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   152篇
  免费   10篇
  2023年   7篇
  2021年   2篇
  2020年   6篇
  2019年   7篇
  2018年   18篇
  2017年   22篇
  2016年   17篇
  2015年   6篇
  2014年   13篇
  2013年   25篇
  2012年   4篇
  2011年   5篇
  2010年   6篇
  2009年   6篇
  2008年   2篇
  2007年   4篇
  2006年   2篇
  2004年   1篇
  2003年   2篇
  2001年   1篇
  2000年   2篇
  1998年   1篇
  1996年   1篇
  1992年   2篇
排序方式: 共有162条查询结果,搜索用时 281 毫秒
1.
African Archaeological Review - A set of beads made of glass, gastropod mollusk shell, and fishbone from a Swahili occupation level on Ibo Island (northern Mozambique) is dated to the eleventh and...  相似文献   
2.
A new generation of greenways has emerged in recent years, the most ambitious of which are nationwide, interconnected networks of multi-use, multi-purpose greenways and trails, clustered under a single national vision. However, because these initiatives have been the focus of so few research studies, opportunities to glean lessons from their planning and implementation have been limited. This paper contributes to addressing this knowledge gap by presenting a comparative account of two networks, the Trans Canada Trail in Canada and Sendero de Chile in Chile. Using document analysis and interviews with officials closely involved in their development, the evolution of both networks is documented over time, emphasizing similarities and differences related to their planning and implementation. Both initiatives have faced significant challenges in reaching their connection goals and have availed themselves of a diverse range of opportunities and strategies to advance their agendas. A simple model of a virtuous cycle is proposed to highlight the positive feedback—between political and public support, sustained funding, partnership development, accessibility for urban residents, and connectivity of the network—generated by sustained network expansion over time. It is hoped that the insights offered from this analysis may offer guidance to inform the development of similar scale projects elsewhere.  相似文献   
3.
We analyze the general equilibrium effects of an asymmetric decrease in transport costs, combining a large-scale spatial dynamic general equilibrium model for 267 European NUTS-2 regions with a detailed transport model at the level of individual road segments. As a case study, we consider the impact of the road infrastructure investments in Central and Eastern Europe of the European Cohesion Policy. Our analysis suggests that the decrease in transportation costs benefits the targeted regions via substantial increases in gross domestic product (GDP) and welfare compared to the baseline, and a small increase in population. The geographic information embedded in the transport model leads to relatively large predicted benefits in peripheral countries such as Greece and Finland, which hardly receive funds, but whose trade links cross Central and Eastern Europe, generating profit from the investments there. The richer, Western European nontargeted regions also enjoy a higher GDP after the investment in the East, but these effects are smaller. Thus, the policy reduces interregional disparities. There are rippled patterns in the predicted policy spillovers. In nontargeted countries, regions trading more intensely with regions where the investment is taking place on average benefit more compared to other regions within the same country, but also compared to neighboring regions across an international border. We uncover that regions importing goods from Central and Eastern Europe enjoy the largest spillovers. These regions become more competitive and expand exports, to the detriment of other regions in the same country.  相似文献   
4.
The standard theory of optimal jurisdictional size hinges on the existence of economies of scale in the provision of local public goods and services. However, despite its relevance for forced local amalgamation programs and related policies, the empirical evidence on the existence of such economies of scale remains elusive. The main goal of this paper is to produce an updated and comprehensive quantitative review of the existence of economies of scale in the provision of local public goods using a meta-analysis approach to systematize the wide range of empirical approaches and modeling frameworks found in the previous literature. Our analysis confirms the presence of moderately increasing to constant returns to scale in the provision of local services with no reduction in the average costs of production in the delivery of most local public services beyond a certain, modest jurisdictional size, which many studies have estimated at 10,000 residents. Also, the potential for economies of scale differs at least across three traditional services: education, water and sanitation, and garbage collection, being highest for education and lowest for garbage collection. Our analysis also offers guidelines for future empirical research in this area. Physical output and production cost data should be used, together with translog specifications for the modeling of cost functions. Last, we find evidence that the determinants of output cost elasticity include bidirectional publication bias and population density but do not include the presence or absence of modern “lean” production technologies or the (perceived) capital intensity of the sector, contrary to conventional wisdom. These findings have significant policy implications for countries considering jurisdictional consolidation programs.  相似文献   
5.
This paper analyses social transformations in the Early Iron Age based on a holistic and longue durée approach applied to the first fortified habitats in the Iberian north-west. Through a comprehensive review of two paradigmatic settlements of the EIA in the province of A Coruña (Galicia, north-west Iberia), Punta de Muros and A Graña, a comparison is drawn between the social and territorial dynamics of this period by means of an in-depth analysis of the main characteristics of both settlements. Accordingly, a greater level of social complexity during the phases of occupation of the settlement of Punta de Muros has been identified, in contrast to the resistance to change observed in A Graña. Based on these conclusions, the role of metalworking and its symbolic value in fostering and legitimizing these social and territorial transformations and in the development of Iron Age communities are analysed.  相似文献   
6.
The defining element of island regions is their isolation, the separation of the islands from the mainland; there is an inherent notion of natural border. This condition has preserved ecosystems and protected against outside threats, stimulating ‘coevolution’ between man and the environment, a fundamental ingredient of sustainability. But insularity also means the evident added costs of access to markets which, together with territorial limits and the scarcity of basic resources, especially on small islands, hinders their socioeconomic development. These costs are even greater in the case of outlying islands, which suffer from a ‘double insularity’ in the form of both external and internal borders. For this reason, it is common for governments to establish various forms of support, from tax exemptions to the creation of permanent aid funds, like those implemented by the European Union for the outermost regions. This article discusses these aspects in the case of the Canary Islands, an example of a European outermost island region. The findings show that the support measures have not always been favourable for all the islands.  相似文献   
7.
ABSTRACT

The “Quartel das Esquadras” is an 18th century infantry barrack located within the limits of the bulwarked fortress of Almeida, in Portugal. An ongoing adaptive reuse project of the building aims to recover its full capacity and also its importance, by implementing a variety of new uses. The architectural intervention results in the need of the structure to withstand new and diverse imposed loads. As the current configuration of the structure will be altered, the main objective of this article is to evaluate the suitability of some of the proposed structural interventions. The current condition has been characterized following a multidisciplinary approach comprising historical research, visual inspection, non-destructive testing, and structural analysis to identify the possible sources of major structural problems. A portion of the building particularly affected by the alterations has been selected to carry out structural analysis. A comparative safety assessment of the selected area in both current and altered condition has been done through finite element modelling and nonlinear static analysis, resulting in an identification of the weaker points against the new implemented loads and alterations. Finally, proposals for the implementation of the studied intervention, as well as recommendations for future research and analyses, have been given.  相似文献   
8.
The aim of this article is to focus on the technology of archeological plasters at Teotihuacan (Central Mexico), from the Classic Period (200–650 A.D.), focusing in the study of Teopancazco, a neighborhood center in the city. Petrographic and chemical analyses by OM, SEM-EDS, and LA-ICP-MS were conducted to characterize samples from different constructive phases and sectors of the neighborhood center, to determine the provenance of the raw materials employed in the manufacturing (e.g., volcanic glass shards) and to assess whether a shift occurred in the manufacturing of plasters and in the procurement strategies of raw materials during the different phases. The results of the analyses show that almost no changes occurred in the making of the plaster during more than four centuries and allow us to consider the presence of a technological style in their manufacture, which is characterized by the making of plaster by mixing lime with volcanic glass shards, which in the case of Teopancazco were derived from the Altotonga (Veracruz) magmatic system. The data at our disposal suggest that this style was developed in Teopancazco and later introduced throughout the city of Teotihuacan in the Early Xolalpan phase (A.D. 350), although we still do not know whether the provenance of the raw materials is the same. The wide distribution of this technological tradition could be due to the technological properties of the materials and/or the influence of the intermediate elite who ruled over Teopancazco. The paper confirms that the study of material culture and technology sheds light on broader cultural aspects of ancient societies.  相似文献   
9.
10.
Broca coined the neologism “aphemia” to describe a syndrome consisting of a loss of the ability to speak without impairment of language and paralysis of the faciolingual territories in actions unrelated to speech, such as protruding the tongue or pursing the lips. Upon examining the brains of patients with aphemia, Broca concluded that the minimum possible lesion responsible for aphemia localized to the posterior left inferior frontal gyrus and lower portion of the middle frontal gyrus. A review of Broca’s writings led us to conclude that (a) Broca localized speech, not language, to the left hemisphere, (b) Broca’s aphemia is a form of apraxia, (c) Broca’s aphemia is not, therefore, a terminological forerunner of aphasia, and (d) Broca was an outspoken equipotentialist concerning the cerebral localization of language. Broca’s claim about the role of the left hemisphere in the organization of speech places him as the legitimate forebear of the two most outstanding achievements of Liepmann’s work, namely, the concepts of apraxia and of a left hemisphere specialization for action.  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