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   171篇
  免费   26篇
  2024年   3篇
  2023年   4篇
  2022年   1篇
  2021年   1篇
  2020年   5篇
  2019年   8篇
  2018年   7篇
  2017年   12篇
  2016年   12篇
  2015年   7篇
  2014年   7篇
  2013年   17篇
  2012年   17篇
  2011年   15篇
  2010年   15篇
  2009年   20篇
  2008年   13篇
  2007年   3篇
  2006年   10篇
  2005年   4篇
  2004年   3篇
  2003年   6篇
  2002年   2篇
  2000年   1篇
  1998年   1篇
  1997年   1篇
  1993年   1篇
  1987年   1篇
排序方式: 共有197条查询结果,搜索用时 15 毫秒
31.
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   
32.
Eighty‐one samples taken from 68 glass beads found in southwestern Poland on sites of the Lusatian culture from the Hallstatt C and Hallstatt D subphases were analysed by EPMA. A subsample of 18 of these were additionally subjected to analysis by means of LA–ICP–MS in order to validate the results obtained by EPMA. Some glass was made using mineral soda and some using plant ash rich in sodium. Both high‐magnesium soda–lime glass (HMG) and low‐magnesium soda–lime glass (LMG) were identified. A large number of samples are characterized by low MgO content and medium K2O content (LMMK glass), combined with low concentrations of CaO and high Fe2O3 and Al2O3. All the LMMK glass contains numerous silica crystals and inclusions composed of a number of elements (most frequently Cu, Co, Sb, As, Ag, Ni and Fe). The LMMK glass was presumably made in Europe during the Hallstatt C.  相似文献   
33.
The geological sources of obsidian in the Red Sea region provide the raw material used for the production of obsidian artefacts found in prehistoric sites on both sides of the Red Sea, as far afield as Egypt, the Persian Gulf and Mesopotamia. This paper presents the chemical characterization of five obsidian geological samples and 20 prehistoric artefacts from a systematically excavated Neolithic settlement in highland Yemen. The major element concentrations were determined by SEM–EDS analysis and the trace element concentrations were analysed by the LA–ICP–MS method, an almost non‐destructive technique capable of chemically characterizing the volcanic glass. A comparison of archaeological and geological determinations allows the provenance of the obsidian used for the Neolithic artefacts to be traced to definite sources in the volcanic district of the central Yemen Plateau.  相似文献   
34.
Obsidian is an effective material for the study of prehistoric raw material use and exchange, due to the high degree of homogeneity and redundancy of obsidian materials and manufactured objects in the archaeological record. The destructive nature of many analytical techniques often impedes compositional research because of the damage that may occur to priceless archaeological artefacts. The combination of time‐of‐flight (TOF) ICP–MS with a laser ablation sample introduction system provides a highly efficient means of chemically characterizing obsidian. This study shows that sample size limit capabilities of TOF–ICP–MS analysis of obsidian can reach less than 100 μm. Sampling and analysis of microartefacts enables researchers to overcome problems of sampling bias with very little damage to the valuable existing materials within the archaeological record and expands the potential for chemical compositional analyses in archaeology.  相似文献   
35.
Tell Halaf is the locality of the ancient Aramaic city of Guzāna (c. 1000–800 bc ) in Syria. The statues of Tell Halaf were made from monolithic basalt blocks, comprising massive as well as amygdaloidal types. However, the exact location of the original quarries was as yet unknown. Reconnaissance mapping and sampling concentrated on the four basaltic centres in the vicinity of Tell Halaf, covering both south‐eastern Turkey and north‐eastern Syria. In addition, basaltic artefacts from the two archaeological sites of Tell Beydar (c. 2700–2300 bc ) and Djebelet el Beda (c. 2600–2350 bc ) were investigated. All basalt samples were analysed for their bulk rock major and trace element compositions by X‐ray fluorescence, ICP–MS analysis and the mineral chemistry of individual minerals by combined electron microprobe analysis and laser‐ablation ICP–MS. The data show that basalt works of art from all three archaeological sites were derived from the Syrian basalt plateau of Ard esh‐Sheikh, approximately 57 km south of Tell Halaf. Accordingly, this basalt quarry was actively exploited over a considerable time span of c. 1900 years. This study demonstrates that petrographic and geochemical investigations of basalt, combined with electron microprobe and laser‐ablation ICP–MS analysis of minerals, are powerful tools to discriminate between possible sources of raw materials, especially if isotopic data yield unsatisfying results.  相似文献   
36.
In this paper we analyzed the natural dyes in well-preserved, ancient textiles from Yingpan, an important archaeological site on the Silk Road, using high-performance liquid chromatography with diode array and mass spectrometric detection. Dyes were removed from textile fibers using a soft extraction method (pyridine, water and oxalic acid). Two species of madder-type plants, Rubia tinctorum and Rubia cordifolia were identified as the dye sources in red and brown samples. We also were able to detect unusual flavonoid glycosides in yellow and green woolen yarns, although we have not been able to pinpoint with certainty a specific plant that may have been used to produce this dye(s). On the other hand, we found that yellow and green silk threads had been colored with protoberberine-type dyes, probably obtained from species of cork tree, Phellodendron spp., and/or other protoberberine producing plant. We propose that the textile dyes found at Yingpan reflect a merging of Eastern and Western practices and technologies during the 800-year period (206 BCE–618 CE) encompassing the early years of the Silk Road.  相似文献   
37.
We have determined the composition of rock art pigments from two megalithic barrows located in the north of Portugal. The use of XRD, SEM–EDS and FT–IR spectroscopy confirmed the presence of hematite and kaolinite in the red pigments from the Eireira barrow, and kaolinite in the white pigment from the Leira das Mamas barrow. The organic composition of the pigments was studied by GC–MS, suggesting that the red sinuous lines and dots from the Eireira barrow were prepared with cooked or heated algae and/or aquatic plants, with egg as binder, while the white pigment from the Leira das Mamas barrow revealed a mixture of vegetable oils for kaolinite moulding, which could be stabilized by temporary exposure to high temperatures. The multi‐analytical approach used on this study of megalithic pigments allowed the recovery of important data about north‐western prehistoric communities, namely the way in which they exploited existing resources and their ability to transform them.  相似文献   
38.
This contribution focuses on the study of historical mortars from a Roman archaeological site known as Villa dei Quintili, a monumental villa located in the south‐eastern part of Rome (Italy). The study was carried out on 38 mortar samples, collected from several edifices within the complex. A multi‐analytical approach, including polarized optical microscopy, scanning electron microscopy coupled with energy‐dispersive system and laser ablation inductively coupled plasma mass spectrometry, was used to analyse the pozzolanic material used for the preparation of mortars. Data obtained on both major and trace elements were compared with the compositions of Pozzolana Rossa, Pozzolana Nera and Pozzolanella samples from the Alban Hills volcanic district, collected from a historic quarry nearby, as well as with literature data. The results of such a multidisciplinary approach allowed us to recognize the use of all three pozzolan types for the aggregate fraction of examined mortars from the Villa dei Quintili.  相似文献   
39.
The petrography as well as the major and trace element compositions of the Selinunte grinding stones, made of grey vesicular lava, were analysed. By comparison with geochemical data from volcanic rocks in the Mediterranean, we were able to determine that only a minor number of the tools were extracted from the nearest volcanics of Mount Etna and the Hyblean Mountains, while the majority of the grinding stones were most probably imported from the Aeolian Islands, although an origin from the Aegean cannot be excluded entirely. The results are important in order to scrutinize trading connections, especially for the earlier times of settlement during the sixth century bc .  相似文献   
40.
Calcium oxalate patinas have been sampled on architectural elements of two ancient churches located on Torcello Island (Venetian Lagoon) and subsequently analyzed. The site had been selected presenting patinas of exceptional amount and thickness, elsewhere generally found as thin alteration layers covering stone surfaces or within black crusts on monuments in urban environments. Optical and mineralogical analyses suggest that these patinas are not the result of a simple deposition process, but originate as surface “transformations” of the substrate, and are mainly composed of dihydrate calcium oxalate (weddellite) and gypsum. Among the experimental techniques, isotope analyses (C and S) have been specifically carried out aiming at achieving a better understanding of their origin and possible causes of formation. The observed carbon isotopic fingerprint reveals in fact a strong biological fractionation recorded in the oxalate patina (δ13C ranging from ?22.3‰ to ?28.0‰), almost exclusively attributable to C3 pathway photosynthesis processes. Slightly negative sulfur isotope ratio values seem to be inversely correlated with patina exposure to atmospheric agents and pollutants. The results obtained prove that calcium oxalate originates from a biomineralization process induced by lichen colonization in specific environmental conditions.  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