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   56篇
  免费   1篇
  2019年   1篇
  2018年   1篇
  2017年   5篇
  2016年   2篇
  2015年   1篇
  2013年   11篇
  2012年   3篇
  2011年   3篇
  2010年   10篇
  2009年   7篇
  2008年   5篇
  2007年   2篇
  2006年   5篇
  2001年   1篇
排序方式: 共有57条查询结果,搜索用时 15 毫秒
51.
Electron spin resonance (ESR) can be used to determine the thermal history of charred organic material. Maize seeds were heated under controlled conditions in order to produce calibration curves relating g‐values (the rate of electron splitting) and spin intensities (the number of spin centres) to heating temperatures, times and conditions. These experiments reproduced results that had been previously obtained by other laboratories, with some minor exceptions. The calibration curves were then used to reconstruct the thermal histories of charred maize kernels from several prehistoric sites in eastern North America. At these sites, the differing thermal histories of maize kernels are correlated with depositional contexts.  相似文献   
52.
Wood exposed to a heat source can be transformed into charcoal if subject to conditions of carbonisation (in the absence of air) or charring (in restricted air). Charcoal recovered from archaeological sites can yield fundamental information to our understanding of human economic and cultural development over time and (ecological) setting. This work describes the morphological (anatomy, degree of shrinkage), physical (reflectance) and chemical (elemental, molecular composition) properties of charcoal in relation to heat source and wood variables. In this study charcoal and charcoal fuel were experimentally produced whereby temperature (160–1200 °C), time of exposure (2–1440 min), heating rate (high and low) and wood type (angiosperm and conifer) were varied. The results show that charcoal, often described as an inert, black material, has different chemical and physical properties in relation to the investigated variables. By using these different properties it is possible to distinguish between the different types of fires (domestic and industrial) exploited by humans in the past. Morphological analyses and reflectance measurements are effective tools for this purpose and can be used in wood exposed to temperatures of 300 °C and above—temperatures which are relevant to archaeological research. Angiosperm and conifer wood react in different ways when exposed to heat and thus the taxonomic identity of archaeological material needs to be known. Chemical analyses can be used for wood exposed to temperatures below 400 °C whereas elemental analyses of the carbon content can be used for wood exposed to temperatures up to a maximum of 650 °C.  相似文献   
53.
Wild rice (Zizania spp.) is an important native grain of north-central North America, with spiritual and subsistence significance to many native peoples. Due to lack of suitable proxies, its past distribution and pattern of use are poorly known. This study demonstrates the diagnostic value of silica phytoliths from Z. palustris as a proxy tool to detect its past occurrence in a variety of paleoenvironmental and archaeological contexts. Our main findings are: 1) Dominant wetland grass species in Minnesota produce phytoliths distinct from Zizania phytoliths; 2) Closely related Leersia oryzoides produces a few Zizania-like phytolith morphotypes; however, these potential confusers can be identified based on 2-D and 3-D morphologies; 3) Z. palustris produces a wide variety of phytolith morphotypes, many of which are only found in certain parts of the plant (e.g., Inflorescence Type 1 from the spikelet); 4) Z. palustris produces 23 locally diagnostic phytolith morphotypes that can be used to determine the presence and abundance of wild rice in modern and paleo lake sediments; and 5) Wild rice phytolith Inflorescence Type 1 is the morphotype most likely to be observed in archaeological contexts, and may be unequivocally diagnostic for the genera Zizania.  相似文献   
54.
Archaeobotanical analyses were carried out on layers from the site of Piazza Garibaldi in Parma, a town located in the plain of Emilia Romagna, in northern Italy. The layers dated to the 3rd–2nd centuries BC, around the time of the foundation of the Roman town, and to the 10th–11th centuries AD. According to archaeological data, the site was a sacred area in Roman times, while it was a market square in Mediaeval times. Data from pollen and seeds/fruits were useful for both palaeoenvironmental and palaeoethnobotanical reconstructions, and together with NPPs including parasite remains contributed to add details on the function of the site in the different chronological phases.  相似文献   
55.
The paper presents the large set of basketry and other worked fibre artefacts constituting the perishable artefacts assemblage from the Takarkori rock shelter. This site is located in southwestern Libya, central Sahara. Its well-preserved Holocene stratigraphy testifies to human occupations by foraging groups (Late Acacus culture; ca. 9000–7400 uncal years bp; ca. 8300–6100 BCE) and herders (Pastoral cultures; ca. 7400–4500 uncal years bp; ca. 6400–3000 BCE).  相似文献   
56.
The accumulation of recent data from archaeobotany, archaeozoology and Neolithic excavations from across South Asia warrants a new overview of early agriculture in the subcontinent. This paper attempts a synthesis of these data while recommending further systematic work and methodological developments. The evidence for origins and dispersals of important crops and livestock from Southwest Asia into South Asia is reviewed. In addition evidence for indigenous plant and animal domestication in India is presented. Evidence for probable indigenous agricultural developments in Gujarat, the Middle Ganges, Eastern India, and Southern India are reviewed. An attempt is made to highlight regions of important frontiers of interaction between early farmers and hunter-gatherers. The current evidence suggests that the Neolithic trajectories in different parts of South Asia differ from each other. Indigenous centers of plant domestication in India also differ from the often discussed trajectory of Southwest Asia, while suggesting some similarities with agricultural origins in Africa and Eastern North America as well as secondary agricultural developments on the peripheries of Eurasia. An erratum to this article can be found at  相似文献   
57.
The recovery of new plant remains from eastern Croatia are discussed here in order to determine their ritual significance and how this evidence may fit into chronological and regional observations on ritual plant offerings in the Roman world. Samples collected from inhumations, cremations and an altar dedicated to Silvanus Domesticus, dating from the 2nd to 4th centuries AD, are presented and show that a range of more ‘common’ plant remains, such as cereals and pulses, were an important part of ritual life. These results are also compared to the growing archaeobotanical data collected from shrine and cremation burials across Europe. Although the archaeobotanical data from the Croatian sites are limited, the increasing evidence of ritual plant use allows observations regarding the wider context of Roman social and religious change.  相似文献   
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