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   321篇
  免费   21篇
  342篇
  2021年   2篇
  2020年   8篇
  2019年   12篇
  2018年   13篇
  2017年   15篇
  2016年   17篇
  2015年   19篇
  2014年   11篇
  2013年   84篇
  2012年   11篇
  2011年   6篇
  2010年   14篇
  2009年   7篇
  2008年   12篇
  2007年   10篇
  2006年   5篇
  2005年   8篇
  2004年   7篇
  2003年   4篇
  2002年   6篇
  2001年   3篇
  1999年   3篇
  1998年   2篇
  1997年   1篇
  1996年   2篇
  1995年   1篇
  1994年   2篇
  1993年   3篇
  1992年   2篇
  1991年   7篇
  1990年   1篇
  1989年   3篇
  1987年   2篇
  1986年   2篇
  1985年   4篇
  1984年   2篇
  1982年   1篇
  1981年   3篇
  1980年   3篇
  1978年   2篇
  1977年   3篇
  1976年   1篇
  1975年   1篇
  1974年   4篇
  1973年   3篇
  1972年   2篇
  1971年   1篇
  1970年   1篇
  1969年   2篇
  1968年   1篇
排序方式: 共有342条查询结果,搜索用时 15 毫秒
321.
322.
323.
Vattel's Mélanges de littérature, de morale et de politique (Thoughts on literature, morals and politics) was published at Neuchâtel by the Editeurs du Journal Helvétique in 1760 and this is the first English translation. It was republished under the title, Amusemens de littérature, de morale et de politique in 1765. Vattel's text provides evidence of his response to the issues facing Europe's states in the 1750s, and in doing so provides another perspective on his best known work, Le droit des gens (Law of Nations) of 1757. Vattel emerges as a reformer steeped in debates about the future of the European state system, and particularly Europe's small states and republics like Switzerland.  相似文献   
324.
    
A skull of a young specimen of Dipnorhynchus sussmilchi (Etheridge Jr), from the base of the Bloomfield Limestone Member (mid-Emsian, probably perbonus Zone) at Taemas, has both sides of the skull roof preserved, but the cheeks are missing. The posterior end of the endocranium, up to its dorsal extremity, provides new data on the endolymphatic sacs, and the attachment of the epaxial muscles. The endolymphatic region is compared with that of Chirodipterus australis. The palate is not fully formed and the marginal ridges are not fully developed. The fine structures around the dermopalatines and the pterygoids are preserved, indicating the manner in which the plates grew. The position of the parasphenoid is clearly outlined against the pterygoids, and confirms the view that this primitive genus of dipnoans did not have the pterygoids divided by the parasphenoid. All these features provide new information and comparison with Dipterus valenciennesi, the next oldest genus on which the same regions are preserved. In addition, a new mandible from a horizon low in the Cavan Bluff Formation is well preserved and provides information on the external bones of Dipnorhynchus.  相似文献   
325.
    
This article formulates a model to analyze the role of fixed costs in the design of optimal transportation hub networks. The primary purpose of this article is to better model costs in hub networks, an issue that has attracted considerable attention. This article allows particular versions of hub networks to emerge from the cost structure, rather than by imposing a rigid predefined connectivity protocol. The article integrates modeling approaches from an environmental hub location model with the three‐index formulation of Ernst and Krishnamoorthy to produce a hub location model with fixed and variable costs for all arcs. Our goal is to demonstrate how the inclusion of a richer cost model in transportation hub location can generate a wide range of different network types, depending on the relative magnitudes of the cost elements. While the existence of special case network solutions is well known and has been exploited in optimization, the current research provides added insight to the cost of flow in a more, or less, connected hub network. Eight fundamental prototype networks are derived as special cases, and some additional unanticipated network types also emerge. The results are illustrated with a standard CAB25 data set.  相似文献   
326.
    
The Weipa Mission (1898–1932) on Cape York Peninsula (north‐eastern Australia) was one of seven Australian missions designed and staffed by the Moravian Church during the nineteenth and early twentieth centuries. We present findings of archaeological and historical research that illustrate key aspects of the settlement's development and operations. Moravian missionaries at Weipa aimed to create a built landscape that reshaped Aboriginal social, cultural and economic relations, with particular emphasis on children through the use of a dormitory system. However, their efforts were mediated by the open spatial and social boundaries of the settlement, which enabled Aboriginal people to make choices about the nature and extent to which they engaged with the mission. Adopting a political economy approach, we show that this openness emerged through complex social relationships between missionaries and Aboriginal people. While missionaries required access to children and adults, they lacked the ability (or will) to maintain a resident population through force, with limited financial resources also hampering their activities. Instead, Aboriginal people came and went from the settlement, with some establishing and maintaining social relationships with missionaries to access economic and social benefits. We argue that these social relationships led to the development of the settlement as a more open domain.  相似文献   
327.
Ancient masonry structures are often damaged by soluble salt crystallization, which is activated by even small microclimatic variations. Unsuitable environmental conditions can accelerate this process, affecting the type and the quantity of salts and the consequent damage to the masonry. Therefore the importance of monitoring salt diffusion to control salt crystallization and microclimate over time is widely recognized. This study proposes an integrated monitoring methodology to obtain information on the relationship between salt efflorescence and microclimate in the Crypt of the Duomo of Lecce (South Italy). By combining ion chromatography, powder X-ray diffraction analysis, and Raman microscopy with environmental monitoring and deterioration maps, salt components were identified and efflorescence diffusion on masonry was monitored over time. Due to this approach, a possible explanation for the process is finally given.  相似文献   
328.
329.
330.
Journal of Archaeological Research - In this article we argue that several of the dominant narratives concerning the political economy of the Chinese Bronze Age are in need of major revision,...  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