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   303篇
  免费   6篇
安全科学   18篇
废物处理   8篇
环保管理   81篇
综合类   37篇
基础理论   78篇
环境理论   1篇
污染及防治   56篇
评价与监测   19篇
社会与环境   5篇
灾害及防治   6篇
  2023年   5篇
  2022年   3篇
  2021年   3篇
  2019年   3篇
  2018年   2篇
  2017年   4篇
  2016年   12篇
  2015年   7篇
  2014年   5篇
  2013年   23篇
  2012年   13篇
  2011年   14篇
  2010年   5篇
  2009年   11篇
  2008年   17篇
  2007年   13篇
  2006年   10篇
  2005年   11篇
  2004年   16篇
  2003年   9篇
  2002年   12篇
  2001年   13篇
  2000年   3篇
  1999年   3篇
  1998年   6篇
  1997年   5篇
  1996年   3篇
  1995年   3篇
  1994年   4篇
  1993年   6篇
  1992年   6篇
  1991年   3篇
  1990年   8篇
  1989年   4篇
  1987年   6篇
  1985年   2篇
  1984年   5篇
  1982年   3篇
  1981年   5篇
  1980年   3篇
  1979年   2篇
  1978年   2篇
  1977年   1篇
  1972年   4篇
  1971年   1篇
  1969年   1篇
  1968年   2篇
  1961年   1篇
  1959年   1篇
  1929年   1篇
排序方式: 共有309条查询结果,搜索用时 328 毫秒
1.
To comply with EU recycling targets for packaging waste, the UK relies on an industry run and market based eco-tax levied by reprocessors on obligated businesses. After examining the details of this approach, the use of Packaging Waste Recovery Notes is assessed in terms of its allocative impact and the contribution made to eco-efficiency. The evidence indicates the UK system has minimized the cost of delivering current EU targets, but has not been able to deliver allocative efficiency or to demonstrate dynamic improvements in resource use. Its effectiveness in meeting impending higher targets remains open to question.  相似文献   
2.
Progress in the greening of UK local government has been hampered by uncertainty about the relationship between resource use and environmental protection. Ecological modernizationmay offer the most appropriateparadigm to reconcile economic, social and environmentalinterpretationsof sustainability. The transition from corporate to strategic environmental management currently being attempted by some 'green' authorities can be construed as an attempt to promote ecological modernization in the form of institutional learning. Fife Council in Scotland provides an interesting case study. Progress with corporate environmental management has become bound up with a radical devolution of decision making. Efforts to link the authority's Sustainable Development Policy to a Local Agenda 21 programme have been initiated with the piloting of sustainability indicators.  相似文献   
3.
4.
5.
6.
7.
Amniocentesis at 17 weeks' gestation revealed a mosaic karyotype—46,XX/46,XX, — 14,+dic(14)(p11). No abnormalities were detected on ultrasound. Growth and placentation were normal. The fetus was examined after termination of pregnancy and micrognathia and pulmonary hyperlobation were the only abnormalities detected. Several tissues were set up for cytogenetics, including fetal skin, kidney, ovary, and placenta. The diagnosis was confirmed by these studies. The level of mosaicism varied between tissues, with the trisomy 14 cell line highest in amniotic fluid.  相似文献   
8.
9.
Recovering dense nonaqueous‐phase liquid (DNAPL) remains one of the most difficult problems facing the remediation industry. Still, the most common method of recovering DNAPL is to physically remove the contaminants using common technologies such as total fluids recovery pumps, vacuum systems, and “pump‐and‐treat.” Increased DNAPL removal can be attained using surfactants to mobilize and/or solubilize the pollutants. However, very little is understood of the methods developed by petroleum engineers beginning in the 1960s to overcome by‐passed, low‐permeability zones in heterogeneous oil reservoirs. By injecting or causing the formation of viscous fluids in the subsurface, petroleum engineers caused increased in‐situ pressures that forced fluid flow into low permeability units as well as the higher permeability thief zones. Polymer flooding involves injecting a viscous aqueous polymer solution into the contaminated aquifer. Foam flooding involves injecting surfactant to decontaminate the high‐permeability zones and then periodic pulses of air to cause a temporary viscous foam to form in the high‐permeable zones after all DNAPL is removed. Later surfactant pulses are directed by the foam into unswept low‐permeable units. These methods have been applied to DNAPL removal using surfactants but they can also be applied to the injection of bio‐amendments into low‐permeability zones still requiring continued remediation. Here we discuss the principles of mobility control as practiced in an alluvial aquifer contaminated with chlorinated solvent and coal tar DNAPLs as well as some field results. © 2003 Wiley Periodicals, Inc.  相似文献   
10.
Research on urban insect pollinators is changing views on the biological value and ecological importance of cities. The abundance and diversity of native bee species in urban landscapes that are absent in nearby rural lands evidence the biological value and ecological importance of cities and have implications for biodiversity conservation. Lagging behind this revised image of the city are urban conservation programs that historically have invested in education and outreach rather than programs designed to achieve high‐priority species conservation results. We synthesized research on urban bee species diversity and abundance to determine how urban conservation could be repositioned to better align with new views on the ecological importance of urban landscapes. Due to insect pollinators’ relatively small functional requirements—habitat range, life cycle, and nesting behavior—relative to larger mammals, we argue that pollinators put high‐priority and high‐impact urban conservation within reach. In a rapidly urbanizing world, transforming how environmental managers view the city can improve citizen engagement and contribute to the development of more sustainable urbanization.  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