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   1259篇
  免费   396篇
  2021年   26篇
  2020年   22篇
  2019年   140篇
  2018年   110篇
  2017年   99篇
  2016年   118篇
  2015年   115篇
  2014年   108篇
  2013年   227篇
  2012年   123篇
  2011年   114篇
  2010年   85篇
  2009年   38篇
  2008年   67篇
  2007年   61篇
  2006年   37篇
  2005年   34篇
  2004年   29篇
  2003年   30篇
  2002年   22篇
  2001年   24篇
  2000年   23篇
  1999年   3篇
排序方式: 共有1655条查询结果,搜索用时 15 毫秒
991.
Approaching the study of camelid bone size change in the meridional portion of the South Central Andes is a significant subject especially when the assemblages are associated to radiocarbon dates placed at a time of social transition from an extractive to a producer economy. In this sense, this paper presents the results of applying osteometric techniques on a set of 10 elements from the Peñas Chicas 1.5 site dated around 3800 BP . The analysis shows the presence of at least three individuals, one of which corresponds to an Andean guanaco (Lama guanicoe) morphotype. The second and the third are similar in size to a modern llama (Lama glama) in their ‘intermediate’ and ‘cargo’ morphotypes. This is consistent with patterns already seen for sites from the Argentinian and Chilean Puna where the identification of larger individuals than the Andean guanaco modern standard shows the early stages of an increasingly bone size variability of South American camelids. This paper contributes with new data to understand the complex processes that occurred in the South Central Andes that led to the domestication of one of the most conspicuous animals in the archaeological record of the Argentinian Northwest. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
992.
At the time of the discovery of the Newport medieval ship, it proved impossible to date the timbers used in its original construction through dendrochronology. Associated British timbers and artefacts provided dating to the mid 15th century, with the latter pointing to strong Iberian connections. The development of regional oak ring‐width chronologies in the Basque Country, and their extension back in time to overlap with the ring‐width mean developed for the Newport Ship, has allowed absolute dating and provenance of timbers used in its original construction. Further research is required to clarify the geographical source of the timbers and to develop a high‐resolution network of tree‐ring data for the region.  相似文献   
993.
Underwater excavation of a shipwreck‐site off Hof Carmel, south of Haifa, Israel, yielded numerous artefacts associated with a ship and cargo dated to the 3rd century AD. Among them were eight sewing needles: six of bronze, one of copper and one of brass. This article describes the needles including their chemical composition, discusses comparable finds from nautical and domestic contexts, and their possible uses and roles aboard a Roman ship.  相似文献   
994.
This paper presents both archaeological evidence and technical features that allows the identification of two of the wooden objects discovered in 2001 at the site of a 1st‐century‐AD shipyard in Olbia, Sardinia, as masts. The structure and dimensions of the objects are presented and compared with similar artefacts which have been interpreted as rudder‐stocks in order to establish their specific and distinct features. Possible retaining and lowering systems for the masts, and evidence of wooden mast‐ladders are discussed through examination of archaeological parallels and Roman iconography.  相似文献   
995.
One of the classical questions in the study of nationalism concerns the end of empires. Is nationalism, to use the phrase of Hiers and Wimmer, the cause or consequence of the end of empire? This paper considers a neglected case, that of the decomposition of the Danish imperial monarchy in the years between 1848 and 1864. We find that nationalist conflicts indisputably caused the end of this political entity. Crucially, Danish nationalists in the imperial core preferred to downsize the territories controlled by the Oldenburgs rather than to share power with German speakers in the periphery. Decomposition was not, however, inevitable: an early introduction of power‐sharing schemes might have saved the imperial monarchy.  相似文献   
996.
The ethnic‐civic framework remains widely used in nationalism research. However, in the context of European immigrant integration politics, where almost all ‘nation talk’ is occurring in civic and liberal registers, the framework has a hard time identifying how conceptions of national identity brought forth in political debate differ in their exclusionary potential. This leads some to the conclusion that national identity is losing explanatory power. Building on the insights of Oliver Zimmer, I argue that we may find a different picture if we treat cultural content and logic of boundary construction – two parameters conflated in the ethnic‐civic framework – as two distinct analytical levels. The framework I propose focuses on an individual and collective dimension of logic of boundary construction that together constitute the inclusionary/exclusionary core of national identity. The framework is tested on the political debate on immigrant integration in Denmark and Norway in selected years. Indeed, the framework enables us to move beyond the widespread idea that Danish politicians subscribe to an ethnic conception of the nation, while Norwegian political thought is somewhere in between an ethnic and civic conception. The true difference is that Danish politicians, unlike their Norwegian counterparts, do not acknowledge the collective self‐understanding as an object of political action.  相似文献   
997.
There is a substantial body of literature on nation‐building that, from a variety of theoretical approaches, examines the role of symbolic constructs in the process of construction and consolidation of new nation‐states. Among these works, the dramatic and symbolic aspects of election and their function in the nation‐building project have been investigated by political scientists and anthropologists alike. However, analysis of electoral emblems as constitutive elements in the nation‐building process has been largely missing from most studies of nation‐building and official nationalism. A case study of postindependence India suggests how national belonging was also made to hinge upon on competent democratic participation of the masses in the political life of the country. Central to this process of identity work was the establishment of an independent Election Commission and of strict rules for the design, selection and allotment of election emblems. Conventional accounts have argued that these procedures were introduced primarily for the benefit of the uneducated masses who were suddenly invited to participate in India's democratic process. I argue against this simplistic interpretation. Far from being only tools for the simplification of electoral processes, India's election symbols were one of India's institutional mechanisms designed to nurture the development of a correct democratic conduct and therefore ultimately contributing to the Nehruvian national project.  相似文献   
998.
In this study, we employed Geographical Information Systems and remote sensing techniques to investigate the impact of land‐use/cover change on land surface temperature (LST) in a rapidly urbanisation city, Kunming in south‐west China. Spatial patterns of LST and land use for 1992 and 2006 were derived from Landsat images to examine how LST responded to urban growth. Remote sensing indices were used to quantify land‐use types and employed as explanatory variables in LST modelling. The geographically weighted regression (GWR), a location dependent model, was performed to explore the influences of the spatially varied land‐use conditions on the LST patterns. Results revealed that rapid urbanisation in Kunming altered the local thermal environment, particularly in increasing the LST in the zone surrounding the urban core. Remote sensing indices demonstrated that water and vegetation played an important role in mitigating the urban heat island effect, while built‐up and barren land accounted for the increase in LST. The GWR improved the goodness‐of‐fit for LST modelling and provided insights into the spatially varied relationship between LST and land‐use conditions.  相似文献   
999.
Natural resource management is typically defined by landscape‐scale management zones, such as the Catchment Management Authority boundaries of the southern Murray‐Darling Basin in Australia. Ecological research generally deals with local‐scale phenomena, with studies at the scale of such landscape management units arising only recently. We developed a method that links local‐scale ecological research to landscape‐scale management zones, which is presented here as a geographical bibliographic database. This research proceeded in four phases. First, we assessed three decades of ecological research in the Goulburn‐Broken Catchment in Victoria, Australia, using this method, revealing the locations where research has taken place across the landscape, and the research themes dominant in different bioregions. Second, we assessed the purposes to which the method could be applied. Third, we tested the method against one of these potential purposes to review ecological research in a subcatchment case study. Last, we interrogated the method to answer an ecological question. This methodological analysis demonstrated that mapping ecological research in this way allows the user to identify geographic gaps in research coverage, assist in limiting search results to a location of interest and to address location‐specific ecological questions. In combination with landscape classification methods, such as biogeographic regionalisation units, this method can be used to evaluate research coverage across similar ecological communities.  相似文献   
1000.
Deciphering patterns and inferring processes in multicausal floodplain river ecosystems is a challenge in river science. The effects of larger‐scale top‐down constraints and smaller‐scale bottom‐up influences on the spatial patterns of nutrient concentrations across multiple inset‐floodplain surfaces was studied in a large dryland floodplain river (Barwon‐Darling River, south‐east Australia). The distribution of sediment‐associated carbon, nitrogen, and phosphorus was primarily related with significant differences in the textural character of the different floodplain surfaces. Elevation of the different floodplain surfaces above the active channel was a secondary influence on the distribution of carbon and phosphorus. Combined, these factors produce a spatial patch mosaic of sediment associated carbon, nitrogen, and phosphorous across these floodplain surfaces.  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