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   229篇
  免费   13篇
  2024年   1篇
  2023年   2篇
  2022年   1篇
  2021年   2篇
  2020年   1篇
  2019年   13篇
  2018年   20篇
  2017年   13篇
  2016年   22篇
  2015年   14篇
  2014年   10篇
  2013年   48篇
  2012年   18篇
  2011年   10篇
  2010年   10篇
  2009年   13篇
  2008年   10篇
  2007年   7篇
  2006年   2篇
  2005年   4篇
  2004年   1篇
  2003年   1篇
  2002年   3篇
  2001年   1篇
  2000年   1篇
  1999年   2篇
  1998年   3篇
  1997年   1篇
  1996年   3篇
  1995年   2篇
  1993年   1篇
  1978年   1篇
  1975年   1篇
排序方式: 共有242条查询结果,搜索用时 0 毫秒
41.
A review of studies carried out since 1978 on the Madrague de Giens ship remains have enabled a reassessment of the vessel's shell‐first construction process. Hypotheses concerning moulding criteria are developed, with the profile (sheer plan), main cross section (body plan), and active sections and reference planks used to mould the hulll proposed and evaluated. These are compared to the Marsala (3rd century BC), and Yass?ada 2 (4th century AD) ships, which have similar wine‐glass‐shaped bottoms. Some aspects of these moulding criteria appear common to those used in the Mediterranean during the Middle Ages and the Renaissance.  相似文献   
42.
43.
44.
Brexit means that regions of the United Kingdom will lose access to the EU Cohesion Policy. Have EU funds been effective, and what might be the consequences of an interruption of EU financial support? This paper studies the impact of “Objective 1” funding—the highest form of EU aid—in Cornwall and South Yorkshire, two of the U.K.’s most subsidized regions. Counterfactual methodologies assessing their labor market and economic performance provide evidence of a positive effect of EU Objective 1 funds. When in 2006 South Yorkshire lost Objective 1 eligibility, this massively reduced its share of EU funds and the region was unable to sustain the gains obtained in previous years. This suggests that while Structural Funds may be effectively improving socio‐economic conditions of poorer regions, the performance of subsidized areas could be deeply affected by a reduction (or worse, an interruption) of EU aid.  相似文献   
45.
In the early years of the atomic era, several developing countries attempted to establish a nuclear programme, yet Brazil's case is less well-known. As new documents show, from 1951 Brazil aimed to acquire the nuclear fuel cycle capability in spite of legislation imposed by the United States to limit the emergence of new nuclear powers. This article will analyse the origins of the Brazilian nuclear programme from 1951 to 1955 and will explore its cooperation in the atomic field with international partners.  相似文献   
46.
47.
48.
49.
50.
Here we show the results of two morpho-bathymetric surveys carried out on the underwater archaeological area of the Pozzuoli Bay (Naples, Italy). Such area is enclosed in the Campi Flegrei active volcanic complex, where bradyseism and recent volcanic activity strongly influenced the coastline shape over the last 2 Ka. The Digital Elevation Model (DTM) of the seafloor allowed to draw the main archaeological features of the Bay, that also include the military complex of Portus Iulius and the ancient thermal and villa complex of Baianus Lacus. The extraction of archaeological features from DTM was achieved thanks to the use of a GIS-derived tool based on the profile curvature algorithm. Thus, the Villa dei Pisoni (1st Century B.C.) and the thermal complex of Secca delle Fumose were investigated by using ultra-high resolution DTMs, that show the presence of Roman pilae for the protection of coastal buildings and also the inner planimetry of the Villa dei Pisoni complex. The observation of coastal engineering structures give also the opportunity to formulate some hypothesis on the evolution of morphology and of the sedimentary pattern of the area, while depth of archaeological remains allowed a rough computation of the rate of subsidence, resulted to be 2.55 (±0.5) mm/y for the Eastern sector (Pozzuoli) and 2.90 (±0.5) mm/y for the western (Baia).  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