全文获取类型
收费全文 | 966篇 |
免费 | 24篇 |
国内免费 | 2篇 |
专业分类
测绘学 | 71篇 |
大气科学 | 65篇 |
地球物理 | 210篇 |
地质学 | 362篇 |
海洋学 | 52篇 |
天文学 | 153篇 |
综合类 | 2篇 |
自然地理 | 77篇 |
出版年
2022年 | 11篇 |
2021年 | 18篇 |
2020年 | 13篇 |
2019年 | 9篇 |
2018年 | 34篇 |
2017年 | 31篇 |
2016年 | 47篇 |
2015年 | 16篇 |
2014年 | 38篇 |
2013年 | 63篇 |
2012年 | 39篇 |
2011年 | 29篇 |
2010年 | 39篇 |
2009年 | 32篇 |
2008年 | 36篇 |
2007年 | 38篇 |
2006年 | 27篇 |
2005年 | 22篇 |
2004年 | 25篇 |
2003年 | 21篇 |
2002年 | 14篇 |
2001年 | 17篇 |
2000年 | 17篇 |
1999年 | 13篇 |
1998年 | 16篇 |
1997年 | 10篇 |
1996年 | 14篇 |
1995年 | 16篇 |
1994年 | 9篇 |
1993年 | 16篇 |
1992年 | 8篇 |
1991年 | 8篇 |
1990年 | 13篇 |
1989年 | 8篇 |
1988年 | 13篇 |
1987年 | 8篇 |
1986年 | 8篇 |
1985年 | 16篇 |
1984年 | 14篇 |
1983年 | 16篇 |
1982年 | 18篇 |
1981年 | 14篇 |
1980年 | 12篇 |
1979年 | 16篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1975年 | 7篇 |
1973年 | 14篇 |
1972年 | 13篇 |
1968年 | 6篇 |
排序方式: 共有992条查询结果,搜索用时 203 毫秒
991.
Ben De Mol Max Kozachenko Andy Wheeler Hugo Alvares Jean-Pierre Henriet Karine Olu-Le Roy 《International Journal of Earth Sciences》2007,96(1):103-120
High-resolution seismic profiles, swath bathymetry, side-scan sonar data and video imageries are analysed in this detailed
study of five carbonate mounds from the Belgica mound province with special emphasis on the well-surveyed Thérèse Mound. The
selected mounds are located in the deepest part of the Belgica mound province at water depths of 950 m. Seismic data illustrate
that the underlying geology is characterised by drift sedimentation in a general northerly flowing current regime. Sigmoidal
sediment bodies create local slope breaks on the most recent local erosional surface, which act as the mound base. No preferential
mound substratum is observed, neither is there any indication for deep geological controls on coral bank development. Seismic
evidence suggests that the start-up of the coral bank development was shortly after a major erosional event of Late Pliocene–Quaternary
age. The coral bank geometry has been clearly affected by the local topography of this erosional base and the prevailing current
regime. The summits of the coral banks are relatively flat and the flanks are steepest on their upper slopes. Deposition of
the encased drift sequence has been influenced by the coral bank topography. Sediment waves are formed besides the coral banks
and are the most pronounced bedforms. These seabed structures are probably induced by bottom current up to 1 m/s. Large sediment
waves are colonised by living corals and might represent the initial phase of coral bank development. The biological facies
distribution of the coral banks illustrate a living coral cap on the summit and upper slope and a decline of living coral
populations toward the lower flanks. The data suggest that the development of the coral banks in this area is clearly an interaction
between biological growth processes and drift deposition both influenced by the local topography and current regime. 相似文献
992.
A range of mineral magnetic measurements have been carried out on archaeological sediments from Orkney and Cyprus. In a soil profile from Orkney, a magnetic enhancement factor of over 200 is observed in susceptibility data between the bedrock and a Norse sediment. The magnetic enhancement is associated with an increase in superparamagnetic grains probably caused by burning. Until now it has proved difficult to confirm the presence of superparamagnetic grains in natural samples using room temperature magnetic measurements. However, clear differences are to be found between the hysteresis loops of various magnetic domain states, including superparamagnetism. An algorithm has been developed to unmix hysteresis loops in terms of constituent domain states of ferrimagnetic iron oxides. Unmixing 128 hysteresis loops of archaeological sediments has shown that the dominant domain state in all sediments is superparamagnetic. Remarkably uniform superparamagnetic grain sizes of between 80 and 95 Å were found for all 128 sediments. © 1999 John Wiley & Sons, Inc. 相似文献