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   273篇
  免费   3篇
  国内免费   1篇
安全科学   4篇
废物处理   4篇
环保管理   20篇
综合类   67篇
基础理论   77篇
污染及防治   68篇
评价与监测   22篇
社会与环境   14篇
灾害及防治   1篇
  2023年   1篇
  2022年   2篇
  2021年   3篇
  2020年   2篇
  2019年   3篇
  2018年   5篇
  2017年   10篇
  2016年   9篇
  2015年   15篇
  2014年   14篇
  2013年   18篇
  2012年   14篇
  2011年   18篇
  2010年   12篇
  2009年   14篇
  2008年   15篇
  2007年   19篇
  2006年   11篇
  2005年   9篇
  2004年   11篇
  2003年   7篇
  2002年   6篇
  2001年   3篇
  2000年   2篇
  1999年   5篇
  1998年   3篇
  1997年   6篇
  1996年   3篇
  1995年   4篇
  1994年   5篇
  1993年   2篇
  1991年   3篇
  1981年   2篇
  1977年   1篇
  1969年   1篇
  1966年   1篇
  1964年   1篇
  1963年   1篇
  1961年   1篇
  1960年   3篇
  1959年   3篇
  1958年   2篇
  1957年   1篇
  1955年   2篇
  1953年   1篇
  1952年   1篇
  1949年   1篇
  1925年   1篇
排序方式: 共有277条查询结果,搜索用时 31 毫秒
121.
Climate change adaptation strategies that aim to minimize harm and maximize benefits related to climate change impacts have mushroomed at all levels of government in recent years. While many studies have explored barriers that stand in the way of their implementation, the factors determining their potential to mainstream adaptation into various sectors are less clear. In the present paper, we aim to address this gap for two international, six national, and six local adaptation strategies. Based on document analyses and 35 semi‐structured interviews, the 14 case studies also explore in how far the factors facilitating climate change adaptation are similar across levels of government or level‐specific. Although located at three different levels of government, we find that the 14 adaptation strategies analyzed here represent “one‐size‐fits‐all governance arrangements” that are characterized by voluntariness and a lack institutionalization. Since adaptation strategies are relatively weak coordination hubs that are unable to force adaptation onto sectoral policy agendas, they rely mainly on sectoral self‐interest in adapting to climate change, largely determined by problem pressure. We conclude that one‐size‐fits‐all governance arrangements are rarely adequate responses to complex challenges, such as climate change. Although climate change adaptation depends more on framework conditions such as problem pressure than on administrative or governance features, the findings presented here can help to understand under what circumstances adaptation is likely to make progress.  相似文献   
122.
Environmental Science and Pollution Research - Technical dichlorodiphenyltrichloroethane (DDT) has been used worldwide as a pesticide since the beginning of the 1940s. Due to its persistence, DDT...  相似文献   
123.
124.
125.
126.
In 2010, the Renewable Energy Directive (RED) came into force in the EU and establishes a framework for achieving legally binding greenhouse gas (GHG) emission reductions. Only sustainable biofuels can be counted towards Member State targets. The aim of this paper is to calculate realistic and transparent scenario-based CO2-emission values for the GHG emissions savings of palm oil fuel compared with fossil fuel. Using the calculation scheme proposed by the RED, we derive a more realistic overall GHG emissions saving value for palm oil diesel by using current input and output data of biofuel production (e.g. in South-East Asia). We calculate different scenarios in which reliable data on the production conditions (and the regarding emission values during the production chain) of palm oil diesel are used. Our results indicate values for the GHG emissions savings potential of palm oil biodiesel not only above the 19 % default and 36 % typical value published in RED but also above the 35 % sustainable threshold. Our findings conclude the more accurate GHG emissions saving value for palm oil feedstock for electricity generation to be 52 %, and for transportation biodiesel between 38.5 and 41 %, depending on the fossil fuel comparator. Our results confirm the findings by other studies and challenge the official typical and default values published in RED. As a result, the reliability of the Directive to support the EU’s low-carbon ambitions is being undermined, exposing the EU and commission to charges of trade discrimination and limiting the ability of Member States to achieve their legally binding GHG emission reductions.  相似文献   
127.
A global monitoring system for atmospheric xenon radioactivity is being established as part of the International Monitoring System to verify compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The isotopic activity ratios of (135)Xe, (133m)Xe, (133)Xe and (131m)Xe are of interest for distinguishing nuclear explosion sources from civilian releases. Simulations of light water reactor (LWR) fuel burn-up through three operational reactor power cycles are conducted to explore the possible xenon isotopic signature of nuclear reactor releases under different operational conditions. It is studied how ratio changes are related to various parameters including the neutron flux, uranium enrichment and fuel burn-up. Further, the impact of diffusion and mixing on the isotopic activity ratio variability are explored. The simulations are validated with reported reactor emissions. In addition, activity ratios are calculated for xenon isotopes released from nuclear explosions and these are compared to the reactor ratios in order to determine whether the discrimination of explosion releases from reactor effluents is possible based on isotopic activity ratios.  相似文献   
128.
129.
130.
Agricultural intensification can affect biodiversity and related ecosystem services such as biological control, but large-scale experimental evidence is missing. We examined aphid pest populations in cereal fields under experimentally reduced densities of (1) ground-dwelling predators (-G), (2) vegetation-dwelling predators and parasitoids (-V), (3) a combination of (1) and (2) (-G-V), compared with open-fields (control), in contrasting landscapes with low vs. high levels of agricultural intensification (AI), and in five European regions. Aphid populations were 28%, 97%, and 199% higher in -G, -V, and -G-V treatments, respectively, compared to the open fields, indicating synergistic effects of both natural-enemy groups. Enhanced parasitoid: host and predator: prey ratios were related to reduced aphid population density and population growth. The relative importance of parasitoids and vegetation-dwelling predators greatly differed among European regions, and agricultural intensification affected biological control and aphid density only in some regions. This shows a changing role of species group identity in diverse enemy communities and a need to consider region-specific landscape management.  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