全文获取类型
收费全文 | 1550篇 |
免费 | 10篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 1篇 |
2020年 | 6篇 |
2019年 | 7篇 |
2018年 | 281篇 |
2017年 | 204篇 |
2016年 | 258篇 |
2015年 | 13篇 |
2014年 | 7篇 |
2013年 | 17篇 |
2012年 | 50篇 |
2011年 | 176篇 |
2010年 | 179篇 |
2009年 | 42篇 |
2008年 | 74篇 |
2007年 | 77篇 |
2006年 | 1篇 |
2005年 | 95篇 |
2004年 | 36篇 |
2003年 | 13篇 |
2002年 | 7篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1997年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1973年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有1560条查询结果,搜索用时 15 毫秒
901.
Ceramic findings collected from Ye?ilova Hoyuk located in Izmir were dated using the thermoluminescence dating technique. The area is of significant archaeological importance since it is the first prehistoric settlement in Izmir. Recent archeological observations suggest that human occupation of the region took place about 8500 years ago comparing to previously determined dates of 5000 years. Three samples collected from the same archaeological layer (Neolithic period) in Ye?ilova Hoyuk were dated using the thermoluminescence method. Archaeological doses (AD) were obtained by single aliquot regenerative dose method (SAR) for thermoluminescence (TL) using coarse grain quartz minerals extracted from samples. Thick and thin Al2O3:C thermoluminescence dosimeters (TLD) were used to determine the annual dose rate. The archaeological doses were found to vary from 25.91±0.78 to 26.82±0.68 Gy, and the annual doses were found to be between 3.34±0.24 and 3.47±0.24 mGy/a. The ages obtained for the samples were determined to be 6000±830 BC, 5740±670 BC and 5460±740 years for samples ND1, ND2 and ND3, respectively, which supports the prediction of archeologist that the sampling layer dates from the Neolithic period. 相似文献
902.
Martin J. Smith Paul Kneller Denise Elliott Christine Young Harry Manley David Osselton 《Archaeological and Anthropological Sciences》2012,4(1):75-89
This article presents a multidisciplinary analysis of a human skull with preserved soft tissue curated by a small museum in
Boscastle, Cornwall, UK. The skull lacks a mandible and is coated in a black tar-like substance. Records left by a previous
museum curator (now deceased) claimed the skull to be the head of a medieval execution victim. The skull was purportedly recovered
from a London church that was destroyed during the Second World War where it had been kept in a carved oak box. If these details
are correct, the skull would appear to have been venerated as a relic. The skull and box have been analysed using a range
of techniques including computerised tomography, laser scanning, microscopy, infrared spectroscopy and radiocarbon dating.
These analyses demonstrated the skull in fact to be that of an Egyptian mummy dating from the Ptolemaic period. Other instances
have been noted of parts of Egyptian mummies being presented as European saintly relics, and the ‘Boscastle skull’ would appear
to be an example of such. A wider point illustrated by the work presented here is that sufficient application of modern analytical
techniques may reveal considerable information regarding human remains which otherwise have little or no provenance. This
point strengthens arguments for the retention of such remains by curating institutions. 相似文献
903.
904.
905.
Ivan Briz i Godino José Ignacio Santos José Manuel Galán Jorge Caro Myrian Álvarez Débora Zurro 《Journal of Archaeological Method and Theory》2014,21(2):343-363
This paper presents the theoretical basis and first results of an agent-based model (ABM) computer simulation that is being developed to explore cooperation in hunter–gatherer societies. Specifically, we focus here on Yamana, a hunter-fisher-gatherer society that inhabited the islands of the southernmost part of Tierra del Fuego (Argentina–Chile). Ethnographical and archaeological evidence suggests the existence of sporadic aggregation events, triggered by a public call through smoke signals of an extraordinary confluence of resources under unforeseeable circumstances in time and space (a beached whale or an exceptional accumulation of fish after a low tide, for example). During these aggregation events, the different social units involved used to develop and improve production, distribution and consumption processes in a collective way. This paper attempts to analyse the social dynamics that explain cooperative behaviour and resource-sharing during aggregation events using an agent-based model of indirect reciprocity. In brief, agents make their decisions based on the success of the public strategies of other agents. Fitness depends on the resource captured and the social capital exchanged in aggregation events, modified by the agent’s reputation. Our computational results identify the relative importance of resources with respect to social benefits and the ease in detecting—and hence punishing—a defector as key factors to promote and sustain cooperative behaviour among population. 相似文献
906.
Estimation of soil erosion on cultivated fields on the hilly Meghalaya Plateau,North-East India 总被引:1,自引:0,他引:1
The estimation of soil erosion rates in complex subtropical agricultural systems of hilly environment is difficult and most
of the traditional methods have serious limitations. The 137Cs technique allows to obtain relatively quickly retrospective medium term soil erosion results. The objective of this study
was using 137Cs approach to quantify soil loss under agricultural system which develops under growing human pressure on the hilly terrain
of the Meghalaya Plateau. The measured values of caesium inventory for all sampling points are between 2% and 63% of the reference
value of caesium inventory. The estimated annual soil loss for sampling points located on the slope are between 29 and 79
Mg·ha−1·yr−1 in the case of an improved mass balance model. It means that soil erosion in this manually tilled agricultural area cannot
be neglected. 相似文献
907.
Bone catapult and hammer-headed pins played one of very specific roles in funerary offerings in the Bronze Age graves uncovered
in the Eurasian Steppes and the North Caucasus. Scholars used different types of pins as key grave offerings for numerous
chronological models. For the first time eight pins have been radiocarbon dated. 14C dating of bone pins identified the catapult type pin as the earliest one. They marked the period of the Yamnaya culture
formation. Then Yamnaya population produced hammer-headed pins which became very popular in other cultural environments and
spread very quickly across the Steppe and the Caucasus during 2900–2650 cal BC. But according to radiocarbon dating bone pins
almost disappeared after 2600 cal BC. 相似文献
908.
Ana-Voica Bojar Stanislaw Halas Hans-Peter Bojar Dan Grigorescu Stefan Vasile 《Geochronometria》2011,38(2):182-188
In order to constrain the age of the Upper Cretaceous continental Densuş-Ciula Formation from the Haţeg basin, South Carpathians,
and correlate it with the other continental unit that occurs in the region, the Sanpetru Formation, we separated and dated
by the K-Ar method biotites and amphiboles from volcanoclastic deposits. The mineral phases analysed are from two tuff layers
and volcanic bombs cropping out near Rachitova village. Two tuff layers from the Densuş-Ciula Formation give early Maastrichtian
ages of 69.8±1.3 and 71.3±1.6 Ma, respectively. The ages determined for the tuff layers constrain the age of deposition for
the Densuş-Ciula Formation and enable further correlations with the available palaeomagnetic data from the deposits occurring
along the Sibişel Valley that belong to the Sanpetru Formation. The volcanic bombs collected near to Răchitova village are
andesites and dacites. The age determined by K-Ar method on hornblende separated from a volcanic bomb is 82.7±1.5 Ma, which
is older than the underlying Campanian marine deposits in turbidite facies. This suggests that the volcanic bombs were re-deposited
during the early Maastrichtian. Thus, the volcanics found at Răchitova have at least two origins: one type is related to an
explosive synsedimentary volcanic activity, and the other type is represented by older andesitic/dacitic bombs, which most
probably originate from a volcanic centre situated in the Haţeg region. 相似文献
909.
Piotr Weckwerth Krzysztof Przegiętka Alicja Chruścińska Barbara Woronko Hubert L. Oczkowski 《Geochronometria》2011,38(4):397-412
The deposits of the Toruń Basin are dominated by a few-metre thick sand series which fill up buried valley-like depressions.
In many cases they underlie the Weichselian till which builds up the ice marginal streamway (pradolina) terraces or they are
exposed at the basin slopes. As the results of the geological and sedimentological studies, as well as of the dating of the
deposits at the sites in the Toruń Basin indicate, the deposits include two fluvial series accumulated before the advancement
of the Leszno Phase ice sheet, i.e. in Middle Weichselian and at the beginning of Late Weichselian. The oldest fluvial series
connected with the Saalian Glaciation was found at the mouth section of the Drwęca Valley. The fluvial system of the Toruń
Basin during Middle Weichselian and at the beginning of Late Weichselian developed in two phases of the sand-bed braided river.
During the first one the river channel were dominated by large mid-riverbed sandbars, while during the second phase the water
flow was smaller and, as a result, low transverse sandbars and two-dimensional dunes developed. Other active river channel
also showed low-energy flows, more intensive meandering than in the case of the braided rivers, as well as sandy side-bars.
Analysis of the rounding and frosting of the quartz grains indicate that the studied series of the Weichselian sandy deposits
represent alluvia of a river which were fed from two diverse sources. The first one might have represented the alluvia of
a warm river which transformed its load, while the other one might have mainly carried the underlying Quaternary deposits. 相似文献
910.