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   89篇
  免费   3篇
  2023年   1篇
  2022年   2篇
  2021年   2篇
  2020年   3篇
  2019年   2篇
  2018年   3篇
  2017年   5篇
  2016年   5篇
  2015年   2篇
  2014年   5篇
  2013年   17篇
  2012年   6篇
  2011年   3篇
  2010年   4篇
  2009年   7篇
  2008年   4篇
  2007年   2篇
  2006年   4篇
  2005年   2篇
  2003年   3篇
  2001年   1篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1984年   1篇
  1983年   1篇
  1979年   1篇
  1978年   1篇
  1975年   1篇
排序方式: 共有92条查询结果,搜索用时 15 毫秒
1.
The spatial analysis literature recognizes three sources of aggregation error, termed Source A, Source B, and Source C, which affect models relying on distance measurements between populations and facilities. We consider these effects with respect to aggregating from census enumeration areas to census tracts, on a popular location model. We identify a further source of aggregation error, which we dub Source D error, arising from the representation of facility sites by discrete points. Source D effects are of the same magnitude as Source A and B combined, much greater than Source C effects. Source D error is further significant, because, unlike Source A and B error, it can be eliminated only by disaggregating .
La littérature sur Vanalyse spatiale reconnaît trois sources d'erreur d'agrégation appelées erreurs de source A, B, et C. Ces erreurs influencent les modèles qui reposent sur des mesures de distance entre des populations et des installations. On considère les effets d'agrégation des secteurs de dénombrement en secteurs de recensement sur un modèle de localisation courant. On identifie une quatrième source d'erreur d'agrégation appelée erreur de source D. Cette erreur découle de la représentation des sites des installations par des points discrets. Ses effets sont du même ordre de grandeur que ceux des sources A et B combinées et beaucoup plus grands que les effets de source G. L'erreur de source D est d'autant plus significative à cause du fait que, contrairement aux erreurs de source A et B, elle ne peut être éliminée que par la désagrégation .  相似文献   
2.
An analysis of the scale used by the designer of the Plan of St Gall allows for no other conclusion than that the mill and mortars shown on this Plan were water driven. Because of the paradigmatic nature of the Plan this means that hydraulically operated mills and mortars were by the makers of the Plan considered to be standard equipment of a Carolingian monastery — a conclusion supported by a wealth of other documentary source material available for this period.The Romans knew the water mill, but made little use of it. Its general adoption and diffusion in Merovingian and Carolingian Europe is in this study attributed to the rise and spread of Benedictine monasticism. It received its primary impetus from the need to provide milled and crushed grain in bulk for communities of considerable size, including a leisure class of men who had to be freed from the normal chores of toiling for life so that their energies could be directed to their primary task: the Work of God (Opus Dei). Water-powered trip hammers were in use in China before the birth of Christ. Their portrayal on the Plan of St Gall suggests that they were introduced in western Europe, not by Marco Polo, as some propose, but in the age of folk migrations or the early Carolingian Period.  相似文献   
3.
4.
Diffusionist theories have often been invoked to explain how ancient African cultures were formed and developed. Explanations were either in terms of waves of migrations or by infiltration by people of less African origin or people alleged to have had a high culture. This article provides new evidence for a Neolithic cultural sequence on the islands and coast of East Africa. It proposes that archaeological cultural horizons such as these should be re-examined using a revised diffusionist theory. On this basis, it can be shown that the people who were smelting iron in Sub-Saharan Africa around the first century a.d. were not marauding communities of Bantu peoples with no inclination to settle and build up empires, but of people who were well settled, and had a long history of building stable settlements and trading from Neolithic times.  相似文献   
5.
6.
7.
8.
The Iron Age cemetery of Münsingen in Switzerland with 220 abundantly equipped burials marked a milestone for Iron Age research. The horizontal spread throughout the time of its occupancy laid the foundation for the chronology system of the Late Iron Age. Today, skulls of 77 individuals and some postcranial bones are still preserved. The aim of the study was to obtain information about diet, mobility and social stratification of the individuals. Stable isotope ratios of carbon, nitrogen and sulphur were analysed for 63 individuals. For all of them, C3 plants were found to be the staple food. There are significant differences between males and females in δ13C and δ15N values. This points to a gender restriction in the access to animal protein with males probably having more access to meat and dairy products. Differences in δ15N values were also observed for different age classes. δ34S values indicate a terrestrial-based diet with no significant intake of marine or freshwater fish. Seven adults with enriched δ34S values might have immigrated to Münsingen, four of which were found in the oldest part of the cemetery. Furthermore, possible changes of the vegetation are indicated by the more positive stable carbon ratios in the later phases. The results lead to the suggestion that especially males buried with weapons might have played a special role in the Iron Age society.  相似文献   
9.
10.
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