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   1387篇
  免费   11篇
  2023年   4篇
  2022年   1篇
  2021年   1篇
  2020年   4篇
  2019年   7篇
  2018年   287篇
  2017年   203篇
  2016年   238篇
  2015年   15篇
  2014年   7篇
  2013年   33篇
  2012年   30篇
  2011年   161篇
  2010年   178篇
  2009年   38篇
  2008年   72篇
  2007年   71篇
  2005年   28篇
  2004年   10篇
  2003年   4篇
  2002年   1篇
  2001年   1篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1992年   1篇
排序方式: 共有1398条查询结果,搜索用时 17 毫秒
991.
The identification of residues is traditionally based on the distinctive morphologies of the residue fragments by means of light microscopy. Most residue fragments are amorphous, in the sense that they lack distinguishing shapes or easily visible structures under reflected light microscopy. Amorphous residues can only be identified by using transmitted light microscopy, which requires the extraction of residues from the tool’s surface. Residues are usually extracted with a pipette or an ultrasonic bath in combination with distilled water. However, a number of researchers avoid residue extraction because it is unclear whether current extraction techniques are representative for the use-related residue that adheres to a flaked stone tool. In this paper, we aim at resolving these methodological uncertainties by critically evaluating current extraction methodologies. Attention is focused on the variation in residue types, their causes of deposition and their adhesion and on the most successful technique for extracting a range of residue types from the stone tool surface. Based on an experimental reference sample in flint, we argue that a stepwise extraction protocol is most successful in providing representative residue extractions and in preventing damage, destruction or loss of residue.  相似文献   
992.
Xiongnu was a confederation of nomadic pastoral tribes (~200 bc–100 ad) that founded the first nomadic empire in Central Asia. According to archeological and historical data, the tribes played a key role in ethnic and cultural processes in Central Asia and adjacent regions of Eurasia. Genetic studies of the Xiongnu published to date have focused on remains from burial grounds in present-day Mongolia, in the southern part of the ancient Xiongnu area. However, paleoanthropological materials from numerous Xiongnu cemeteries and settlements in Transbaikalia (the southern region of Eastern Siberia, Russia) in the northern part of the Xiongnu Empire have not been examined genetically. Here, we analyzed mitochondrial DNA variation in a Transbaikalian Xiongnu population based on ancient DNA obtained from skeletal remains (n = 18) at four burial grounds to complement available Xiongnu genetic diversity data. We detected 16 mitochondrial DNA haplotypes belonging to seven East Eurasian haplogroups (A, B5, C, D4, G2a, N9a, and Y) in the Transbaikalian Xiongnu series. We observed substantial similarity between Transbaikalian and Mongolian Xiongnu series with respect to main haplogroup composition and frequencies. We observed several mitochondrial DNA clusters (N9a, Y, B5, and A16) and 11 of 16 haplotypes that were previously undetected in the Xiongnu gene pool. We also observed high similarity between the Xiongnu and contemporary indigenous populations of eastern Central Asia, particularly Mongolian-speaking groups. These findings extend our knowledge of Xiongnu genetic diversity.  相似文献   
993.
This study presents the overview of ironware excavations of the third–fifth century demolished tombs from Marvele necropolis. Three axes, four spearheads, two knives and a clasp were excavated in 2006. Afterwards, a metallographic and chemical analysis as well as mechanical properties of artefacts, also metallurgical slag, clinkers and iron concretions found in the surroundings of tombs were tested and presented in this article. General tests were executed in order to compare results with other archaeological and scientific researches. Metallographic analysis and hardness tests’ results revealed that axes were forged from two separate billets of iron, whilst spearheads and knives from one. The results of chemical analysis have affirmed earlier results of other Lithuanian archaeological sites. Although some differences in chemical composition were observed, this fact shows possible not local origin of some ironware.  相似文献   
994.
Archaeological deposits are often complex and illustrative of an intricate interplay between geogenic and anthropogenic inputs and formation processes. Even for those archaeologists—particularly prehistorians—who consider the basic principles of natural stratigraphy to excavate their sites, they nonetheless typically underutilize the observations and data available at the microstratigraphic level. The technique of soil micromorphology—or archaeological micromorphology as referred to throughout this paper—has seen an astounding increase in its use to answer archaeological questions and archaeological sediments in the last decades. However, we consider that this tool is still quite underutilized and not as mainstream as other techniques. In this paper, we briefly reflect on what can be some of the causes underlying this situation and how we (that is, both producers and consumers of micromorphology data) can go about to change it. The main idea is that we need to establish a better and more approachable way to present micromorphological results and be better at integrating them with the macroscopic archaeological data and research questions.  相似文献   
995.
The paper reports and discusses data obtained by archaeological and archaeometric studies of glass vessels and tesserae from the qasr of Khirbet al-Mafjar (near Jericho, Palestine). Archaeological contextualisation of the site and chrono-typological study of glass vessels were associated to EPMA and LA–ICP–MS analyses, performed to characterise the composition of the glassy matrix (major and minor components as well as trace elements). Analyses allowed achieving meaningful and intriguing results, which gain insights into the production and consumption of glass vessels and tesserae in the near East during the Umayyad period (seventh–eighth centuries). Within the analysed samples, both an Egyptian and a Levantine manufacture have been identified: such data provide evidence of a double supply of glass from Egypt and the Syro-Palestinian coast in the Umayyad period occurring not only in the glassware manufacture but also in the production of base glass intended to be used in the manufacture of mosaic tesserae. Thus, the achieved results represent the first material evidence of a non-exclusive gathering of glass tesserae from Byzantium and the Byzantines in the manufacture of early Islamic mosaics.  相似文献   
996.
The finding of a male red deer (Cervus elaphus L.) skeleton at Brandýs nad Labem (Central Bohemia, Czech Republic) dated to the Únětice culture (Early Bronze Age), radiocarbon dated to 1881–1679 cal BC (P 93 %), unique in the region, was analysed archaeozoologically. The depositing of a whole, unbutchered and entirely undamaged, but curled up body of a stag in a relatively small pit dug into the bottom of a large storage pit undoubtedly had some kind of special meaning or significance. It is interpreted as the burial of a ritually sacrificed beast. The deer male aged 2.5–3 years, with a withers height ca 129 cm, was in good health and had well-developed antlers. The stag most probably died between January and April, probably more towards the spring, but exactly how it died is unclear. The ritual appears to have been quite complex since it included a fire at the bottom of the storage pit. Deposition in a place designed for storage could suggest a ceremony relating to a sacrifice for prosperity and a good harvest. Despite a lack of evidence for the use of deer in rituals and the symbolic sphere during the Bronze Age, deer burials and the symbolic significance of the stag are known from other archaeological cultures and ethnicities. Interestingly, the entire foreleg of a younger red deer (aged 4–7 months), an isolated humerus of another young fawn (0.5–2 months) and the remains of two dog puppies (3.5–4.5 months) were present in upper horizons of the storage pit, which could also have a special meaning.  相似文献   
997.
998.
Lavishly decorated wagons excavated from royal Xiongnu burials are generally regarded as tribute items from China offered to Xiongnu elites, symbolizing important political and economic interactions between the Xiongnu state (209 BC–155 AD) and the Han dynasty (206 BC–220 AD). This theory views such vehicles as having no relation to indigenous Xiongnu craftsmanship. Furthermore, specialized products delivered to the northern nomadic peoples from the Han state are often cited in support of the notion of Xiongnu dependency on foreign states for technological and political development. Expecting to find evidence of China’s traditional iron and bronze technology, we examined a number of key metallic components of these wagons excavated from the royal Xiongnu burial at Golmod 2 in central Mongolia, radiocarbon dated to 109 BC–AD 75. Surprisingly, the iron metallurgy in question was based primarily on the bloomery process while low tin bronze and arsenical copper alloys dominated the pertinent bronze production. These respective technological traditions are typical of Xiongnu manufacture but significantly different from traditional Han metallurgy. We interpret this evidence as suggesting the need for a more balanced evaluation of foreign influence on the rise and development of the Xiongnu state.  相似文献   
999.
The measurement of the fineness of debased ancient silver coins has proven to be a very difficult issue, which has been studied for a long time. In this paper, this subject is analysed, and the various consequences of the silver surface enrichment (SSE) are discussed exploiting the most recent investigations. A new model is proposed for the complex object that is an ancient-debased silver coin, based on the silver profiles measured on some sectioned specimens. The model is applied to a sample of 43 coins, mainly Roman victoriati, Cisalpine and Illyrian drachms (from late III to I century B.C.). The coins are investigated in two different ways: neutron diffraction (ND) and specific gravity (SG). The results of the two measurements are combined via the proposed model to provide a more complete numismatic information of the original fineness of the monetary alloy. As a result, a relation between SSE thickness and SG is derived, which, for these coinages, allows to estimate the original alloy silver content from a simple SG measurement; the same method can be used to study other debased coinages, provided that all the procedure (ND and SG) is applied.  相似文献   
1000.
Archeological research has been trying to provide evidence relevant to understanding both the timing of and processes responsible for human colonization of the Qinghai-Tibetan Plateau (QTP). Hearth is one of the most extensive, important, and typical prehistoric humanity activity evidence on the QTP. However, there are a number of hearths lacking charcoal material because of the wind and water erosion. Fortunately, most of these hearths can be dated by luminescence dating on the remnant sediments around the hearth. In this study, 18 optically stimulated luminescence (OSL) samples from 14 hearths in Yandongtai site (YDT) and Bronze Wire site (BW) in the northeast of Qinghai Lake area were systematically dated. The OSL ages range from 6.8 ± 0.7 to 14.4 ± 1.2 ka. There is a good agreement between OSL dating results and charcoal ages during the last deglaciation period, which indicates that OSL method has great potential in dating hearth on QTP. Combined with the previous dating results from other hearths, the age of hearths concentrates in 11–13 ka BP, i.e., the Younger Dryas (YD) chronozone. The increased number of hearths indicates reinforced colonization in the Qinghai Lake area during YD cold event, implying that the cold climate during YD event was not severe enough to hinder the inhabitation of prehistoric humanity at an elevation of 3.2 km.  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