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   1345篇
  免费   303篇
  2021年   15篇
  2020年   11篇
  2019年   105篇
  2018年   74篇
  2017年   74篇
  2016年   131篇
  2015年   88篇
  2014年   86篇
  2013年   280篇
  2012年   87篇
  2011年   95篇
  2010年   70篇
  2009年   53篇
  2008年   70篇
  2007年   69篇
  2006年   46篇
  2005年   19篇
  2004年   36篇
  2003年   33篇
  2002年   21篇
  2001年   21篇
  2000年   31篇
  1999年   4篇
  1998年   14篇
  1997年   17篇
  1996年   14篇
  1995年   14篇
  1994年   11篇
  1993年   4篇
  1992年   6篇
  1991年   2篇
  1990年   2篇
  1989年   2篇
  1988年   2篇
  1987年   5篇
  1986年   2篇
  1985年   3篇
  1982年   4篇
  1981年   1篇
  1980年   4篇
  1979年   2篇
  1978年   1篇
  1977年   6篇
  1976年   2篇
  1975年   2篇
  1974年   2篇
  1971年   1篇
  1969年   1篇
  1968年   2篇
  1951年   1篇
排序方式: 共有1648条查询结果,搜索用时 15 毫秒
991.
992.
When experimental archaeology began 100–150 years ago, it was carried out scientifically alongside regular archaeology. However, while general archaeology has continued intensively, scientific experimental archaeology has continued very sporadically during this century. The fact that there is a considerable amount of so‐called ‘experimental archaeology’ does not mean that it has been carried out scientifically. This is exemplified by house reconstructions, which despite their great number have only in a few cases added something new to archaeological research. Although these particular house reconstructions serve a pedagogic function, it would be better if, instead, scientific education was made available in the area of experimental archaeology.  相似文献   
993.
‘Iron Age People in Norway’ is an interdisciplinary research project. The source material consists of archaeological finds of graves containing human skeletal remains. Archaeological and physical anthropological methods and data will be combined in analyses of the people, their living conditions, aspects of social organization and questions about ethnic groups, using a specially developed computer registration system and database structure. The in‐depth analyses concentrate on the five northernmost counties in Norway, while the catalogue covers the whole country.  相似文献   
994.
995.
The Blue Mountains region of New South Wales, including the World Heritage listed Blue Mountains National Park, is arguably one of Australia's most highly valued and iconic wilderness areas. Common to this region are upland swamps (formally ‘temperate highland peat swamps on sandstone’), which play a vital hydrological role at the headwaters of the river catchments, as well as providing the habitat for an array of flora and fauna species. This paper involves an interdisciplinary examination into the need and potential for adaptive management in the Blue Mountains. It uses geomorphic (physical) knowledge of swamp condition and social data about the volunteers who rehabilitate them. Research involved using the River Styles river condition framework across 47 swamps and questionnaires and interviews with local rehabilitation volunteers. It is proposed that there is a need and a potential to combine geomorphic understanding with further engagement of community volunteers in order to enable an interdisciplinary approach to adaptive management. Such an approach could result in the effective environmental management of upland swamps in the Blue Mountains.  相似文献   
996.
The Civil War was America’s defining conflict, the war that made the nation and the fulcrum for the development of American national identity in the later nineteenth and early twentieth centuries. Yet the role that the Civil War dead played in this process has only begun to be explored. Although the monuments raised to honor the dead, along with the battlefields on which they fought, attract considerable interest, the cemeteries constructed to inter them have been integrated into the landscape – literal and figurative – of the American nation so fully that the need they answered, the manner of their development, the form they took, and their longer‐term symbolic message has been relatively neglected. Yet the Civil War dead were a crucial – indeed, the crucial – component in the construction of American national identity. Although scholars interpret American attitudes toward the Civil War dead within the context of the mourning rituals of the antebellum era, the war required, and produced, a different approach to death, for which antebellum precedent had ill‐prepared Americans. Removed from its antebellum religious and societal framework, death in the Civil War acquired a new and more potent national meaning that not only validated American nationalism through warfare, but anticipated the response to fallen soldiers in future European conflicts.  相似文献   
997.
Diagenetic iron (oxyhydr)oxide minerals are common precipitates expected in CO2 reservoirs, and these minerals record fluid flow for application to carbon capture and sequestration (CSS). Multiple mineralogy and spectroscopy analyses on a pore to meter scale characterize a well‐exposed, lithologically controlled, iron (oxyhydr)oxides reaction front in the Jurassic Navajo Sandstone. Dolomite is the most prevalent cement (up to 23 area%), followed by only several percent or less of iron (oxyhydr)oxides, kaolinite, illite, and gypsum cements. Bulk geochemistry based on diagenetic mineralogies in the reaction front is compared with the water chemistry from nearby modern spring effluent emanating from the Navajo Sandstone to conclude that similar fluids (i.e., CO2‐charged, saline waters containing hydrocarbons) are responsible for the precipitation. A second comparison of bulk geochemistry and diagenetic mineralogies of the reaction front with data from other abundant Navajo Sandstone concretions in the Spencer Flat region (in south central Utah) shows that reservoir fluids likely vary spatially and temporally in the porous and permeable Navajo Sandstone. CO2 injection into porous and permeable, quartz arenite, saline aquifers will likely result in minor clay and abundant dolomite precipitation that will significantly decrease porosity.  相似文献   
998.
999.
1000.
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