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131.
J.A. Esposito E.R. Christian V.K. Balasubrahmanyan L.M. Barbier J.F. Ormes R.E. Streitmatter B. Acharya B. Luzietti A. Hesse U. Heinbach W. Heinrich M. Henkel C. Pfeifer M. Simon 《Astroparticle Physics》1992,1(1)
A Large Isotopic Composition Experiment (ALICE) is a balloon-borne spectrometer which can determine the elemental and isotopic composition of galactic cosmic rays with energies near 1 GeV/nucleon. ALICE was flown from Prince Albert, Canada in August 1987, and remained at float altitude (120000 feet) for 14.7 hours. In this paper, we describe the experimental methods and analysis which will be used for subsequent isotopic analysis. We obtained very precise charge resolution over the entire designed range: 0.10 and 0.16 charge units at neon and iron, respectively. Results on the galactic cosmic ray abundances and absolute fluxes of the elements from neon through nickel are reported. 相似文献
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Peta-Gaye Burnett Hannah Heinrich Phil J. Bremer Christopher J. Daughney 《Geochimica et cosmochimica acta》2006,70(8):1914-1927
Numerous studies have utilized surface complexation theory to model proton adsorption behaviour onto mesophilic bacteria. However, few experiments, to date, have investigated the effects of pH and ionic strength on proton interactions with thermophilic bacteria. In this study, we characterize proton adsorption by the thermophile Anoxybacillus flavithermus by performing acid-base titrations and electrophoretic mobility measurements in NaNO3 (0.001-0.1 M). Equilibrium thermodynamics (Donnan model) were applied to describe the specific chemical reactions that occur at the water-bacteria interface. Acid-base titrations were used to determine deprotonation constants and site concentrations for the important cell wall functional groups, while electrophoretic mobility data were used to further constrain the model. We observe that with increasing pH and ionic strength, the buffering capacity increases and the electrophoretic mobility decreases. We develop a single surface complexation model to describe proton interactions with the cells, both as a function of pH and ionic strength. Based on the model, the acid-base properties of the cell wall of A. flavithermus can best be characterized by invoking three distinct types of cell wall functional groups, with pKa values of 4.94, 6.85, and 7.85, and site concentrations of 5.33, 1.79, and 1.42 × 10−4 moles per gram of dry bacteria, respectively. A. flavithermus imparts less buffering capacity than pure mesophilic bacteria studied to date because the thermophile possesses a lower total site density (8.54 × 10−4 moles per dry gram bacteria). 相似文献
134.
George D. Miron Thomas Wagner Markus Wälle Christoph A. Heinrich 《Contributions to Mineralogy and Petrology》2013,165(5):981-1008
The chemical composition of fluid inclusions in quartz crystals from Alpine fissure veins was determined by combination of microthermometry, Raman spectroscopy, and LA-ICPMS analysis. The veins are hosted in carbonate-bearing, organic-rich, low-grade metamorphic metapelites of the Bündnerschiefer of the eastern Central Alps (Switzerland). This strongly deformed tectonic unit is interpreted as a partly subducted accretionary wedge, on the basis of widespread carpholite assemblages that were later overprinted by lower greenschist facies metamorphism. Veins and their host rocks from two locations were studied to compare several indicators for the conditions during metamorphism, including illite crystallinity, graphite thermometry, stability of mineral assemblages, chlorite thermometry, fluid inclusion solute thermometry, and fluid inclusion isochores. Fluid inclusions are aqueous two-phase with 3.7–4.0 wt% equivalent NaCl at Thusis and 1.6–1.7 wt% at Schiers. Reproducible concentrations of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, B, Al, Mn, Cu, Zn, Pb, As, Sb, Cl, Br, and S could be determined for 97 fluid inclusion assemblages. Fluid and mineral geothermometry consistently indicate temperatures of 320 ± 20 °C for the host rocks at Thusis and of 250 ± 30 °C at Schiers. Combining fluid inclusion isochores with independent geothermometers results in pressure estimates of 2.8–3.8 kbar for Thusis, and of 3.3–3.4 kbar for Schiers. Pressure–temperature estimates are confirmed by pseudosection modeling. Fluid compositions and petrological modeling consistently demonstrate that chemical fluid-rock equilibrium was attained during vein formation, indicating that the fluids originated locally by metamorphic dehydration during near-isothermal decompression in a rock-buffered system. 相似文献
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Empirical-statistical downscaling and error correction of regional climate models and its impact on the climate change signal 总被引:7,自引:3,他引:4
Realizing the error characteristics of regional climate models (RCMs) and the consequent limitations in their direct utilization
in climate change impact research, this study analyzes a quantile-based empirical-statistical error correction method (quantile
mapping, QM) for RCMs in the context of climate change. In particular the success of QM in mitigating systematic RCM errors,
its ability to generate “new extremes” (values outside the calibration range), and its impact on the climate change signal
(CCS) are investigated. In a cross-validation framework based on a RCM control simulation over Europe, QM reduces the bias
of daily mean, minimum, and maximum temperature, precipitation amount, and derived indices of extremes by about one order
of magnitude and strongly improves the shapes of the related frequency distributions. In addition, a simple extrapolation
of the error correction function enables QM to reproduce “new extremes” without deterioration and mostly with improvement
of the original RCM quality. QM only moderately modifies the CCS of the corrected parameters. The changes are related to trends
in the scenarios and magnitude-dependent error characteristics. Additionally, QM has a large impact on CCSs of non-linearly
derived indices of extremes, such as threshold indices. 相似文献
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140.
Horst R. Marschall Christian Meyer Bernd Wunder Thomas Ludwig Wilhelm Heinrich 《Contributions to Mineralogy and Petrology》2009,158(5):675-681
Tourmaline synthesised in an experiment with low boron excess was analysed in situ by secondary ion mass spectrometry. It
revealed significant B isotope zonation with 11B/10B ratios increasing in the growth direction of the crystals. Trend, magnitude and absolute values strongly support results
from high-B-excess isotope fractionation experiments. Furthermore, the closed system B-isotopic evolution of the experimental
fluid was modelled by Rayleigh fractionation. The model results are in excellent agreement with the measured B-isotope composition
of the run-product fluid. Consequently, low-element-excess experiments are proposed as an ideal approach to determine fluid-solid
isotope fractionation factors for systems that are characterised by Rayleigh fractionation. 相似文献