全文获取类型
收费全文 | 97篇 |
免费 | 3篇 |
专业分类
100篇 |
出版年
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
1.
G. DE G. SIEVEKING P. BUSH J. FERGUSON P. T. CRADDOCK M. J. HUGHES M. R. COWELL 《Archaeometry》1972,14(2):151-176
This paper is a statistical and geological study of the results of analysis of flint from British and West European flint mines, carried out by emission and atomic absorption spectroscopy. Groups of flint specimens were studied from each geographically separate flint mining area. Flints were analysed for a group of easily measured trace elements shown by previous work to be generally present. The ratios between the trace elements form a consistent pattern for each flint mine and statistically valid differences of pattern can be recognized between different flint mines. A geological investigation shows that the measured trace elements may be derived from clay minerals and explains geographical and statistical variation in the composition of flint in terms of its mode of origin in the chalk. An advanced statistical technique allows individual flint specimens of unknown origin to be attributed by their composition to one or other of the identified flint sources. The archaeological implications of this study are discussed. 相似文献
2.
A method is described for the identification of the origin of flint artefacts. The method is based on the variation in the trace element concentrations for different origins. The trace element concentrations were determined by non-destructive neutron activation analysis. The identification was obtained from a pattern recognition analysis. 相似文献
3.
4.
ELIAS LOPEZ-ROMERO GONZALEZ DE LA ALEJA 《Oxford Journal of Archaeology》2008,27(3):217-239
Summary. In the context of territorial analyses in archaeology, the visual attributes of sites play a key role in the definition of location strategies. This paper studies the Neolithic evidence from the south-western Morbihan area in Brittany (France) from a visual point of view, integrating the previous Mesolithic and the later Bronze Age occupation of the region in order to understand the diachronic evolution of the visual settlement patterns. The role played by the sea seems to be significant throughout the entire occupation of the area, but differences in both intervisibility of sites and the extension of visual areas allow us to make particular observations regarding different cultural uses of the landscape through time. 相似文献
5.
NGUYEN VAN DE IAN DOUGLAS JULIA MCMORROW SARAH LINDLEY DAO KIM NGUYEN THUY BINH TRAN THI VAN LE HUU THANH NGUYEN THO 《Geographical Research》2008,46(1):4-16
To help improve the well‐being of the local people, a joint Vietnamese‐UK team set out to establish a way of estimating soil and nutrient losses under different land management scenarios, using field data extrapolated through remote sensing and GIS, to obtain catchment‐wide estimates of the impact of land cover change. Immigration from remote provinces to the Dong Phu District of Binh Phuóc Province, about 120 km north of Ho Chi Minh City, has led to disruption of soil surface stability on easily eroded clayey sandstones, creating rapid nutrient depletion that affects crop yields and siltation in the channel of the Rach Rat river downstream. The poor farmers of the areas see crop yields drop dramatically after two or three years of cultivation due to the fertility decline. Soil loss varies dramatically between wet season and dry season and with ground cover. Erosion bridge measurements showed a mean loss of 85.2 t ha?1 y?1 under cassava saplings with cashew nuts, 43.3 t ha?1 y?1 on uncultivated land and 41.7 t ha?1 y?1 under mature cassava. The rates of erosion were higher than those reported in many other parts of Vietnam, reflecting the high erodibility of the friable sandy soils on the steep side‐slopes of the Rach Rat catchment. However, although the actual measurements provide better soil loss data than estimates based on the parameters of soil loss equations, a large number of measurement sites is needed to provide adequate coverage of the crop and slope combinations in this dissected terrain for good prediction using GIS and remote sensing. 相似文献
6.
We investigated the major and trace element composition and Pb and Sr isotope characteristics of a series of about 20 colourless glass objects from a single high‐status Roman burial from the Netherlands (Bocholtz). The major elements show a relatively homogeneous group, with one outlier. This is corroborated by the Sr isotopes. Based on the Sb and Pb content, three major groups can be discerned, with two other outliers. This grouping is corroborated by the contents of the trace elements Bi, Sn, Ag, As and Mo, and by variations in lead isotopic ratios. On the basis of these results, we conclude that the glass of all objects was probably made with sand and lime from the same source. The variation in trace elements and lead isotope composition is most likely the result of variations in the composition of the sulphidic antimony ore(s) that were used to decolourize the glass. The composition of the Bocholtz glass is compared with that of other Roman glass, and implications for production models, trade and use of colourless glass objects are discussed. On the basis of isotopic and major element variation, we conclude that the antimony ore presumably originated from different mines. 相似文献
7.
8.
Oil-rich Venezuela is being hit by the largest crisis in living memory. Now, more than 4.8 million Venezuelans have fled the country in search of food and safety. News about migration and humanitarian aid dominate. Yet, many Venezuelans stay and seek alternative strategies to cope with scarcity and insecurity. Ad hoc solutions mainly depend on alternative economies in the borderlands that do not always fit within frameworks of human rights and rule of law, but do provide relief and produce opportunities along with new inequalities that (un)willingly sustain the crisis. Amid collapsing state infrastructures, these transborder economies tie into the global trade of basic supplies, narcotics, drugs, natural resources and human trafficking that operate in the interface of the legal and the illegal. The complex humanitarian crisis in Venezuela is as much about poverty and scarcity as it is about wealth and abundance benefiting only a very few. An ‘anthropology of abundance’ allows us to grasp these underlying socio-economic dynamics that turn crisis management into crisis maintenance. 相似文献
9.
10.
Since the early years of the twentieth century, Brazil's major foreign policy aspiration has been to achieve international recognition based upon the belief that it should assume its 'natural' role as a 'big country' in world affairs. Although the bases for an autonomous foreign policy have become more restricted in the post-Cold War period, Brazil still seeks to preserve an independent voice within the international community and a certain level of independent capacity to determine its actions. In addition, the country has demonstrated a clear intention of wanting to expand the roles that it plays and the responsibilities that it assumes in regional politics, in Third World agendas and in multilateral institutions. As democracy deepens its roots within the country, Brazil has attempted to link an increasingly activist stance in world affairs with political support at home based upon a more active partisan involvement in foreign policy. In this context, the present government's fight against poverty and unequal income distribution at home and its assertive and activist foreign policy can be viewed as two sides of the same coin. In this article the authors provide an overview of the core features of Brazilian foreign policy, focusing upon four aspects: (i) the instrumental nature of Brazilian foreign policy and its close relationship with the country's economic and development objectives; (ii) the commitment of Brazil to multilateralism; (iii) the growing importance for Brazil of regional politics and security; and (iv) the recent evolution of Brazil's relations with the United States. The conclusion reviews the main challenges facing Brazil and the difficulty of matching increased ambition with concrete results. 相似文献