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91.
Under the impression of decreasing ore grades and increasing production costs in conventional mining, seafloor minerals came into focus. Having gained a basic understanding of geological settings, there is still a lack of tools to assess and plan future mining projects in the deep-sea. This paper contributes to a mining concept which is inspired by the high-tech farming industry: strip mining. Potential mining fields are identified using image filters in conjunction with hydroacoustic backscatter data and slope angles and are portioned into long, narrow strips. In the framework of the EU-funded Blue Mining project, these methods were applied to a part of the eastern German exploration area, located in the manganese nodule belt of the Clarion Clipperton Zone, Pacific Ocean. Both, the mapping technique and the mining concept presented in this paper can be used in early-stage feasibility studies to derive estimates on production key figures for seafloor manganese nodule mining. 相似文献
92.
John D. Monnier Stefan Kraus Michael J. Ireland Fabien Baron Amelia Bayo Jean-Philippe Berger Michelle Creech-Eakman Ruobing Dong Gaspard Duchêne Catherine Espaillat Chris Haniff Sebastian Hönig Andrea Isella Attila Juhasz Lucas Labadie Sylvestre Lacour Stephanie Leifer Antoine Merand Ernest Michael Stefano Minardi Christoph Mordasini David Mozurkewich Johan Olofsson Claudia Paladini Romain Petrov Jörg-Uwe Pott Stephen Ridgway Stephen Rinehart Keivan Stassun Jean Surdej Theo ten Brummelaar Neal Turner Peter Tuthill Kerry Vahala Gerard van Belle Gautam Vasisht Ed Wishnow John Young Zhaohuan Zhu 《Experimental Astronomy》2018,46(3):517-529
The Planet Formation Imager (PFI, www.planetformationimager.org) is a next-generation infrared interferometer array with the primary goal of imaging the active phases of planet formation in nearby star forming regions. PFI will be sensitive to warm dust emission using mid-infrared capabilities made possible by precise fringe tracking in the near-infrared. An L/M band combiner will be especially sensitive to thermal emission from young exoplanets (and their disks) with a high spectral resolution mode to probe the kinematics of CO and H2O gas. In this paper, we give an overview of the main science goals of PFI, define a baseline PFI architecture that can achieve those goals, point at remaining technical challenges, and suggest activities today that will help make the Planet Formation Imager facility a reality. 相似文献
93.
Sebastian F. Hönig Almudena Alonso Herrero Poshak Gandhi Makoto Kishimoto Jörg-Uwe Pott Cristina Ramos Almeida Jean Surdej Konrad R. W. Tristram 《Experimental Astronomy》2018,46(3):413-419
Infrared (IR) interferometry has made widely recognised contributions to the way we look at the dusty environment of supermassive black holes on parsec scales. It finally provided direct evidence for orientation-dependent unification of active galaxies, however it also showed that the classical “torus” picture is oversimplified. New scientific opportunities for AGN have been suggested, and will soon be carried out, focusing on the dynamical aspects of spectrally and spatially resolved interferometry, as well as the potential to employ interferometry for cosmology. This will open interferometry to new scientific communities. 相似文献
94.
Arne Lohrberg Klaus Schwarzer Daniel Unverricht Andreas Omlin Sebastian Krastel 《第四纪科学杂志》2020,35(7):892-906
Tunnel valleys are assumed to form near the margin of ice sheets. Hence, they can be used to reconstruct the dynamics of former ice margins. The detailed formation and infill of tunnel valleys, however, are still not well understood. Here, we present a dense grid of high-resolution 2D multi-channel reflection seismic data from the German sector of the southeastern North Sea imaging tunnel valleys in very great detail. Three tunnel valley systems were traced over distances ranging between 11 and 21 km. All tunnel valleys are completely filled and buried. They differ in incision depth, incision width and number of incisions. The tunnel valleys cut 130–380 m deep into Neogene, Palaeogene and Cretaceous sediments; they show a lower V-shaped and an upper U-shaped morphology. For individual tunnel valleys, the overall incision direction ranges from east–west to northeast–southwest. Two tunnel valleys intersect at an oblique angle without reuse of the thalweg. These valleys incise into a pre-existing glaciotectonic complex consisting of thrust sheets in the northwest of the study area. The analysis of the glaciotectonic complex and the tunnel valleys leads us to assume that we identified several marginal positions of (pre-)Elsterian ice lobes in the southeastern North Sea. 相似文献
95.
Global assessment of the European Union fishing fleet: An update 总被引:1,自引:0,他引:1
This paper provides a global analysis of recent trends in the EU fishing fleet. Analysis of the capital productivity, labour rates, and economic benefits of the fleet revealed that considerable replacement of fishermen by better technology and well-equipped vessels occurred between 1990 and 2006. The analysis confirms that the Common Fisheries Policy (CFP) has been ineffective in reducing fishing capacity. In addition, the changes in capacity that occurred in this time interval differed among the different sectors of the fleet. Some members of the high sea fishing fleet increased their capacity (range 11–57%), and the deep-sea sector, which has greater tonnage and fishing power, increased its fishing capacity by 34–44%. These results confirm the ineffectiveness of the CFP in reducing overcapacity and illustrate the continuing threat of overcapacity to the long-term sustainability of fishery resources. 相似文献
96.
Andrew C. Hill Peter W. Haines Kathleen Grey Sebastian Willman 《Meteoritics & planetary science》2007,42(11):1883-1891
Abstract— New occurrences of the Acraman impact ejecta layer were recently discovered in two South Australian drillholes, SCYW‐79 1a (Stuart Shelf) and Munta 1 (Officer Basin) using lithostratigraphy, acritarch biostratigraphy, carbon isotope stratigraphy, and biomarker anomalies to predict the stratigraphic position. The ejecta layer is conspicuous because it consists of pink, sandsized, angular fragments of volcanic rock distributed along the bedding plane surface of green marine siltstone. In SCYW‐79 1a it forms a layer 5 mm thick; in Munta 1 the ejecta layer is thin and discontinuous because of its distance (?550 km) from the impact structure. Palynological, biomarker, and carbon isotope anomalies can now be shown to coincide with the ejecta layer in SCYW‐79 1a and Munta 1 suggesting the Acraman impact event may have had far reaching influences on the rapidly evolving Ediacaran biological and geochemical cycles. 相似文献
97.
Esther Hintersberger Frank Scherbaum Sebastian Hainzl 《Bulletin of Earthquake Engineering》2007,5(1):1-16
Scherbaum et al. [(2004) Bull Seismolo Soc Am 94(6): 2164–2185] proposed a likelihood-based approach to select and rank ground-motion
models for seismic hazard analysis in regions of low-seismicity. The results of their analysis were first used within the
PEGASOS project [Abrahamson et al. (2002), In Proceedings of the 12 ECEE, London, 2002, Paper no. 633] so far the only application
of a probabilistic seismic hazard analysis (PSHA) in Europe which was based on a SSHAC Level 4 procedure [(Budnitz et al.
1997, Recommendations for PSHA: guidance on uncertainty and use of experts. No. NUREG/CR-6372-V1). The outcome of this project
have generated considerable discussion (Klügel 2005, Eng Geol 78:285–307, 2005b) Eng Geol 78: 285–307, (2005c) Eng Geol 82:
79–85 Musson et al. (2005) Eng Geol 82(1): 43–55]; Budnitz et al. (2005), Eng Geol 78(3–4): 285–307], a central part of which
is related to the issue of ground-motion model selection and ranking. Since at the time of the study by Scherbaum et al. [(2004.)
Bull Seismolo Soc Am 94(6): 2164–2185], only records from one earthquake were available for the study area, here we test the
stability of their results using more recent data. Increasing the data set from 12 records of one earthquake in Scherbaum
et al. [(2004) Bull Seismolo Soc Am 94(6): 2164–2185] to 61 records of 5 earthquakes, which have mainly occurred since the
publication of the original study, does not change the set of the three top-ranked ground-motion models [Abrahamson and Silva
(1997) Seismolo Res Latt 68(1): 94–127; Lussou et al. (2001) J Earthquake Eng 5(1):13–33; Berge-Thierry et al. (2003) Bull
Seismolog Soc Am 95(2): 377–389. Only for the lower-ranked models do we obtain modifications in the ranking order. Furthermore,
the records from the Waldkirch earthquake (Dec, 5th, 2004, M
w = 4.9) enabled us to develop a new stochastic model parameter set for the application of Campbell’s [(2003) Bull Seismolo
Soc Am 93(3): 1012–1033] hybrid empirical model to SW Germany and neighbouring regions. 相似文献
98.
Permeability and degassing of dome lavas undergoing rapid decompression: An experimental determination 总被引:1,自引:1,他引:0
Sebastian Mueller Oleg Melnik Oliver Spieler Bettina Scheu Donald B. Dingwell 《Bulletin of Volcanology》2005,67(6):526-538
The gas permeability of volcanic rocks may influence various eruptive processes. The transition from a quiescent degassing dome to rock failure (fragmentation) may, for example, be controlled by the rocks permeability, in as much as it affects the speed by which a gas overpressure in vesicles is reduced in response to decompression. Using a modified shock-tube-based fragmentation bomb (Alidibirov and Dingwell 1996a,b; Spieler et al. 2003a), we have measured unsteady-state permeability at a high initial pressure differential. Following sudden decompression above the rock cylinder, pressurized gas flows through the sample. Two pressure transducers record the pressure signals above and below the sample. A transient 1D filtration code has been developed to calculate permeability using the experimental decay curve of the lower pressure transducer. Additionally an analytical steady-state method to achieve permeability is presented as an alternative to swiftly predict the sample permeability in a sufficiently precise manner. Over 100 permeability measurements have been performed on samples covering a wide range of porosity. The results show a general positive relationship between porosity and permeability with a high data scatter. Our preferred interpretation of the results is a combination of two different, but overlapping effects. We propose that at low porosities, gas escape occurs predominantly through microcracks or elongated micropores and therefore could be described by simplified forms of Kozeny–Carman relations (Carman 1956) and fracture flow models. At higher porosities, the influence of vesicles becomes progressively stronger as they form an increasingly connected network. Therefore, a model based on the percolation theory of fully penetrable spheres is used, as a first approximation, to describe the permeability-porosity trend. In the data acquired to date it is evident, that in addition to the porosity control, the samples bubble size, shape and distribution strongly influence the permeability. This leads to a range of permeability values up to 2.5 orders of magnitude at a given porosity. 相似文献
99.
100.
Gómez-Navarro Juan José Werner Johannes Wagner Sebastian Luterbacher Jürg Zorita Eduardo 《Climate Dynamics》2015,45(5-6):1395-1413
Climate Dynamics - This study aims at assessing the skill of several climate field reconstruction techniques (CFR) to reconstruct past precipitation over continental Europe and the Mediterranean at... 相似文献