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361.
First Late Triassic Record of a Paleoentomofauna from South America(Malargüe Basin,Mendoza Province,Argentina) 总被引:1,自引:0,他引:1
Carsten BRAUCKMANN Oscar F. GALLEGO Norbert HAUSCHKE Rafael G. MARTINS-NETO Elke GROENING Jan-M. ILGER María B. LARA 《《地质学报》英文版》2010,84(4):915-924
<正>Late Middle Triassic to early Late Triassic insects from Argentina have been previously described from the Bermejo and Cuyana Basins where they have been recovered from the Ischichuca-Los Rastros and Potrerillos-Cacheuta Formations,respectively.The insect fauna discussed herein was collected during field studies in 1986/1987 from the Llantenes section(Norian to Rhaetian? Late Triassic),which is situated in the Malargue Basin in southern Mendoza province.The insect remains were found in the upper part of the Llantenes section (Llantenes Formation),which is built up of two coarsening-upwards cycles reflecting a deltaic progradation of a fluvial into a lacustrine environment(lower part),succeeded by repeated progradations into a floodplain-dominated environment(upper part;with finds of insects,conchostracans,fish remains,plant fragments,and drifted logs).The new finds represent the youngest Triassic insect records described from Argentina and even from South America in its entirety.There is only one contemporaneous fossil assemblage in Gondwana:in the Clarence/Moreton Basin(Aberdare Conglomerate;Late Norian)in Australia.The new Triassic insects include an impression of an isolated Mecopterida-like wing(Mendozachorista volkheimeri gen.et sp.nov.; Mendozachoristidae fam.nov.),coleopteran elytra of the Permosynidae(Ademosyne rosenfeldi sp.nov.and Ademosyne llantenesensis sp.nov.)and other isolated body fragments.This new Late Triassic entomofauna from Argentina is of considerable importance in the reconstruction of the biotic recovery of continental environments in Gondwana after the catastrophic mass extinction at the P/T boundary. 相似文献
362.
Heavy metal mobility assessment in sediments from the Odiel River (Iberian Pyritic Belt) using sequential extraction 总被引:1,自引:1,他引:0
Rafael Beltrán J. D. de la Rosa J. C. Santos M. Beltrán J. L. Gómez-Ariza 《Environmental Earth Sciences》2010,61(7):1493-1503
The Tessier sequential extraction scheme (SES) was applied to sediments from the Odiel river catchment (Iberian Pyritic Belt,
SW of Spain), one of the most acid rivers on Earth, to assess the chemical association (exchangeable, carbonatic, bound to
manganese and iron oxides, bound to organic matter and residual mineral) of heavy metals (Zn, Cd, Pb, Cu, Cr, Mn, Ni, Fe,
and Hg). Sediments are very heterogeneous in their textural characteristics, showing different grain size. Twenty-seven samples
were studied from from areas along the Odiel River, from the source to the mouth, with special interest in the Odiel Marshes
Natural Park due to its ecological significance. Samples were classified as sandy (especially at the river mouth with low
iron oxide and organic matter content) and clay-silty (in the middle of the river catchment with high iron oxide content).
The numerous sandy samples with low pH values explain the low levels of metals upstream, although potential metals contributions
arise from mining and ore. However, the presence of sulfate in the mining area and carbonate at the mouth may explain the
high presence of lead and iron in these sandy zones. Some percentage of mobile Ni, Cu, and Zn were detected in the mining
area, but the elevated relative percentage of exchangeable Cd in the estuary is even more remarkable. The percentage of Zn
bound to carbonate is considerable in the catchment but especially in the estuary. However, Cu is only detected in the carbonate
phase downstream, in spite of the low concentration of carbonate, which represents a drawback in the application of the Tessier
SES to these types of samples. Finally, relatively high percentages of residual, non-mobile, Hg and Pb were observed, in the
estuarine and mining areas, respectively. Sand, lime, and clay fractions of representative samples from Areas I, II, and III
were used in a metal speciation study. Mainly, the elements analyzed had accumulated in the non-residual fractions. In the
mining area of the Pyrite Belt, the elements analyzed are mainly bound to Fe–Mn oxides (Fe + Mn + Cu + Cr + Pb + Mn ± Zn)
and the organic matter/sulfide fraction (Ni + Zn + Hg ± Cd), independent of sediment grain size. In conclusion, we show that
the results of the study of chemical speciation in sediments from acid rivers are independent of the sediment grain size considered. 相似文献
363.
Rafael Pérez-López José Miguel Nieto Israel López-Coto Juan Luis Aguado Juan Pedro Bolívar María Santisteban 《Applied Geochemistry》2010
The dynamics of trace elements from phosphate rock ore to the environment in a phosphoric acid plant located in SW Spain and the impact of phosphogypsum wastes were investigated through total digestion and BCR-sequential extraction. Based on total concentration, element transfer factors as criteria for examining the potential environmental risk of waste with respect to ore rock were calculated, and it was observed that most trace elements are only transferred into phosphogypsum at rates of 2–12%. However, based on those concentrations that are likely to be most readily mobile in the environment, phosphogypsum acts as a higher emission source of contaminants than the original rock. About 100 million tonnes of phosphogypsum are stack-piled in a dump of 1200 ha over salt-marshes of an estuary formed by the confluence of the Tinto and Odiel rivers. Phosphogypsum has been applied, at the recommended rate of 20–25 t/ha since 1978–2001, to improve fertility and reduce Na saturation in agricultural soils of the Guadalquivir river valley (140 km2). Phosphogypsum capacity as a source of mobile contaminants in three environmental scenarios (water leaching, exposure to oxidising and reducing conditions) was quantified by combining sequential extraction and waste mass. The amounts of mobile contaminants that could be released for every tonne of phosphogypsum are approximately 7 × 102 g Sr, 1.1 × 102 g Fe, 55 g Y, 30 g Ce, 12 g Cr, 11 g Ti, 5 g Zn, 4 g each of Cu and Pb, 3 g each of V and Cd, 2 g each of As and Ni and 1 g U. Multiplying these amounts by 100 Mt and 20–25 t/ha, it is possible to calculate risk assessments of phosphogypsum for both estuarine zones, e.g. in a hypothetical stack collapse and waste spilling, and agricultural soils, respectively. 相似文献
364.
365.
Branimir egvi Lucijana eelj Damir Slovenec Boko Lugovi Rafael Ferreiro Mhlmann 《Geoarchaeology》2012,27(1):63-87
Archaeological excavations in Dalmatia have yielded a large amount of Hellenistic pottery that has yet to be archaeometrically analyzed. Stylistic analyses suggest that some vessels were imported, but the bulk of the material must have been produced locally. Our objectives are to demonstrate local ceramic production in both Greek colonies and native settlements in Dalmatia, and also to report on the composition and manufacture technology associated with this pottery. We examine 36 Hellenistic potsherds recovered from the coast of Croatia: a sanctuary on Cape Ploča, the native settlement of Resnik, and the Greek colony Issa. For the first time, archaeometric evidence supporting local production in Resnik is presented, while two local manufacturing centers are proposed for the bulk of the Cape Ploča pottery. The term Dalmatian production is suggested here to describe these indigenous ceramics. Material characteristics of the Issa samples suggest local colonial production and sophisticated ceramic technology. 相似文献