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   285篇
  免费   7篇
  2023年   2篇
  2022年   5篇
  2021年   6篇
  2020年   13篇
  2019年   12篇
  2018年   9篇
  2017年   14篇
  2016年   10篇
  2015年   5篇
  2014年   10篇
  2013年   55篇
  2012年   8篇
  2011年   13篇
  2010年   7篇
  2009年   12篇
  2008年   10篇
  2007年   12篇
  2006年   14篇
  2005年   15篇
  2004年   5篇
  2003年   11篇
  2002年   7篇
  2001年   6篇
  2000年   14篇
  1999年   1篇
  1998年   5篇
  1997年   1篇
  1996年   4篇
  1995年   2篇
  1992年   1篇
  1991年   2篇
  1982年   1篇
排序方式: 共有292条查询结果,搜索用时 15 毫秒
291.
Numerous studies and various interpretations of the prevalence of linear enamel hypoplasias (LEH) based on populations living in different cultural and economic conditions are causing some confusion and raising doubts about whether or not such LEH are reliable indicators of life conditions. An analysis of LEH prevalence patterns was performed on the adults of three populations: Tirup—a Danish Medieval rural population of the 12–14th centuries (131 individuals), Subačiaus str. in Vilnius—a Lithuanian Late Medieval urban population of the 16–17th centuries (88 individuals), and the aristocracy—a Lithuanian pooled sample population from several churches of the 15–18th centuries (66 individuals). Statistical testing of the influence of population affinity, sex and age at death was also performed. Since the same investigator scored all the samples, possible inter‐observer error bias was minimized. In all the populations, LEH formation ages were similar. Statistically significant sex differences were found only in the aristocratic sample (with higher male frequency). It was found that the town population was characterized by the highest frequency of affected individuals, with the highest severity and highest number of stress episodes per individual. A reliable relationship with age at death was found only in the town sample: individuals with more numerous and more marked LEH had shorter life expectancies in adulthood. Different “most vulnerable years” for subsequent life expectancies were noted for different populations. A tentative explanation of these differences could be the pooled effect of differential morbidity and mortality. It seems that the rural population experienced the highest morbidity and nutrition deficiency as well as the highest child mortality whereas, in the urban sample, high morbidity was accompanied by a lower child mortality. Both lower morbidity and mortality seem to be characteristic for the aristocracy. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
292.
ABSTRACT

Climate niches that modern humans and earlier hominin ancestors occupied have changed dramatically over time, but the extent of those changes has gone largely undocumented. This study investigates the manner in which the realised hominin climate niche has expanded, contracted, or stayed stationary across four time periods (Last Interglacial, Last Glacial Maximum, Mid-Holocene, and 1950–2000) in Western Eurasia. Using spatially gridded general circulation model data and site locations this study examines climate variables from archaeological sites and current Western Eurasian cities to describe both the regional Western Eurasian fundamental and realised climate niches. Changes between the three prehistoric periods and modern-day time period are analysed by calculating each realised niche breadth, overlap, position, and variance. Results indicate that as global temperatures cooled from the Last Interglacial to Last Glacial Maximum, populations expanded their climate niche breadth beyond that of earlier Neanderthal groups, shifting toward regions with less seasonal variation. Conversely, Mid-Holocene humans, who saw the proliferation of both agriculture and population, contracted their realised climate niche space. The contraction and expansion of realised climate niche space illustrates how hominins have evolved the capacity to shift their niche through changes to their subsistence strategy and adaptations to overall climatic conditions.  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