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   306篇
  免费   21篇
  2024年   2篇
  2023年   9篇
  2022年   2篇
  2021年   1篇
  2020年   15篇
  2019年   18篇
  2018年   31篇
  2017年   35篇
  2016年   27篇
  2015年   17篇
  2014年   21篇
  2013年   80篇
  2012年   5篇
  2011年   5篇
  2010年   5篇
  2009年   8篇
  2008年   11篇
  2007年   2篇
  2005年   2篇
  2004年   1篇
  2001年   2篇
  2000年   2篇
  1999年   1篇
  1998年   4篇
  1996年   3篇
  1993年   2篇
  1992年   2篇
  1990年   2篇
  1989年   1篇
  1988年   1篇
  1987年   3篇
  1986年   1篇
  1985年   1篇
  1982年   1篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1957年   1篇
排序方式: 共有327条查询结果,搜索用时 15 毫秒
321.
322.
Abstract

Among the three recognized species of Smilodon, S. populator is the largest in size and has the widest distribution across South America. The present contribution describes an almost complete skull assigned to the aforementioned felid. The material was recovered from sediments of the Dolores Formation (Lujanian Stage/Age) from the southern part of Uruguay. This specimen is remarkable for its unusual craniodental measurements, indicating that it is one of the largest known specimens of the genus. Estimates of body mass indicate that this individual weighed over 400?kg. In addition, maximum prey size estimation greatly surpasses 1 t and approach nearly 3 t. Based on this, aspects of the paleobiology and paleoecology of S. populator are discussed. Undoubtedly, this kind of carnivorous mammal was at the top of the food chain, with clear adaptations for feeding upon the largest available herbivores, which potentially includes several megafaunal mammal species found in South America during the late Pleistocene.

Aldo Manzuetti [], Facultad de Ciencias (UdelaR), Iguá 4225, CP 11400, Montevideo, Uruguay; Daniel Perea [], Facultad de Ciencias (UdelaR), Iguá 4225, CP 11400, Montevideo, Uruguay; Washington Jones [], Museo Nacional de Historia Natural, 25 de Mayo 582, CP 11000, Montevideo, Uruguay; Martín Ubilla [], Facultad de Ciencias (UdelaR), Iguá 4225, CP 11400, Montevideo, Uruguay; Andrés Rinderknecht [], Museo Nacional de Historia Natural, 25 de Mayo 582, CP 11000, Montevideo, Uruguay.  相似文献   
323.
During the 20th century, the need for raw material promoted a commercial transportation trade of iron ores from the deposits in north-western Spain, where Vigo city was considered one of the most important ports. The global energy crisis in the 1970s, as well as the strong competition from other exporting countries, dented the prolific activity of companies dedicated to the extraction and trading of iron ore. The main goal of this article is the evaluation of one particular element of the mining and industrial heritage — two old mineral loading docks in Ría de Vigo in the Rande Strait, linking the municipalities of Redondela and Moaña. Their development as a tourist resource would add to the cultural and economic activities already developed in the area.  相似文献   
324.
Abstract

This is a concluding comment on the chapters of this special issue. After a discussion of the articles, we will take a closer look at the new view of European diplomacy and foreign relations. The historiographical change regarding early modern foreign relations has fundamentally altered the way we interpret the roles, the agencies and the loyalties of early modern envoys. Taking the conclusions of this research into account, we ask if diplomatic actors of the ancient regime differed distinctly from their Asian counterparts at all. Then, as a final point, we examine how fundamental changes in the Sattelzeit–particularly in Europe, but also in the context of global power relations–affected intercultural diplomacy.  相似文献   
325.
ABSTRACT

Recently, Colombia’s post-conflict transition has experienced strong international attention. In Bogota, commemorative politics of the conflict insert themselves in complex processes of place branding: employing culture to rescale the city image from unsafe and violent to culturally vibrant. However, how to reckon with the country’s violent past in the culture-led renaissance of Bogota? Based on the author’s four-month of in-depth qualitative fieldwork on the main street Avenida 26 – at the center of both branding strategies and politics of memory – this paper shows the failure of institutional efforts to promote a brand of Bogota as a ‘City of Memory’. Socio-political divisions over the interpretations of the country’s past result in multi-scalar conflictive negotiations between politics and practices on the street: they reveal the tight link between memory, social justice, and urban segregation while denouncing the exclusionary visions of citizenship bared in political efforts to display memory as a territorial mark.  相似文献   
326.
Sub-national economic policies increasingly use labor market areas (LMAs) rather than administrative areas for analysis and implementation. How a set of LMAs was defined influences the results of such analyses, and so accurate policy delivery needs appropriately defined LMAs. Multinational bodies need comparable LMA definitions in many countries, calling for a definition method that is transferable across national boundaries. This article applies quantitative metrics to evaluate LMAs defined in three contrasting countries by three methods that represent the main methodological approaches. The deductive approach—based on a center and hinterland—is too inflexible to deal with differing geographical circumstances and cannot cope with statistical zones that are very small, or do not respect settlement structure. The alternative inductive methods tested define appropriate LMAs in each country, with the newer method performing slightly better in statistical terms. The article also exemplifies the usefulness of the metrics for comparisons of alternative regionalizations.  相似文献   
327.
Large radiocarbon datasets are increasingly used as a paleodemographic proxy, although potential sources of bias in such records are poorly understood. In this paper, we use more than 25,000 radiocarbon dates extracted from the Canadian Archaeological Radiocarbon Database (CARD) to estimate long-term population trends in North America, while critically examining biases in such records. The frequency distribution of CARD dates shows a positive curvilinear pattern, such that older dates exist in lower numbers than more recent dates, which in part reflects the removal of cultural carbon from the archaeological record through processes such as erosion and dissolution. The average annual growth rate of radiocarbon dates in CARD was calculated and used to derive estimates of the population of North America from the Paleo-Indian to the Contact Periods. While taphonomic bias has likely affected the CARD data, other factors, such as the overrepresentation of Paleo-Indian and Archaic radiocarbon dates, may have offset any bias due to taphonomy. A quantitative reconstruction of Native American population shows that population increased rapidly around 2000 cal yr BP, reaching a maximum of 2,500,000 people by ~AD 1150. From this time until European contact, the population declined, possibly due to the effects of increased sedentism and population density.  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