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   51篇
  免费   3篇
  54篇
  2020年   1篇
  2019年   3篇
  2018年   4篇
  2017年   4篇
  2016年   3篇
  2015年   3篇
  2013年   13篇
  2012年   5篇
  2011年   2篇
  2010年   1篇
  2009年   4篇
  2008年   2篇
  2007年   1篇
  2006年   2篇
  1999年   1篇
  1997年   2篇
  1991年   1篇
  1965年   1篇
  1963年   1篇
排序方式: 共有54条查询结果,搜索用时 0 毫秒
31.
Although it has been generally held that Saxton in his later life did not work far from home, two previously unrecognized maps in The National Archives show him surveying in 1607 for the Earl of Cumberland in the dangerous Border country. These maps throw new light onto the working methods of Saxton and his son, suggesting that by this date Robert was doing most of the work. The original map appears to have been commissioned as an estate map but was then copied to be re-used as evidence in a law suit, thus separating the maps from their context.  相似文献   
32.
33.
In the 1890s, those opposed to women's suffrage in the borderlands of Maine and New Brunswick held a lot of the same arguments, but expressed them in different ways, and with different outcomes. In New Brunswick, the most vocal adversaries were male and represented in the Legislative Assembly. In Maine, a group of elite women, mostly from Portland, led the fight to keep women from voting. This article will explore the motivations, comparisons, and differences between the anti-suffragists of the borderlands, as well as explain some of the outcomes of the anti-suffrage movement that are still present today.  相似文献   
34.
Chemical analysis of residue extracted from stone pipes and pipe fragments excavated at sites in the southern Pacific Northwest Coast of North America demonstrate that hunter-gatherers smoked the psychostimulant tobacco (Nicotiana sp.) by at least AD 860. Non-farming ethno-historic Native Americans throughout the west gathered and sometimes cultivated tobacco for ritual and religious purposes, but until now the antiquity of the practice on this part of the continent was unknown. Method validation includes chemical characterization of a suite of smoke plants and experimental reproduction of “smoked” pipe chemistry; results indicate biomarkers are traceable for several species commonly smoked by ethnographic native peoples, including tobacco (nicotine, cotinine), tree tobacco (anabasine), and kinnikinnick (arbutin). Developed methods—where residue is extracted directly from the stone or clay matrix of whole and fragmentary archaeological pipes—may be applied in similar studies investigating the spread and use of ritual smoke plants in the ancient Americas and elsewhere.  相似文献   
35.
In the summer of 1988, television viewers across the United States and Canada were transfixed by images of Yellowstone National Park seemingly consumed by flames as wildfires burned almost one million acres of land within the Greater Yellowstone Area. In the wake of the fires, the governments of the United States and Canada both reassessed their policy approaches to fire management and came to two very different conclusions. The purpose of this study is to explore how the wildfire problem was defined in Canada and the United States in the wake of the Yellowstone wildfires, why these definitions were so different, and what effects these different definitions have had on fire policy. As a subtext, this research also highlights the challenges inherent in science‐based decision making.  相似文献   
36.
This paper reports a series of radiocarbon dates on bone samples coming from the Mousterian of Acheulian Tradition (MTA) Layer 3 at the top of the Pech de l'Azé IV (Pech IV, France) Middle Palaeolithic sequence. All of these samples showed evidence of human impact, and they were prepared using current pre-treatment techniques to remove or identify contamination. The results indicate that the MTA at Pech IV started prior to the current limit of radiocarbon calibration (circa 50 ka BP) and ended by 45 ka cal. BP. These dates are supported by additional TL and ESR dates from the sequence, confirm previously suggested correlations between Pech I and IV, and generally fit within the known age range for the MTA. The oldest dates reported here may also lend support to still older TL dates for the MTA that taken together suggest that the MTA extended from late MIS 4 or early OIS 3 through to the end of the Middle Palaeolithic in southwest France.  相似文献   
37.
38.
This paper examines the relationship between size of land holding and family income, based on a recent survey of rural households in Poland. In general, the results indicate a positive relationship between income and size of land holdings, suggesting that successful Polish farmers are expanding their farm holdings through land market transactions. Constraints to efficient functioning of these land markets in Poland are investigated as well, which include high government-determined land transaction costs, complex registration procedures, poor access to mortgage facilities, and a bias against larger farms built into the unemployment benefits system. Journal of Economic Literature, Classification Numbers: O18, Q15, Q24. 5 figures, 12 tables, 10 references.  相似文献   
39.
Carbon and nitrogen isotopic analysis was undertaken on well-preserved human and animal skeletal remains from two sites in northern Ethiopia, both of which span the pre-Aksumite and Proto-Aksumite periods. The human remains constitute one individual collected at the site of Etchmare East which was directly radiocarbon dated to 2290 ± 50 BP. In addition 28 animal bone samples were excavated from the nearby site of Mezber, occupied from 2960 ± 60 to 1980 ± 50 BP. These results are consistent with those obtained in palaeoethnobotanical studies, which suggest that some members of pre/Proto-Aksumite society in the Horn of Africa had a diet that favoured the consumption of Near Eastern domesticates over indigenous crops.  相似文献   
40.
This paper contributes to a discussion on networks as political spaces by examining the work of an environmental activist group in Kaliningrad, Russia. Drawing from geographic work on communication and from literature on organizational structure and communication technology provides a useful means of understanding and conceptualizing computer networks from a social science perspective. The case study of grassroots activism illustrates how computer-based communication may support a unique space of political activity. Electronic mail (e-mail) communication can be a channel through which activists may overcome the constraints of location as an information container in order to create spaces of interaction and action appropriate to their political agenda. This case study is an example where organization members use e-mail communication to connect their activities, information sources and collaborative partners at different scales to create a viable space for environmental activism and information distribution within a shifting political context.  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