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31.
Dozent Dr. Lothar Greiling 《International Journal of Earth Sciences》1967,56(1):336-340
Zusammenfassung Kalkknollengesteine können in Eugeosynklinalen innerhalb von Rutschmassen, durch Beben, durch unterschiedliche Setzung und durch sedimentäre Boudinage entstehen. Daran gebunden sind syndiagenetische Zerbrechung und örtlich intensive syndiagenetische Faltung.Die mesozoischen Kalk-Mergel-Folgen der Miogeosynklinalen und der Innenbecken sind über weite Strecken dicht mit pseudonodules erfüllt. Die pseudonodules sind wahrscheinlich durch die Aufarbeitung einer älteren Schüttung durch eine jüngere Schüttung hervorgegangen. Vorausgesetzt wird ein unruhiges Relief infolge unterschiedlicher Setzung. Ein großer Teil der mesozoischen Kalke liegt auf zweiter Lagerstätte.
Rocks containing limestone nodules may develop in eugeosynclines within slump masses, by earthquakes, differential compaction and boudin-shaped sedimentary accumulations. Syndiagenetic fracturing and strongly developed syndiagenetic folding are related to these structures.Pseudonodules are densely distributed throughout extensive areas of the mesozoic limestone-marl series within the miogeosynklines and the interior basins. They probably resulted from the reworking of an older sediment. An uneven relief, produced by differential compaction can be assumed. A large portion of the mesozoic limestone occurs within this reworked type of deposit.
Résumé Il est possible que des calcaires noduleux se forment dans des eugéosynclines au milieu d'éboulements ou par des tremblements de terre ou par un tassement differencié ou bien par un boudinage sédimentaire. En relation avec ces phénomènes on trouve une tectonique syndiagénétique de style cassant et localement une tectonique syndiagénétique de plis intenses.Les successions calcaro-marneuses du Mésozoique des miogéosynclines ainsi que des bassins intérieurs contiennent bien des pseudonodules à longues distances. Il est probable que ces pseudonodules résultent de la reprise d'une ancienne par une nouvelle couche de sédimentation sous la condition d'un relief accentué à cause d'un tassement differencié. Une grande partie des calcaires mésozoiques se trouve maintenant en gîte secondaire.
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32.
Friedrich Schüler 《Ocean Dynamics》1954,7(3-4):140-143
Summary Echo records from the Atlantic west of the Faroe Islands are presented which, for the first time, give evidence of the influence exerted by day on the vertical movement of pelagic fishes by a considerable reduction of luminous intensity (solar eclipse). This phenomenon corresponds with the fact well known since some years from investigations in the North Sea which prove that by night pelagic fishes move in a vertical direction according to the variation in luminous intensity.
Sur des enregistrements ultra-sonores caractérisant le comportement des poissons pélagiques pendant l'éclipsé de soleil au 30 juin 1954
Résumé On présente des enregistrements ultra-sonores faits en océan Atlantique à l'ouest de l'archipel de Færoé. Ces enregistrements font, pour la première fois, preuve de l'influence exercée de jour sur le mouvement vertical des poissons pélagiques par une réduction sensible de l'intensité lumineuse (éclipse de soleil). Ce phénomène correspond avec le fait bien connu depuis quelques ans par des recherches dans la mer du Nord. Suivant ces recherches, les poissons pélagiques se meuvent nuitamment dans la direction verticale suivant la variation de l'intensité lumineuse.相似文献
33.
Ohne Zusammenfassung 相似文献
34.
To decipher the geodynamic significance of Cenozoic magmatism along the Red River shear belt, geochemical analyses, U-Pb and Rb-Sr dating, and Pb-Sr-Nd isotope tracing were undertaken. Zircon, monazite, titanite, and a Ti-U-oxide from foliated granitoid intrusions in the shear belt gneisses yield U-Pb emplacement ages of 33.1?±?0.2 (2σ), 31.9?±?0.3, 25.8?±?0.2 and 24.7?±?0.2?Ma, and an age of 35.0?±?0.3?Ma was obtained for the roughly 100?km long, adjacent Jinping (Phan Si Pang) alkali granite. Together with our previous data the new ages suggest that magmatism and left-lateral strike-slip movements occurred coevally during latest Eocene–Oligocene times from 33 to 22?Ma. The Rb-Sr dating of muscovite and biotite from the northernmost gneisses indicates that cooling to 500?°C occurred at 52.6?±?1.1?Ma, pre-dating the onset of magmatism, whereas further cooling to 300?°C took place at 28.9?±?0.6. This shows that unroofing in the north took place almost 9?million years earlier than in the central gneiss segments of the shear zone. Geochemical data substantiate two types of magmas: (1) amphibole-bearing intrusions of alkaline trend which are derived from sources with Isr: 0.7065–0.7089 and i Nd: ?3.7 to ?6.6; (2) leucogranitic layers and bodies having Isr: 0.7084–0.7354 and i Nd: ?3.3 to ?13.4. The former type of intrusion is found in both the gneisses and the adjacent unmetamorphosed cover rocks, whereas leucogranites are restricted to the shear belt gneisses. Source signatures of the alkaline intrusions lie adjacent to the those of OIB, plotting at the lower end of the Mantle Array. Contamination of these melts by continental material seems to be very limited. On the other hand, the leucogranitic layers are essentially crustal derived but none of the them has country rock isotope signatures, requiring melting of crust different from the actually exposed gneisses. Magma sources similar to those of ocean island basalt indicate magmatism to involve melting of light rare earth element and large ion lithophile element enriched mantle domains, most likely present in the lithosphere underneath the region. Since lithospheric thickening or subduction can be ruled out to produce both types of magmas, the presence of an important thermal anomaly is required, which is coevally active with left-lateral strike-slip shear. Adiabatic decompression and melting within the rising anomaly is the most plausible mechanism to produce the mantle magmas, which successively migrate through the crust to induce anatectic melting at 20–15?km crustal depth. Alkaline magmas largely dominate the volume of magmatism along the belt, being continuously present in the shear zone for millions of years. Such lubrication potentially explains how very large amounts of displacement can be absorbed in surprisingly narrow shear zones such as the Red River belt, possibly also playing a rôle for where and when zones of plate-scale lateral extrusion develop. 相似文献
35.
Comparison of Transient Network Brightenings and Explosive Events in the Solar Transition Region 总被引:1,自引:0,他引:1
I analyze the properties of the pulsed emission from the accreting millisecond pulsar SAX J1808.4-3658 in observations of its 1998 April outburst by the Rossi X-Ray Timing Explorer. Pulse phase spectroscopy shows that the emission evolves from a hard spectrum (power law with photon index of 2.39+/-0.06) to a soft spectrum (index of 3.39+/-0.24). This softening is also observable as a phase lag in the fundamental of low-energy photons with respect to high-energy photons. I show that this lag is roughly constant over 10 days of the outburst. I fit these data with a model in which the pulse emission is from a hot spot on the rotating neutron star and the flux as a function of phase is determined in a calculation which includes the effects of general relativity. The energy-dependent lags are very well described by this model. The harder spectra at earlier phases (i.e., as the spot approaches) are the result of larger Doppler-boosting factors that are important for this fast pulsar. Since this model is sensitive to the equatorial speed as an independent parameter and since the spin frequency is known, this offers us a new means of measuring the neutron star radius, which is notoriously difficult to determine. 相似文献
36.
A realistic assessment of the total uncertainty budget of Global Positioning System (GPS) observations and its adequate mathematical treatment is a basic requirement for all analysis and interpretation of GPS-derived point positions, in particular GPS heights, and their respective changes. This implies not only the random variability but also the remaining systematic errors. At present in geodesy, the main focus is on stochastic approaches in which errors are modeled by means of random variables. Here, an alternative approach based on interval mathematics is presented. It allows us to model and to quantify the impact of remaining systematic errors in GPS carrier-phase observations on the final results using deterministic error bands. In this paper, emphasis is given to the derivation of the observation intervals based on influence parameters and to the study of the complex linear transfer of this type of uncertainty to estimated point positions yielding zonotopes. From the presented simulation studies of GPS baselines, it turns out that the uncertainty due to remaining systematic effects dominates the total uncertainty budget for baselines longer than 200 km. 相似文献
37.
38.
Steffen Schön 《GPS Solutions》2007,11(2):107-117
GPS is a promising tool for real-time monitoring of deformations of slopes or large structures. However, remaining systematic
effects in GPS phase observations after double differencing and application of a priori models affect the resulting coordinates.
They complicate the proper separation of the actual deformations from pseudo-deformations induced by the systematic effects.
This paper shows that for small monitoring networks (baseline lengths <5 km) only affine distortions of the network geometry
are generated by the remaining distance dependent systematic effects, e.g. unmodelled tropospheric and ionospheric propagation
effects, or satellite orbit errors. Hence, a generic correction model is given by a three-dimensional affine transformation
involving a maximum of 12 transformation parameters. For the determination of these parameters, four high quality GPS stations
are necessary which are not affected by the actual deformations to be monitored. Based on the analysis of network geometries
of synthetic GPS networks with large height differences and considering the physics of the GPS observations it is shown, however,
that less than 12 parameters are sufficient for the computation of the corrections. The proposed 8 parameter model was applied
to the GPS monitoring network of the Gradenbach landslide. For this small network with large height differences, it was shown
that the distortions can be reduced by about 75%. 相似文献
39.
40.