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   208篇
  免费   9篇
  2023年   2篇
  2021年   1篇
  2019年   5篇
  2018年   6篇
  2017年   11篇
  2016年   6篇
  2015年   5篇
  2014年   5篇
  2013年   73篇
  2012年   8篇
  2011年   4篇
  2010年   5篇
  2009年   7篇
  2008年   7篇
  2007年   1篇
  2006年   4篇
  2005年   2篇
  2004年   4篇
  2003年   1篇
  2002年   6篇
  2001年   1篇
  2000年   5篇
  1999年   1篇
  1998年   1篇
  1997年   2篇
  1996年   2篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1990年   2篇
  1986年   2篇
  1985年   1篇
  1984年   4篇
  1983年   4篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1979年   3篇
  1978年   2篇
  1977年   2篇
  1976年   4篇
  1975年   3篇
  1974年   1篇
  1973年   1篇
  1972年   2篇
  1971年   1篇
  1968年   1篇
  1954年   1篇
排序方式: 共有217条查询结果,搜索用时 15 毫秒
11.
Rozefelds, A.C., Dettmann, M.E., Clifford, H.T. & Lewis, D., August 2015. Macrofossil evidence of early sporophyte stages of a new genus of water fern Tecaropteris (Ceratopteridoideae: Pteridaceae) from the Paleogene Redbank Plains Formation, southeast Queensland, Australia. Alcheringa 39,. ISSN 0311-5518.

Water fern foliage is described from the Paleogene Redbank Plains Formation at Dinmore in southeast Queensland. The material, which is based upon leaf impressions, records early sporophyte growth stages. The specimens occur at discrete levels in clay pits at Dinmore, and the different leaf stages present suggest that they represent colonies of young submerged plants, mats of floating leaves, or a mixed assemblage of both. The leaf material closely matches the range of variation evident in young sporophytes of Ceratopteris Brongn., but in the complete absence of Cenozoic fossils of the spore genus Magnastriatites Germeraad, Hopping & Muller emend. Dettmann & Clifford from mainland Australia, which are the fossil spores of this genus, it is referred to a new genus, Tecaropteris. The record of ceratopterid-like ferns adds significantly to our limited knowledge of Cenozoic freshwater plants from Australia. The geoheritage significance of sites, such as Dinmore, is discussed briefly.

Andrew C. Rozefelds [], Queensland Museum GPO Box 3300, South Brisbane, 4101, Queensland, Australia and School of Earth Sciences, University of Queensland, St Lucia, 4072, Queensland, Australia; Mary Dettmann [], H. Trevor Clifford [] and Debra Lewis [], Queensland Museum, GPO Box 3300, South Brisbane, 4101, Queensland, Australia.  相似文献   

12.
Excavations at the site of Langley’s Lane, Bath and North-East Somerset, have revealed an important sequence of Late Mesolithic activity focused around an active tufa spring. The sequence of activity starts off as an aurochs kill and primary butchery site. Culturally appropriate depositional practices occur through the placement of a selection of bone in the wetland of the spring and the digging of pits around the spring margins. The spring at Langley’s Lane continued to be visited and more animal bone and lithic material was placed in the wetland. Finally, visits to the site involved yet more formalized activity in the form of pit digging and the creation of a stone surface. Activities such as these are difficult to locate in the archaeological record and Mesolithic ritual activity rare, making this a site of some significance to studies of Mesolithic NW Europe.  相似文献   
13.
In this essay David Lewis Schaefer summarizes and defends the argument set forth in his book The Political Philosophy of Montaigne (Cornell University Press, 1990; second edition 2019) that Michele de Montaigne's Essays (first edition, 1580) merits consideration as a founding text of modern political liberalism. After responding to the most extensive published critique of his interpretation (by James Supple) and citing other recent studies that harmonize with his argument, Schaefer compares his analysis of Montaigne's political aims and political-ethical teaching with those set forth in two other recent studies: Philippe Desan's Montaigne: A Life and Pierre Manent's Montaigne: La Vie sans loi.  相似文献   
14.
新中国诞生后,百废待兴。冀朝鼎在帝国主义实施禁运和经济封锁的困难面前,积极探索中国外经贸的新体制,加强外汇管理,以灵活的外交,与11个国家签定了外贸协定,还成功地与日本、英国等未建交国家进行“民间贸易”.打破西方列强的孤立政策.开创了中国对外交往与贸易的新局面。  相似文献   
15.
16.
17.
Swords have been one of the major weapons used in violent conflicts for much of human history. Certain archaeological situations, especially those dealing with the recovery and analysis of battle casualties, may raise questions about what type(s) of bladed weapon was used in a particular conflict (e.g., the battle of Kamakura, Japan, AD 1333; the battle of Wisby, Sweden, AD 1361; the battle of Towton, England, AD 1461). Little work has been done, however, on developing criteria to differentiate sword cut marks from other types of cut marks, or to distinguish between marks created by different sword types. To develop such criteria, bovine tibiae (n = 7) were struck using six different types of bladed weapon and the resulting marks (n = 92) were analyzed. Eight traits describing the morphology of the cut mark – such as shape, the presence and unilateral/bilateral state of flaking and feathering, the presence of bone shards, associated breaks, etc. – are defined and related to blade type used. Sword marks were found to be easily distinguishable from knife marks. The variation in marks made by different sword types is significantly correlated with differences in blade weight (p < 0.0001), grip (p < 0.0113), and sharpness (p ≤ 0.0179). The criteria and analyses developed and implemented in this study will be of use to researchers in forensics and osteoarchaeology who want to infer bladed weapon type from marks on bones.  相似文献   
18.
19.
20.
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