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191.
Anna Belehaki Ivan Kutiev Bodo Reinisch Norbert Jakowski Pencho Marinov Ivan Galkin Chris Mayer Ioanna Tsagouri Themistocles Herekakis 《Acta Geophysica》2010,58(3):432-452
The purpose of this paper is to evaluate the performance of the TSMP-assisted Digisonde (TaD) topside profiling technique.
We present systematic comparisons between electron density profiles and TEC parameters extracted from TaD model with (a) CHAMP-derived TEC parameters, (b) CHAMP reconstructed profiles, (c) ground based GPSderived TEC parameters, and (d) profiles reconstructed from RPI/IMAGE plasmagrams. In all cases, TaD follows the general trend of plasmaspheric
observations derived from the above datasets. Especially during storm cases, TaD shows remarkable agreement with the variations
of the ground based GPS-derived TEC parameters. Overall, the comparison results shows that TaD method can be adopted by EURIPOS to provide the electron density
distribution up to plasmaspheric heights in real-time. 相似文献
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193.
Gabriel Katul Olli Peltola Tiia Grönholm Samuli Launiainen Ivan Mammarella Timo Vesala 《Boundary-Layer Meteorology》2018,169(2):163-184
The three turbulent velocity components, water vapour (\(\text {H}_2\text {O}\)), carbon dioxide (\(\text {CO}_{2}\)), and methane (\(\text {CH}_{4}\)) concentration fluctuations are measured above a boreal peatland and analyzed using conditional sampling and quadrant analysis. The overarching question to be addressed is to what degree lower-order cumulant expansion methods describe transport efficiency and the relative importance of ejections and sweeps to momentum, \(\text {CH}_{4}\), \(\text {CO}_{2}\) and \(\text {H}_2\text {O}\) fluxes across a range of atmospheric flow regimes. The patchy peatland surface creates distinctly different source and sink distributions for the three scalars in space and time thereby adding to the uniqueness of the set-up. The measured and modelled fractional contributions to the momentum flux show that sweep events dominate over ejections in agreement with prior studies conducted in the roughness sublayer. For scalar fluxes, ejections dominate the turbulent fluxes over sweeps. While ejective motions persist longer for momentum transport, sweeping events persist longer for all three scalars. Third-order cumulant expansions describe many of the results detailed above, and the results are surprising given the highly non-Gaussian distribution of \(\text {CH}_{4}\) turbulent fluctuations. Connections between the asymmetric contributions of sweeps and ejections and the flux-transport term arising in scalar turbulent-flux-budget closure are derived and shown to agree reasonably well with measurements. The proposed model derived here is much simpler than prior structural models used to describe laboratory experiments. Implications of such asymmetric contributions on, (i) the usage of the now proliferating relaxed-eddy-accumulation method in turbulent flux measurements, (ii) the constant-flux assumption, and (iii) gradient-diffusion closure models are presented. 相似文献
194.
Giant versus small porphyry copper deposits of Cenozoic age in northern Chile: adakitic versus normal calc-alkaline magmatism 总被引:63,自引:0,他引:63
Roberto Oyarzun Alvaro Márquez Javier Lillo Ivan López Sergio Rivera 《Mineralium Deposita》2001,36(8):794-798
Cenozoic magmatic activity in northern Chile led to the formation of two contrasting porphyry copper belts: (1) a Paleocene-Early Eocene belt comprising small porphyry copper deposits (e.g., Lomas Bayas) of normal calc-alkaline affinity; and (2) a Late Eocene-Early Oligocene belt hosting huge porphyry copper deposits (e.g., Chuquicamata) of adakitic affinity. Although the first belt comprises both volcanic and plutonic rocks (andesitic-basaltic and rhyolitic lavas and tuffs, and associated sub-volcanic porphyries and felsic stocks), the latter only includes intrusions (mostly granodioritic types, including porphyry copper deposits). We suggest that the Late Eocene-Early Oligocene belt formed when fast and oblique convergence between the South America and Farallon plates led to flat subduction and direct melting of the subducting plate, hence giving rise to plutonic rocks of adakitic affinity. The absence of volcanism, under prevailing compressional conditions, prevented the escape of SO2 from the adakitic, sulfur-rich, highly oxidized magmas ("closed porphyry system"), which allowed formation of huge mineral deposits. On the contrary, coeval volcanic activity during formation of the Paleocene-Early Eocene calc-alkaline porphyries allowed development of "open systems", hence to outgassing, and therefore, to small mineral deposits. 相似文献
195.
Pirin Erdodu Ofer Lahav Saleem Zaroubi George Efstathiou Steve Moody John A. Peacock Matthew Colless Ivan K. Baldry Carlton M. Baugh Joss Bland-Hawthorn Terry Bridges Russell Cannon Shaun Cole Chris Collins Warrick Couch Gavin Dalton Roberto De Propris Simon P. Driver Richard S. Ellis Carlos S. Frenk Karl Glazebrook Carole Jackson Ian Lewis Stuart Lumsden Steve Maddox Darren Madgwick Peder Norberg Bruce A. Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2004,352(3):939-960
196.
Summary . The most complicated part in the computation of ray amplitudes of seismic body waves in laterally inhomogeneous media with curved interfaces lies in the evaluation of the geometrical spreading. Geometrical spreading can be simply expressed in terms of the Jacobian J of the transformation from the Cartesian into ray coordinates. Several systems of ordinary differential equations to compute the function J are suggested. For general three-dimensional media, in which the velocity changes with all the three spatial coordinates, a system of three non-linear ordinary differential equations of the first order is derived. If the velocity does not depend on one coordinate, the system of equations reduces to only one non-linear differential equation. The initial conditions for these differential equations at point (or line) source and at points of intersection of the ray with curved interfaces are presented. 相似文献
197.
198.
199.
Lopez Ivan Oyarzun Roberto Marquez Alvaro Doblas-Reyes Francisco Laurrieta Alejandro 《Earth, Moon, and Planets》1998,81(3):187-192
In absence of other mechanisms, the main input of CO2into the Venusian atmosphere is via volcanic out gassing. Since Venus can be regarded as a planet-wide large igneous province,
we can expect large quantities of CO2 being transferred into its atmosphere via volcanic out gassing. We have quantified the maximum possible amount of CO2 that can be out gassed via a single massive episode of resurfacing of the planet. This figure (5.6 × 1019 kg of CO2) is about 8 times smaller than the total CO2 present in the Venusian atmosphere (4.55 × 1020 kg CO2). The lack of planet-wide, efficient mechanisms for the recycling of CO2 on Venus indicates that CO2 has progressively accumulated in the atmosphere. Based on these considerations we suggest that the “equivalent” to eight
global resurfacing episodes would be required to account for the present values of CO2 atmosphere.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
200.
Golem Petar Toman Ivan Večenaj Željko Kozmar Hrvoje Grisogono Branko 《Boundary-Layer Meteorology》2022,183(3):495-504
Boundary-Layer Meteorology - Unique data from a 100-m meteorological mast located on the windward side of the Dinaric Alps, Croatia, are compared to high-resolution Weather Research and Forecasting... 相似文献