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   1429篇
  免费   307篇
  2023年   3篇
  2021年   15篇
  2020年   13篇
  2019年   107篇
  2018年   71篇
  2017年   78篇
  2016年   126篇
  2015年   88篇
  2014年   89篇
  2013年   276篇
  2012年   89篇
  2011年   100篇
  2010年   81篇
  2009年   58篇
  2008年   69篇
  2007年   77篇
  2006年   48篇
  2005年   26篇
  2004年   39篇
  2003年   36篇
  2002年   23篇
  2001年   25篇
  2000年   31篇
  1999年   4篇
  1998年   14篇
  1997年   18篇
  1996年   13篇
  1995年   14篇
  1994年   16篇
  1993年   3篇
  1992年   7篇
  1991年   3篇
  1990年   4篇
  1988年   3篇
  1987年   5篇
  1986年   4篇
  1985年   5篇
  1984年   3篇
  1983年   3篇
  1982年   5篇
  1981年   2篇
  1980年   5篇
  1979年   3篇
  1978年   3篇
  1977年   7篇
  1976年   5篇
  1975年   4篇
  1974年   2篇
  1968年   2篇
  1959年   2篇
排序方式: 共有1736条查询结果,搜索用时 15 毫秒
971.
Ancient bones in a good preservation state, ascertained by microscopic techniques, conserve extracellular matrix proteins over thousands of years. With new techniques, intact extracellular matrix proteins from ancient bones and teeth are extracted and separated by one‐dimensional and two‐dimensional electrophoresis. Proteins were identified in Western blots by special antibodies against different human extracellular matrix (ECM) molecules of bone. We have confirmed different types of ECM human bone molecules such as osteonectin, osteopontin, and alkaline phosphatase with specific antibodies in human bone samples from different age groups. Additionally, we selected bone samples from different cultural time periods, such as the Middle Ages, the Bronze Age and the Late Pre‐Pottery Neolithic Phase (PPNB), and teeth from individuals from the Early Middle Ages and from the Late PPNB. The survival of intact extracellular matrix proteins in ancient bones and teeth dating from recent times to the Late PPNB, and reliable techniques to identify these proteins, present a great challenge to further research. A Match Set with PD‐Quest 7.2 shows that only 16% of protein spots in the teeth are also found in the bone of the same individual. In combination with the results of macro‐ and microscopic investigation, biochemical techniques will help us in obtaining a better understanding of bone and teeth in health and disease. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
972.
This paper examines the osteological evidence for a case of long‐term labret use in pre‐Columbian north Chile and the pathological conditions associated with it. The burials from the site of Solcor 3 (AD 400–900) included a complete skeleton associated with two quartz labrets. Analysis of the skeleton of this adult male revealed wear and polish on the labial surface of both mandibular canines, indicating that the labrets were worn as a pair on either side of the midline of the lower lip. In addition to these abrasion facets, there were also areas of periosteal reaction in the alveolar bone of the canines. These patterns were analysed from the perspective of the clinical dentistry literature and compared to archaeological data. It is concluded that this individual's dental health was affected by wearing labrets, although not as seriously as might be expected based on contemporary medical reports. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
973.
974.
This paper reexamines the welfare implications of three pricing regimes (mill, uniform, and discriminatory) for a monopoly. Assuming linear demand and constant marginal costs, I show that with the introduction of endogenous location choice, uniform delivered pricing may provide the highest social welfare when demands in different markets are sufficiently heterogeneous; whereas discriminatory pricing always dominates uniform pricing when demands in different markets are similar.  相似文献   
975.
976.
977.
REVIEW ESSAY     
Rednecks, Eggheads and Blackfellas: a study of racial power and intimacy in Australia. By Gillian Cowlishaw Sydney: Allen and Unwin. 1999. Pp. xix + 352. Figures, Maps, Photos & Index $35  相似文献   
978.
Biography as a genre of historiography had been dismissed for some years, criticized for being conservative, resistant to theoretical approaches, and hostile to methodological innovations. But the predominance of a historiography devoted to structures, functions, and statistics has, however, led to a renewed interest in the human factor in history. This paper argues that the pluralism of methods and theories which has emerged thereafter reopened the case for an innovative biography, thus facilitating the convergence of general history and the history of science.  相似文献   
979.
980.
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