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   99篇
  免费   6篇
  2024年   1篇
  2023年   1篇
  2022年   1篇
  2020年   4篇
  2019年   6篇
  2018年   4篇
  2017年   10篇
  2016年   6篇
  2015年   1篇
  2014年   2篇
  2013年   45篇
  2011年   1篇
  2009年   2篇
  2007年   1篇
  2006年   1篇
  2005年   2篇
  2003年   1篇
  1993年   1篇
  1990年   2篇
  1987年   1篇
  1985年   1篇
  1984年   3篇
  1983年   3篇
  1982年   3篇
  1981年   2篇
排序方式: 共有105条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
The rapid expansion of non‐ferrous metallurgy in the late Middle Ages (14th–15th centuries) enhanced ore demand, which was supported by mining intensification. Metallurgical workshops developed various supply strategies based on geological, political and economic constraints. This is particularly true for the Pyrenean multi‐metals workshop of Castel‐Minier (Ariège, France), where recent excavations unearthed an exceptional corpus of non‐ferrous ores. A specific analytical methodology combining micro‐Raman spectroscopy and environmental scanning electron microscopy with energy dispersive X‐ray (ESEM‐EDX) was set up to study these artefacts. This composite methodology permitted the fast characterization of both mineral and gangue as well as a discussion of their economic potential. Ores identified were compared with ancient mines in neighbouring mining districts in order to sketch a geography of the mineral resources available to medieval metallurgists. Moreover, a chrono‐stratigraphic study of ore distribution in Castel‐Minier revealed the supply strategies, technological choices as well as spatializing of copper and lead metallurgies.  相似文献   
6.
The “coupes-à-socle” (footed cups) are ceramics which can be found in domestic Neolithic contexts in Brittany (Castellic, Auzay-Sandun), but more generally in non-domestic areas. Their ceremonial function has often been evoked, in particular as a perfume burner. The analysis by GC and GC/MS of two samples from the “Hougue Bie” (Jersey) passage graves showed the presence of vegetable fatty acids, degraded n-alkanes and terpenoïds, biomarkers of birch bark tar. The presence of such substances could be explained either by the use of the “coupes-à-socle” for burning birch bark tar as an odoriferous product or their use as an everyday vessel for heating and increasing tar plasticity. However, the limited occurrence of this type of ceramic in habitat sites supports the former utilisation. This first report of the presence of birch bark tar in “coupes-à-socle” thus suggests use of this tar as an odoriferous product, in addition to its numerous, previously recognised, more technical uses.  相似文献   
7.
Can age, period and cohort effects help explain support for Quebec sovereignty? Previous work on this question has focused mostly on the effects of age and cohort. We contribute to this debate by adding a period perspective. As such, our study is the first to investigate the impact of age, cohort and period effects in a single study of opinion towards sovereignty in Quebec. We take advantage of an original dataset that includes survey data collected between 1985 and 2012. We use these data to examine the impact of age, birth year and survey year on support for this constitutional option among francophone Quebeckers. Our results are in line with previous work: we show that younger Quebeckers are more likely to support sovereignty, and that some cohorts – namely, respondents born between 1945 and 1959 – are also more likely to favour this option. Perhaps more surprisingly, we find that specific events are comparatively the most important factor to explain fluctuations in Quebeckers' attitudes towards sovereignty.  相似文献   
8.
The aim of this article is to present an experimental approach for studying the formation and transformation processes of archaeological fire structures. We present a synthetic review of our experimental project, which was developed in many different natural archaeological contexts. We report the results and problems associated with experimental fires lit on different kinds of soils and in different environments, followed by the observation of natural and anthropic transformations. Finally, we analyse the nature and significance of these results for the archaeological interpretation process, while describing some general trends and showing the complexity of the approach.  相似文献   
9.
Small mammals are considered to be good indicators of ancient environments. One particular layer in a fortification tower of a Mediterranean Iberian village, Alorda Park (4th century BC), provided a large amount of well-preserved small mammal bones (about 19,200 remains) probably accumulated by barn owls (Tyto alba). Such an accumulation is rarely available from the Iron Age. It provides not only palaeoenvironmental data, but also further information about other studies such as morphometrics, ancient DNA and zoogeography. This article focuses on the ecological data, and attempts to develop an accurate taphonomic study to assess the reliability and statistical significance of this archaeological sample.  相似文献   
10.
The purpose of this paper is to spatially and regionally examine academic engagement within Brazil, identifying patterns. Moreover, our investigation can contribute to a better understanding of how knowledge can be turned into a tool to fight regional inequality. We depart from two hypotheses: first, universities situated in peripheral regions interact more with companies from relatively more dynamic regions, and second, in the absence of industrial knowledge demand, universities tend to collaborate more closely with a diverse range of stakeholders in the region. To evaluate these hypotheses and find empirical evidence, we consider 4497 research groups and 4603 nonacademic organizations as “nodes” connected by 8830 collaborations throughout all Brazilian regions. Social network tools are used to illustrate the spatial and regional dimensions of academic engagement more accurately. The results show that academic engagement is not regionally homogeneous, demonstrating essential differences regarding local nonacademic partnerships. Innovation policies, which encourage only university–firm interactions, perpetuate regional inequality.  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