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   600篇
  免费   49篇
  2023年   3篇
  2021年   2篇
  2020年   17篇
  2019年   14篇
  2018年   26篇
  2017年   42篇
  2016年   38篇
  2015年   21篇
  2014年   28篇
  2013年   156篇
  2012年   17篇
  2011年   27篇
  2010年   27篇
  2009年   19篇
  2008年   16篇
  2007年   17篇
  2006年   14篇
  2005年   8篇
  2004年   8篇
  2003年   16篇
  2002年   12篇
  2001年   9篇
  2000年   11篇
  1999年   6篇
  1998年   10篇
  1997年   9篇
  1996年   2篇
  1995年   5篇
  1994年   3篇
  1993年   3篇
  1992年   3篇
  1991年   4篇
  1990年   4篇
  1989年   6篇
  1988年   3篇
  1987年   4篇
  1986年   4篇
  1985年   4篇
  1983年   4篇
  1979年   2篇
  1978年   3篇
  1976年   3篇
  1972年   1篇
  1971年   1篇
  1969年   1篇
  1968年   1篇
  1967年   3篇
  1965年   2篇
  1964年   1篇
  1963年   1篇
排序方式: 共有649条查询结果,搜索用时 31 毫秒
51.
52.
The effect of skeletal exposure in a marine environment is an area of taphonomy that has been little investigated at the microscopic level. Understanding the peri‐mortem and subsequent post mortem history of deposition and/or redeposition is extremely important for event reconstruction and to identify deliberate or accidental redeposition. The material used for this study comes primarily from the Mary Rose shipwreck (a marine mass fatality dated AD 1545), and forensic material recovered from marine, lacustrine and terrestrial contexts is retrospectively referenced. Work presented here outlines a definitive type of marine exposure seen in temperate shallow off‐shore and intertidal marine contexts, and illustrates how it may be differentially identified from terrestrial deposition and exposure. Furthermore, the effects of rapid deposition on skeletal remains have been documented, and results indicate that marine organism fouling activity can be fully inhibited by rapid deposition of sediment. The responsible organism itself remains unidentified, but produces tunnels which are peripheral in their distribution and maintain fixed dimensions and morphology and are here associated with marine exposure. This type of microstructural change is unique and is not found in terrestrial or freshwater contexts. The study demonstrates a taphonomic microstructural change to bone and teeth which may be identified microscopically and interpreted as evidence of marine exposure. Secondarily, the history of depositional exposure between the two main Tudor layers has provided a new level of detail concerning exposure and site formation processes. The earliest Tudor layer formed rapidly over a period of months and contained no evidence of microstructural tunnelling, whereas microstructural tunnelling was seen exclusively in the second Tudor layer, formed over a period of decades, a period during which the ship's hull collapsed and a more open marine environment dominated. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
53.
54.
This paper examines the wider effects of inward foreign directinvestment (FDI) to the UK on improving the practices and competitivenessof domestic industry. Surveyed domestic suppliers, competitors,and customers to foreign investors reported extensive positiveimpacts on their practices, focused particularly on reductionsin X-inefficiencies, and on their competitiveness, althoughin the case of competitors benefits had to be balanced againstadverse effects. Knowledge transfers through personal contactsand the demonstration effect, were important to the transmissionof impacts, but a number of other channels were also important,including additional supplier sales, improved customer inputs,and the competitive spur. Regional policymakers should takethese wider benefits into account in the design of policiesfor attracting and embedding foreign investment. However, whilstthere was no evidence that foreign firms in assisted regionshad fewer benefits than those in core regions, there was a lotof leakage outside of the areas attracting foreign firms, suggestingthat policies to promote spillovers should not be developedentirely in a local or regional framework.  相似文献   
55.
56.
57.
One purpose of the Advocacy Coalition Framework (ACF) is to explain policy change. Previous holistic reviews of the ACF by Weible, Sabatier, and McQueen (2009) and Pierce, Peterson, Jones, Garrard, and Vu (2017) of the framework have not explicitly analyzed all the concepts and their interactions in a systematic manner. To address this gap and inform scholars and practitioners about past findings, strengths, weaknesses, and opportunities for future research, this article analyzes how the ACF's theory of policy change is applied to 148 policy processes among 67 journal articles from 2007 to 2014. Similar to Weible et al. (2009), this research finds the frequent use of multiple primary pathways to policy change, infrequent use of many of the ACF's concepts, a plurality of applications in the environment and energy domain, comparison of subsystems, and a need for greater clarity and transparency among applications. Unlike Weible et al. (2009), this article explores associations between primary pathways and policy domains, the frequency of associations between primary pathways and secondary components, policy change and stasis, and identifies threats to internal validity of key ACF concepts.  相似文献   
58.
59.
60.
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