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31.
32.
Zusammenfassung In Fortfühung einer früheren Arbeit der Autoren werden einige weitere theoretische Untersuchungen skizziert, bei denen die elastischen Eigenschaften der Verwitterungschicht geeignet abgeändert sind. Bei Anregung der Schicht durch einen momentanen Impuls (Nadelimpuls) ergibt sich, daß die Frequenz der seismischen Welle nicht durch den Gradienten der Geschwindigkeit, sondern durch den Gradienten des Schallwiderstandes bestimmt wird.
Summary Continuating an earlier paper the authors present some further theoretical investigations on the influence of the weathering layer; the assumptions with regard to the elastic nature of the layer are properly modified. The result is as follows: If the layer is acted on by a momentary pulse (needle pulse) then the frequency of the seismic wave is determined by the gradient of the acoustical resistance, not by the gradient of the velocity of propagation.相似文献
33.
Heinz Ebert 《International Journal of Earth Sciences》1957,45(3):471-521
Zusammenfassung Aufnahmen im Kristallin südostwärts und südlich der EsphinhaÇo-Zone, ausgedehnt bis an die Südgrenze des Staates Minas Gerais, ergaben eine neue stratigraphische und tektonische Gliederung. Große Gebiete, die bisher als tiefstes Archaikum galten, erhielten ihre metamorphe Überprägung erst in der assyntischen Phase. Auch die vormetamorphe sedimentäre Substanz ist weithin algonkischen, wahrscheinlich neo-algonkischen Alters. Im Inneren besitzen diese Sedimente nur schwache epizonale Metamorphose und erlauben weitgehende stratigraphische Gliederung (Formationen Tiradentes, Carandaí, Barroso, Prados). Sie sind Überwiegend klastisch. Küstenwärts folgen die sedimentär-lithologisch gleichen, aber stärker (mesozonal) metamorphe Andrelandia-Serie und die katazonalen Juiz de Fora- bzw. Paraíba-Serien (Metamorphose charnockitisch bzw. mikroklingranitisch). Die Küstenzone stellt daher eine kristalline Zentralzone dar, von der aus die Bewegungen binnenwärts gerichtet sind. An der Westgrenze des Arbeitsgebietes erfolgt eine Virgation der Faltenzüge in Araxaiden und Paraibiden. Das ordovizische Alter der Füllung des Beckens des Rio SÃo Francisco (Bambuí) ist zu bezweifeln. Die EsphinhaÇo-Zone ist algomisch konsolidiert, die alt-algonkische Minas-Serie auf diese Zone beschränkt. Sie bildet, zusammen mit dem Bambuí-Becken, das Vorland der assyntischen Faltenzüge. Eine Aufgliederung des Archaikums ist begonnen; im bisher untersuchten Gebiet sind die archäischen Strukturen co-axial den jüngeren. 相似文献
34.
The term variangular is introduced to emphasize a significant difference between the present and certain earlier solutions to the problem of organized airmotion within the planetary boundary layer. The latter belong to the family of equiangular wind spirals and have the characteristic that the angle () formed by the vectors of shearing stress and geostrophic departure is invariant with height; it is shown that in this spiral-family, parabolic height-dependency of the effective (eddy) diffusivity (K) alone is permitted, including the asymptotic case of constant K; the famous Ekman spiral as well as the Rossby spiral are two prominent members of the family of equiangular wind spirals. The new variangular theory, as the name implies, permits variation of with height (z) and produces more versatile profiles of wind and stress due to less restraint in K (z). As an example of comparison with observed data, monthly mean wind profiles obtained at Plateau Station, Antarctica, are selected since they exhibit a noteworthy degree of variangularity, in relatively satisfactory agreement with properties of the new theoretical model for wind spirals.National Research Council Visiting Scientist Research Associate, Regional Environments Division, Earth Sciences Laboratory. 相似文献
35.
Martin Hartmann Heinz Lange Eugen Seibold 《Contributions to Mineralogy and Petrology》1971,31(2):159-163
Ohne Zusammenfassung 相似文献
36.
Prof. Dr. H. G. Scharbert 《Mineralogy and Petrology》1971,16(4):252-267
Zusammenfassung Der Cyanit tritt immer nur in biotitfreien Granuliten auf; in den biotitreicheren kommt Sillimanit vor. Der Cyanit gehört einer frühen Kristallisationsphase im polymetamorphen Ablauf der Granulitgenese an und ist immer älter als der Sillimanit. Cyanit kann sich direkt in Sillimanit umwandeln, meistens jedoch wächst der Sillimanit unabhängig von Cyanit. Die Fe-Gehalte beider Aluminiumsilikate werden angegeben und die Granulitgenese kurz diskutiert.
Mit 8 Abbildungen
Herrn Prof. DDr.H. Wieseneder zum 65. Geburtstag gewidmet. 相似文献
Kyanite and sillimanite in moldanubian granulites
Summary Kyanite always occurs in granulites free from any biotite; in micaceous granulite kyanite is replaced by sillimanite. Kyanite belongs to an early phase of crystallization with in the polymetamorphic genesis of the granulite complexes, and is therefore older than sillimanite. Sillimanite may grow directly out of kyanite, in most cases, however, sillimanite appears to grow independently from kyanite. The iron-contents of both aluminium-silicates are indicated and the genesis of the granulites is shortly discussed.
Mit 8 Abbildungen
Herrn Prof. DDr.H. Wieseneder zum 65. Geburtstag gewidmet. 相似文献
37.
38.
39.
Harald Geiger Ian Barnes Karl H. Becker Birger Bohn Theo Brauers Birgit Donner Hans-Peter Dorn Manfred Elend Carlos M. Freitas Dinis Dirk Grossmann Heinz Hass Holger Hein Axel Hoffmann Lars Hoppe Frank Hülsemann Dieter Kley Björn Klotz Hans G. Libuda Tobias Maurer Djuro Mihelcic Geert K. Moortgat Romeo Olariu Peter Neeb Dirk Poppe Lars Ruppert Claudia G. Sauer Oleg Shestakov Holger Somnitz William R. Stockwell Lars P. Thüner Andreas Wahner Peter Wiesen Friedhelm Zabel Reinhard Zellner Cornelius Zetzsch 《Journal of Atmospheric Chemistry》2002,42(1):323-357
Within the German Tropospheric Research Programme (TFS) numerous kinetic and mechanistic studies on the tropospheric reaction/degradation of the following reactants were carried out: oxygenated VOC, aromatic VOC, biogenic VOC, short-lived intermediates, such as alkoxy and alkylperoxy radicals.At the conception of the projects these selected groups were classes of VOC or intermediates for which the atmospheric oxidation mechanisms were either poorly characterised or totally unknown. The motivation for these studies was the attainment of significant improvements in our understanding of the atmospheric chemical oxidation processes of these compounds, particularly with respect to their involvement in photooxidant formation in the troposphere. In the present paper the types of experimental investigations performed and the results obtained within the various projects are briefly summarised. The major achievements are highlighted and discussed in terms of their contribution to improving our understanding of the chemical processes controlling photosmog formation in the troposphere. 相似文献
40.
Records of hydrologic parameters, especially those parameters that are directly linked to air temperature, were analyzed to
find indicators of recent climate warming in Minnesota, USA. Minnesota is projected to be vulnerable to climate change because
of its location in the northern temperate zone of the globe. Ice-out and ice-in dates on lakes, spring (snowmelt) runoff timing,
spring discharge values in streams, and stream water temperatures recorded up to the year 2002 were selected for study. The
analysis was conducted by inspection of 10-year moving averages, linear regression on complete and on partial records, and
by ranking and sorting of events. Moving averages were used for illustrative purposes only. All statistics were computed on
annual data.
All parameters examined show trends, and sometimes quite variable trends, over different periods of the record. With the exception
of spring stream flow rates the trends of all parameters examined point toward a warming climate in Minnesota over the last
two or three decades. Although hidden among strong variability from year to year, ice-out dates on 73 lakes have been shifting
to an earlier date at a rate of −0.13 days/year from 1965 to 2002, while ice-in dates on 34 lakes have been delayed by 0.75
days/year from 1979 to 2002. From 1990 to 2002 the rates of change increased to −0.25 days/year for ice-out and 1.44 days/year
for ice-in. Trend analyses also show that spring runoff at 21 stream gaging sites examined occurs earlier. From 1964 to 2002
the first spring runoff (due to snowmelt) has occurred −0.30 days/year earlier and the first spring peak runoff −0.23 days/year
earlier. The stream water temperature records from 15 sites in the Minneapolis/St Paul metropolitan area shows warming by
0.11∘C/year, on the average, from 1977 to 2002. Urban development may have had a strong influence. The analysis of spring stream
flow rates was inconclusive, probably because runoff is linked as much to precipitation and land use as to air temperature.
Ranking and sorting of annual data shows that a disproportionately large number of early lake ice-out dates has occurred after
1985, but also between 1940 and 1950; similarly late lake ice-in has occurred more frequently since about 1990. Ranking and
sorting of first spring runoff dates also gave evidence of earlier occurrences, i.e. climate warming in late winter.
A relationship of changes in hydrologic parameters with trends in air temperature records was demonstrated. Ice-out dates
were shown to correlate most strongly with average March air temperatures shifting by −2.0 days for a 1°C increase in March air temperature. Spring runoff dates also show a relationship with March air temperatures; spring runoff
dates shift at a rate of −2.5 days/1°C minimum March air temperature change. Water temperatures at seven river sites in the Minneapolis/St Paul metropolitan area
show an average rise of 0.46°C in river temperature/1°C mean annual air temperature change, but this rate of change probably includes effects of urban development.
In conclusion, records of five hydrologic parameters that are closely linked to air temperature show a trend that suggests
recent climate warming in Minnesota, and especially from 1990 to 2002. The recent rates of change calculated from the records
are very noteworthy, but must not be used to project future parameter values, since trends cannot continue indefinitely, and
trend reversals can be seen in some of the long-term records. 相似文献