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   97篇
  免费   3篇
  100篇
  2020年   1篇
  2019年   3篇
  2016年   1篇
  2015年   2篇
  2014年   2篇
  2013年   13篇
  2012年   5篇
  2011年   6篇
  2010年   7篇
  2009年   9篇
  2008年   5篇
  2007年   5篇
  2006年   5篇
  2004年   4篇
  2003年   2篇
  2002年   1篇
  2001年   2篇
  2000年   1篇
  1999年   1篇
  1997年   3篇
  1996年   2篇
  1995年   3篇
  1993年   3篇
  1992年   1篇
  1991年   3篇
  1990年   1篇
  1985年   1篇
  1982年   1篇
  1976年   2篇
  1975年   1篇
  1974年   1篇
  1973年   1篇
  1972年   2篇
排序方式: 共有100条查询结果,搜索用时 15 毫秒
11.
One hundred and twenty‐five new lead isotopic analyses on galena, mainly from the Los Pedroches – Alcudia Valley area of southern Iberia, are presented. These data allow us to define four compositional groups in the 207Pb/206Pb versus 208Pb/206Pb and 207Pb/206Pb versus 206Pb/204Pb diagrams. Group I compositions are intermediate between those previously reported for southeastern and southwestern Iberian ore mineral locations. The compositions of Group II, the largest group, overlap with ore data from southwestern Spain. Groups III and IV have compositions that have never before been identified in this region and are comparable to those from the Sardinian Cu ores, which might explain the previously assumed exotic origin for local Bronze Age artefacts.  相似文献   
12.
Historians study the living and the dead. If we can identify the rights of the living and their responsibilities to the dead, we may be able to formulate a solid ethical infrastructure for historians. A short and generally accepted answer to the question of what the rights of the living are can be found in the Universal Declaration of Human Rights. The central idea of human rights is that the living possess dignity and therefore deserve respect. In addition, the living believe that the dead also have dignity and thus deserve respect too. When human beings die, I argue, some human traces survive and mark the dead with symbolic value. The dead are less than human beings, but still reminiscent of them, and they are more than bodies or objects. This invites us to speak about the dead in a language of posthumous dignity and respect, and about the living, therefore, as having some definable core responsibilities to the dead. I argue further that these responsibilities are universal. In a Declaration of the Responsibilities of Present Generations toward Past Generations, then, I attempt to cover the whole area. I identify and comment on four body‐ and property‐related responsibilities (body, funeral, burial, and will), three personality‐related responsibilities (identity, image, and speech), one general responsibility (heritage), and two consequential rights (memory and history). I then discuss modalities of non‐compliance, identifying more than forty types of failures to fulfill responsibilities toward past generations. I conclude that the cardinal principle of any code of ethics for historians should be to respect the dignity of the living and the dead whom they study.  相似文献   
13.
14.
This paper makes the case for advancing sustainability science partnerships (SSPs) both within universities and through innovative means of integrating universities with external public‐private and civil sectors. It links the basic principles of sustainable development with an emerging science of cooperative learning that connects researchers to a wide range of partners. SSPs are specifically designed to be transformational through becoming active agents for societal change. Universities play a special role here because they can act both as communication networks and as laboratories for developing the capability to design and manage SSPs in the creative transition to sustainability. It is gratifying to note that these ideas are beginning to emerge in a number of universities, with European examples being highlighted in this paper. Further steps towards introducing full‐blooded SSPs across the university spectrum are suggested.  相似文献   
15.
16.
The employment of synchrotron techniques complemented by conventional laboratory systems has allowed us to deepen and improve our knowledge of Roman wall painting procedures. The palette identified in wall paintings from Pompeii and Herculaneum from the second century bc includes goethite, hematite, cinnabar, glauconite, Egyptian blue, and other components such as calcite and aragonite. Proof of the use of organic binders is provided by FTIR and PY–GC/MS. Therefore, the possibility of the use of ‘a secco’ techniques cannot be ruled out. Pigments in wall paintings are usually found in small percentages and conventional X‐ray diffractometers do not detect them. Synchrotron radiation – high‐resolution X‐ray powder diffraction has allowed identification with only a few micrograms of sample.  相似文献   
17.
This study presents the first ever lead isotope ratio data for copper ore samples (malachite and azurite) from the Sierra El Aramo (Asturias, northwestern Spain). The aim of this study was to supplement information in the existing reference database on the lead isotopic composition of Spanish ores. The Sierra El Aramo is particularly important because, while no data for the Asturian ores have been published so far, this northern province of Spain has played a significant role in terms of copper exploitation and metallurgy since the Copper Age.  相似文献   
18.
In prehistory, serpentinite was one of the most frequently used raw materials to produce polished stone artefacts. Several conventional analytical techniques can be applied to identify the serpentine minerals, but their application generally requires a powdered sample. This implies that the artefacts to be analysed must be damaged, and the possibility of analysing a mixture of different serpentine polytypes is high. The use of spatially resolved techniques is therefore a necessity to overcome this problem. Several thin sections of serpentinitic rocks and prehistoric axes have been analysed by synchrotron radiation Fourier transform infrared micro‐spectroscopy. The spectra were acquired directly on specific points of polished stone artefacts and this allowed the recognition of the different polytypes of serpentine minerals without causing any damage to the objects. The results show the infrared micro‐spectroscopy technique to be a useful tool for the characterization of archaeological lithic material.  相似文献   
19.
This study presents the application of neutron tomography to the analysis of ironstone slabs found in a late Earlier Stone Age context (Fauresmith industry) at the back of Wonderwerk Cave, Northern Cape Province, South Africa. These slabs have markings on the surface that might be anthropogenic, and thus significant to understanding the emergence of human symbolic behaviour. Neutron tomography proved to be an effective tool for distinguishing surface incisions from lines that are the expression of internal fissures in the rock.  相似文献   
20.
We report a molecular methodology to obtain and analyse ancient bacterial DNA from archaeological dental calculus. Recent and archaeological DNA samples, as old as 4000 bp , were successfully extracted and amplified with species‐specific PCR primers. We propose this approach in order to: detect the presence of specific bacterial species infecting past human populations; compare the composition of ancient oral microbiomes among human populations; and analyse the genetic variability and covariation of bacteria and human host populations. Genomic analysis of bacteria from dental calculus is a promising source of evidence for palaeopathological and micro‐evolutionary studies, focused either on micro‐organisms or their human hosts.  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