全文获取类型
收费全文 | 1348篇 |
免费 | 46篇 |
国内免费 | 14篇 |
专业分类
测绘学 | 32篇 |
大气科学 | 99篇 |
地球物理 | 340篇 |
地质学 | 582篇 |
海洋学 | 106篇 |
天文学 | 148篇 |
综合类 | 5篇 |
自然地理 | 96篇 |
出版年
2023年 | 3篇 |
2021年 | 9篇 |
2020年 | 8篇 |
2019年 | 8篇 |
2018年 | 27篇 |
2017年 | 31篇 |
2016年 | 46篇 |
2015年 | 34篇 |
2014年 | 35篇 |
2013年 | 80篇 |
2012年 | 50篇 |
2011年 | 73篇 |
2010年 | 74篇 |
2009年 | 80篇 |
2008年 | 62篇 |
2007年 | 66篇 |
2006年 | 59篇 |
2005年 | 84篇 |
2004年 | 60篇 |
2003年 | 45篇 |
2002年 | 43篇 |
2001年 | 37篇 |
2000年 | 22篇 |
1999年 | 31篇 |
1998年 | 22篇 |
1997年 | 10篇 |
1996年 | 20篇 |
1995年 | 15篇 |
1994年 | 19篇 |
1993年 | 10篇 |
1992年 | 18篇 |
1991年 | 11篇 |
1990年 | 16篇 |
1989年 | 9篇 |
1988年 | 10篇 |
1987年 | 10篇 |
1986年 | 16篇 |
1985年 | 16篇 |
1984年 | 15篇 |
1983年 | 10篇 |
1982年 | 10篇 |
1981年 | 15篇 |
1980年 | 8篇 |
1979年 | 11篇 |
1978年 | 8篇 |
1977年 | 10篇 |
1976年 | 11篇 |
1975年 | 5篇 |
1974年 | 13篇 |
1973年 | 4篇 |
排序方式: 共有1408条查询结果,搜索用时 359 毫秒
371.
Joseph Canérot Jacques Bauer Michel Bilotte Chantal Bourdillon Jean-Paul Colin Elie-Jean Debroas Françoise Magniez Francis Mediavilla Yves Ternet 《Comptes Rendus Geoscience》2004,336(10):951-958
By us considered as Albo-Aptian in age and generated through halokinetic processes, the Bosmendiette breccias have been recently interpreted as Selandian (Palaeocene) globigerine-bearing sediments deposited in sub-marine canyons within a deep trough crossing the Pyrenees, from the Mediterranean Sea to the Atlantic Ocean. These breccias are really azoic in their lower part and contain a scarce microfauna including radolarians and benthic foraminifera at the top of the formation. They are unconformably covered by the Urgo-Aptian limestones and marls and indicate, under opening marine conditions, Lower Cretaceous collapse movements and northward sliding of the Jurassic slumped cover, related to the growth of the Béloscare–Apoura diapir. To cite this article: J. Canérot et al., C. R. Geoscience 336 (2004). 相似文献
372.
The North-Pyrenean Front overthrust in northern direction was particularly active during the Upper Cretaceous, before the Upper Eocene tectonic renewal. Indeed, in the Eastern Pyrenees (Aude), ‘Garumnian’ (continental Upper Cretaceous–Palaeocene) formations lie transgressively upon the North-Pyrenean Triassic (Keuper) formation and upon the Albian beds of the Sub-Pyrenean Cucugnan slice. Relations between the North-Pyrenean Frontal Thrust and, to the northeast, the Corbières Nappe are discussed. To cite this article: A. Charrière, M. Durand-Delga, C. R. Geoscience 336 (2004). 相似文献
373.
Recent very high-resolution seismic profiles ground-truthed by vibrocores allow us to evidence an atypical incised valley fill in a drowned valley segment, the ‘Pertuis Breton’ (Bay of Biscay, France). The sedimentary valley-fill architecture mainly includes five superimposed progradational wedges composed by marine sands. Sandbodies show a landward migration of their depocentres upward and are topped by almost flat unconformities extended by submarine terraces. This sedimentary infill pattern is similar to backstepping wedges, described on continental shelfs. It suggests that this valley fill records sea-level rise during the last transgression. To cite this article: N. Weber et al., C. R. Geoscience 336 (2004). 相似文献
374.
Mathieu Schuster Philippe Duringer Jean‐Francois Ghienne Patrick Vignaud Alain Beauvilain Hassan Taisso Mackaye Michel Brunet 《地球表面变化过程与地形》2003,28(10):1059-1069
This paper reports on a study dealing with the rhyolitic inselbergs of Hadjer el Khamis that formed palaeoislands during Lake Mega‐Chad events. Field observations have shown that: (1) conglomeratic patches of immature to mature clasts are preserved at the feet of the Hadjer el Khamis inselbergs; (2) in cross‐section, their pro?le reveals a well de?ned cliff–platform junction at a constant elevation (325 m). The monolithological clasts show all degrees of roundness, from angular cobbles to well rounded pebbles. This wide range of maturity suggests a coastal origin for these cobbles. The system was permanently fed with angular clasts, which were progressively worn by waves. Cobbles that were wave‐worked for the longest time are the best rounded. The cliff–platform junction is the result of erosion by waves, which attacked and undercut the inselberg cliffs during Lake Mega‐Chad events. Asymmetrical erosion pro?les moreover suggest a wind regime dominated by SW to NE oriented winds. These interpretations have two implications. The elevation of the cliff–platform junction is an indication of the highest water level of Lake Mega‐Chad at 320–325 m, which is in agreement with other observations elsewhere in the basin. The SW to NE oriented winds show that monsoon‐related winds were prevalent during Lake Mega‐Chad events, suggesting the Inter‐Tropical Convergence Zone was located higher in latitude than today. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
375.
376.
Movement of water through the thick unsaturated zone underlying Oro Grande and Sheep Creek Washes in the western Mojave Desert,USA 总被引:1,自引:0,他引:1
Previous studies indicate that a small quantity of recharge occurs from infiltration of streamflow in intermittent streams
in the upper Mojave River basin, in the western Mojave Desert, near Victorville, California. Chloride, tritium, and stable
isotope data collected in the unsaturated zone between 1994 and 1998 from boreholes drilled in Oro Grande and Sheep Creek
Washes indicate that infiltration of streamflow occurs to depths below the root zone, and presumably to the water table, along
much of Oro Grande Wash and near the mountain front along Sheep Creek Wash. Differences in infiltration at sites along each
wash are the result of hydrologic variables such as proximity to the mountain front, quantity of streamflow, and texture of
the subsurface deposits. Differences in infiltration between the washes are the result of large-scale geomorphic processes.
For example, Oro Grande wash is incised into the Victorville fan and infiltration has occurred at approximately the same location
over recent geologic time. In contrast, Sheep Creek Wash overlies an active alluvial fan and the stream channel can move across
the fan surface through time. Infiltration does not occur to depths below the root zone at control sites outside of the washes.
Electronic Publication 相似文献
377.
378.
379.
Thierry Sempere Gabriel Carlier Pierre Soler Michel Fornari Víctor Carlotto Javier Jacay Oscar Arispe Didier Nraudeau Jos Crdenas Silvia Rosas Nstor Jimnez 《Tectonophysics》2002,345(1-4)
Integrated studies and revisions of sedimentary basins and associated magmatism in Peru and Bolivia (8–22°S) show that this part of western Gondwana underwent rifting during the Late Permian–Middle Jurassic interval. Rifting started in central Peru in the Late Permian and propagated southwards into Bolivia until the Liassic/Dogger, along an axis that coincides with the present Eastern Cordillera. Southwest of this region, lithospheric thinning developed in the Early Jurassic and culminated in the Middle Jurassic, producing considerable subsidence in the Arequipa basin of southern Peru. This 110-Ma-long interval of lithospheric thinning ended 160 Ma with the onset of Malm–earliest Cretaceous partial rift inversion in the Eastern Cordillera area.The lithospheric heterogeneities inherited from these processes are likely to have largely influenced the distribution and features of younger compressional and/or transpressional deformations. In particular, the Altiplano plateau corresponds to a paleotectonic domain of “normal” lithospheric thickness that was bounded by two elongated areas underlain by thinned lithosphere. The high Eastern Cordillera of Peru and Bolivia results from Late Oligocene–Neogene intense inversion of the easternmost thinned area. 相似文献
380.
The fractured Coniacian chalk from the Omey area (Paris Basin, France) displays strong evidence of modifications controlled by brittle deformation. Fracturing is associated with important changes in pore space (decrease in total porosity and pore interconnection, change in distribution of pore access diameters and capillary characteristics), nannofacies (gradual evolution from a point-contact fabric to a welded, interlocked or coalescent fabric) and chemical composition (Sr concentration decrease). These modifications result from fluid–rock interaction that control significant mass transfer (percentage of secondary calcite >50%). Sr is a remarkable indicator of these mass transfers. Sr analyses allowed us to prove that the deformed zone (26.7 m) is wider than the fractured zone (11.3 m). They also indicate that the footwall block is less affected than the hanging wall block. A physicochemical model of the deformation mechanism is proposed. It shows that a cyclic process of fracturing controls the temporal evolution of the fluid saturation and fluid pressure and, consequently, the mass transfer. 相似文献