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891.
Zur Bildungsgeschichte der oberen Trias am Nordrand der Kalkalpen zwischen Oberstdorf und Schliersee
Manfred Frank 《International Journal of Earth Sciences》1934,25(2):98-110
Zusammenfassung Profile zwischen Hauptdolomit und Fleckenmergel im Bereich der Allgäudecke und der Lechtaldecke und deren Zusammenstellung zu Längsprofilen lassen einen Hiatus zwischen Hauptdolomit und Lias in den nördlichsten Teilen der Allgäudecke erkennen. Breccien, Oolithe und Sandlagen im Rät bzw. Plattenkalk der südlicher gelegenen Gebiete deuten die Aufarbeitungserscheinungen im Norden ebenfalls an. Die roten Schattwalder Schichten und rote Tonlagen in den Allgäufleckenmergeln südlich des Tegernsees werden als eingeschwemmte rote Verwitterungsmassen der freigelegten Hauptdolomitflächen des Nordens gedeutet. Ein Längsschnitt durch die Trias-Lias-Schichten von der Ötztalmasse südlich Innsbruck zur Benediktenwand zeigt ein Wandern der größten Mächtigkeiten von Süden nach Norden im Verlauf der Zeit an. Es wird daraus auf ein Verschieben der Hauptsenkungsneigung in dieser Richtung geschlossen. 相似文献
892.
893.
Frank Dixey 《Journal of Hydrology》1976,30(3):303
894.
By considering high-temperature (classical) thermal oscillations of atoms in certain simple crystal structures with purely central interatomic forces, the treatment of anharmonic oscillations is generalised to random three-dimensional motion, yielding the Vashchenko and Zubarev relationship for the Grüneisen ratio γ at any pressure. If one-dimensional atomic oscillations only are considered the equation reduces to the Dugdale-MacDonald expression. To account for non-central forces additional terms must be introduced, giving: where f = 0 for purely central forces. Calculations of f in terms of the Poisson ratio for different crystal structures have not been made, but for many materials the central-force approximation suffices. This is believed to be true both for the outer core and for the close-packed structures of the lower mantle . For the upper mantle non-central atomic forces are important and we have no estimate of ( independently of laboratory values for plausible minerals which suggest γ ≈ 0.8. 相似文献
895.
Summary ARM has been measured in a range of inducing, steady fields up to 50 oersteds and for 6 sizes of magnetite grains with average diameters 5 m to 174 m. For all sizes a slight non-linearity of ARM with inducing field was found, apparently comprising a non-linear contribution independent of grain size plus a linear contribution which increased with decreasing grain size. In the largest grains induced ARM agreed well with multidomain grain theory. Relative enhancement of ARM in smaller grains is comparable to the enhancement of thermoremanence and therefore appears to indicate a pseudosingle domain contribution to ARM in small grains. However the observations allow an alternative explanation in terms of more extreme dimension ratios in the smaller grains. Presentation of the equations for multidomain ARM and TRM using observed instead of intrinsic susceptibilities makes it appear that the inadequacy of multidomain theory (and consequent necessity for pseudo-single domain theory) are less serious than has been supposed. 相似文献
896.
897.
David J. Dunlop Frank D. Stacey David E.W. Gillingham 《Earth and Planetary Science Letters》1974,21(3):288-294
The pseudo-single-domain (PSD) intensity and stability of thermoremanent magnetization (TRM) in multidomain magnetite grains 0.05–15 μm in size are attributed to residual magnetic moments not removed by demagnetization. Barkhausen discreteness in domain wall positions is a possible source of such moments, but the observed grain size and applied field dependences of TRM in the lower PSD range are more convincingly explained by a new theory (F.D. Stacey and S.K. Banerjee, 1974) in which the moments of domain walls and the surface terminations of domain walls play a central role. The magnitudes of PSD moments and the average number of moments per grain required by this theory are deduced from low-field (0–25 Oe) TRM measurements on magnetite grains of controlled sizes between 0.04 and 0.22 μm. The predicted maximum PSD moment is about equal to the saturation moment in grains ≤ 0.1 μm in size but is only 10% of the saturation moment in 0.22-μm grains. Since blocking temperature and hysteresis data independently suggest two-domain structure in 0.22-μm grains and wall-like domain structure in smaller grains, the predicted PSD moments are quantitatively reasonable. 相似文献
898.
Intensive infiltrometer studies were made over a 4-year period on a plowed big sagebrush (Artemisia tridentata) site in southern Idaho. Results of the study indicate there was a natural decay in absorptive capabilities of surface soils due to the plowing treatment. The apparent result of grazing was not to reduce the minimal infiltration capacities measured on the respective site, but rather to eliminate seasonal trends so that infiltration rates were at the low end of the scale throughout the year. Grazing did not increase sediment production potentials beyond the increases expected as a result of mechanical disturbance associated with plowing. Attempts at predicting infiltration rates and potential sediment production indicated that easily measured soil cover characteristics do not adequately reflect the potential (actual) hydrologic performance of a big sagebrush site which has been grossly modified by activity such as plowing or grazing. 相似文献
899.
Several commercially available spill control agents interfere with gas chromatographic correlation of spilled oils with suspected sources. The effects of four such products are presented. Two of these interfere seriously. One is removable by a simple clean-up procedure, and the other is not removable in principle. In favourable cases, its interference may be minimized by extrapolation. Anticipated interference with other analytical methods is surveyed. 相似文献