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371.
Comet outburst activity and the structure of solar wind streams were compared on the basis of Pioneer 10, 11, Vela 3 and IMP
7, 8 measurements at the heliocentric distance r ≈ 1–6 AU. It is shown that the solar wind velocity waves which are evolving into corotating shock waves beyond the Earth
orbit may be responsible for comet outburst activity. The correlation between variations of comet outburst activity with heliocentric
distance and the behavior of the solar wind velocity waves is established. The closeness of the characteristic times for the
velocity waves and comet outburst activity (7–8 days at r = 1 AU) as well as the simultaneous growth of both the characteristic times with r are noted. The observed distribution of the comet outburst activity parameters during the 11-year cycle is also in good agreement
with the phase distributions during the 11-year cycle of variations of the coronal hole areas and the rate of change of the
sunspot area δS
p. 相似文献
372.
Kömle Norbert I. Tiefenbacher Patrick Pitcher Craig Richter Lutz Tattusch Tim Paul Robert 《Acta Geotechnica》2019,14(2):429-442
Acta Geotechnica - Two laboratory test series were performed with the aim of ensuring the proper functionality of the key sampling mechanisms installed aboard the Mars rover ExoMars, currently... 相似文献
373.
The concentrations of free dissolved carbon dioxide in lake water were measured with a newly developed CO2 sensor, which was installed in a through-flow measurement system. The results of measurements demonstrate the CO2 dynamics in lake Willersinnweiher. The CO2 concentrations showed a correlation with the oxidation of CH4 in the metalimnion and caused shifts in the carbonate system, thus affecting the autochthonous precipitation and dissolution of calcite.
From the results of measurement appears that the CO2 sensor is capable of very exact measurements of dissolved free CO2 in lake water. At the same time, the parameter is easily determined in the field without large expenditures. 相似文献
374.
Wolfram Richter 《Mineralogy and Petrology》1965,10(1-4):265-296
Zusammenfassung Der Mauthausner Granit bildet im österreichischen Moldanubikum eine Anzahl von gang- und stockförmigen Durchbrüchen. Er wurde an Hand von vier Vorkommen—Mauthausen selbst, Gloxwald (bei Sarmingstein), Plöcking und Schrems—einer detaillierten chemischen und mineralogischen Untersuchung unterzogen.Das Gestein ist ein Biotitgranit mit geringen Mengen primären Muskovits. Der Plagioklas (bis 38 Vol. %) besitzt einen progressiven und oszillatorischen Zonarbau, primäre und sekundäre Verzwillingung und einen durchschnittlichen An-Gehalt von An=20% (Plöckinger Granit An=25%). Der Alkalifeldspat (durchschnittlich 28 Vol. %) ist ein scharf gegitterter perthitischer Mikroklin (entmischte Phase Or=89%, >90) mit durchschnittlich Ab+15%. Der Biotit (ca. 10 Vol.%) bildet 2M1 Polymorphe, ebenso der Muskovit (<1 Vol.%). Der Zirkon bildet zwei Typen verschiedener Herkunft; das Gestein ist hybrid. Aus den Komponentenanalysen ergeben sich als Bildungsbedingungen: relativ rasche Kristallisation bei steigendem pH2O im Bereich von ca. 5000 bar, fallende Temperatur und fallender Belastungsdruck, was auf große Bildungstiefen hinweist. Die Intrusion erfolgte während der Plagioklaskristallisation und während des Abklingens der variskischen Regionalmetamorphose in eine relativ kühle Umgebung.
Mit 8 Textabbildungen
Herrn Professor Dr.F. Machatschki zum 70. Geburtstag gewidmet. 相似文献
Summary The Mauthausen granite belongs to the Moldanubian zone of Austria, and is represented by a number of dike-and plug-like minor intrusions. Four representative localities were chosen for a detailed chemical and mineralogical investigation (Mauthausen, Gloxwald near Sarmingstein, Plöcking and Schrems).The rock is a biotite granite with subordinated amounts of primary muscovite. The rock contains up to 38 vol.-% plagioclase which shows progressive and oscillatory zoning, primary and secondary twinning and an average An-content of 20% (Plöcking 25%). The alkali feldspar forms about 28 vol.-% of the rock. It is strongly cross-hatched microcline-perthite with average Ab 15%. Its unmixed potassium phase contains Or=89%, >90. Biotite (ca. 10 vol.-%) and muscovite (<1 vol.-%) are 2M1 polymorphs. Investigations on zircons show types of different origin expressing a remarkable hybridity of the rock in question. From the analyses of the components the following conclusions elucidate: Relatively rapid crystallisation under increasing pH2O around 5000 bar, falling temperature and load pressure. This indicates great depth of formation. The intrusion took place during the crystallisation of the plagioclase into a relatively cool surrounding. The time of intrusion can be fixed near the end of the variscian regional metamorphism.
Mit 8 Textabbildungen
Herrn Professor Dr.F. Machatschki zum 70. Geburtstag gewidmet. 相似文献
375.
376.
Prof. G. Richter Dr. 《GeoJournal》1980,4(3):279-287
Conclusion Previous research on soil erosion in Central Europe was mainly focused on historical aspects, with soil erosion forms and their regional setting. It is now time to utilize a more quantitative approach. Furthermore in the future, soil erosion should be seen in the context of the entire equilibrium of landscape systems, that means as part of economic-ecological research. 相似文献
377.
D. Van Rooij D. Blamart T. Richter A. Wheeler M. Kozachenko J.-P. Henriet 《International Journal of Earth Sciences》2007,96(1):121-140
The Belgica cold-water coral banks on the eastern slope of the Porcupine Seabight are closely associated with bottom currents.
In order to better understand the local temporal and spatial characteristics, as well as the palaeoclimatologic influences,
a 26 m long core, taken on a small contourite drift, was studied. This sediment record of approximately 100 ka BP reveals
new insights into the regional glacial and sedimentary processes, which are intrinsically linked to several geological, climatological,
biological and hydrodynamic variables. The glacial sequences in the core contain six ice-rafting events (IRE). They are comparable
with the North Atlantic Heinrich Events, although their characteristics show dominant influences from the proximal British–Irish
Ice Sheet (BIIS). These IRE have a low magnetic susceptibility and are deposited during two or three ice-rafting pulses. The
record of ice-rafting suggests a millennial-scaled BIIS destabilisation and confirms the start of a final retreat about 25 ka
ago. Additionally, the glacial sequence corresponds to a muddy contourite, influenced by bottom-current strength variations
during interstadials, possibly triggered by sporadic reintroductions of Mediterranean Outflow Water in a glacial North Atlantic
Ocean. The interglacial sequence features an 11-m thick deep-water massive sand unit, probably deposited under a high-energy
bottom-current regime. 相似文献
378.
Christiane Richter Christopher-Bastian Roettig Daniel Wolf Andreas Gärtner Thomas Kolb Dominik Faust 《第四纪科学杂志》2021,36(3):426-440
Dune palaeosurface sequences on the Eastern Canary Islands were investigated for stable isotope records in gastropod shells of the genus Theba. Due to the ecology of the taxon and the special oceanic insularity of the study site, we assume that δ18Oshell signals in our case mainly reflect shifts in δ18O signals of sea surface water. We found that a rapid decrease in δ18Oshell signals is associated with significant changes in gastropod associations. We suggest that these faunal changes were caused by strong (hot) winds at the end of glacial phases, that were described previously by Moreno et al. In addition, we assume that rapid declines in δ18Oshell signals due to marine transgressions were followed by geomorphologically stable phases, dominated by dust enrichment. Such palaeosurfaces correlate with maxima of gastropod biodiversity and with more negative δ13Cshell signals indicating a higher proportion of C3 plants. Based on our results, we also assume that these silty palaeosurfaces were associated with increased soil moisture conditions due to a higher water storage capacity of the finer substrate, independent of climatic moisture conditions. 相似文献
379.
Johanna Marin-Carbonne Kevin D. McKeegan Andrew M. Davis Glenn J. MacPherson Ruslan A. Mendybaev Frank M. Richter 《Meteoritics & planetary science》2023,58(4):546-571
Oxygen, magnesium, and silicon isotopic abundances in Vigarano 1623-5 were studied using secondary ion mass spectrometry to investigate correlations between isotopic and petrologic properties of this unique forsterite-bearing FUN inclusion. Vigarano 1623-5 displays large, correlated mass-dependent fractionation effects, tightly linked to mineralogy within distinct petrologic units of the inclusion. The pyroxene-rich and melilite-rich interior parts of the inclusion display highly mass-fractionated isotopic compositions of oxygen, magnesium, and silicon, consistent with Rayleigh distillation during evaporation of a melt with initial oxygen composition close to a solar composition. However, the chemical composition, enriched in magnesium and silicon, suggests a precursor already fractionated by prior melt evaporation. A discontinuous igneous rim was produced by a flash-melting event followed by isotopic exchange in the rim melilite with planetary-like oxygen, mechanical fragmentation, and reassembly with an accretionary rim of heterogeneous materials. Al-rich minerals in 1623-5 show evidence for having crystallized with live 26Al but at less than the “canonical” level of most CV calcium-aluminum-rich inclusions. However, well-defined 26Al-26Mg isochrons are not found and temporal implications are ambiguous. 相似文献
380.
Mário Mil-Homens Miguel Caetano Ana M. Costa Susana Lebreiro Thomas Richter Henko de Stigter Maria A. Trancoso Pedro Brito 《Marine pollution bulletin》2013
Stable Pb isotope ratios (206Pb/207Pb, 208Pb/206Pb), 210Pb, Pb, Al, Ca, Fe, Mn and Si concentrations were measured in 7 sediment cores from the west coast of the Iberian Peninsula to assess the Pb contamination throughout the last 200 years. Independently of their locations, all cores are characterized by increasing Pb/Al rends not related to grain-size changes. Conversely, decreasing trends of 206Pb/207Pb were found towards the present. This tendency suggest a change in Pb sources reflecting an increased proportion derived from anthropogenic activities. The highest anthropogenic Pb inventories for sediments younger than 1950s were found in the two shallowest cores of Cascais and Lisboa submarine canyons, reflecting the proximity of the Tagus estuary. Lead isotope signatures also help demonstrate that sediments contaminated with Pb are not constrained to estuarine–coastal areas and upper parts of submarine canyons, but are also to transferred to a lesser extent to deeper parts of the Portuguese Margin. 相似文献