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21.
R. Mayer 《Meteorology and Atmospheric Physics》1953,5(4):478-489
Zusammenfassung Es wird versucht, die Methoden der statistischen Mechanik auf die statistische Behandlung der kontinuierlichen Mannigfaltigkeit der Erdatmosphäre zu übertragen. Dazu ist es notwendig, daß die hydrodynamischen Bewegungsgleichungen auf eine Hamiltonsche Form gebracht werden. In Analogie zur statistischen Mechanik wird ein Gibbsscher Ansatz einer kanonischen Gesamtheit gemacht, in den die Energiefunktion, die die Atmosphäre als Ganzes beschreibt, eingeht. Mit diesem Ansatz wird die Wahrscheinlichkeit angegeben, daß ein bestimmter Zustand der Atmosphäre, der als Phasenpunkt in einem Phasenraum aufgefaßt wird, in einem Volumelement dieses Phasenraumes anzutreffen ist. Diese Ausgangswahrscheinlichkeit gestattet es, in einem Anwendungsbeispiel eine Verbindung zwischen der mittleren geometrischen Temperaturzustandskurve und der Verteilung der Gesamtmasse der Atmosphäre auf die verschiedenen Dichtewerte herzustellen.
Summary An attempt is made to apply methods of statistical mechanics to the continuous diversity of the terrestrial atmosphere. To this purpose the hydrodynamic equations of motion must be expressed in Hamiltonian form. In analogy to statistical mechanics a Gibbs arrangement of a canonical totality is set up involving the energy-function by which the atmosphere is described as a whole. By this arrangement the probability is given that a certain state of the atmosphere considered as phase point in a phase space exists in a volume-element of this phase space. This initial probability makes it possible to establish, in a practical example, a relation between the average geometrical curve of temperature state and the distribution of the whole mass of the atmosphere over the different density values.
Résumé On tente d'appliquer les méthodes de la mécanique statistique au traitement statistique de la diversité continue de l'atmosphère terrestre. Il est nécessaire pour cela de ramener les équations hydrodynamiques du mouvement aux formes de Hamilton. Par analogie à la mécanique statistique on établit un théorème de Gibbs concernant un ensemble canonique et dans lequel s'insère la fonction d'énergie décrivant l'atmosphère dans son ensemble. Ce théorème fournit la probabilité qu'un état détermié de l'amtosphère considéré comme point de phase dans un espace de phase est rencontré dans un élément de volume de cet espace. Cette probabilité initiale permet, dans un exemple concret, d'établir une relation entre la courbe géométrique moyenne d'état de température et la distribution de la masse totale de l'atmosphère selon les différentes valeurs de la densité.相似文献
22.
Frank?BraunschweigEmail author Flávio?Martins Paulo?Chambel Ramiro?Neves 《Ocean Dynamics》2003,53(3):137-145
High-resolution hydrodynamic models are a common tool to simulate water dynamics in estuaries. Results from these models are, however, difficult to interpret without the aid of additional parameters to integrate the information. In this paper a methodology to understand the transport patterns in the Tagus Estuary is proposed. It is based on the computation of two renewal time scales: residence time and integrated water fraction. This last parameter is used to build a dependency matrix that gives the integrated influence of each region of the estuary at a selected point. The parameters are computed using a Lagrangian transport model coupled to the hydrodynamic model. Results show that Tagus Estuary has two different types of regions: the central part of the estuary, with low renewal efficiency, and three regions with higher renewal efficiency. Renewal mechanisms are, however, different for each region as shown by the dependency matrix. Comparison of renewal time scales with results from a water-quality model revealed that residence time is not a limiting parameter for primary production in the Tagus Estuary.Responsible Editor: Hans Burchard 相似文献
23.
Jos María Viramonte Raúl Alberto Becchio Jos Germn Viramonte Marcio Martins Pimentel Roberto Donato Martino 《Journal of South American Earth Sciences》2007,24(2-4):167-183
New field, petrological, geochemical, and geochronological data (U–Pb and Sm–Nd) for Ordovician rock units in the southeastern Puna, NW Argentina, indicate two lithostratigraphic units at the eastern–northeastern border of salar Centenario: (1) a bimodal volcanosedimentary sequence affected by low- to medium-grade metamorphism, comprising metasediments associated with basic and felsic metavolcanic rocks, dated 485 ± 5 Ma, and (2) a plutonic unit composed of syenogranites to quartz-rich leucogranites with U–Pb zircon ages between 462 ± 7 and 475 ± 5 Ma. Felsic metavolcanic and plutonic rocks are peraluminous and show similar geochemical differentiation trends. They also have similar Sm–Nd isotopic compositions (TDM model ages of 1.54–1.78 Ga; εNd(T) values ranging from −3.2 to −7.5) that suggest a common origin and derivation of the original magmas from older (Meso-Paleoproterozoic?) continental crust. Mafic rocks show εNd(T) ranging from +2.3 to +2.5, indicating a depleted mantle source. The data presented here, combined with those in the literature, suggest Ordovician magmatism mainly recycles preexisting crust with minor additions of juvenile mantle-derived material. 相似文献
24.
Coregistration Based on Three Parts of Two Complex Images and Contoured Windows for Synthetic Aperture Radar Interferometry 总被引:2,自引:0,他引:2
The coregistration of complex image pairs is a very important step in synthetic aperture radar interferometry (InSAR) data processing. This letter proposes a novel coregistration method that only needs three arbitrary parts of the two complex images instead of four parts in the existing coregistration methods. This method constitutes an integrated three-part method for InSAR data processing with our contoured-correlation-interferometry method for phase-image generation. Saving one part transmission makes a significant advantage when processing SAR images on satellites. Furthermore, we demonstrate that, by means of using fringe contoured windows instead of squared windows, the accuracy of the coregistration for both the three-part coregistration method and the existing methods can be improved considerably 相似文献
25.
Montegriffo Bellazzini Ferraro Martins Sarajedini & Fusi Pecci 《Monthly notices of the Royal Astronomical Society》1998,294(2):315-326
We present deep V - and I -band CCD photometry of the globular cluster Terzan 8, recently found to be a member of the globular cluster system of the Sagittarius dwarf spheroidal galaxy. We accurately estimate the metallicity of Terzan 8, and provide the first direct determination of the colour excess toward this cluster. Our robust age estimate confirms that this cluster is indeed coeval with typical Galactic globulars of comparable metal content, and thus it is probably significantly older than at least two other Sagittarius clusters, Terzan 7 and Arp 2. The implications of this result on the star formation history of the Sagittarius galaxy are briefly discussed. 相似文献
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