全文获取类型
收费全文 | 436篇 |
免费 | 27篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 8篇 |
大气科学 | 31篇 |
地球物理 | 110篇 |
地质学 | 167篇 |
海洋学 | 40篇 |
天文学 | 65篇 |
自然地理 | 43篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 7篇 |
2019年 | 11篇 |
2018年 | 10篇 |
2017年 | 5篇 |
2016年 | 14篇 |
2015年 | 14篇 |
2014年 | 17篇 |
2013年 | 34篇 |
2012年 | 20篇 |
2011年 | 25篇 |
2010年 | 24篇 |
2009年 | 29篇 |
2008年 | 24篇 |
2007年 | 25篇 |
2006年 | 25篇 |
2005年 | 21篇 |
2004年 | 25篇 |
2003年 | 17篇 |
2002年 | 17篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 9篇 |
1997年 | 5篇 |
1996年 | 6篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1974年 | 3篇 |
1971年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有464条查询结果,搜索用时 109 毫秒
461.
462.
Steerable wavelet analysis of CMB structures alignment 总被引:2,自引:0,他引:2
Patricio Vielva Yves Wiaux Enrique Martínez-Gonzlez Pierre Vandergheynst 《New Astronomy Reviews》2006,50(11-12):880
This paper reviews the application of a novel methodology for analysing the isotropy of the universe by probing the alignment of local structures in the CMB. The strength of the proposed methodology relies on the steerable wavelet filtering of the CMB signal. One the one hand, the filter steerability renders the computation of the local orientation of the CMB features affordable in terms of computation time. On the other hand, the scale-space nature of the wavelet filtering allows to explore the alignment of the local structures at different scales, probing possible different phenomena. We present the WMAP first-year data analysis recently performed by the same authors (Wiaux et al.), where an extremely significant anisotropy was found. In particular, a preferred plane was detected, having a normal direction with a northern end position at (θ, ) = (34°, 331°), close to the northern end of the CMB dipole axis. In addition, a most preferred direction was found in that plane, with a northern end direction at (θ, ) = (71°, 91°), very close to the north ecliptic pole. This result synthesised for the first time previously reported anomalies identified in the direction of the dipole and the ecliptic poles axes. In a forthcoming paper (Vielva et al.), we have extended our analysis to the study of individual frequency maps finding first indications for discarding foregrounds as the origin of the anomaly. We have also tested that the preferred orientations are defined by structures homogeneously distributed in the sky, rather than from localised regions. We have also analysed the WMAP 3-year data, finding the same anomaly pattern, although at a slightly lower significance level. 相似文献
463.
Michel Ritz Henri Robain Evgeni Pervago Yves Albouy Christian Camerlynck Marc Descloitres Adama Mariko 《Geophysical Prospecting》1999,47(2):85-101
Near-surface inhomogeneities (NSIs) can lead to severe problems in the interpretation of apparent resistivity pseudosections because their effects significantly complicate the image aspect. In order to carry out a more efficient and reliable interpretation process, these problematic features should be removed from field data. We describe a filtering scheme using two-sided half-Schlumberger array data. The scheme was tested on synthetic data, generated from a simple 2D resistivity model contaminated by NSIs, and is shown to be suitable for eliminating such contaminations from apparent resistivity data. Furthermore, the original model without NSIs can be recovered satisfactorily from the inversion of filtered apparent resistivity data. The algorithm is also applied efficiently to a real data set collected at Nsimi, in southern Cameroon, along a 200-m shallow depth profile crossing a complex transitional zone. For this case, the filtering scheme provides accurate structural and behavioural interpretations of both the geometry of the major soil constituents and the groundwater partitioning. 相似文献
464.
Rock slope failure in a recently deglaciated permafrost rock wall at Piz Kesch (Eastern Swiss Alps), February 2014 下载免费PDF全文
Marcia Phillips Andrea Wolter Rachel Lüthi Florian Amann Robert Kenner Yves Bühler 《地球表面变化过程与地形》2017,42(3):426-438
In February 2014, a rock pillar with a volume of around 150 000 m3 collapsed at Piz Kesch in the Eastern Swiss Alps. A reconstruction of the conditions prior to the event and of the event itself is presented on the basis of different sources of data. The methods applied include photogrammetry, terrestrial laser scanning, structural geological analysis, examination of meteorological data, carbon‐14 (14C) dating of organic material in permafrost ice from a tension crack and numerical modelling of likely modes of failure. Despite a complete lack of in situ measurements in the rock wall prior to the event and of direct observations during the event, the available data allow the determination of the approximate timing of the event as well as the structural predisposition, the probable mode of failure and the timescale of several millennia involved in the triggering of the failure of the rock pillar. The interdisciplinary analysis of this event contributes towards understanding the complex interaction of processes involved in large rock slope failures currently occurring in warming mountain permafrost regions. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献