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41.
Geomagnetic data of north, east, and vertical components at Croatian repeat stations and ground survey sites, as well as European geomagnetic observatories and repeat stations, were used to obtain a regional geomagnetic model over Croatia at 2009.5 epoch. Different models were derived, depending on input data, and three modelling techniques were used: Taylor Polynomial, Adjusted Spherical Harmonic Analysis, and Spherical Harmonic Analysis. It was derived that the most accurate model over Croatia was the one when only Croatian data were used, and by using the Adjusted Spherical Harmonic Analysis. Based on Croatian repeat stations’ data in the interval 2007.5–2010.5, and a global Enhanced Magnetic Model, it was possible to estimate the crustal field at those sites. It was also done by taking into account the empirical adjustment for long-term external field variations. The higher crustal field values were found at those stations which are on or close to the Adriatic anomaly. 相似文献
42.
Ground survey within the Nature Park Lonjsko Polje, placed in the middle-northern Croatia was performed during the time interval
2007–2010 in order to find the best location for installing the geomagnetic observatory. The total magnetic field has been
measured a few times using the Overhauser proton magnetometers. The horizontal and vertical gradients of the total field,
and its temporal behaviour were investigated over the restricted region that we estimated as suitable for the observatory.
The results obtained from thoroughly conducted measurements allowed us to find definitive positions for the instrument pillars.
These results are in agreement with previously suggested location found based on combination of Comprehensive CM4 model prediction
and measurements conducted from 2003 to 2005. This study contributes to the development of geomagnetism in Croatia and paves
a way to install the first geomagnetic observatory in Croatia. 相似文献
43.
Christos Makris Panagiota Galiatsatou Konstantia Tolika Christina Anagnostopoulou Katerina Kombiadou Panayotis Prinos Kondylia Velikou Zacharias Kapelonis Elina Tragou Yannis Androulidakis Gerasimos Athanassoulis Christos Vagenas Ioannis Tegoulias Vassilis Baltikas Yannis Krestenitis Theodoros Gerostathis Kostantinos Belibassakis Eugen Rusu 《Ocean Dynamics》2016,66(12):1603-1635
44.
At the beginning of the 19th century it was still not understood how erratic blocs were transported. Leopold von Buch's answer echoed Horace Bénedict de Saussure's flood theory from 1780. Von Buch's letter of 1818, published here, shows that he tried to support Saussure's theory to which he adhered to throughout his life with quantitative arguments. Even close contacts and several visits to Jean de Charpentier, the then director of the salt mines at Bex, who could demonstrate that the Rhône Glacier had once reached the Swiss Jura, and field trips with Louis Agassiz in the Neuchâtel area in 1837, failed to change von Buch's flood theory. His authority was one of the reasons why the Skandinavian iceshield was not generally thought to have extended into Northern Germany until 1875, when Otto Martin Torell located surfaces polished by ice near Berlin—an observation that provoked a sudden surge of affirmative publications. Erratic blocks were not the only topic on which von Buch was mistaken, but because of his many important contributions in other areas, including his shift from neptunism to plutonism or his observations concerning the uplift of Scandinavia, Alexander von Humboldt characterized him as "the greatest geognosist of our time". 相似文献
45.
Some results from phytoplankton counting intercalibrations 总被引:34,自引:0,他引:34
Dr. Eugen Rott 《Aquatic Sciences - Research Across Boundaries》1981,43(1):34-62
Phytoplankton samples from 7 different lakes were processed in 2 intercalibration series using Utermöhl's sedimentation method. Total biomass volumes obtained by most of the investigators give reliable results in respect to the mean. Numbers of individuals and mean volumes of selected species obtained by the different participants were compared and show larger variations than the overall results. Therefore a certain delimitation of particular sources of errors was tried in the 2nd intercalibration series by giving recommendations for the different steps of the whole procedure. 相似文献
46.
E. F. Stumpfl 《Mineralium Deposita》1979,14(2):207-217
Primary manganese haloes "survive" medium to high-grade regional metamorphism: stratabound base metal deposits in Namaqualand, N. W. Cape Province (Proterozoic) and in the Eastern Alps (Paleozoic and Mesozoic) reveal an increase in Mn as the ore horizon (and associated BIF) is approached from the hangingwall or the footwall. Electron microprobe analyses show Mn to be preferentially concentrated in garnets; compositions vary considerably and include pure spessartine (40 % MnO). Compositional inhomogeneities (zoning) appear to be confined to garnets in lower grade metamorphic terranes. Iron contents of associated sphalerite vary within meters of the stratigraphic sequence and even within one polished section; sphalerite geobarometry does not appear promising in these environments. 相似文献
47.
Tom N. Clifford Eugen F. Stumpfl Alwyn J. Burger Terence S. McCarthy David C. Rex 《Contributions to Mineralogy and Petrology》1981,77(3):225-250
The northwestern part of South Africa and southern South-West Africa/Namibia is amongst the most extensive granulite terranes
in Africa. This work reports the results of electron microprobe studies of minerals from two-pyroxene, cordieriteorthopyroxene
(-gedrite) (-sapphirine) and garnet and/or cordierite parageneses from Namaqualand, in the N.W. Cape Province of South Africa.
Determined PT conditions of prograde metamorphism based on thermodynamic calculations are 800°–900° C and ca. 6–7 Kb; and it is argued
that rocks of unusual composition, notably cordierite-orthopyroxene rocks, are restites after the extraction of granitic liquid
from former argillites. This interpretation is consistent with previously published data on similar rocks, and with McCarthy's
(1976) suggestion of extensive partial melting in the quartzofeldspathic rocks in the area.
U-Pb isotopic studies of some 50 zircon fractions have been carried out and confirm an age of 1,200 m.y. for the high-grade
regional metamorphism; but certain zircon populations record inherited ages greater than 1,700 m.y. Garnet-sillimanite rocks
that contain retrograde kyanite reflect PT conditions of 550°–650° C and ca. 7–8 Kb; and constituent biotite has yielded a K-Ar age of ca. 950 m.y. These data, the
regional stratigraphy and structure, and the mineralisation are compared with data from the Grenville Province of Canada.
Notable similarities are the possible basement-cover relationships, and the calendar of tectonothermal events, while differences
include the important stratiform base-metal mineralisation in the supracrustal sequence in Namaqualand, and the Cu-mineralisation
in hypersthenebearing intrusives, emplaced some 1,100 m.y. ago, that are areally, and believed to be genetically, related
to the granulite facies metamorphic regime. 相似文献
48.
49.
Ohne Zusammenfassung 相似文献
50.