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331.
Hamza Valiya M. Vieira Fabio P. Silva Raquel T. A. 《International Journal of Earth Sciences》2018,107(1):19-33
International Journal of Earth Sciences - A comprehensive analysis of thermal gradient and heat flow data was carried out for sedimentary basins situated in the continental margin of Brazil (CMB).... 相似文献
332.
Alessandro Tibaldi Fabio Luca Bonali Federico Aligi Pasquaré Derek Rust Alessandro Cavallo Alessandro D’Urso 《Bulletin of Volcanology》2013,75(11):1-16
A detailed understanding of pāhoehoe emplacement is necessary for developing accurate models of flow field development, assessing hazards, and interpreting the significance of lava morphology on Earth and other planetary surfaces. Active pāhoehoe lobes on Kīlauea Volcano, Hawai'i, were examined on 21–26 February 2006 using oblique time series stereo-photogrammetry and differential global positioning system measurements. During this time, the local discharge rate for peripheral lava lobes was generally constant at 0.0061?±?0.0019 m3/s, but the areal coverage rate of the lobes exhibited a periodic increase every 4.13?±?0.64 min. This periodicity is attributed to the time required for the pressure within the liquid lava core to exceed the cooling-induced strength of its margins. The pāhoehoe flow advanced through a series of down-slope and cross-slope breakouts, which began as ~0.2-m-thick units (i.e., toes) that coalesced and inflated to become approximately meter-thick lobes. The lobes were thickest above the lowest points of the initial topography and above shallow to reverse-facing slopes, defined relative to the local flow direction. The flow path was typically controlled by high-standing topography, with the zone directly adjacent to the final lobe margin having an average relief that was a few centimeters higher than the lava-inundated region. This suggests that toe-scale topography can, at least temporarily, exert strong controls on pāhoehoe flow paths by impeding the lateral spreading of the lobe. Observed cycles of enhanced areal spreading and inflated lobe morphology are also explored using a model that considers the statistical likelihood of sequential breakouts from active flow margins and the effects of topographic barriers. 相似文献
333.
Giancarlo Della Ventura Francesco Radica Fabio Bellatreccia Andrea Cavallo Francesco Capitelli Simon Harley 《Contributions to Mineralogy and Petrology》2012,164(5):881-894
We report a FTIR (Fourier transform infrared) study of a set of cordierite samples from different occurrence and with different H2O/CO2 content. The specimens were fully characterized by a combination of techniques including optical microscopy, single-crystal X-ray diffraction, EMPA (electron microprobe analysis), SIMS (secondary ion mass spectrometry), and FTIR spectroscopy. All cordierites are orthorhombic Ccmm. According to the EMPA data, the Si/Al ratio is always close to 5:4; X Mg ranges from 76.31 to 96.63, and additional octahedral constituents occur in very small amounts. Extraframework K and Ca are negligible, while Na reaches the values up to 0.84 apfu. SIMS shows H2O up to 1.52 and CO2 up to 1.11 wt%. Optically transparent single crystals were oriented using the spindle stage and examined by FTIR micro-spectroscopy under polarized light. On the basis of the polarizing behaviour, the observed bands were assigned to water molecules in two different orientations and to CO2 molecules in the structural channels. The IR spectra also show the presence of small amounts of CO in the samples. Refined integrated molar absorption coefficients were calibrated for the quantitative microanalysis of both H2O and CO2 in cordierite based on single-crystal polarized-light FTIR spectroscopy. For H2O the integrated molar coefficients for type I and type II water molecules (ν3 modes) were calculated separately and are [I]ε?=?5,200?±?700?l?mol?1?cm?2 and [II]ε?=?13,000?±?3,000?l?mol?1?cm?2, respectively. For CO2 the integrated coefficient is $ \varepsilon_{{{\text{CO}}_{ 2} }} $ ?=?19,000?±?2,000?l?mol?1?cm?2. 相似文献
334.
Naoual Gamrani Khalid R’kha Chaham Mouncif Ibnoussina Fabio Fratini Luisa Rovero Ugo Tonietti Mohammed Mansori Lehcen Daoudi Claude Favotto Nasrrddine Youbi 《Environmental Earth Sciences》2012,66(1):129-140
This work focuses on the building material used in the Saadian sugar refinery of Chichaoua (about 70 km southwest of Marrakesh).
The study involved a classification of different types of rammed earth, followed by their mineralogical characterization based
on optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). These studies are complemented by chemical
investigations, X-ray fluorescence, and thermal analysis (DTA and TGA). The results demonstrate the use of two types of earth
for the realisation of rammed earth, the first one non-plastic, -grained with added lime, the other one of low plasticity,
and fine grained without addition of lime. Mechanical tests on site and in laboratory how at the first type of material exhibits
great strength, exceeding the values known for rammed earth. 相似文献
335.
336.
337.
Adriatic ‘opisthobranchs’ (Gastropoda,Heterobranchia): shedding light on biodiversity issues 下载免费PDF全文
Argyro Zenetos Vesna Mačić Andrej Jaklin Lovrenc Lipej Dimitris Poursanidis Riccardo Cattaneo‐Vietti Sajmir Beqiraj Federico Betti Diego Poloniato Lefter Kashta Stelios Katsanevakis Fabio Crocetta 《Marine Ecology》2016,37(6):1239-1255
We herein review the Adriatic opisthobranch fauna, provide an updated checklist of 223 species and assess their distribution at regional and country levels. New Adriatic records are provided for 67 opisthobranch taxa, adding three new records for the Italian coastline, five new records for Albania, eight for Croatia and 15 for Montenegro. The presence of Hermaea bifida (Montagu, 1815), Hermaea variopicta (Costa A., 1869) and Facelina annulicornis (Chamisso & Eysenhardt, 1821) is reported for the first time from anywhere in the Adriatic Sea. Including the new findings, our inventory includes 28 species from Albania, 163 from Croatia, 178 from the Italian coastline of the Adriatic, 41 from Montenegro and 74 from Slovenia. No records were available from Bosnia and Hercegovina. Ninety species (40.4%) are widespread, and were recorded from all three main divisions (Northern, Western and Eastern Adriatic), whilst 79 species (35.4%) were reported from only one of them. At sub‐division levels, the Albanian inventory is the most dissimilar to the other country/regional lists, presumably because of the lack of targeted field surveys. The highest similarity is observed amongst the Western Adriatic, Croatia and the Italian Ionian coastline. Seven alien, one possible alien and three cryptogenic opisthobranchs were reliably recorded from the Adriatic Sea. The first Mediterranean records of five species were in the Adriatic Sea, of which four species have not been found elsewhere in the Mediterranean. Shipping and aquaculture are the probable pathways for most of the alien species. A steady rate of one to two alien introductions per decade since the 1970s was evident. The Northern Adriatic coasts are the most affected by alien invasions, probably due to repeated local introductions along with shellfish transfers (oysters, mussels, Manila clams), and heavy maritime transport. 相似文献
338.
Fabio Zulbati 《Geological Journal》2011,46(1):82-103
Metabasites from the northern Adula Nappe Complex (ANC) display a complex microstructural evolution recording episodes of deformation and metamorphic re‐equilibration that were obliterated in the surrounding phengite‐bearing schists. Pre‐D1 and D1 deformation episodes are preserved as mineral inclusions within garnet cores of some amphibole‐bearing eclogites and record high‐temperature greenschist‐/amphibolite‐facies conditions. D2 produced an eclogite‐facies foliation which developed at 580 ± 70°C and 19 ± 3 kbar. D3 was a composite deformation episode which can be divided into three sub‐episodes D3m, D3a and D3b which occurred as the metamorphism evolved from post‐eclogitic high‐pressure and low‐temperature conditions through to amphibolite‐facies conditions at 590 ± 30°C and 11.7 ± 1.3 kbar. The D3 deformation episode was responsible for the development of the S3 regional‐scale foliation in the surrounding schists, whilst D4 caused the development of an S4 greenschist foliation. The composite nature of the D3 episode indicates that rocks of the northern ANC experienced a protracted post‐eclogitic structural reworking and that the current structure of this part of the Alps is a late‐Alpine feature. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
339.
Marco Maffione Stefano Pucci Leonardo Sagnotti Fabio Speranza 《International Journal of Earth Sciences》2012,101(3):849-861
Anisotropy of magnetic susceptibility (AMS) represents a valuable proxy able to detect subtle strain effects in very weakly
deformed sediments. In compressive tectonic settings, the magnetic lineation is commonly parallel to fold axes, thrust faults,
and local bedding strike, while in extensional regimes, it is perpendicular to normal faults and parallel to bedding dip directions.
The Altotiberina Fault (ATF) in the northern Apennines (Italy) is a Plio-Quaternary NNW–SSE low-angle normal fault; the sedimentary
basin (Tiber basin) at its hanging-wall is infilled with a syn-tectonic, sandy-clayey continental succession. We measured
the AMS of apparently undeformed sandy clays sampled at 12 sites within the Tiber basin. The anisotropy parameters suggest
that a primary sedimentary fabric has been overprinted by an incipient tectonic fabric. The magnetic lineation is well developed
at all sites, and at the sites from the western sector of the basin it is oriented sub-perpendicular to the trend of the ATF,
suggesting that it may be related to extensional strain. Conversely, the magnetic lineation of the sites from the eastern
sector has a prevailing N–S direction. The occurrence of triaxial to prolate AMS ellipsoids and sub-horizontal magnetic lineations
suggests that a maximum horizontal shortening along an E–W direction occurred at these sites. The presence of compressive
AMS features at the hanging-wall of the ATF can be explained by the presence of gently N–S-trending local folds (hardly visible
in the field) formed by either passive accommodation above an undulated fault plane, or rollover mechanism along antithetic
faults. The long-lasting debate on the extensional versus compressive Plio-Quaternary tectonics of the Apennines orogenic
belt should now be revised taking into account the importance of compressive structures related to local effects. 相似文献
340.
The NCEP twentieth century reanalyis and a 500-year control simulation with the IPSL-CM5 climate model are used to assess the influence of ocean-atmosphere coupling in the North Atlantic region at seasonal to decadal time scales. At the seasonal scale, the air-sea interaction patterns are similar in the model and observations. In both, a statistically significant summer sea surface temperature (SST) anomaly with a horseshoe shape leads an atmospheric signal that resembles the North Atlantic Oscillation (NAO) during the winter. The air-sea interactions in the model thus seem realistic, although the amplitude of the atmospheric signal is half that observed, and it is detected throughout the cold season, while it is significant only in late fall and early winter in the observations. In both model and observations, the North Atlantic horseshoe SST anomaly pattern is in part generated by the spring and summer internal atmospheric variability. In the model, the influence of the ocean dynamics can be assessed and is found to contribute to the SST anomaly, in particular at the decadal scale. Indeed, the North Atlantic SST anomalies that follow an intensification of the Atlantic meridional overturning circulation (AMOC) by about 9 years, or an intensification of a clockwise intergyre gyre in the Atlantic Ocean by 6 years, resemble the horseshoe pattern, and are also similar to the model Atlantic Multidecadal Oscillation (AMO). As the AMOC is shown to have a significant impact on the winter NAO, most strongly when it leads by 9 years, the decadal interactions in the model are consistent with the seasonal analysis. In the observations, there is also a strong correlation between the AMO and the SST horseshoe pattern that influences the NAO. The analogy with the coupled model suggests that the natural variability of the AMOC and the gyre circulation might influence the climate of the North Atlantic region at the decadal scale. 相似文献