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排序方式: 共有168条查询结果,搜索用时 15 毫秒
11.
The atmospheric response to the evolution of the global sea surface temperatures from 1979 to 1992 is studied using the Max-Planck-Institut 19 level atmospheric general circulation model, ECHAM3 at T 42 resolution. Five separate 14-year integrations are performed and results are presented for each individual realization and for the ensemble-averaged response. The results are compared to a 30-year control integration using a climate monthly mean state of the sea surface temperatures and to analysis data. It is found that the ECHAM3 model, by and large, does reproduce the observed response pattern to El Nino and La Niña. During the El Nino events, the subtropical jet streams in both hemispheres are intensified and displaced equatorward, and there is a tendency towards weak upper easterlies over the equator. The Southern Oscillation is a very stable feature of the integrations and is accurately reproduced in all experiments. The inter-annual variability at middle- and high-latitudes, on the other hand, is strongly dominated by chaotic dynamics, and the tropical SST forcing only modulates the atmospheric circulation. The potential predictability of the model is investigated for six different regions. Signal to noise ratio is large in most parts of the tropical belt, of medium strength in the western hemisphere and generally small over the European area. The ENSO signal is most pronounced during the boreal spring. A particularly strong signal in the precipitation field in the extratropics during spring can be found over the southern United States. Western Canada is normally warmer during the warm ENSO phase, while northern Europe is warmer than normal during the ENSO cold phase. The reason is advection of warm air due to a more intense Pacific low than normal during the warm ENSO phase and a more intense Icelandic low than normal during the cold ENSO phase, respectively. 相似文献
12.
Zusammenfassung Schiefer- und Phyllitgebiete sind auch tektonisch voneinander verschieden. An Beispielen werden Charakteristika der beiden Einheiten erläutert. Im Schiefergebirge Ostthüringens sind die Beziehungen zwischen Faltung und Schieferung von besonderem Interesse. Im Schiefer- und Phyllitgebiet des Schwarzburger Sattels lassen sich mehreres-Flächensysteme und Achsen unterscheiden; zum Liegenden hin ist hier entsprechend den Vorstellungen einer Stockwerktektonik eine Änderung des tektonischen Stils zu beobachten.
Tectonically, regions of shale and areas of phyllite are different. In the shale and phyllite area of the Schwarzburg Anticline several systems of s-surfaces and axes are represented. Toward the base a change in structural style can be observed in accordance with the concept of Stockwerk tectonics.
Résumé Les domaines de schistes et de phyllites sont différents les uns des autres également du point de vue tectonique. Des exemples illustrent les caractéristiques des 2 unités. Dans le Massif schisteux de la Thuringe orientale, les relations entre le plissement et la schistosité sont particulièrement intéressantes. Dans le domaine des schistes et des phyllites de l'anticlinal de Schwarzburg, on peut distinguer plusieurs axes et plans de clivage; vers le bas on observe un changement du style tectonique conformément à une tectonique de Stockwerk.
. .相似文献
13.
Prof. Dr. Erich Schoenberg 《Pure and Applied Geophysics》1959,43(1):1-11
Zusammenfassung Ausgehend von derEmden'schen Theorie der äquatorialen Beschleunigung der Sonne und einer früheren Anwendung derselben auf den Planeten Jupiter, wird auch die Beschleunigung bei Saturn hier erstmalig diskutiert und der Versuch gemacht, dieselbe Theorie zur Erklärung der Ostabweichung der Kontinente der Erde im äquatorialen Gebiet anzuwenden. Das ist nur möglich, wenn man 1.) auf die archaische Periode der Erdentwicklung zurückgreift, bei der aber die wesentlichen Höhenunterschiede der Erdoberfläche schon ausgebildet waren, 2.) der Pol im wesentlichen die jetzige Lage hatte und 3.) der Reibungskoeffizient der festen Erdkruste aber wesentlich geringer war: 1014 gegen etwa 1020 c.g.s.
Summary The hypothesis ofR. Emden to explain the equatorial acceleration of the sun has newly been discussed by the author and 11 years ago applied to the rotation ot the planet Jupiter. It is possible to apply her also to the planet Saturn and to the earth in the archaic period of evolution. The earth shows a striking eastern curvature of the continents in the equatorial zone, which possibly has originatet in times, when the earth crust was capable to yield to the same forces, which drive the equatorial zone forwards in rotating gaseous and liquid spheres, as the sun and the great planets. It is nenessary to suppose an invariable position of the pole and the principal height differences of the crust already developed. It is found, that the viscosity of the earth in that time has been small in comparison to its present value (1014 to 1020 c.g.s.).相似文献
14.
15.
Erich Wisser 《Rock Mechanics and Rock Engineering》1972,4(3):177-183
ZusammenfassungEine einfache Methode zur rechnerischen Ermittlung der Verschiebung eines Hohlraumrandes In diesem Artikel wird gezeigt, daß bei dem im Gebirge oft zulässigen vereinfachten Näherungsansatz für das statische System als unendlich ausgedehnte, im Unendlichen mit einer vertikalen und einer horizontalen Gleichlast belastete, gelochte, isotrope Scheibe die Verschiebung des Hohlraumrandes infolge des Felsausbruches mit einer einfachen Formel gefunden werden können. Im ersten Teil wird die theoretische Ableitung nach der Scheibentheorie kurz dargelegt, im zweiten Teil wurden die Formeln für die praktische Anwendung zusammengestellt und an Hand eines Beispieles erläutert. Mit dieser Methode ist es für den projektierenden Ingenieur auch ohne Kenntnis der Scheibentheorie leicht, Richtung und Größenordnung der zu erwartenden Verschiebungen bei Schaffung eines Felshohlraumes zu bestimmen und den Einfluß der gewählten Querschnittsform auf die Deformationen zu untersuchen.
Mit 1 Abbildung 相似文献
SummaryA Simple Method for the Calculation of the Boundary Displacements of an Excavation A simple formula is presented for the boundary displacements of a hole in an infinite homogeneous isotropic perfectly elastic two-dimensional body with uniform external pressures at infinity. This mathematical model is often permissible for tunnels or other long excavations in rock. In the first part the formula is derived, while the second part gives an example for practical application. The method enables the projecting engineer to evaluate quickly and easily the boundary displacements in direction and magnitude and consequently to investigate the influence of the chosen cross-sectional shape on the displacements of the walls.
RésuméUne méthode simple pour évaluer les déplacements du contour d'une cavité Une formule simple est présentée pour les déplacements du contour d'une cavité dans un corps infini, élastique, isotrope, à deux dimensions, soumis à une pression uniforme à l'infini. Ce modèle mathématique est souvent acceptable pour les tunnels ou autres cavités allongées dans la roche. En première partie, la formule est développée; la seconde partie donne un exemple d'application pratique. Cette méthode permettra à l'ingénieur projeteur de déterminer promptement et facilement les déplacements de la paroi en direction et en grandeur et d'examiner l'influence de la section transversale choisie sur ces déplacements.
Mit 1 Abbildung 相似文献
16.
Lake Constance whitefish (Coregonus lavaretus wartmanni) spawn in the water column. The demersal eggs develop at the mud-water interface at depths down to 250 m. Samples were taken
by dredging areas of 100 m2. Mortality, developmental stages and rate of malformations were determined. Incubation period lasts roughly from December
to March. The percentage of dead eggs increased from 52% in January to 74% in February. Among living eggs deformations of
the trunk raised from 4% to 31% during the same time. It is assumed that larvae with anomalities of the trunk will have no
survival chances. Total losses were 91.7% in the average of all samples.
相似文献
17.
Erich Dimhoth 《International Journal of Earth Sciences》1975,64(1):751-767
It is possible to apply actualistic principles to the interpretation of the paleoenvironment of iron-rich sedimentary rocks, although few iron-rich sediments form today. The sedimentary textures and structures of cherty iron-formations, Minette-tpye ironstones and limestones are similar. These similarities prove that the hydrodynamic processes of the deposition of the three rock types are the same. Therefore, it is possible to define facies of cherty iron-formations and Minette-type ironstones on the basis of their sedimentary textures and structures, disregarding mineralogy, and to interprete the formative environment by comparison with Recent limestones. Shaly sulfide iron-formation and sideritic clay ironstones are ferriferous mudstones. Methods applied to the interpretation of iron-poor shales may also be applied to these two rock types. The mineralogy of iron-rich sedimentary rocks is determined by diagenetic processes. Depositional organic content of the sediment, sediment texture (which controls diffusivity and permeability) and the groundwater flow system during diagenesis are the primary controls of iron-mineral diagenesis. Paleogeography and basin bathymetry are indirect controls of iron mineralogy, because they affect organic content and sediment texture. 相似文献
18.
19.
This work concerns an analysis of inter-basin and inter-layer exchanges in the component ocean part of the coupled ECHAM4/OPYC3
general circulation model, aimed at documenting the simulation of North Atlantic Deep Water (NADW) and related thermohaline
circulations in the Indian and Pacific Oceans. The modeled NADW is formed mainly in the Greenland– Iceland–Norwegian Seas
through a composite effect of deep convection and downward cross-isopycnal transport. The modeled deep-layer outflow of NADW
can reach 16 Sv near 30 °S in the South Atlantic, with the corresponding upper-layer return flow mainly coming from the “cold
water path” through Drake Passage. Less than 4 Sv of the Agulhas “leakage” water contributes to the replacement of NADW along
the “warm water path”. In the South Atlantic Ocean, the model shows that some intermediate isopycnal layers with potential
densities ranging between 27.0 and 27.5 are the major water source that compensate the NADW return flow and enhance the Circumpolar
Deep Water (CDW) flowing from the Atlantic into Indian Ocean. The modeled thermohaline circulations in the Indian and Pacific
Oceans indicate that the Indian Ocean may play the major role in converting deep water into intermediate water. About 16 Sv
of the CDW-originating deep water enters the Indian Ocean northward of 31 °S, of which more than 13 Sv “upwell” mainly near
the continental boundaries of Africa, South Asia and Australia through inter-layer exchanges and return to the Antarctic Circumpolar
Current (ACC) as intermediate-layer water. As a contrast, only 4 Sv of Pacific intermediate water is connected to “upwelling”
flow southward across 31 °S while the magnitude of northward deep flow across 31 °S in the Pacific Ocean is significantly
greater than that in the Indian Ocean. The model suggests that a large portion of the deep waters entering the Pacific Ocean
(about 14 Sv) “upwells” continually into some upper layers through the thermocline, and becomes the source of the Indonesian
throughflow. Uncertainties in these results may be related to the incomplete adjustment of the model’s isopycnal layers and
the sensitivity of the Indonesian throughflow to the model’s geography and topography.
Received: 12 August 1997/Accepted: 12 March 1998 相似文献
20.