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   64篇
  免费   3篇
  2021年   1篇
  2019年   2篇
  2015年   3篇
  2014年   1篇
  2013年   5篇
  2012年   5篇
  2011年   2篇
  2010年   4篇
  2009年   2篇
  2008年   6篇
  2007年   7篇
  2006年   5篇
  2005年   3篇
  2003年   1篇
  2001年   1篇
  1999年   1篇
  1997年   3篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1988年   2篇
  1987年   3篇
  1985年   1篇
  1979年   2篇
  1974年   1篇
  1972年   1篇
  1966年   1篇
排序方式: 共有67条查询结果,搜索用时 15 毫秒
1.
Streamline analyses of mean monthly resultant surface winds over Australia are presented. Mean confluences represent either cyclone trajectories, or modal fronts. These analyses suggest that Australia's annual airstream climate is of two regimes: that of September to March inclusive, and April to August inclusive. The winter half-year is exemplified by a continental airstream source in southern Australia which diverges over virtually the entire continent. It continues into September and October, although dominating only the southern third to half of Australia, and is absent from November to March. During the summer half-year a new pattern emerges, with three maritime air stream sources represented over the continent: first, air from the Southern Ocean penetrates the south coast reaching its furthest northward extension from December to March inclusive; a second source originating over the Pacific Ocean dominates eastern and northern Australia; and a monsoon source originating over the Indian Ocean which flows overland affecting northern Western Australia. Two modal confluences are noted, one over northwestern Australia from November-February separating monsoon flow from that emanating from the east, and another extending from the west central coast east-southeastward to the southeast coast from November-March separating Southern Ocean air from that originating over the Pacific Ocean.  相似文献   
2.
3.
This paper describes the hitherto unreported occurrence of mid‐Holocene mangrove deposits in the Richmond River estuary, southeastern Australia, thereby providing evidence for changes in the distribution and composition of mangrove communities within a subtropical estuarine system during the Holocene. Stratigraphic, radiocarbon and palynological evidence indicates that widespread development of mangrove communities took place in the upstream reaches of the Richmond River estuary during the period 7000 to 6000 years BP. These communities maintained their habitat through substrate aggradation under the conditions of a moderate sea‐level rise, in contrast to other estuaries within the region, which generally experienced the submergence of intertidal substrates. Mangrove species belonging to the family Rhizophoraceae, most likely Bruguiera gymnorrhiza and Rhizophora stylosa, dominated these communities, in strong contrast to contemporary communities, which are dominated by Avicennia marina. Moreover, these mid‐Holocene communities were located a considerable distance upstream of the contemporary occurrences of Rhizophoraceae species within the estuary. The changes in the spatial distribution and composition of mangrove communities parallel the large‐scale evolution of the estuary driven by sea‐level variation. Shallow, buried Pleistocene terraces probably contributed to the regionally unique aggradational response of the mangrove communities and their substrates to a sea‐level rise during mid‐Holocene times.  相似文献   
4.
To help improve the well‐being of the local people, a joint Vietnamese‐UK team set out to establish a way of estimating soil and nutrient losses under different land management scenarios, using field data extrapolated through remote sensing and GIS, to obtain catchment‐wide estimates of the impact of land cover change. Immigration from remote provinces to the Dong Phu District of Binh Phuóc Province, about 120 km north of Ho Chi Minh City, has led to disruption of soil surface stability on easily eroded clayey sandstones, creating rapid nutrient depletion that affects crop yields and siltation in the channel of the Rach Rat river downstream. The poor farmers of the areas see crop yields drop dramatically after two or three years of cultivation due to the fertility decline. Soil loss varies dramatically between wet season and dry season and with ground cover. Erosion bridge measurements showed a mean loss of 85.2 t ha?1 y?1 under cassava saplings with cashew nuts, 43.3 t ha?1 y?1 on uncultivated land and 41.7 t ha?1 y?1 under mature cassava. The rates of erosion were higher than those reported in many other parts of Vietnam, reflecting the high erodibility of the friable sandy soils on the steep side‐slopes of the Rach Rat catchment. However, although the actual measurements provide better soil loss data than estimates based on the parameters of soil loss equations, a large number of measurement sites is needed to provide adequate coverage of the crop and slope combinations in this dissected terrain for good prediction using GIS and remote sensing.  相似文献   
5.
Within trafficking discourses, men appear as predatory and exploitative, while boys appear as victims. This flattens the complexities of social life and obscures the ways that constructs of masculinity frame the trajectories of labour migrants and their brokers. This article challenges those discourses, drawing on research with two groups of labour migrants characterized as ‘victims of trafficking’, as well as with ‘traffickers’ who help them to move and work. The first are adolescents moving from Benin to the gravel quarries of Abeokuta, Nigeria. The second are adults from across West Africa who have made the illegal journey to Italy, where they live in ‘ghettos’ and work as gang labourers on harvests. In each case, migrants and their brokers come from the same or similar communities; (shared) ideals of masculinity structure their mobility and labour. Gendered transitions towards adulthood, the pressure to attain riches and status and a duty of responsibility to those younger and less successful are important. A focus on their masculinities takes us beyond ‘victim-perpetrator’ dyads.  相似文献   
6.
7.
8.
金仁喜 《民俗研究》2010,(4):141-153
本文通过在东夷文化圈中发现的神杆纹样,对韩国神杆的起源和功能展开讨论。我们可以发现,神杆起源于东夷文化圈,与稻作技术一道影响了韩国的南部地区。形态上的相似性,及功能上相似性,充分说明了韩国神杆与东夷文化圈的神杆有着紧密的联系。希望能够通过这样的研究,解决一部分关于神杆的起源和功能的问题。  相似文献   
9.
C. H. LEE    J. KIM  M. S. LEE 《Archaeometry》2010,52(1):31-44
This paper presents material characteristics and raw material provenance of the stone moulds for bronze slender daggers from Galdong. This type of bronze dagger is uniquely distributed in the Korean Peninsula and these stone moulds were the first to be found by excavation. The stone moulds were made of igneous hornblendite with course-grained holocrystalline textures. Based on petrological, mineralogical and geochemical characteristics, the original rock materials of the moulds were inferred to be derived from the Jangsu or Namwon areas which are about 50 km away from the excavation site. It is a notable achievement that this provenance study confirmed the domestic production of Korean-styled daggers.  相似文献   
10.
Evolutionary Perspectives on Rural Australia   总被引:1,自引:0,他引:1  
An enduring concern within Australian rural geography has been to understand the nature and implications of change. Much of the intellectual effort has been focused on interpreting how rural economies, populations, social institutions, cultures, and land uses have been transformed through processes operating across a range of spatial and temporal scales. This paper offers a critical appraisal of recent rural research in Australia and how this body of work has attempted to make sense of change. It argues that despite an ongoing focus on the nature of change, it is often reduced to a relatively simple historical narrative. We suggest that some of the emerging ideas in ‘evolutionary economic geography’ might offer an alternative means of conceptualising the trajectories of rural economies, institutions, and communities. The paper outlines the contours of evolutionary economic geography and the ways in which some of its key conceptual foundations might offer a means of understanding not only rural change, but also continuity.  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