全文获取类型
收费全文 | 7239篇 |
免费 | 280篇 |
出版年
2020年 | 97篇 |
2019年 | 139篇 |
2018年 | 157篇 |
2017年 | 184篇 |
2016年 | 228篇 |
2015年 | 158篇 |
2014年 | 153篇 |
2013年 | 2091篇 |
2012年 | 208篇 |
2011年 | 220篇 |
2010年 | 246篇 |
2009年 | 218篇 |
2008年 | 195篇 |
2007年 | 197篇 |
2006年 | 191篇 |
2005年 | 101篇 |
2004年 | 92篇 |
2003年 | 90篇 |
2002年 | 97篇 |
2001年 | 110篇 |
2000年 | 78篇 |
1999年 | 95篇 |
1998年 | 63篇 |
1997年 | 56篇 |
1996年 | 70篇 |
1995年 | 73篇 |
1994年 | 72篇 |
1993年 | 80篇 |
1992年 | 71篇 |
1991年 | 59篇 |
1990年 | 52篇 |
1989年 | 66篇 |
1988年 | 56篇 |
1987年 | 65篇 |
1986年 | 64篇 |
1985年 | 76篇 |
1984年 | 65篇 |
1983年 | 94篇 |
1982年 | 70篇 |
1981年 | 72篇 |
1980年 | 68篇 |
1979年 | 67篇 |
1978年 | 71篇 |
1977年 | 63篇 |
1976年 | 72篇 |
1975年 | 66篇 |
1974年 | 53篇 |
1973年 | 54篇 |
1972年 | 55篇 |
1970年 | 44篇 |
排序方式: 共有7519条查询结果,搜索用时 873 毫秒
971.
Stable carbon- and nitrogen-isotope ratios were measured for segments along the shafts of hair from eight individuals from the site of Pacatnamu, located in the Jequetepeque Valley on the north coast of Peru. All are from known grave contexts dating from Moche (ca. 450–750 A.D.) to Lambayeque periods (ca. 900–1100 A.D.). The mean δ13C and δ15N values of hair segments from individuals are comparable to those of bone, and demonstrate increased consumption of marine resources in the Lambayeque times relative to the Moche period. 相似文献
972.
Gary A. King M. Thomas P. Gilbert Eske Willerslev Matthew J. Collins Harry Kenward 《Journal of archaeological science》2009
We report the recovery of short fragments of PCR amplifiable ancient DNA from exoskeletal fragments of the grain weevil Sitophilus granarius (L.) extracted from Roman and medieval deposits in Northern England. If DNA preservation in archaeological insect remains is widespread then many applications in the spheres of evolutionary studies and archaeology can be conceived, some of which are outlined. 相似文献
973.
L. Chiarantini M. Benvenuti P. Costagliola M.E. Fedi S. Guideri A. Romualdi 《Journal of archaeological science》2009
Populonia is commonly regarded as one of the most important iron working centres in Europe in the 1st millennium BC. However, multiple layers of copper slags have been recently discovered at the bottom of the slag deposit occurring along the shoreline of the underlying Baratti Gulf. Copper slag layers have been radiocarbon dated to the 9th–8th centuries BC, i.e. to an early metallurgical stage predating the later large-scale iron production. The overall features of copper slags indicate a single-step smelting process of copper-rich ores containing variable amounts of Zn and Pb. Chemical and textural features of copper slags indicate an optimised, high-efficiency metallurgical process. 相似文献
974.
Christian A. Tryon M. Amelia V. Logan Damase Mouralis Steve Kuhn Ludovic Slimak Nur Balkan-Atlı 《Journal of archaeological science》2009
The Central Anatolian Volcanic Province (CAVP) in Turkey preserves widespread deposits of Quaternary tephra, presently associated with a small but growing number of Paleolithic archaeological sites. We use multivariate analyses of the abundances of a suite of nine major and minor element oxides determined by electron probe microanalysis. From these data, we construct a classificatory model for correlating distal tephra to one of five volcanic edifices or eruptive phases within the CAVP. Application of this model to distal deposits of primary tephra-fall and reworked tuffaceous sediments from the archaeological sites of Körkuyu and Kaletepe Deresi 3 indicates Late to possibly Early Pleistocene ages for the artifact assemblages there, and provides a fundamental tephrostratigraphic framework to examine spatial and temporal variation in hominin behavior comparable to that of other regions, such as eastern Africa. 相似文献
975.
H. Eckardt C. Chenery P. Booth J.A. Evans A. Lamb G. Müldner 《Journal of archaeological science》2009,36(12):2816-2825
Artefacts and burial rites in the late Roman cemetery at Lankhills School, Winchester, southern England, were used by Clarke (1979) to distinguish between local Romano-British individuals and migrants thought to be from the Danube region, a suggestion tested through isotope analysis by Evans et al. (2006a,b). This paper reports strontium (87Sr/86Sr) and oxygen (δ18O) isotope data for tooth enamel sampled from a further 40 individuals from more recent excavations on the same site. Results suggest that up to a quarter of the sampled Lankhills individuals were incomers, with several individuals possibly originating from the Hungarian Basin and the Southern Mediterranean. However, there was no clear link between isotopic signature and archaeological origin attribution, suggesting that in many cases burial practice was dictated by factors other than ‘ethnicity’, such as kinship, marriage or cultural and political preferences. 相似文献
976.
The bearded vulture (Gypaetus barbatus), a bird or prey that mainly feeds on bones of large mammal carcasses, has been recently evidenced as an accumulating agent with significant contributions to palaeontological assemblages in caves and shelters, but extremely rare at archaeological sites. The results of the taphonomic analyses carried out in the Upper Palaeolithic layers of El Mirón Cave (Cantabrian Spain), which are presented here, evidence the existence of special digestive marks and a typical skeletal pattern in a noticeable amount of small and medium-sized ungulates bones. This fact suggest that a representative part of the bone assemblage has been caused by bearded vultures, and strengthens the idea that this bird has to be definitely included among other potential non-human accumulators in archaeological sites. 相似文献
977.
R. Tipping M.J. Bunting A.L. Davies H. Murray Shannon Fraser R. McCulloch 《Journal of archaeological science》2009
A methodology is described by which spatial patterns of land use were reconstructed from pollen analyses on anthropogenic sediments at a recently excavated early Neolithic timber ‘hall’ in north east Scotland. The anthropogenic sediments were from a deep, small diameter pit within the building. They present numerous taphonomic and interpretative challenges to the analyst, but from this type of deposit, the power to estimate quantitatively the vegetation structure around the archaeological site makes such difficult deposits very significant. A rigorous methodology is firstly described, therefore, by which confidence in ecological interpretation can be established. Secondly, the source of pollen in the deposit is evaluated. Thirdly, the possible pollen source area and structure of the surrounding vegetation are estimated by quantitative simulation modelling. Finally, these analyses are compared with region-scale pollen analyses from nearby conventional wetland deposits with much larger pollen source areas. The pollen assemblages recovered probably reflect land uses adjacent to the ‘hall’ and up to 2.5 km around. Cereal cultivation was the most important land use immediately around the ‘hall’, possibly grown between stands of scrub Corylus (hazel) woodland. These intensive but local-scale land uses cannot be discerned in region-scale pollen analyses. 相似文献
978.
Eleanor Blakelock Marcos Martinón-Torres Harald A. Veldhuijzen Tim Young 《Journal of archaeological science》2009
Slag inclusions are found within most archaeological bloomery iron artefacts and are remainders of slag created during the smelting and smithing processes. Although they are widely believed to provide data with the potential for provenancing iron artefacts, previous slag inclusion studies have mostly proven inconclusive. The main aim of the work reported here is to analyse experimental smelting and smithing assemblages (including ore, furnace lining, fuel and slag), to compare these to slag inclusions in the resulting bloom and worked objects, and then explore the relationships between ore, slag and slag inclusions. This study has revealed that the composition of slag inclusions most closely relates to the smelting slag produced, whereas provenance to a specific ore would be difficult due to the chemical variability derived from furnace lining, fuel and any fluxes used. Some compounds in the slag inclusions are particularly affected during smithing of the artefact, i.e. those present in the sand flux and fuel used. However, trends are observed in the K2O/MgO, MnO/SiO2, Al2O3/SiO2, Al2O3/MgO, Al2O3/K2O and Al2O3/CaO ratios that allow comparison between slag inclusions and smelting slag in these experiments, and may therefore be used during other provenancing attempts. The knowledge gained from the experimental assemblages was subsequently applied to an archaeological case study, examining objects from the 900 Cal BC smithing site of Tel Beth-Shemesh, Israel and the 930 Cal BC smelting site of Tell Hammeh, Jordan. The analyses suggest that none of the artefacts examined derived from the Hammeh smelting system. 相似文献
979.
The landscape around the prehistoric Peruvian ceremonial center of Chavín de Huántar has undergone extensive geomorphic and anthropogenic change since the beginning of monumental construction at the site in approximately 1200 BCE. Archaeological and geomorphic stratigraphy from the site and its near periphery provide the data necessary to characterize these changes in detail. This paper reports on the use of GIS-based interpolation tools to approximate a complex prehistoric land surface using unevenly scattered point data. Such an interpolated surface serves as the basis for the reconstruction of the pre-Chavín landscape and assessment of landscape change contemporary with the site. 相似文献
980.
Thegn N. Ladefoged Patrick V. Kirch Samuel M. Gon III Oliver A. Chadwick Anthony S. Hartshorn Peter M. Vitousek 《Journal of archaeological science》2009,36(10):2374-2383
Intensive agricultural systems interact strongly and reciprocally with features of the lands they occupy, and with features of the societies that they support. We modeled the distribution of two forms of pre-European contact intensive agriculture – irrigated pondfields and rain-fed dryland systems – across the Hawaiian archipelago using a GIS approach based on climate, hydrology, topography, substrate age, and soil fertility. Model results closely match the archaeological evidence in defined locations. On a broader scale, we calculate that the youngest island, Hawai'i, could have supported 572 km2 of intensive agriculture, 97% as rain-fed dryland field systems, while Kaua'i, the oldest island, could have supported 58 km2, all as irrigated wetland systems. Irrigated systems have higher, more reliable yields and lower labor requirements than rain-fed dryland systems, so the total potential yield from Kaua'i (49k metric tons) was almost half that of Hawai'i (97k metric tons), although Kaua'i systems required only 0.05 of the agricultural labor (8400 workers, versus 165,000 on Hawai'i) to produce the crops. We conclude that environmental constraints to intensive agriculture across the archipelago created asymmetric production efficiencies, and therefore varying potentials for agricultural surplus. The implications both for the emergence of complex sociopolitical formations and for anthropogenic transformation of Hawaiian ecosystems are substantial. 相似文献