒
151.
Emmanuel Masini Gianreto Manatschal Geoffroy Mohn Jean‐François Ghienne François Lafont 《Basin Research》2011,23(6):652-677
We describe the tectono‐sedimentary evolution of a Middle Jurassic, rift‐related supra‐detachment basin of the ancient Alpine Tethys margin exposed in the Central Alps (SE Switzerland). Based on pre‐Alpine restoration, we demonstrate that the rift basin developed over a detachment system that is traced over more than 40 km from thinned continental crust to exhumed mantle. The detachment faults are overlain by extensional allochthons consisting of upper crustal rocks and pre‐rift sediments up to several kilometres long and several hundreds of metres thick, compartmentalizing the distal margin into sub‐basins. We mapped and restored one of these sub‐basins, the Samedan Basin. It consists of a V‐shape geometry in map view, which is confined by extensional allochthons and floored by a detachment fault. It can be restored over a minimum distance of 11 km along and about 4 km perpendicular to the basin axis. Its sedimentary infill can be subdivided into basal (initial), intermediate (widening) and top (post‐tectonic) facies tracts. These tracts document (1) formation of the basin initially bounded by high‐angle faults and developing into low‐angle detachment faults, (2) widening of the basin and (3) migration of deformation further outboard. The basal facies tract is made of locally derived, poorly sorted gravity flow deposits that show a progressive change from hangingwall to footwall‐derived lithologies. Upsection the sediments develop into turbidity current deposits that show retrogradation (intermediate facies tract) and starvation of the sedimentary system (post‐tectonic facies tract). On the scale of the distal margin, the syn‐tectonic record documents a thinning‐ and fining‐upward sequence related to the back stepping of the tectonically derived sediment source, progressive starvation of the sedimentary system and migration of deformation resulting in exhumation and progressive delamination of the thinned crust during final rifting. This study provides valuable insights into the tectono‐sedimentary evolution and stratigraphic architecture of a supra‐detachment basin formed over hyper‐extended crust. 相似文献
152.
This paper examines the possibility of applying a homogenization procedure to analyze the convergence of a tunnel reinforced by bolts, regarded as periodically distributed linear inclusions. Owing to the fact that a classical homogenization method fails to account for the interactions prevailing between the bolts and the surrounding ground and thus tends to significantly overestimate the reinforcement effect in terms of convergence reduction, a so‐called multiphase model is presented and developed, aimed at improving the classical homogenization method. Indeed, according to this model, the bolt‐reinforced ground is represented at the macroscopic scale as the superposition of two mutually interacting continuous phases, describing the ground and the reinforcement network, respectively. It is shown that such a multiphase approach can be interpreted as an extension of the homogenization procedure, thus making it possible to capture the ground–reinforcement interaction in a proper way, provided the constitutive parameters of the model and notably those relating to the interaction law can be identified from the reinforced ground characteristics. The numerical implementation of this model in a finite element method‐based computer code is then carried out, and a first illustrative application is finally presented. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
153.
Danielle Alloin Carme Gallart Emmanuel Fleurence Emanuela Pompei Daniel Raimann Uta Fritze- Von Alvensleben Sukyoung Yi 《Astrophysics and Space Science》2002,281(1-2):109-113
The goal of this project is to analyze the integrated-light spectrum of a region in the LMC bar, for which HST images are
already available yielding color-magnitude diagrams reaching the oldest main-sequence turnoff. Then, we can derive the star
formation history in this field through evolutionary/population synthesis of the integrated light from 330 to 990 nm by a
variety of independent methods and compare the results with the - in principle - more reliable results derived from the analysis
of the color-magnitude diagram (CMD). This confrontation is the key ‘truth-test’ needed for the understanding of the abilities
and the limitations of the evolutionary/population synthesis methods that must be applied of necessity to unresolved nearby
and far-away galaxies. We report here on the observational part of the project.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
154.
This paper presents a direct boundary element method (BEM), formulated in the Laplace transform space, for plane strain poroelasticity. The paper expands on work by Cheng and Liggett by recasting the theoretical foundation of BEM within the framework of Rice and Cleary's formulation of the Biot theory of poroelasticity. Furthermore, the numerical algorithm is generalized to deal with both interior and exterior domain problems, and a method for indirectly calculating the Cauchy principal value of the singular integrals is presented. Formulae for the stress and flux inside the domain are also derived. Finally, the algorithm is validated by comparing the numerical results with the analytical solution of a borehole subject to a far-field deviatoric stress (exterior domain) and with the solution of Mandel's problem (interior domain). These two examples provide a critical test of the algorithm. 相似文献
155.
156.
Jun Deng Changming Wang Leon Bagas Emmanuel John M. Carranza Yongjun Lu 《Mineralium Deposita》2015,50(8):987-1006
157.
Rock texture has a critical influence on the way rocks weather. The most important textural factors affecting weathering are grain size and the presence of cracks and stylolites. These discontinuities operate as planes of mechanical weakness at which chemical weathering is enhanced. However, it is unclear how different rock textures impact weathering rates and the size of weathered grains. Here, we use a numerical model to simulate weathering of rocks possessing grain boundaries, cracks, and stylolites. We ran simulations with either synthetic or natural patterns of discontinuities. We found that for all patterns, weathering rates increase with discontinuity density. When the density was <~25%, the weathering rate of synthetic patterns followed the order: grid > honeycomb > Voronoi > brick wall. For higher values, all weathering rates were similar. We also found that weathering rates decreased as the tortuosity of the pattern increased. Moreover, we show that textural patterns strongly impact the size distributions of detached grains. Rocks with an initial monomodal grain size distribution produce weathered fragments that are normally distributed. In contrast, rocks with an initial log-normal size distribution produce weathered grains that are log-normally distributed. For the natural patterns, weathering produced lower modality distributions. 相似文献
158.
Emmanuel Masini Gianreto Manatschal Julie Tugend Geoffroy Mohn Jean-Marie Flament 《International Journal of Earth Sciences》2014,103(6):1569-1596
In this paper, we present a sedimentary and structural analysis that together with maps, sections and new Ar/Ar data enable to describe the tectono-sedimentary evolution of the Mauléon hyper-extended rift basin exposed in the W-Pyrenees. Hyper-extension processes that ultimately resulted in exhuming mantle rocks are the result of the subsequent development of two diachronous detachment systems related to two evolutional stages of rifting. An initial Late Aptian Early Albian crustal thinning phase is first recorded by the development of a crustal necking zone controlled by the north-vergent Southern Mauléon Detachment system. During a subsequent exhumation phase, active faulting migrates to the north with the emplacement of the Northern Mauléon detachment system that exhumed north section thinned continental crust and mantle rocks. This diachronous crustal thinning and exhumation processes are also recorded by the diachronous deposition of syn-tectonic sedimentary tracts above the two supra-detachment sub-basins. Syn-tectonic sedimentary tracts record the progressive exhumation of footwall rocks along detachment systems. Tectonic migration from the southern to the northern Mauléon Detachment system is recorded by the coeval deposition of “sag” deposits above the necking zone basin and of syn-tectonic tracts above exhumed rocks north section. Located on a hanging-wall situation related to the Mauléon hyper-extension structures, the Arzacq Basin also records a major crustal thinning phase as shown by its subsidence evolution so as by deep seismic images. The absence of major top-basement structures and its overall sag morphology suggest that crustal thinning processes occurred by decoupled extension of lower crustal levels contrasting with the Southern Mauléon Detachment system. Reconciling observations from the Mauléon and Arzacq Basins, we finally propose in this paper that they were the result of one and the same asymmetric crustal thinning and exhumation processes, where extension is accommodated into the upper crust in the Mauléon Basin (lower plate basin) and relayed in ductile lower crust below the Arzacq Basin (upper plate basin). 相似文献
159.
Natural Resources Research - Accurate characterization of geochemical anomaly related to metal mineralization and quantification of uncertainty propagation in space prediction are important for... 相似文献
160.
Theoretical and Applied Climatology - The purpose of this study is to assess spatial and temporal changes in extreme precipitation events from 1983 to 2017 over different climatic regions of... 相似文献