首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   75篇
  免费   18篇
  2021年   1篇
  2020年   2篇
  2019年   7篇
  2018年   3篇
  2017年   7篇
  2016年   7篇
  2015年   5篇
  2014年   5篇
  2013年   7篇
  2012年   4篇
  2011年   6篇
  2010年   6篇
  2009年   3篇
  2008年   7篇
  2007年   6篇
  2006年   3篇
  2005年   2篇
  2004年   1篇
  2003年   1篇
  2002年   4篇
  2000年   2篇
  1998年   2篇
  1997年   1篇
  1982年   1篇
排序方式: 共有93条查询结果,搜索用时 15 毫秒
1.
Kuwait–Georgian archaeological work at Failaka Island showed the need for geological study. Analysis of sediments related to drinking water-collecting cisterns was performed on a Late Islamic settlement (NE part of the island) in 2018. Field sedimentological, grain size and XRD analysis of the sediment profiles showed that the shallow (about 1 m deep) cone-shaped wells are dug in the loose, porous, cross-stratified calcareous coarse-grained quartz sandstones. Three upper layers of quartz sandstones in the profile have high infiltration rate and provide a rare yet ideal material for water retention. The fourth dense layer below, composed of very fine sand and silt fraction, tends to hinder water movement and forms a relatively impermeable water-resistant surface. Thus, the distribution patterns of clay content, grain sizes and porosity of the well-hosting sediments are favourable for freshwater infiltration and harvesting. An additional petrographic analysis was conducted on different types of rocks discovered on the archaeological site, used as building material and fragments of stone artifacts to identify their origin. It was established that archaeological building material is of local origin, whereas the source rocks for stone artifacts were imported.  相似文献   
2.
3.
The Emirate of Fujairah in the UAE has many important cultural and archaeological sites. These include the Fujairah and Al‐Bithnah forts and the Al‐Bidyah Mosque. With increasing tourism patronage and development of major infrastructure projects in and around Fujairah, these sites are increasingly under threat. Their present condition requires careful mapping for proper management and future preservation efforts. This paper presents a research project that is developing a method for surveying and recording important archaeological sites. Using terrestrial laser scanning (TLS), a number of surveys were undertaken in and around the emirate. These surveys enabled a documentation of their present condition and will form an ongoing baseline study to monitor the impact of increased tourist patronage and climate change at these sites. We also investigate and make basic comparisons between our approach and the Structure from Motion (SfM) technique.  相似文献   
4.
In 2010–11 a pedestrian survey of the western end of Wadi al‐Hijr in northern Oman identified 1507 archaeological features in a 124 km2 area. Data were collected on each feature's architectural characteristics, associated artefact assemblages, topographic and environmental locations, condition of remains, and relations to other archaeological features. The majority of datable features belong to the third millennium BC and divide unequally between the Hafit and Umm an‐Nar periods. While the majority of these third‐millennium BC features were tombs, other feature types were identified, including towers, settlements, quarries, dams, enclosures, and possible platforms. Third‐millennium BC features were organised into clusters and ranged considerably in size, from a few features to several hundred. All of the clusters established during the Hafit period were maintained in the Umm an‐Nar period, suggesting a continuity throughout the third millennium. Some preliminary hypotheses regarding settlement patterns are suggested.  相似文献   
5.
6.
7.
8.
A polyphasic tectonic‐fluid system of a fault that involves crystalline and carbonate rocks (Hospital fault, Barcelona Plain) has been inferred from regional to thin section scale observations combined with geochemical analyses. Cathodoluminescence, microprobe analyses and stable isotopy in fracture‐related cements record the circulation of successive alternations of hydrothermal and low‐temperature meteoric fluids linked with three main regional tectonic events. The first event corresponds to the Mesozoic extension, which had two rifting stages, and it is characterized by the independent tectonic activity of two fault segments, namely southern and northern Hospital fault segments. During the Late Permian‐Middle Jurassic rifting, these segments controlled the thickness and distribution of the Triassic sediments. Also, dolomitization was produced in an early stage by Triassic seawater at shallow conditions. During increasing burial, formation of fractures and their dolomite‐related cements took place. Fault activity during the Middle Jurassic–Late Cretaceous rifting was localized in the southern segment, and it was characterized by hydrothermal brines, with temperatures over 180°C, which ascended through this fault segment precipitating quartz, chlorite, and calcite. The second event corresponds to the Paleogene compression (Chattian), which produced exhumation, folding and erosion, favouring the percolation of low‐temperature meteoric fluids which produced the calcitization of the dolostones and of the dolomite cements. The third event is linked with the Neogene extension, where three stages have been identified. During the syn‐rift stage, the southern segment of the Hospital fault grew by tip propagation. In the relay zone, hydrothermal brines with temperature around 140°C upflowed. During the late postrift, the Hospital fault acted as a unique segment and deformation occurred at shallow conditions and under a low‐temperature meteoric regime. Finally, and possibly during the Messinian compression, NW‐SE strike‐slip faults offset the Hospital fault to its current configuration.  相似文献   
9.
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号