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   92篇
  免费   6篇
  98篇
  2024年   1篇
  2023年   4篇
  2022年   1篇
  2020年   4篇
  2019年   3篇
  2018年   6篇
  2017年   7篇
  2016年   4篇
  2015年   6篇
  2014年   3篇
  2013年   22篇
  2012年   5篇
  2011年   4篇
  2010年   6篇
  2009年   6篇
  2008年   3篇
  2007年   3篇
  2006年   3篇
  2004年   1篇
  2003年   1篇
  2002年   1篇
  1997年   1篇
  1996年   1篇
  1983年   1篇
  1976年   1篇
排序方式: 共有98条查询结果,搜索用时 0 毫秒
31.
We examine whether organized crime affects firms’ performance (defined using Total Factor Productivity growth) both directly and indirectly, by downsizing the positive externalities arising from the geographic concentration of (intra‐ and inter‐industry) market‐related firms. The analysis uses a large sample of Italian small‐ and medium‐sized manufacturing firms over the period 2010–2013. The results highlight the negative direct effects of organized crime on firms’ productivity growth. Any positive effect derived from industrial clustering is thoroughly debilitated by a strong presence of organized crime, and the negative moderation effect of organized crime on productivity growth is greater for smaller than for larger firms.  相似文献   
32.
We test whether there is a link between the performance of universities, measured through a concept of efficiency, and the economic development of the regions in which they operate. Indicators of teaching, research, and third mission are considered as outputs. To handle endogeneity problems between the efficiency of universities and economic development, a system generalized method of moments and then an instrumental variable approach are used. Our findings reveal that the presence of efficient universities fosters local economic development. Knowledge spillovers occur to areas that are in close geographical proximity to efficient universities. Results are robust to different estimation strategies.  相似文献   
33.
Technological progress has widely been acknowledged as a key driver in the achievement of environmental sustainability, and a new concern has recently arisen for assessing the role of differences in regional innovation performances with respect to the pursuit of pollution targets. We investigate the impact of innovative activities on environmental efficiency at the regional level, adopting a spatial panel data approach to account for dependence between geographical observations and to get deeper insights into spatial knowledge spillovers arising from agglomeration economies. The spatial panel analysis covers 103 Italian provinces (equivalent to NUTS3 regions) on four major air pollutants (i.e., CO2, CH4, NMVOC, CO) over the 1995–2010 period. Our findings show that the state of local technology development, proxied by patents, has a positive impact on GDP emission efficiency and that its magnitude is higher for more localized pollutants as a result of larger spillover effects. Finally, to analyze the Italian North-South dualism of emission levels of pollutants, we offer a spillover effect study to emphasize the remarkable difference among effects in the territory. This calls for closer attention to the local relevance of the pollution damage when environmental impact of innovation strategies is to be evaluated.  相似文献   
34.
35.
Since all long-distance trade in the Roman world travelled by water, Roman harbour design and construction have special importance. Harbour excavation must be supplemented by analysis of the components of the hydraulic concrete, structural analysis of the cementing materials, and consideration of the design of the wooden formwork. The authors have begun collecting large cores from concrete blocks at Roman harbours and other maritime structures, analysing the materials used, the method of placement, and the structural characteristics of the resulting concrete. These data have provided new information on the engineering properties of Roman concrete, the process of funding and execution, and the trade in the volcanic ash which was the crucial component of hydraulic concrete.
© 2004 The Nautical Archaeology Society  相似文献   
36.
Natural, technical and social factors led to the use of a wide range of rocks for the production of macrolithic artifacts during the later prehistory. In the case of some artifact types, such as the grinding stones, rocks with very different petrographic qualities appear. Analysis of the material behavior, as developed by material sciences, provides a tool which allows the translation of these petrographic characteristics into mechanical properties. Experiments with a group of rocks subjected to different forms of abrasion in industrial machines allow an evaluation of the adjustment between the mechanical properties of the rock and the functions for which they were chosen by prehistoric societies. Finally, the understanding of the mechanical properties of the raw materials together with their forms of exploitation, distribution and use allows the designation of social and economic meaning to the production systems linked to the macrolithic tools.  相似文献   
37.
In 1987, given the importance and complexity of the correct recovery and conservation procedures for underwater archaeological finds, an Underwater Archaeological Operations Unit was set up within the Italian Central Institute for Restoration. This Unit is made up of archaeologists, conservators, biologists and chemists, all of whom are underwater experts. It provides consultancy services and scientific and technical assistance for problems relating to the recovery, conservation, protection, and restoration of underwater archaeological heritage at the request of the Archaeological Superintendents. Great attention is paid to the professional training of underwater conservators. Specialized courses in the conservation of materials of underwater provenance are organized as part of its programme. This paper illustrates some of the main initiatives both in the restoration of archaeological objects and in training, in which the Institute has been involved, since the Underwater Unit was created.  相似文献   
38.
The Port‐Vendres 4 shipwreck is evidence of coastal export trade between Hispania Citerior and Narbonne in 40/30 BC. The cargo is made up of a particular assemblage of Roman wine amphoras (Pascual 1, Dressel 1B and Lamboglia 2) destined for Gallic markets. Archaeological and archaeometric analyses conducted on a selection of the amphoras allowed the provenance of the cargo to be identified as Hispania Citerior and the central‐southern Tyrrhenian coast of Italy. Iluro and/or Baetulo are proposed as the ports of departure, enabling the reconstruction of the trade route and the historical and economic significance of this shipwreck.  相似文献   
39.
Here we examine patterns in stone tool technology among Mesolithic, Neolithic and Iron Age localities in the Sanganakallu–Kupgal site complex, Bellary District, Karnataka, South India. Statistical tests are used to compare proportions of raw materials and artefact types, and to compare central tendencies in metric variables taken on flakes and tools. Lithic-related findings support the inference of at least two distinct technological and economic groups at Sanganakallu–Kupgal, a microlith-focused foraging society on the one hand, and on the other, an agricultural society whose lithic technologies centred upon the production of pressure bladelets and dolerite edge-ground axes. Evidence for continuity in lithic technological processes through time may reflect indigenous processes of development, and a degree of continuity from the Mesolithic through to the Neolithic period. Lithic production appears to have become a specialised and spatially segregated activity by the terminal Neolithic and early Iron Age, supporting suggestions for the emergence of an increasingly complex economy and political hierarchy.  相似文献   
40.
A new method called the Baseline Stiffness Method (BSM), used to locate and quantify damage in buildings without baseline modal parameters (undamaged state), is presented. In order to determine this reference state, the BSM uses modal parameters from the damaged state of the building and the lateral stiffness matrix of the first story without damage. Afterwards, by means of an iterative process using singular value decomposition, location and severity of damage are obtained by comparing information about the damaged and non damaged states. Numerical and experimental examples are presented and discussed showing the advantages of the application of the proposed BSM.  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