全文获取类型
收费全文 | 159篇 |
免费 | 7篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 2篇 |
大气科学 | 11篇 |
地球物理 | 41篇 |
地质学 | 59篇 |
海洋学 | 18篇 |
天文学 | 28篇 |
综合类 | 1篇 |
自然地理 | 7篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 1篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 7篇 |
2016年 | 9篇 |
2015年 | 7篇 |
2014年 | 7篇 |
2013年 | 20篇 |
2012年 | 2篇 |
2011年 | 14篇 |
2010年 | 7篇 |
2009年 | 8篇 |
2008年 | 10篇 |
2007年 | 4篇 |
2006年 | 5篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2002年 | 5篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 5篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 7篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1988年 | 2篇 |
1984年 | 1篇 |
1976年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有167条查询结果,搜索用时 62 毫秒
51.
Pierre Aumond Valery Masson Christine Lac Benoit Gauvreau Sylvain Dupont Michel Berengier 《Boundary-Layer Meteorology》2013,146(1):65-80
We use the mesoscale meteorological model Meso-NH, taking the drag force of trees into account under stable, unstable and neutral conditions in a real case study. Large-eddy simulations (LES) are carried out for real orography, using a regional forcing model and including the energy and water fluxes between the surface (mostly grass with some hedges of trees) and the atmosphere calculated using a state-of-the-art soil-vegetation-atmosphere-transfer model. The formulation of the drag approach consists of adding drag terms to the momentum equation and subgrid turbulent kinetic energy dissipation, as a function of the foliage density. Its implementation in Meso-NH is validated using Advanced Regional Prediction System simulation results and measurements from Shaw and Schumann (Boundary-Layer Meteorol, 61(1):47?C64, 1992). The simulation shows that the Meso-NH model successfully reproduces the flow within and above homogeneous covers. Then, real case studies are used in order to investigate the three different boundary layers in a LES configuration (resolution down to 2 m) over the ??Lannemezan 2005?? experimental campaign. Thus, we show that the model is able to reproduce realistic flows in these particular cases and confirm that the drag force approach is more efficient than the classical roughness approach in describing the flow in the presence of vegetation at these resolutions. 相似文献
52.
53.
Résumé Afin d'évaluer l'impact potentiel de la vidange, les flux de nutriments et de matières sont quantifiés lors du remplissage et de la vidange d'un étang construit en dérivation, à l'aval d'une chaîne d'étangs. La cinétique de vidange a été établie à l'aide d'un modèle numérique de terrain restituant la surface topographique de l'étang. Les matières en suspension et les principaux nutriments ont été régulièrement quantifiés. La qualité hydrobiologique du cours d'eau récepteur a été contrôlée pendant et après la vidange. L'étang a exporté 8.5 tonnes de matières en suspension et des quantités de nutriments relativement élevées. Nos résultats confirment l'existence de deux phases critiques, ne concernant cependant qu'un très faible volume d'effluent. Compte tenu des capacités élevées de sédimentation des matières en suspension, la courte durée d'exposition associée à un linéaire de fossés suffisant pourrait limiter l'impact de ces matières rejetées. Citation Vallod, D. & Sarrazin, B. (2010) Caractérisation de l'effluent de vidange d'un étang de pisciculture extensive. Hydrol. Sci. J. 55(3), 394–402. 相似文献
54.
Pierre Bérest Benoit Brouard Hippolyte Djakeun-Djizanne Grégoire Hévin 《Acta Geotechnica》2014,9(1):181-186
Rapid gas depressurization leads to gas cooling followed by slow gas warming when the cavern is kept idle. Gas temperature drop depends upon withdrawal rate and cavern size. Thermal tensile stresses, resulting from gas cooling, may generate fractures at the wall and roof of a salt cavern. However, in most cases, the depth of penetration of these fractures is small. These fractures are perpendicular to the cavern wall. The distance between two parallel fractures becomes larger when fractures penetrate deeper in the rock mass, as some fractures do not keep growing. These conclusions can be supported by numerical computations based on fracture mechanics. Salt slabs are created. However, these slabs remain strongly bounded to the rock mass and it is believed that in many cases their weight is not large enough to allow them to break off the cavern wall. Depth of penetration of the fractures must be computed to prove that they cannot be a concern from the point of view of cavern tightness. 相似文献
55.
Aur��lien Bideaud Benoit Belier Alain Benoit Laurent Berg�� Philippe Camus Sophie Collin Louis Dumoulin Christian Hoffmann Stefanos Marnieros Alessandro Monfardini 《Experimental Astronomy》2011,32(2):179-191
Microbolometers are at present the most sensitive detectors for mm and sub-mm Astronomy. They are in use in most of the present instruments in that bandwidth. We have developed filled arrays of NbSi-based planar antenna coupled microbolometers. The fabrication details are given, together with characterization of the NbSi thermometers and optical results. The optical performances are potentially good for ground-based mm-wave astronomy applications, while the overall detectors performances are limited by low-frequency excess noise in the thermometric NbSi high-impedance sensors (Anderson insulator). 相似文献
56.
Abstract For the purpose of deriving an analytical parametrization, oceanic mesoscale eddies are represented as a horizontally propagating wave field in a non-uniform environment. The mathematical analysis rests upon the assumption of scale disparity between a short eddy scale and a long mean-flow scale. The novelty resides in the treatment of finite-amplitude eddies, which, moreover, form either a band-like or a cell-like pattern. A barotropic ocean is chosen as a first step to illustrate the mathematical analysis, but dissipation is included. The main result is an analytical derivation of a mesoscale-eddy parametrization: the mean-flow equation contains Reynolds-stress terms which are computed from parameters of the eddy field, which, in turn, are predicted by separate evolution equations. Due to restrictive assumptions (barotropy, orthogonal waves,…), the parametrization established here should be viewed only as a first step toward the design of a more practical parameterization for large-scale modelling. 相似文献
57.
Mallika K.Jonnalagadda Mathieu Benoit Shivani Harshe Romain Tilhac Raymond A.Duraiswami Michel Grégoire Nitin R.Karmalkar 《地学前缘(英文版)》2022,(1):326-349
The Spontang Ophiolite complex represents the most complete ophiolite sequence amongst the South Ladakh ophiolites and comprises mantle rocks(depleted harzburgites,dunites and minor lherzolites)as well as crustal rocks(basalt,isotropic gabbros,layered gabbros etc.).In the present study,detailed geochemistry(whole rock as well as mineral chemistry)and Sr-Nd isotopic analyses of thirty-six ultramaficmafic samples have been attempted to constraint the evolution and petrogenetic history of the Tethyan oceanic crust.Major,trace-element and REE patterns of the peridotites and their minerals indicate that the lherzolites experienced lower degrees of partial melting resembling abyssal peridotites(at higher temperatures,TREE=$1216℃)than the harzburgites(6%–8%versus 15%–17%).Elevated eNd(t)and variable87 Sr/86 Sr(t)ratios along with REE patterns suggest that the Spontang mafic rocks display N-MORB affinity with negligible participation of oceanic sediments in their genesis are originated from a depleted upper mantle with little contribution from subduction-related fluids.MORB-type Neotethyan oceanic crust is associated with the earliest phase of subduction(of older Jurassic age)through which a younger intra-oceanic island arc(Spong arc)subsequently developed.Harzburgites REE display typical U-shaped patterns,suggesting that these rocks have been metasomatized by LREE-enriched fluids.On the other side,mafic rocks are characterized by heterogeneous(Nb/La)PMand(Hf/Sm)PMand relatively homogeneous eNd(t),indicating interaction of subduction-related melts with the upper mantle during the initiation of subduction,in Early Cretaceous times. 相似文献
58.
Lionel G. Vacher Laurent Truche Franois Faure Laurent Tissandier Rgine Mosser‐Ruck Yves Marrocchi 《Meteoritics & planetary science》2019,54(8):1870-1889
Tochilinite/cronstedtite intergrowths are commonly observed as alteration products in CM chondrite matrices, but the conditions under which they formed are still largely underconstrained due to their scarcity in terrestrial environments. Here, we report low temperature (80 °C) anoxic hydrothermal experiments using starting assemblages similar to the constituents of the matrices of the most pristine CM chondrite and S‐rich and S‐free fluids. Cronstedtite crystals formed only in S‐free experiments under circumneutral conditions with the highest Fe/Si ratios. Fe‐rich tochilinite with chemical and structural characteristics similar to chondritic tochilinite was observed in S‐bearing experiments. We observed a positive correlation between the Mg content in the hydroxide layer of synthetic tochilinite and temperature, suggesting that the composition of tochilinite is a proxy for the alteration temperature in CM chondrites. Using this relation, we estimate the mean precipitation temperatures of tochilinite to be 120–160 °C for CM chondrites. Given the different temperature ranges of tochilinite and cronstedtite in our experiments, we propose that Fe‐rich tochilinite crystals resulted from the alteration of metal beads under S‐bearing alkaline conditions at T = 120–160 °C followed by cronstedtite crystals formed by the reaction of matrix amorphous silicates, metal beads, and water at a low temperature (50–120 °C). 相似文献
59.
A prime requirement for hydrological applications,such as sediment budgeting or numerical modelling,is that produced Digital Terrain Models(DTMs)accurately represent the shape of landforms,especially for river reaches where data are not homogeneous.DTM error is a function of data point measurement accuracy and density and also of the field survey strategy when limited amounts of data will be acquired.This paper aims to advance the importance of the field survey strategy for the specific,but common cases,where only limited topographic data will be available.This methodology is based on the idea that any feature can be properly described by a set of cross sections and breaklines describing both main and secondary directions of the flow.Then,a longitudinal linear interpolation can be applied to the defined homogeneous zones.This morphologically oriented(MO)method that includes data acquisition strategy and interpolation,was validated using a reference DTM derived from LiDAR measurements.An estimation of the uncertainties also is suggested based on the distance of the nearest point and the local slope using a geographically weighted regression.The proposed MO method is typically applicable to Alpine river reaches characterized by multiple channels that may always be underwater and not navigable such as an alternate bar system with secondary and transverse channels. 相似文献
60.
Mathematical Geosciences - We present an application of deep generative models in the context of partial differential equation constrained inverse problems. We combine a generative adversarial... 相似文献