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   1141篇
  免费   96篇
  2023年   30篇
  2022年   13篇
  2021年   15篇
  2020年   65篇
  2019年   61篇
  2018年   81篇
  2017年   66篇
  2016年   72篇
  2015年   58篇
  2014年   64篇
  2013年   193篇
  2012年   70篇
  2011年   52篇
  2010年   48篇
  2009年   51篇
  2008年   46篇
  2007年   50篇
  2006年   49篇
  2005年   25篇
  2004年   18篇
  2003年   21篇
  2002年   9篇
  2001年   21篇
  2000年   12篇
  1999年   9篇
  1998年   14篇
  1997年   9篇
  1996年   4篇
  1994年   2篇
  1993年   2篇
  1991年   2篇
  1990年   1篇
  1988年   1篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
排序方式: 共有1237条查询结果,搜索用时 515 毫秒
51.
During recent reinvestigations in the Great Cave of Niah in Borneo, the ‘Hell Trench’ sedimentary sequence seen by earlier excavators was re-exposed. Early excavations here yielded the earliest anatomically-modern human remains in island Southeast Asia. Calibrated radiocarbon dates, pollen, algal microfossils, palynofacies, granulometry and geochemistry of the ‘Hell Trench’ sequence provide information about environmental and vegetational changes, elements of geomorphic history and information about human activity. The ‘Hell’ sediments were laid down episodically in an ephemeral stream or pool. The pollen suggests cyclically changing vegetation with forest habitats alternating with more open environments; indicating that phases with both temperatures and precipitation reduced compared with the present. These events can be correlated with global climate change sequences to produce a provisional dating framework. During some forest phases, high counts of Justicia, a plant which today colonises recently burnt forest areas, point to fire in the landscape. This may be evidence for biomass burning by humans, presumably to maintain forest-edge habitats. There is evidence from palynofacies for fire on the cave floor in the ‘Hell’ area. Since the area sampled is beyond the limit of plant growth, this is evidence for human activity. The first such evidence is during an episode with significant grassland indicators, suggesting that people may have reached the site during a climatic phase characterised by relatively open habitats ∼50 ka. Thereafter, people were able to maintain a relatively consistent presence at Niah. The human use of the ‘Hell’ area seems to have intensified through time, probably because changes in the local hydrological regime made the area dryer and more suitable for human use.  相似文献   
52.
关于利用历史文献信息进行环境演变研究的几点看法   总被引:1,自引:0,他引:1  
针对如何更好地利用我国丰富的历史文献记录,开展历史时期环境演变研究,本文提出四点看法:从地球系统科学与全球变化研究的前沿中寻找研究的主题,在诸多不确定中寻找确定性答案,构建历史文献信息共享的环境演变研究平台,培养文理兼备的复合型人才。  相似文献   
53.
大约以公元前2200年为界, 老虎山文化可分为前、后两大期.前期稳定发展,对外影响有限;后期向南强烈扩张,其陶双鋬鬲、卜骨和细石器镞更流播至黄河中下游广大地区.老虎山文化后期对外扩张的加强和这一时期气候日渐干冷有关.  相似文献   
54.
Archaeological experiments that use modern bones to replicate past animal bone assemblages have often failed to consider the effects of environment, storage and preparation on modern bones. Often, these experiments make little mention of the conditions to which bones were subject during their storage and preparation for use in experiments. In other instances, these variables are reported but not considered as factors that contribute to the nature of the results obtained. This study considers previously reported data concerning the degradation of frozen bones (−20°C), and bones exposed to hot, dry conditions (40°C), and presents new data for bones exposed to room temperature environments (22°C) and refrigerated environments (2°C), and bones that are frozen (−20°C) and then thawed (22°C). These conditions are all relevant to understanding the nature of bone degradation and the use of bones in modern archaeological experimentation. This article also surveys a range of previously reported experiments that utilise modern bones to create analogies to the past and considers different methodological approaches and their relationship to the condition of bones at the time of their fracture and fragmentation. The longitudinal data presented in this study demonstrate differential rates of bone degradation over time in various environmental conditions. This degradation results in dramatic changes in bone fracture morphology, bone strength and utility for bone tool production. These observations have significant implications for experiments that utilise modern bones, especially when experimental data are used to create analogies to the archaeological past. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
55.
在回顾国有文物商店历史成因、分析文物商店困境的基础上提出了对其改制的必要性,进一步分析了国有文物商店改制的特殊性以及国有文物商店改制必须要处理好的四点关系。  相似文献   
56.
对明清江淮西部地区的旱涝史料进行梳理,对逐年州县旱涝灾害资料等级进行量化处理,并通过计算旱涝平均等级值和10年滑动平均值,重建1450—1911年该区域的干湿变化时间序列。结果发现,该区1450—1911年间共出现6个干湿阶段: 1450—1490年,以轻度干旱为主;1491—1545年,旱涝灾害频发,干湿波动较为明显;1546—1625年,旱涝灾害少发,干湿比较平稳;1626—1710年,以中度干旱为主,极端干旱事件发生频率显著增加;1711—1860年,气候湿润;1861—1911年,干湿波动偏湿润。不同的干湿阶段对江淮西部的湖泊也造成了一定的影响,干旱时期,湖盆积水减少,湖周萎缩;湿润时期,降雨增加,湖泊的蓄水量增加。  相似文献   
57.
Many versions of the history of Americanist archaeology suggest there was a stratigraphic revolution during the second decade of the twentieth century—the implication being that prior to about 1915 most archaeologists did not excavate stratigraphically. However, articles and reports published during the late nineteenth century and first decade of the twentieth century indicate clearly that many Americanists in fact did excavate stratigraphically. What they did not do was attempt to measure the passage of time and hence culture change. The real revolution in Americanist archaeology comprised an analytical shift from studying synchronic variation to tracking changes in frequencies of artifact types or styles—a shift pioneered by A. V. Kidder, A. L. Kroeber, Nels C. Nelson, and Leslie Spier. The temporal implications of the analytical techniques they developed—frequency seriation and percentage stratigraphy—were initially confirmed by stratigraphic excavation. Within a few decades, however, most archaeologists had begun using stratigraphic excavation as a creational strategy—that is, as a strategy aimed at recovering superposed sets of artifacts that were viewed as representing occupations and distinct cultures. The myth that there was a stratigraphic revolution was initiated in the writings of the innovators of frequency seriation and percentage stratigraphy.  相似文献   
58.
略论晚清汉学的兴衰与变化   总被引:4,自引:0,他引:4  
晚清时期,兴盛于乾嘉年间的清代儒学主流学派-汉学-尽管走上衰落的道路,但这种衰落并非直线性地下降,而是经历了一个较长的曲折变化的过程。自鸦片战争到中日甲午战争长达半个多世纪的时间里,汉学依然是中国学坛人多势众、著述丰富、分布广泛的强势学派,居于学界“老大”的地位。晚清汉学家们秉承乾嘉宿儒治学传统,在经学、小学、音韵学等领域开展深入研究,取得显著成就,甚至在某些方面直驾乾嘉而上。晚清汉学因处于与乾嘉汉学完全不同的社会环境,形成“实”、“通”、“变”的历史特征,并随着中国传统社会发生根本性的变化而实现着自身的新旧更替。晚清汉学既沿袭了传统儒学的许多消极因素,也包含着其中的积极成分,对中国近代社会文化产生了复杂而多重的影响。  相似文献   
59.
Local earthenware associated with enslaved African populations in the Americas, variously called Colono-Ware, Afro-Caribbean Ware. Yabbas, and Criollo ware, has received considerable attention from researchers. What unifies this disparate group of ceramics is not method of manufacture, design and decoration, or even form and function but the association or potential association with African diaspora populations. The ceramics incorporate some skills and techniques possibly brought by African potters to the Americas, as well as skills reflecting European and Native American traditions, and local adaptations in form, function, and manufacture. Analogies linking African ceramic traditions to American industries have at times been employed uncritically and have relied on generalized characteristics to infer overly specific meanings. With particular reference to low-fired earthenwares from Jamaica, this paper examines the historical and cultural context of these ceramics and the methodological and theoretical problems faced in their interpretation.  相似文献   
60.
Archaeologists can learn from models of evolution as a self-organized critical phenomenon. Self-organized critical systems are large, interactive systems that organize into a critical state where minor events can trigger chain reactions. Such systems demonstrate power-law distributions in the size of changes, or avalanches, that occur. The theory of self-organized criticality is important in that it implies that the evolution of complex systems may be driven more by interactions between agents than by external events or natural selection. Stylistic changes may be examples of avalanches of interconnected events. Evidence for self-organized criticality is shown for stylistic evolution in historical pottery styles from New York State and is used to evaluate the nature of a prehistoric pottery typology from the Southwest.  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