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481.
482.
Georgios Katsigiannis Pedro Ferreira Raul Fuentes 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2018,12(1):45-59
HYD, as described in Eurocode 7 (EC7), is related to the upward flow of water through the soil towards a free surface, such as in front of a retaining wall or in the base of an excavation. The HYD verification, using numerical analysis, can be performed with two different approaches. The first approach is the conventional soil block approach where safety may be checked by calculating the equilibrium of a rectangular block of soil. The second approach is the integration point approach where stability can be verified at every integration point in the numerical analysis by checking that the equilibrium is satisfied for a soil column of negligible width above each point. In this paper, the two approaches are described and their advantages and disadvantages are discussed. Comparisons made using benchmark geometries, extensively studied and discussed between the members of the EC7 Evolution Group 9, on Water Pressures, illustrate that the HYD verification using numerical methods seems very promising. Thorough comparisons between the factors from the two approaches allow designers to better understand the benefits of using more advanced and robust approaches for such stability verifications. 相似文献
483.
In this paper a new methodology to simulate saturated soils subjected to dynamic loadings under large deformation regime (locally up to 40% in equivalent plastic strain) is presented. The coupling between solid and fluid phases is solved through the complete formulation of the Biot’s equations. The additional novelty lies in the employment of an explicit time integration scheme of the \(u-w\) (solid displacement–relative fluid displacement) formulation which enables us to take advantage of such explicit schemes. Shape functions based on the principle of maximum entropy implemented in the framework of Optimal Transportation Meshfree schemes are utilized to solve both elastic and plastic problems. 相似文献
484.
Konopásek Jiří Janoušek Vojtěch Oyhantçabal Pedro Sláma Jiří Ulrich Stanislav 《International Journal of Earth Sciences》2018,107(5):1859-1894
International Journal of Earth Sciences - Early Neoproterozoic metaigneous rocks occur in the central part of the Kaoko–Dom Feliciano–Gariep orogenic system along the coasts of the... 相似文献
485.
Tayyebi Saeid M. Pastor Manuel Stickle Miguel M. Yage ngel Manzanal Diego Molinos Miguel Navas Pedro 《Landslides》2022,19(2):421-435
Landslides - Rapid flow-like landslides, particularly debris flows and debris avalanches, cause significant economic damage and many victims worldwide every year. They are usually extremely fast... 相似文献
486.
Landslides - Submarine landslides are a ubiquitous geohazard in the marine environment and occur at multiple scales. Increasing efforts have been made during the last decade to catalogue and... 相似文献
487.
Guimarães Pedro Veras Ardhuin Fabrice Perignon Yves Benetazzo Alvise Bouin Marie-Noëlle Garnier Valerie Redelsperger Jean-Luc Accensi Mickael Thomson Jim 《Ocean Dynamics》2022,72(8):621-639
Ocean Dynamics - Short waves growth is characterized by nonlinear and dynamic processes that couple ocean and atmosphere. Ocean surface currents can have a strong impact on short wave steepness and... 相似文献
488.
辽宁地震监测中心实时脉动监控系统(RTTS),在"九五"运行期间就发现,不论是短周期还是宽频带的地震仪,在发生5级以上的近震和日本的7级以上地震都有明显的震前异常反映. 相似文献
489.
Rayco Marrero Dina L. López Pedro A. Hernández Nemesio M. Pérez 《Pure and Applied Geophysics》2008,165(1):147-172
Carbon dioxide is one of the first gases to escape the magmatic environment due to its low solubility in basaltic magmas at low pressures. The exsolved CO2 gas migrates towards the surface through rock fractures and high permeability paths. If an aquifer is located between the magmatic environment and the surface, a fraction of the CO2 emitted is dissolved in the aquifer. In this paper, an estimation of the water mass balance and the CO2 budget in Las Cañadas aquifer, Tenerife, Canary Islands, is presented. Magmatic CO2 is transported by groundwater and discharged through man-made sub-horizontal drains or galleries that exist in this island, and by the flow of groundwater discharged laterally towards other aquifers or to the ocean. In addition, the pCO2 at the gallery mouth (or entrance) and at the gallery bottom (internal and deepest discharge point where the gallery starts) are calculated and mapped. The total CO2 advectively transported by groundwater is estimated to range from 143 to 211 t CO2 d?1. Considering that the diffuse soil emission of CO2 for the same area is 437 t d?1, the diffuse/dissolved CO2 flux ratio varies between 2 and 3. The high dissolved inorganic carbon content of groundwater explains the ability of this low temperature hydrothermal water to dissolve and transfer magmatic CO2 at volcanoes, even during quiescence periods. 相似文献
490.
Sergio Zlotnik Manel Fernández Pedro Díez Jaume Vergés 《Pure and Applied Geophysics》2008,165(8):1491-1510
A non-standard new code to solve multiphase viscous thermo–mechanical problems applied to geophysics is presented. Two numerical
methodologies employed in the code are described: A level set technique to track the position of the materials and an enrichment
of the solution to allow the strain rate to be discontinuous across the interface. These techniques have low computational
cost and can be used in standard desktop PCs. Examples of phase tracking with level set are presented in two and three dimensions
to study slab detachment in subduction processes and Rayleigh–Taylor instabilities, respectively. The modelling of slab detachment
processes includes realistic rheology with viscosity depending on temperature, pressure and strain rate; shear and adiabatic
heating mechanisms; density including mineral phase changes and varying thermal conductivity. Detachment models show a first
prolonged period of thermal diffusion until a fast necking of the subducting slab results in the break–off. The influence
of several numerical and physical parameters on the detachment process is analyzed: The shear heating exerts a major influence
accelerating the detachment process, reducing the onset time to one half and lubricating the sinking of the detached slab.
The adiabatic heating term acts as a thermal stabilizer. If the mantle temperature follows an adiabatic gradient, neglecting
this heating term must be included, otherwise all temperature contrasts are overestimated. As expected, the phase change at
410 km depth (olivine–spinel transition) facilitates the detachment process due to the increase in negative buoyancy. Finally,
simple plume simulations are used to show how the presented numerical methodologies can be extended to three dimensions. 相似文献