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   217篇
  免费   5篇
  2024年   1篇
  2022年   1篇
  2021年   2篇
  2020年   3篇
  2019年   4篇
  2018年   9篇
  2017年   8篇
  2016年   11篇
  2015年   6篇
  2014年   6篇
  2013年   69篇
  2012年   5篇
  2011年   11篇
  2010年   5篇
  2009年   7篇
  2008年   6篇
  2007年   5篇
  2006年   5篇
  2005年   4篇
  2004年   6篇
  2003年   7篇
  2002年   2篇
  2001年   5篇
  2000年   5篇
  1998年   1篇
  1996年   1篇
  1995年   2篇
  1994年   2篇
  1993年   2篇
  1992年   1篇
  1987年   1篇
  1984年   1篇
  1981年   2篇
  1980年   2篇
  1979年   1篇
  1978年   4篇
  1977年   2篇
  1976年   2篇
  1975年   2篇
  1974年   1篇
  1973年   1篇
  1966年   1篇
排序方式: 共有222条查询结果,搜索用时 15 毫秒
91.
92.
Many attributes of present day soils can only be explained by reference to land management in the historic past. This is particularly well expressed in the plaggen soils which occur extensively on the north European plain. These deepened soils owe their dominant characteristics to the application from the 12th century of turf materials, often impregnated with dung. Similar deepening of soils can result from the disposal of urban waste. This paper discusses the results of soil research focused on a small Scottish town (Nairn). A soil survey revealed topsoils of over 1 m overlying fluvioglacial sands and gravels; such deepening is explained by the use of town waste on the burgh's arable lands from at least the 17th century up until the mid-19th century when an integrated sewerage system was installed. Micromorphological study of this deepened topsoil revealed the presence of many small black carbonaceous particles. Oxygen:carbon ratios were calculated from microprobe results as a means of confirming the carbonaceous nature of these particles. Soil phosphorus was primarily concentrated on the perimeter of these particles. The high quality of present day soils on the edge of the town is explained by the disposal of waste material, which included much carbonised material. This paper is the first to highlight the importance and potential of examining the gradation in soils from urban to rural contexts.  相似文献   
93.
Documenting the history of settlement in Hawaii during the last few centuries before European contact, is crucial to charting the evolution of the most complex chiefdom in Polynesia. It is precisely this period that Hawaii, and many Polynesian societies, underwent their most rapid changes in political, economic and social organisation. The last ∼500 to 300 years in the 14C calibration curve is problematic with wide fluctuations often rendering large age spans that do not precisely date single events, especially troubling with a culture-historical record of ∼1000 years duration. Here we present an extremely high precision 230Th chronology for archaeologically constrained coral samples from a range of occupancy sites. Our high precision dates allow the time of site use to be clearly demonstrated. They also provide the first dates for habitation sites in Hawaii that clearly show contemporaneous occupation—the major problem in settlement pattern archaeology. We demonstrate that two sites were occupied within the same year. Our refined chronology, provides new and exciting opportunities for tracking sociopolitical and economic developments during the last few centuries—the crucial period in the evolution and transformation of Polynesian societies.  相似文献   
94.
This paper presents a case study aimed at correlating archaeological ‘events’ (obtained from radiocarbon measurements and dendrochronology) from the site of Sutton Common with a radiocarbon-dated pollen sequence obtained from a palaeochannel deposit adjacent to the area of the main archaeological activity. It demonstrates the use of a Bayesian approach to quantifying whether the timing of palynological ‘events’ interpreted as reflecting anthropogenic impacts are likely to be associated with archaeological ‘events’. The results suggest that Bronze Age activity in the form of a mortuary enclosure and associated cremation burials are probably not contemporary with the palynological evidence for disturbance to the oak–hazel woodland in this period. Subsequent evidence for local woodland clearance and agriculture is estimated to precede the construction of the large Iron Age enclosure in 372 BC, with increases in ‘anthropogenic indicators’ following this ‘event’. The construction of the site does not appear to have had a pronounced impact on the local vegetation, with hazel the only woody taxon to show clear reductions. Despite the use of a substantial number of oak timbers in the enclosure palisade, percentages of oak remain remarkably stable. Later farming activity on the site probably post-dates the end of activity in the enclosures. The value of the methodology is discussed in relation to quantifiable and robust correlations of archaeological and palaeoenvironmental narratives of landscape and human activity.  相似文献   
95.
96.
97.
98.
99.
Under the right conditions, compounding socio‐political and economic change can dramatically alter government policy. From 2000, Western Australia, a resource‐rich jurisdiction, experienced significant change owing to a once‐in‐a‐generation resources boom, which forced a break with earlier development approaches. In 2008, regional interventionism returned to the State via the State Government's Royalties for Regions program. Departing from the neo‐liberal tradition, the program allocated 25 per cent of the State's royalty income to non‐metropolitan regions, over and above existing regional allocations, and its success remains disputed. While it is easy to question the program retrospectively, the socio‐economic and political circumstances from 2000 to 2008 reveal a “perfect storm” of conditions enabling the transition from neo‐liberalism to interventionism in regional development. This paper sets out to understand the multi‐faceted conditions that enabled the dramatic paradigm shift embodied by the program. To this end, it examines the State's rural–urban settlement dichotomy, its staples economy, and the policy context leading up to the program. Following that, the paper proposes a causal framework mapping out the factors driving and rationalising the program. These factors are then examined in detail and include perceived rural voter disenchantment, ineffectual regional development policy, the State's mining boom, inadequate regional development funding, the contrasting fortunes of two regions (illustrative of the impact of growth, and the lack thereof), and the political manoeuvring during the 2008 election. Finally, the paper concludes by considering how the conversion of these conditions resulted in the State's most significant regional policy redirection in decades.  相似文献   
100.
This paper reports on the results of archaeological field excavations at the site of Kara-tepe, in the semi-autonomous region of Karakalpakstan in northwestern Uzbekistan. Investigations at the site in 2008–2009 turned up an unusually rich assemblage of remains from a household context. Combined analysis of the household botanical and faunal remains has allowed us to reconstruct the agropastoral practices of local inhabitants in this oasis region during a critical period of social and environmental change in the Early Medieval transition (4th–5th centuries a.d.). The results of the study raise important new questions about agropastoralism in the oases of Central Eurasia, highlighting continuities of practice between oasis and steppe populations, and revealing dynamic changes in these systems over time.  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