全文获取类型
收费全文 | 312篇 |
免费 | 5篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 18篇 |
大气科学 | 20篇 |
地球物理 | 70篇 |
地质学 | 135篇 |
海洋学 | 12篇 |
天文学 | 46篇 |
自然地理 | 17篇 |
出版年
2021年 | 2篇 |
2020年 | 4篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2016年 | 11篇 |
2015年 | 6篇 |
2014年 | 10篇 |
2013年 | 11篇 |
2012年 | 19篇 |
2011年 | 17篇 |
2010年 | 5篇 |
2009年 | 21篇 |
2008年 | 15篇 |
2007年 | 19篇 |
2006年 | 18篇 |
2005年 | 22篇 |
2004年 | 19篇 |
2003年 | 18篇 |
2002年 | 8篇 |
2001年 | 5篇 |
2000年 | 10篇 |
1999年 | 6篇 |
1998年 | 12篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1987年 | 2篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有318条查询结果,搜索用时 343 毫秒
211.
Mahdi Motagh Jürgen Klotz Farokh Tavakoli Yahya Djamour Siavash Arabi Hans-Ulrich Wetzel Jochen Zschau 《Pure and Applied Geophysics》2006,163(1):1-18
We used new precise leveling data acquired 40 days after the Bam earthquake in combination with radar interferometry observations
from both ascending and descending orbits to investigate static deformation associated with the 2003 Bam earthquake. We invert
this geodetic data set to gain insight into the fault geometry and slip distribution of the rupture. The best-fitting dislocation
model is a steeply east-dipping right-lateral strike-slip fault that has a size of 11 by 8 km and strikes N2°W. We find that
such smooth geometry fits available geodetic data better than previously proposed models for this earthquake. Our distributed
slip model indicates a maximum strike slip of 3 m occurring about 3 to 5 km deep. The slip magnitude and depth of faulting
taper to the north, where the fault approaches the Bam city. Inclusion of crustal layering increases the amount of maximum
slip inferred at depth by about 4%. 相似文献
212.
213.
Books reviewed:
MARSHA ALIBRANDI, GIS in the Classroom: Using Geographic Information Systems in Social Studies and Environmental Science
JO WOOD, Java Programming for Spatial Sciences 相似文献
MARSHA ALIBRANDI, GIS in the Classroom: Using Geographic Information Systems in Social Studies and Environmental Science
JO WOOD, Java Programming for Spatial Sciences 相似文献
214.
The Southern Alps of New Zealand are the topographic expression of active oblique continental convergence of the Australian and Pacific plates. Despite inferred high rates of tectonic and climatic forcing, the pattern of differential uplift and erosion remains uncertain. We use a 25-m DEM to conduct a regional-scale relief analysis of a 250-km long strip of the western Southern Alps (WSA). We present a preliminary map of regional erosion and denudation by overlaying mean basin relief, a modelled stream-power erosion index, river incision rates, historic landslide denudation rates, and landslide density. The interplay between strong tectonic and climatic forcing has led to relief production that locally attains 2 km in major catchments, with mean values of 0.65–0.68 km. Interpolation between elevations of major catchment divides indicates potential removal of l01–103 km3, or a mean basin relief of 0.51–0.85 km in the larger catchments. Local relief and inferred river incision rates into bedrock are highest about 50–67% of the distance between the Alpine fault and the main divide. The mean regional relief variability is ± 0.5 km.Local relief, valley cross-sectional area, and catchment width correlate moderately with catchment area, and also reach maximum values between the range front and the divide. Hypsometric integrals show scale dependence, and together with hypsometric curves, are insufficient to clearly differentiate between glacial and fluvial dominated basins. Mean slope angle in the WSA (ψ = 30°) is lower where major longitudinal valleys and extensive ice cover occur, and may be an insensitive measure of regional relief. Modal slope angle is strikingly uniform throughout the WSA (φ = 38–40°), and may record adjustment to runoff and landsliding. Both ψ and φ show non-linear relationships with elevation, which we attribute to dominant geomorphic process domains, such as fluvial processes in low-altitude valley trains, surface runoff and frequent landsliding on montane hillslopes, “relief dampening” by glaciers, and rock fall/avalanching on steep main-divide slopes. 相似文献
215.
Jochen Aberle 《Acta Geophysica》2007,55(1):23-32
The roughness geometry function of the interfacial sublayer of a gravel-bed armour layer was measured directly by filling
water stepwise into a laboratory flume and indirectly from a digital elevation model (DEM) of the surface. The results of
both methods are compared and show that the DEM can be used to reliably estimate the roughness density function for a wide
range of the interfacial sublayer. The direct measurements revealed an absolute minimum of porosity at the level of the roughness
trough which is significantly smaller than porosity in the undisturbed subsurface and porosity estimates obtained from relationships
found in the literature. The significance of the results for hydraulic engineering and ecological applications is highlighted. 相似文献
216.
Gunnar Fjeldbo Arvydas Kliore Donald Sweetnam Pasquale Esposito Boris Seidel Taylor Howard 《Icarus》1976,29(4):439-444
An analysis of the Mariner 10 dual frequency radio occultation recordings has yielded new information on the radius and atmosphere of Mercury. The ingress measurements which were conducted near 1.1° North latitude and 67.4° East longitude on the night side of the planet, gave a value for the radius of 2439.5 ± 1 km. Egress near 67.6° North latitide and 258.4° East longitude in the sunlit side yielded a radius of 2439.0 ± 1 km. The atmospheric measurements showed the electron density to be less than 103 cm?3 on both sides of the planet. From the latter result one may infer an upper limit to the dayside surface gas density of 106 molecules per cm3. 相似文献
217.
We present proper motion measurements for a number of knots in the jets and bow shocks of the outflows from DG Tau, DG Tau B, T Tau, CoKu Tau 1, FS Tau, and FS Tau B in the nearby Taurus-Auriga star forming region. From these measurements and the available radial velocity data we derive tangential velocities, spatial velocities, angles of the outflows with respect to the plane of the sky, and in a couple of cases the pattern motions of the knots relative to the flow speed. 相似文献
218.
219.
B. Flores Humanante E. Giroletti J. Idrovo M. Monnin R. Pasinetti J. -L. Seidel 《Pure and Applied Geophysics》1990,132(3):505-520
A radon concentration measurement survey was carried out in Ecuador using the SSNTD technique. The data analysis shows a definite radon anomaly prior to March 6, 1987;M=6.9 earthquake. Anomalies found before October 18 and October 28th mild earthquakes in 1986 could be correlated with these events. Other anomalies that we cannot correlate with any geophysical event were also found. 相似文献
220.
Early Tertiary carbonates (Gebel Abyad Formation) are described from an isolated limestone plateau from the northwestern Sudan. They represent the southernmost outskirts of marine, Tertiary sediments in northeast Africa, which can be connected with transgressive/regressive cycles of the Tethys onto the African craton. Microfacies studies of the carbonates yielded exclusively shallow marine sediments which dried up temporarily, and with changing rates of terrigenous input. They contain a low diverse fauna and flora, poor in individuals. The paleogeographic reconstruction of this isolated occurrence was possible by comparing sediments from southern Egypt.
Zusammenfassung Aus dem nordwestlichen Sudan werden alttertiäre Karbonate (Gebel Abyad Formation) beschrieben, die ein isoliertes Vorkommen darstellen. Diese repräsentieren die südlichsten marinen tertiären Ablagerungen in Nordost-Afrika, die mit transgressiv/regressiven Zyklen der Tethys auf den afrikanischen Kraton in Verbindung gebracht werden können. Die mikrofaziell bearbeiteten Kalke stellen ausschlie\lich flachmarine Ablagerungen dar, mit Anzeichen für zeitweiliges Trockenfallen, und wechselnden Anteilen terrigener Zufuhr. Sie enthalten eine gering-diverse, individuenarme Fauna und Flora. Faziell vergleichbare Ablagerungen in Südägypten lassen eine Rekonstruktion dieses isolierten Kalkvorkommens zu einem paläogeographischen Modell zu.
Résumé Cette note décrit des roches carbonatées d'âge tertiaire inférieur (formation du Jebel Abyad) qui font partie d'un plateau isolé dans le nord-ouest du Soudan. Elles représentent l'extension méridionale maximale de la sédimentation marine tertiaire dans le nord-est de l'Afrique, sédimentation qui peut Être reliée aux cycles de transgressionsrégressions de la Téthys sur le bloc continental africain. L'étude des microfacies amène à les identifier comme des dépÔts marins de faible profondeur, temporairement asséchés et mÊlés d'apports terrigènes en quantité variable. Ils renferment une flore et une faune pauvres en espèces et en individus. La comparaison avec des sédiments du Sud égyptien permet de les intégrer dans un modèle paléogéographique.
- ( Gebel Abyad), . - , . , . . , .相似文献