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   54篇
  免费   4篇
  2023年   2篇
  2020年   1篇
  2018年   4篇
  2017年   1篇
  2016年   6篇
  2015年   2篇
  2014年   3篇
  2013年   15篇
  2012年   3篇
  2011年   3篇
  2010年   2篇
  2008年   3篇
  2007年   1篇
  2006年   2篇
  2005年   2篇
  2003年   3篇
  2002年   2篇
  2001年   1篇
  1999年   1篇
  1989年   1篇
排序方式: 共有58条查询结果,搜索用时 31 毫秒
41.
42.
43.
This paper presents the preliminary results of a survey project which is being carried out in the small village of Fatschenbrunn, in Lower Franconia, Germany. The project combines archaeological, historical geographical, botanical, geological and pedological data to reconstruct the farming regimes and land use in the late medieval and post-medieval era. Although the project is still on-going, the collected data allows the formulation of hypotheses on the formation of fertile agricultural soils through long-term human intervention in the past.  相似文献   
44.
45.
46.
The conventional theoretical and empirical references related to the inter-governmental fiscal transfer system in Germany appear to heavily concentrate on the issues surrounding the measurement of local expenditure needs of a municipality and their coverage through the down-flow grants when the municipal tax revenue is insufficient to match the needs. This study introduces additional important research fields in this context. Firstly, it attempts to analyse the role of the development of tax revenue and fiscal power of the grant provider (the State) as well as the joint financial relationship between the State and (different types of rural and urban) municipalities in the determination of inter-governmental grants. Secondly, when the total volume of the State grants is determined, this study examines in the next step under the particular consideration of different tax capacities in varied categories of municipalities, how this amount should be horizontally distributed among these groups to achieve the equal growth of hypothetical per capita fiscal capacity.  相似文献   
47.
48.
The infrared radiofluorescence (IR-RF) dating technique was applied to eight fluvial samples that were collected from two sediment cores at the Heidelberg Basin located near Viernheim and Ludwigshafen in southwest Germany. Based on the IR-RF derived ages of the samples it was possible to establish a chronological framework for the Mid-Pleistocene fluvial deposits of the Heidelberg Basin. The results allow us to distinguish between four main periods of aggradation. The lowermost sample taken from 100 m core depth lead to an IR-RF age of 643 ± 28 ka pointing to a Cromerian period of aggradation (OIS 17–16). For the Elsterian it is now possible to distinguish between two aggradation periods, one occurring during the Lower Elsterian period (OIS 15) and a second during the Upper Elsterian period (OIS 12–11). For the so called Upper interlayer (or “Oberer Zwischenhorizont” — a layer of organic-rich and finer-grained deposits), the IR-RF results point to a deposition age of around 300 ka, with samples taken directly on top and out of this layer yielding IR-RF ages of 288 ± 19 ka and 302 ± 19 ka, respectively. Hence, the measured IR-RF ages clearly point to a deposition during the Lower Saalian period (OIS 9–8) whereas earlier studies assumed a Cromerian age for the sediments of the Upper Interlayer based on pollen records and also mollusc fauna. The new IR-RF dataset indicates that significant hiatuses are present within the fluvial sediment successions. In particular the Eemian and Upper Saalian deposits are missing in this part of the northern Upper Rhine Graben, as the 300 ka deposits are directly overlain by Weichselian fluvial sediments. It is obvious that time periods of increased fluvial aggradation were interrupted by time periods of almost no aggradation or erosion which should have been mainly triggered by phases of increased and decreased subsidence of the Heidelberg Basin.  相似文献   
49.
ABSTRACT This paper suggests a cause of low density urban development or urban sprawl that has not been given much attention in the literature. There have been a number of arguments put forward for market failures that may account for urban sprawl, including incomplete pricing of infrastructure, environmental externalities, and unpriced congestion. The problem analyzed here is that urban growth creates benefits for an entire urban area, but the costs of growth are borne by individual neighborhoods. An externality problem arises because existing residents perceive the costs associated with the new residents locating in their neighborhoods, but not the full benefits of new entrants which accrue to the city as a whole. The result is that existing residents have an incentive to block new residents to their neighborhoods, resulting in cities that are less dense than is optimal, or too spread out. The paper models several different types of urban growth, and examines the optimal and local choice outcomes under each type. In the first model, population growth is endogenous and the physical limits of the city are fixed. The second model examines the case in which population growth in the region is given, but the city boundary is allowed to vary. We show that in both cases the city will tend to be larger and less dense than is optimal. In each, we examine the sensitivity of the model to the number of neighborhoods and to the size of infrastructure and transportation costs. Finally, we examine optimal subsidies and see how they compare to current policies such as impact fees on new development.  相似文献   
50.
As common wisdom has it, Pierre Duhem was one of the most important proponents of French philosophy of science around 1900. Usually, his conception of physical theories is regarded as the incarnation of the ancient — proto-positivistic - programme of “saving the phenomena”. This view is correct, but it needs to be supplemented by taking account of the discursive context of Duhem’s position. In this paper it is argued that Duhem’s philosophical colleague Abel Rey played a central role in this connection.  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