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   2148篇
  免费   424篇
  2023年   15篇
  2022年   14篇
  2021年   29篇
  2020年   64篇
  2019年   170篇
  2018年   159篇
  2017年   157篇
  2016年   176篇
  2015年   134篇
  2014年   140篇
  2013年   436篇
  2012年   162篇
  2011年   154篇
  2010年   121篇
  2009年   80篇
  2008年   110篇
  2007年   96篇
  2006年   64篇
  2005年   52篇
  2004年   47篇
  2003年   49篇
  2002年   37篇
  2001年   39篇
  2000年   30篇
  1999年   9篇
  1998年   2篇
  1997年   3篇
  1996年   4篇
  1995年   4篇
  1993年   1篇
  1992年   3篇
  1991年   1篇
  1990年   1篇
  1989年   4篇
  1988年   1篇
  1983年   1篇
  1982年   1篇
  1980年   1篇
  1979年   1篇
排序方式: 共有2572条查询结果,搜索用时 15 毫秒
981.
The Upper Palaeolithic skeleton from Vado all'Arancio (Italy), dated to about 11,330 BP, exhibits a severe ankle fracture healed with residual deformation. Following recovery, this young hunter‐gatherer continued to walk for an extended period of time, albeit in a mechanically altered manner. While right‐left differences in external lower limb bone measurements are relatively low, biomechanical analysis of femur and tibia indicates unusually pronounced asymmetry in all cross‐sectional measures of diaphyseal strength. Asymmetry results primarily from normal side endosteal hypertrophy, and not from hypotrophy of the injured limb, suggesting that this individual resumed active life following recovery. This pattern of asymmetry underscores the role of physical activity in maintaining bone mass. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
982.
P. Holakooei 《Archaeometry》2014,56(5):764-783
This study investigated the technological features of the Neo‐Elamite glazed bricks discovered at the Acropolis of Susa, south‐western Iran, by conducting micro‐Raman spectroscopy, differential thermal analysis/thermogravimetry (DTA/TG), X‐ray diffraction (XRD) and scanning electron microscopy–energy‐dispersive X‐ray spectroscopy (SEM–EDS). The results showed that calcium antimonate white and lead antimonate yellow were used as opacifiers in the white, yellow and green glazes, and that green and turquoise glazes were achieved using copper. Coloured glazes were separated by a Si‐rich brown glaze to prevent them from running together during firing. The glazed bricks most probably were not fired at temperatures higher than 900°C.  相似文献   
983.
熊家冢土遗址保护概述   总被引:1,自引:0,他引:1  
本文介绍了熊家冢墓地的概况以及地质、土壤状况,分析了保护中需要解决的主要问题。通过对殉葬墓和车马坑的综合保护,实现了防止殉葬墓坑、车马坑的崩裂、垮塌和各类遗迹的开裂、塌陷。熊家冢土遗址保护工作的开展,对我国南方地区土遗址保护技术的发展有一定借鉴作用。  相似文献   
984.
虢城、焦城与陕城考   总被引:1,自引:0,他引:1  
历史上曾有南虢、北虢两虢之称,清人王先谦认为南北虢实属一虢.若从南北虢两虢说,则必有南虢都城与北虢都城之别;若从南北虢一虢说,北虢之"下阳"则为虢之都邑,虢之真正都城应在上阳.关于上阳城的具体位置,目前考古界有李家窑址说和陕州故城东部说.本文拟就虢城、焦城与陕城的地望以及它们的关系作一讨论.  相似文献   
985.
Chlorozyga, a new genus of Australian Tournaisian (Early Carboniferous) caenogastropod, is proposed and assigned to the Imoglobidae. Chlorozyga has a larval shell like Imogloba from the Early Carboniferous of North America but differs in teleoconch morphology. As in Imogloba, the initial whorl of Chlorozyga is openly coiled, a feature unknown in Mesozoic and Recent caenogastropods. However, Chlorozyga and Imogloba belong to the Caenogastropoda, given their multi-whorled orthostrophic larval shells.  相似文献   
986.
This article is focused upon exploring the development of the green economy in particular locations, with the aim of identifying why some cities and regions have been successful in engendering green growth. To date we have little idea where the green economy is developing, nor much insight, beyond anecdotal evidence, into why certain cities and regions appear to be more successful than others in this regard. We position our analysis within the context of research on socio‐technical transitions that has theorized the potential shift to a more sustainable economy. We review the literature on sustainability transitions and the development of the multi‐level perspective encompassing niches, regimes and landscapes. However, most research into socio‐technical transitions has not given adequate consideration to the influence of places and spatial scale in these transition processes, and we therefore critique the socio‐technical transitions literature from a geographical perspective. In this article we are interested in four key questions. What role does the enabling and facilitative state play in these cities and regions? What new institutional forms and governance structures are being developed? How do actors in particular cities and regions construct their green vision, and how do they encourage other actors to buy‐in to this vision? How are links across levels and spatial scales developed to connect niches with the regime? We address these through a focus upon the Boston city‐region in the USA, drawing upon both primary and secondary research material. We utilize this case study example to re‐examine and re‐theorize work on sustainability transitions from a spatial perspective.  相似文献   
987.
The article discusses health policies towards school children in Norway from 1900 until the Second World War. It is concerned with dominant definitions of health threats against children and the variables used in defining the groups conceived as most vulnerable to poor health. A distinct change took place in the period. Whereas in the early 1900s poor and working‐class children in urban surroundings were considered to be under severe threats, in the 1920s a less specific category of ‘children’ were conceived as threatened. Eventually rural children were singled out as the important target group for health measures. The shifts had medical as well as political motivations. Another prominent feature in the period was that poverty took on a new meaning in the dominant medical discourse on children: from having been conceived as a material reality impinging upon health, it came to be considered mainly a cultural problem. Especially medical officers within the social democratic camp contested this argument although they did not rule out education and cultural transformation as a means to promote children's health. Despite the conceptual shift, however, social benefits and equal access to health services – measures that lay at the heart of the post‐war welfare state – remained in the 1930s an essential part of promoting children's health.  相似文献   
988.
While the history of cartography has freed itself from debilitating debates over the scientific and artistic status of maps, considerations of the relationship between art and cartography have continued to focus largely on pre‐modern maps, avoiding critical examination of twentieth‐century art and science in cartography and leaving intact the impression that these followed distinct paths in the modern period. In this paper, however, I have drawn on theoretical work in Science Studies and taken account of modern art's separation from aesthetics to suggest that an examination of art and cartography in the twentieth century should focus on mapping practices rather than on maps as such. A summary overview of modern‐art movements and selected works indicates a continued, if critical, engagement of avant‐garde artists with cartography, and the examination of more popular newspaper artwork produced in the context of the intensely modern visual culture of mid‐twentieth century Los Angeles indicates a similarly close connection between modernity, art and cartography.  相似文献   
989.
The article discusses different conceptions of space and place in refugee studies, especially contributions from anthropology and geography. A main distinction is drawn between two understandings of space and place; an essentialist conception, stating a natural relationship between people and places and an alternative conception attempting to de-naturalize the relationship between people and places. The consequences of applying different conceptions of space and place for the development of refugee policies and representations of refugees and displaced persons are addressed. For many displaced persons, displacement is experienced as being physically present at one place, but at the same time having a feeling of belonging somewhere else. It is argued that though attempts to de-naturalize the relationship between people and places have been important for how the refugee experience is conceptualized, there has been too much focus on imagination accompanied by a neglect of the local perspective of migrants and displaced people. In the local perspective of forced migration, the present lives of displaced people are emphasized. Especially the attitudes from the host communities, the policy environment that displaced people are part of, and their livelihood opportunities are the focus of regard. 'Territoriality' and 'reterritorialization' of the relationship between people and places are discussed as tools to analyse the local perspective of forced migration in general and the strategies of internally displaced persons and their hosts in Sri Lanka in particular.  相似文献   
990.
The occurrence of Apatopygus gaudensis sp. nov. in the upper part of the late Oligocene (Chattian) Lower Coralline Limestone division, and the lower part of the early Miocene (probably late Aquitanian) Lower Globigerina Limestone division of the Maltese Islands (Central Mediterranean), is the first confirmed record of Apatopygus outside the Australia-New Zealand region. Apatotygus vincentinus (Tate, 1891) from the middle to late Eocene of southern Australia is the earliest known occurrence of the genus, possibly suggesting that Apatotygus may have evolved earlier in the Australasian region, or merely that it is yet to be discovered in pre-Oligocene strata in the Mediterranean area.  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