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281.
A graphical approach for documenting peatland hydrodiversity and orienting land management strategies 下载免费PDF全文
Eric Rosa Pierre‐Luc Dallaire Simon Nadeau Vincent Cloutier Jean Veillette Simon van Bellen Marie Larocque 《水文研究》2018,32(7):873-890
This study focuses on the development of an approach to document the hydrological characteristics of peatlands and understand their potential influence on runoff processes and groundwater flow dynamics. Spatial calculations were performed using geographic information systems data in order to evaluate the distribution of peatlands according to (a) neighbouring hydrogeological units and (b) their position within the hydrographic network. The data obtained from these calculations were plotted in a multiple trilinear diagram (two ternary plots projected into a diamond‐shaped diagram) that illustrates the position of a given peatland within the hydrogeological environment. The data allow for the segregation of peatlands according to groups sharing similarities as well as the identification of peatlands that are most likely to have similar hydrological functions. The approach was tested in a 19,549 km2 region of the southern portion of the Barlow‐Ojibway Clay Belt (in Abitibi‐Témiscamingue, Canada) and lead to a conceptual model representing the hydrological interactions between peatlands, aquifers, and surface waters. This approach allows for a geographic information systems‐based differentiation of headwater peatland complexes that are likely to interact with aquifers and to supply continuous baseflow to small streams from lowland peatland complexes of the clay plain that are isolated from surrounding aquifers but that can act as storage reservoirs within the hydrographic network. The typology is further used to discuss land management strategies aimed at preserving peatland hydrodiversity within the study region. The proposed approach relies on widely applicable hydrogeological and hydrographic criteria and provides a tool that could be used for assessing peatland hydrodiversity in other regions of the planet. 相似文献
282.
Rachel Marie Wilson Jeffrey Chanton F. Graham Lewis Douglas Nowacek 《Estuaries and Coasts》2010,33(6):1406-1419
The goals of this study were to quantify organic matter source utilization by consumers in the freshwater-dominated region
(East Bay) of a high river flow estuary and compare the results to consumers in marine-influenced sites of the same estuary
to understand how organic matter utilization by consumers may be changing along the salinity gradient. We used the results
from these evaluations to establish the baseline against which we isotopically determined trophic level for consumers in East
Bay. Average isotope values for consumers sampled in East Bay ranged from −20.1‰ to −24.8‰ for carbon and from 8.9‰ to 14.3‰
for sulfur. These values were well-constrained by the four identified sources: plankton, benthic organic matter, macroalgae,
and terrestrial detritus. Application of a concentration-corrected mixing model resulted in contributions of benthic production
and detrital sources (averaged over the food web) to East Bay consumers of 41% and 33%, respectively, with the remainder made
up of plankton and benthic macroalage. While benthic organic matter was an important organic matter source for consumers at
both sites, we found that the influence of terrestrial detritus varied significantly throughout the bay. Terrestrial detritus
contributed only 18% of average total organic matter in organisms inhabiting marine-influenced sites. Although terrestrial
detritus did contribute to all consumers examined, most fish species in Apalachicola Bay reflect a greater reliance on autochthonous
sources. Our results suggest that, while terrestrial detritus does appear to be a major contributor to commercially important
shellfish species (most notably oysters and penaeid shrimp), it is not the major source fueling the diversity of secondary
production in Apalachicola Bay. Thus, production in Apalachicola Bay is highly dependent on riverine influx in two ways: (1)
economically important bivalves and crustaceans are being fueled by terrestrial organic matter supplied by river flooding
and (2) secondary and above consumer fish species are supported by in situ production which, in turn, is reliant on nutrients
supplied by the Apalachicola River. These findings are significant in light of decisions regarding water usage and river flow
restrictions in the Apalachicola-Chattahoochee-Flint drainage basin. The results of this study confirm that in situ estuarine
organic matter is the dominant source supporting secondary production in this river-dominated estuary. 相似文献
283.
Didier Miallier Pierre Boivin Catherine Deniel Alain Gourgaud Philippe Lanos Marie Sforna Thierry Pilleyre 《Comptes Rendus Geoscience》2010,342(11):847-854
The Puy de Dôme volcano is a trachytic lava dome, about 11,000 y old. New pyroclastic layers originating from the volcano itself were discovered covering the summit and the flanks of the volcano. These pyroclastic layers do not fit with the previous interpretation, assuming a non-explosive dome-forming eruption. The tephra display pyroclastic surge features and exhibit fresh trachytic lapilli, basement lithics, allogeneous basaltic lava and clinker fragments requiring an open vent eruption. This ultimate eruption occurred after a period of rest, long enough for vegetation to develop on the volcano, as evidenced by carbonized plant fragments. Radiocarbon dating of some of these fragments gave an age of c.10,700 y also suggesting a significant rest duration. 相似文献
284.
Anne Marie de Grosbois 《Environmental Earth Sciences》2010,61(8):1763-1765
285.
Anne Marie de Grosbois 《Environmental Earth Sciences》2010,60(7):1569-1574
Events
Upcoming international events 相似文献286.
Anne Marie de Grosbois 《Environmental Earth Sciences》2010,61(6):1325-1326
287.
288.
Anne Marie de Grosbois 《Environmental Geology》2006,51(4):665-671
Events
Upcoming International Events 相似文献289.
When using the Weather Research and Forecasting (WRF) modelling system it is necessary to choose between many parametrisations for each physics option. This study examines the performance of various physics scheme combinations on the simulation of a series of rainfall events near the south-east coast of Australia known as East Coast Lows. A thirty-six member multi-physics ensemble was created such that each member had a unique set of physics parametrisations. No single ensemble member was found to perform best for all events, variables and metrics. This is reflected in the fact that different climate variables are found to be sensitive to different physical parametrisations. While a standardised super-metric can be used to identify best performers, a step-wise decision approach described here, allows explicit recognition of the “robustness” of choosing one parameterisation over another, allowing the identification of a group of “equally robustly” performing physics combinations. These results suggest that the Mellor-Yamada-Janjic planetary boundary layer scheme and the Betts-Miller-Janjic cumulus scheme can be chosen with some robustness. Possibly with greater confidence, the results also suggest that the Yonsei University planetary boundary layer scheme, Kain-Fritsch cumulus scheme and RRTMG radiation scheme should not be used in combination in this region. Results further indicate that the selection of physics scheme options has larger impact on model performance during the more intensive rainfall events. 相似文献
290.
Roger Guérin Jean-Michel Baltassat Marie Boucher Konstantinos Chalikakis Pierre-Yves Galibert Jean-François Girard Valérie Plagnes Rémi Valois 《Comptes Rendus Geoscience》2009,341(10-11):810-817
In the framework of the management of karstic aquifers, geophysical reconnaissance can be used to locate conduits and caves, and to characterise the surrounding limestone matrix. Suitable characterisation of heterogeneities in the karstic environment is, however, challenging for ground-based geophysical methods. The present article describes the results, and evaluates the response and accuracy of combined geophysical measurements carried out at the Poumeyssen test site in France, involving electrical resistivity imaging (ERI), magnetic resonance sounding (MRS), “mise-à-la-masse” electrical mapping, and seismic tomography. This site provides the opportunity to study a relatively wide, shallow, water-filled conduit whose location and shape are known from topographic work carried out by cave divers. Seismic and MRS provided the exact location and width of the conduit, to within a few meters. The seismic and electrical data suggest that the limestone medium surrounding the conduit is not homogeneous. 相似文献