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We study the scale dependence of the saturated hydraulic conductivity Ks through the effective porosity ne by means of a newly developed power‐law model (PLM) which allows to use simultaneously measurements at different scales. The model is expressed as product between a single PLM (capturing the impact of the dominating scale) and a characteristic function κ? accounting for the correction because of the other scale(s). The simple (closed form) expression of the κ?‐function enables one to easily identify the scales which are relevant for Ks. The proposed model is then applied to a set of real data taken at the experimental site of Montalto Uffugo (Italy), and we show that in this case two (i.e. laboratory and field) scales appear to be the main ones. The implications toward an important application (solute transport) in Hydrology are finally discussed. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
34.
Gazzola Laura Ferronato Massimiliano Frigo Matteo Janna Carlo Teatini Pietro Zoccarato Claudia Antonelli Massimo Corradi Anna Dacome Maria Carolina Mantica Stefano 《Computational Geosciences》2021,25(5):1731-1750
Computational Geosciences - Anthropogenic land subsidence can be evaluated and predicted by numerical models, which are often built over deterministic analyses. However, uncertainties and... 相似文献
35.
Giovanni Musumeci Francesco Mazzarini Massimo Tiepolo Gianfranco Di Vincenzo 《Geological Journal》2011,46(4):288-310
In the northern Apennines, the Palaeozoic basement involved in the Late Oligocene–Middle Miocene nappe stack contains metamorphic units for which hypothetical ages have been assigned on the basis of lithological correlations with the Palaeozoic formations of the Variscan chain in Sardinia. This uncertainty concerning the age poses limitations to reconstructing the Palaeozoic stratigraphy, defining the Alpine and pre‐Alpine histories and correlations with other domains of the Variscan chain. We present the U Pb age of detrital zircon and the 40Ar 39Ar age of metamorphic muscovite for the Calamita Schist and Ortano Porphyroid, two metamorphic units of undetermined Palaeozoic age cropping out in the eastern Elba Island. The radioisotopic data allows us to: (i) define the Early Carboniferous and Middle Ordovician ages for the Calamita Schist and Ortano Porphyroid, respectively, as well as their derivation (flysch deposit and magmatic rocks); (ii) pose some constraints concerning their alpine tectonic and metamorphic histories. These new data generate a more precise reconstruction of the Palaeozoic sequence in the northern Apennines, and they document that the Palaeozoic basement involved in the alpine deformation underwent internal stacking with an inversion of the original sequence. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
36.
Maurizio?Romanelli Francesco?Di BenedettoEmail author Laura?Bartali Massimo?Innocenti Gabriele?Fornaciai Giordano?Montegrossi Luca?A.?Pardi Alfonso?Zoleo Fabio?Capacci 《Physics and Chemistry of Minerals》2012,39(6):479-490
A set of raw industrial materials, that is, pure quartz and quartz-rich mixtures, were investigated through electron paramagnetic
resonance and electron spin echo-envelope modulation spectroscopies, with the aim of evaluating the effective role played
by defect centres and of assessing whether they can be used to monitor changes in the physical properties of quartz powders
with reference to their health effects. The obtained results point to two interactions of the Al defect centres with H+, hosted in sites within the channels parallel and perpendicular to the c axis of quartz, respectively. These two Al/H+ (hAl) centres exhibit a weak chemical bond, and their relative amounts appear to be modified/controlled by the thermo-mechanical
processes underwent by powders. Indeed, a mechanically promoted inter-conversion between the two kinds of site is suggested.
As a consequence, the hAl centres are effective in monitoring even modest activations of powders, through thermal or mechanical processes, and they
are also supposed to play a specific, relevant role in quartz reactivity during the considered industrial processes. 相似文献
37.
Since the 1960s, there has been an increasing interest in the understanding of the hydraulic flow inside a hard rock mass, since water inflow into deep tunnels constitute a hazard, in addition to being an important factor in controlling the advancement of excavation. The characterisation of fluid flow through hard rock masses is still one of the most challenging problems faced by geologists and engineers. A rock mass is characterised by networks of discrete and ubiquitous discontinuities that strongly affect its hydraulic properties, but detailed knowledge of the discontinuity properties allows for the evaluation of the hydraulic flow in the rock mass affected by the excavation of a tunnel. A geostructural field survey is fundamental in order to correctly define the discontinuity types, settings and networks. Numerous approaches have been proposed to estimate the water inflow based on empirical relations supported by field experience and case studies, as well as analytical solutions. Often, however, these approaches are not easily applicable in standard practice and in complex scenarios. The most appropriate approach to characterising the hydraulic flow of the rock mass and to predicting in the most effective way the expected water inflow during the excavation of a tunnel is based on a detailed geological model and geostructural analysis as described in this paper. 相似文献
38.
Anil Maheshwari A.N. Sial Massimo Coltorti V.K. Chittora Manoel J.M. Cruz 《Gondwana Research》2001,4(1)
The bimodal Malani suite, West of Barmer, Rajasthan is characterized by discontinuous, ring shaped outcrops of Siwana peralkaline granite with minor outcrops of basalt. The peralkaline, within- plate and A-type nature of granite are evident by its chemical characteristics. The granite is characterized by high Na2O+K2O, Fe/Mg, Zr, Nb, Y, Zn; low Al2O3, CaO and Sr and is significantly low in absolute abundance of trace and REE elements compared to type area Siwana granite. The granite is correlated to the “Pan-African” event and its petrogenesis and tectonic significance are discussed. 相似文献
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Maurizio Gemelli Massimo D'Orazio Luigi Folco 《Geostandards and Geoanalytical Research》2015,39(1):55-69
We evaluate the performance of a hand‐held XRF (HHXRF) spectrometer for the bulk analysis of iron meteorites. Analytical precision and accuracy were tested on metal alloy certified reference materials and iron meteorites of known chemical composition. With minimal sample preparation (i.e., flat or roughly polished surfaces) HHXRF allowed the precise and accurate determination of most elements heavier than Mg, with concentrations > 0.01% m/m in metal alloy CRMs, and of major elements Fe and Ni and minor elements Co, P and S (generally ranging from 0.1 to 1% m/m) in iron meteorites. In addition, multiple HHXRF spot analyses could be used to determine the bulk chemical composition of iron meteorites, which are often characterised by sulfide and phosphide accessory minerals. In particular, it was possible to estimate the P and S bulk contents, which are of critical importance for the petrogenesis and evolution of Fe‐Ni‐rich liquids and iron meteorites. This study thus validates HHXRF as a valuable tool for use in meteoritics, allowing the rapid, non‐destructive (a) identification of the extraterrestrial origin of metallic objects (i.e., archaeological artefacts); (b) preliminary chemical classification of iron meteorites; (c) identification of mislabelled/unlabelled specimens in museums and private collections and (d) bulk analysis of iron meteorites. 相似文献