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   3770篇
  免费   178篇
  2020年   51篇
  2019年   82篇
  2018年   141篇
  2017年   108篇
  2016年   173篇
  2015年   99篇
  2014年   97篇
  2013年   854篇
  2012年   124篇
  2011年   159篇
  2010年   110篇
  2009年   115篇
  2008年   84篇
  2007年   96篇
  2006年   96篇
  2005年   116篇
  2004年   74篇
  2003年   66篇
  2002年   42篇
  2001年   65篇
  2000年   55篇
  1999年   59篇
  1998年   51篇
  1997年   47篇
  1996年   41篇
  1995年   32篇
  1994年   23篇
  1993年   48篇
  1992年   34篇
  1991年   22篇
  1990年   32篇
  1989年   37篇
  1988年   30篇
  1987年   36篇
  1986年   29篇
  1985年   32篇
  1984年   25篇
  1983年   49篇
  1982年   37篇
  1981年   35篇
  1980年   33篇
  1979年   28篇
  1978年   34篇
  1977年   37篇
  1976年   32篇
  1975年   30篇
  1974年   27篇
  1973年   26篇
  1972年   29篇
  1971年   25篇
排序方式: 共有3948条查询结果,搜索用时 15 毫秒
971.
There is a strong relation between people's structured identities and their chemical biographies: these can reflect the way individuals choose to reside and/or move. The strontium isotope ratio (87Sr/86Sr) of skeletal remains is considered a useful proxy to assess residential mobility and social practices in past populations; however, so far, it has only occasionally been applied to prehistoric contexts in the Mediterranean. In this paper, we present 87Sr/86Sr data of human and animal samples from several Neolithic sites in the Apulian Tavoliere (southeastern Italy), namely, Grotta Scaloria, Passo di Corvo, Masseria Candelaro and La Torretta/Poggio Imperiale. Data obtained from dental enamel reflect the local origin of the individuals and allowed us to differentiate function and meaning of the sites examined. In particular, within a generally homogeneous background of Sr signatures, the range of 87Sr/86Sr at Scaloria Cave is greater than at the other sites, with variation likely to be related to funerary practices. We interpret this as the evidence of the ritual use of the cave, which implied the gathering of people of different origin. The relative variation of the Sr signature among individuals, either intersite or intrasite can be tentatively associated with mobility during life as well as with social practices, such as access to foods from geologically different environments. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
972.
During the late Longshan period (ca. 4200–3900 BP) settlements on the Central Plains of China underwent a diversification in food production technologies, which set the stage for rapid economic and social development. The introduction of novel domesticates such as rice, wheat, cattle, and sheep not only provided more food choices, but also changed ideas concerning land use, farming techniques, and the use and mobilization of large scale labor forces. To better understand the contribution that these new dietary items and practices made to shaping the late Longshan period societies, a stable isotope ratio study of humans (n = 12) and animals (n = 42) was conducted at the late Longshan period site of Wadian. The human δ13C and δ15N values are clustered into two distinct groups. One group of nine individuals (δ13C = −9.9 ± 0.7‰; δ15N = 7.5 ± 0.5‰) had a predominately C4 diet based on millet grains with little protein input from the domestic animals. The other group of three individuals (δ13C = −14.3 ± 0.8‰; δ15N = 10.2 ± 0.3‰) had a mixed C3/C4 diet of millets and rice and were consuming sheep and cattle. The animals also displayed dietary diversity with the pigs (δ13C = −11.3 ± 2.5‰; δ15N = 6.9 ± 1.0‰, n = 10) and dogs (δ13C = −10.1 ± 1.0‰; δ15N = 7.2 ± 1.1‰, n = 7) having mostly a C4 plant based diet (millets). In contrast, the cattle (δ13C = −12.8 ± 2.1‰; δ15N = 7.6 ± 0.7‰, n = 9), sheep (δ13C = −16.7 ± 0.9‰; δ15N = 7.6 ± 0.1‰, n = 2), and cervids (δ13C = −20.8 ± 0.9‰; δ15N = 5.0 ± 1.2‰, n = 10) had diets with a greater contribution from C3 sources such as rice and wild plants. The discovery that humans and animals had different subsistence patterns indicates dietary complexity at Wadian and that rice agriculture, and cattle and sheep husbandry practices were already an important part of the local economy by the late Longshan period in the southern region of the Central Plains of China. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
973.
Located in the Central Plains of China, the early Xia Dynasty site of Xinzhai (2050 BC–1750 BC) with large archaeological features and exquisite artifacts of jade and copper is pivotal for probing the origin and formation of Chinese civilisation. Here, stable isotope ratios analysis, supplemented by zooarchaeological results, was used to investigate the exploitation and management of animals utilised by humans. It was demonstrated that a diverse pattern of animal raising and exploitation was present at the Xinzhai site. The domestic pigs were fed with substantial amounts of millets or their byproducts to guarantee a food source for the dietary demands of the humans. Dogs were also found to have consumed large amounts of C4 protein sources, likely in the form of human food scraps or leftovers. The domestic herbivores, sheep and cattle, showed different dietary characteristics in that the former mainly grazed in the natural environment, while the latter species were fed with large amounts of C4 products. This intra‐species variation was somewhat related to their physiological characteristics but seems to have been more determined by their different status in social and ritual activities. Thus, this research at Xinzhai provides a glimpse of the organisation of animal resources during the initial formation of Chinese civilisation. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
974.
This article explores the living conditions and specifically the possible etiologies of subperiosteal reactions among those seafarers who did not survive Christopher Columbus' second voyage to the Americas and died at La Isabela, the first permanent European settlement in the New World, which is located in the present‐day Dominican Republic. The town was founded in 1494 by Christopher Columbus (1451–1506) and occupied for only 4 years. This study analyses the macroscopic and histological evidence of the skeletal series excavated from this contact cemetery, which is presently curated at the Museo del Hombre Dominicano. Twenty of the 27 systematically scored individuals reveal subperiosteal bone accretions, and in at least 15 individuals, these accretions appear bilaterally. The morphology, distribution and healing stages of the majority of these lesions provide new, direct evidence suggesting severe adult scurvy, a condition caused by sustained vitamin C deprivation, which was common among seafarers before the 18th century. The historical context surrounding the individuals' death at the European contact settlement and the conditions and duration of Christopher Columbus' second transatlantic voyage to the New World represent key elements in the interpretation of these lesions. In this case, the evidence also corroborates the known failure of Columbus' crew to exploit the locally available foods rich in vitamin C. Scurvy probably contributed significantly to the outbreak of sickness and collective death within the first months of La Isabela's settlement, an aspect that inflects the current discussion about the degree of virulence of New World infections that decimated the European newcomers, who we conclude to have been already debilitated and exhausted by scurvy and general malnutrition. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
975.
Although a patchwork of projects shows a process of agriculture intensification in North China during the Neolithic, the impact of cereal farming on animal husbandry and their mutual interaction remain cloudy. This study reports bone collagen δ13C and δ15N of humans and animals from Wayaogou (ca 6.5–6.0 kyrs bp ) and Dongying (ca 5.9–5.6 kyrs bp , 4.6–4.0 kyrs bp ) to explore temporal trend of livestock raising and particularly the importance of millet fodder to stock raising practices in the Wei River valley, North China. The isotopic evidence overall shows that millet products increased in human and domestic animal diets during the mentioned chronological span. δ13C values of pigs and dogs at Dongying are higher than those at Wayaogou, implying that the importance of millet nutrients increased to animal husbandry diachronically. Interestingly, δ13C results of domestic cattle of Dongying late phase (−14.1 ± 1.1‰, N = 5) are more enriched than Wayaogou wild Bos (−17.8 ± 0.3‰, N = 3), indicating that millet fodder had taken a significant place in early cattle husbandry. Besides, differences between Bos species of the two periods also imply that δ13C values of bone collagen constitute a potential indicator for tracing the origin of cattle husbandry in North China. In addition, domestic sheep at Dongying produced similar isotope data to wild ovicaprid at Wayaogou, suggesting that they possibly had grazed for the most in grassland and therefore experienced a different lifestyle from cattle. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
976.
Equid remains are scarce and very fragmented in Iberian Neolithic and Bronze Age sites. Evidence suggesting that horses were domesticated does exist, but it is often inconclusive, thus leaving the question unanswered. Today, DNA analyses have provided information about a, most likely Iberian, nucleus of horse domestication, making it crucially important to expand the database. The Holocene sequence (6th and 3rd millennium cal bc ) of the Cueva de El Mirador (Sierra de Atapuerca, Spain) has yielded 92 equid remains distributed in 12 Neolithic and Bronze Age levels. In this paper, we present the study of the equid remains from the Cueva de El Mirador from an archaeozoological perspective, giving indirect evidence of horse domestication. Our results vary widely and lead to open interpretations about horse domestication and how humans used these animals. This study of horse remains focuses on species identification and on determining how humans economically used these animals. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
977.
Museums and other curatorial bodies face the significant challenge of storing large volumes of material recovered from decades of archaeological excavation, amongst which are very large collections of animal bones. As stores fill up, there is pressure to reconsider curation policies, to the point of refusing further deposition and disposal of existing material. Faced with this situation, York Archaeological Trust looked to develop and implement a strategy to reduce the curated research resource of animal bones, accepting that some excavated assemblages are of low research potential. Applying this strategy to animal bones from the Hungate excavation resulted in a substantial reduction in the volume of material regarded as of significant future research value. The strategy also generated a digital record, including images, that provides the justification for those retention decisions as well as a useful survey that facilitates the location of suitable material for further research. This pilot study shows that it is possible to rationalise what would otherwise be a substantial store of bone assemblages to give a smaller, better‐documented and more research‐relevant archive of material. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
978.
The thermoluminescence dating method was applied to 77 heated flints from the Mousterian layers of Hayonim Cave in order to provide a precise TL-based chronology for this important Levantine sequence. A detailed dosimetric study was performed by using 76 dosimeter capsules and revealed strong spatial dose-rate variations. In parallel, Fourier transform infrared spectrometry enabled the identification of various mineral assemblages in the sediments of the cave and to localize the boundaries of these assemblages. By comparing these two data sets, it is shown that low dose-rate values (∼500 μGy/a) are systematically recorded in areas where the calcite-dahllite (CD) assemblage is preserved, whereas higher values (up to 1300 μGy/a) are associated with the leucophosphite, montgomeryite, variscite and siliceous aggregates (LMVS) assemblage. The dosimetric and mineralogical information was combined in order to assess, where possible, the dose-rate experienced by each flint during its burial. Some of the flint samples analyzed were too close to mineral assemblage boundaries and were therefore discarded. This rigorous selection led to TL ages ranging from 230 to 140 ka for the lower part of the Mousterian sequence (layers F and Lower E), which contains lithic industries characterized by blade production using the laminar method.  相似文献   
979.
980.
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