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   776篇
  免费   62篇
  国内免费   58篇
安全科学   52篇
废物处理   8篇
环保管理   262篇
综合类   193篇
基础理论   127篇
环境理论   11篇
污染及防治   27篇
评价与监测   26篇
社会与环境   101篇
灾害及防治   89篇
  2024年   3篇
  2023年   17篇
  2022年   18篇
  2021年   24篇
  2020年   30篇
  2019年   32篇
  2018年   40篇
  2017年   68篇
  2016年   75篇
  2015年   60篇
  2014年   23篇
  2013年   120篇
  2012年   33篇
  2011年   34篇
  2010年   29篇
  2009年   39篇
  2008年   19篇
  2007年   40篇
  2006年   27篇
  2005年   21篇
  2004年   22篇
  2003年   20篇
  2002年   13篇
  2001年   14篇
  2000年   24篇
  1999年   17篇
  1998年   4篇
  1997年   5篇
  1996年   2篇
  1995年   5篇
  1994年   3篇
  1990年   3篇
  1987年   1篇
  1986年   2篇
  1981年   1篇
  1979年   1篇
  1977年   3篇
  1973年   3篇
  1972年   1篇
排序方式: 共有896条查询结果,搜索用时 15 毫秒
1.
Mitigation and adaptation synergy in forest sector   总被引:1,自引:1,他引:1  
Mitigation and adaptation are the two main strategies to address climate change. Mitigation and adaptation have been considered separately in the global negotiations as well as literature. There is a realization on the need to explore and promote synergy between mitigation and adaptation while addressing climate change. In this paper, an attempt is made to explore the synergy between mitigation and adaptation by considering forest sector, which on the one hand is projected to be adversely impacted under the projected climate change scenarios and on the other provide opportunities to mitigate climate change. Thus, the potential and need for incorporating adaptation strategies and practices in mitigation projects is presented with a few examples. Firstly, there is a need to ensure that mitigation programs or projects do not increase the vulnerability of forest ecosystems and plantations. Secondly, several adaptation practices could be incorporated into mitigation projects to reduce vulnerability. Further, many of the mitigation projects indeed reduce vulnerability and promote adaptation, for example; forest and biodiversity conservation, protected area management and sustainable forestry. Also, many adaptation options such as urban forestry, soil and water conservation and drought resistant varieties also contribute to mitigation of climate change. Thus, there is need for research and field demonstration of synergy between mitigation and adaptation, so that the cost of addressing climate change impacts can be reduced and co-benefits increased.  相似文献   
2.
黄土高原地区生态建设的关键问题   总被引:1,自引:0,他引:1  
从黄土高原地区水土保持生态建设的实际情况出发,结合历史经验教训,探讨了生态建设与农业发展、农民脱贫致富的关系.指出生态环境问题归根结底是人的问题,减少人类对生态环境的破坏和干扰,因地制宜地进行植被建设和生态恢复,激励广大农民自觉参与生态建设对黄土高原地区水土保持生态建设成败至关重要.  相似文献   
3.
火电厂烟气脱硫工程往往是在场地或其他条件受到诸多限制的情况下进行的,设计中总平面布置的作用显得尤其突出。以几个电厂脱硫工程的设计为例,探讨如何充分利用已有务件,协调脱硫与整个厂区总平面布置的关系,以使设计合理,经济。  相似文献   
4.
Large‐scale change in human values and associated behavior change is believed by some to be the ultimate solution to achieve global biodiversity conservation. Yet little is known about the dynamics of values. We contribute to this area of inquiry by examining the trajectory of values affecting views of wildlife in North America. Using data from a 19‐state study in the United States and global data from the Schwartz Value Survey, we explored questions of value persistence and change and the nature of attitudinal responses regarding wildlife conservation issues. We found support, based on subjects’ ancestry, for the supposition that domination is a prevalent American value orientation toward wildlife that has origins in European Judeo‐Christian traditions. Independent of that effect, we also found indications of change. Modernization is contributing to a shift from domination to mutualism value orientations, which is fostering attitudes less centered on human interests and seemingly more consistent with a biocentric philosophy. Our findings suggest that if value shift could be achieved in a purposeful way, then significant and widespread behavior change believed necessary for long‐term conservation success may indeed be possible. In particular, greater emphasis on mutualism values may help provide the context for more collaborative approaches to support future conservation efforts. However, given the societal forces at play, it is not at all clear that human‐engineered value shift is tenable. Instead of developing strategies aimed at altering values, it may be more productive to create strategies that recognize and work within the boundaries of existing values. Whereas values appear to be in a period of flux, it will be difficult to predict future trends without a better understanding of value formation and shift, particularly under conditions of rapid social‐ecological change.  相似文献   
5.
城镇污水处理排放标准改革的费效分析   总被引:2,自引:0,他引:2  
从费用效果角度对提高城镇污水处理排放标准的科学性和可实施性进行探讨,利用污染源普查数据,通过城镇污水治理投资和运行函数的构建,计算不同处理规模和排放标准下的污水处理投资和运行费用,在全国层面上计算提高污水处理排放标准所需费用和污染物的减排效果.研究表明:污水处理厂的投资和运行费用的增加随着污水处理规模的增加而递减.以污...  相似文献   
6.
潮汐流人工湿地低温下 NH4+ -N去除模型的比较和优化   总被引:2,自引:1,他引:1  
针对目前人工湿地在低温条件下脱氮效能降低的问题,本研究对每天3个运行周期的潮汐流人工湿地在低温条件下对NH4+ -N的处理效能进行研究,同时利用表观动力学模型、多元参数回归模型及Monod机制模型对NH4+-N的去除过程进行拟合.结果显示,在平均水温为9~13℃条件下,每天3个运行周期的潮汐流人工湿地对NH4+-N有良...  相似文献   
7.
利用2013年11月武汉市逐日空气质量资料、地面气象观测资料、NCEP/NCAR再分析资料和L波段雷达探空资料,通过WRF模式模拟空气污染生消过程中的局地气象条件变化,探讨特殊地形条件下边界层结构变化和局地环流在污染物生消过程中的作用和影响。结果表明:(1)武汉地区当背景环流场强的时候,由地形引起的局地流场对污染物扩散的影响就弱,反之当背景环流场弱的时候, 地形对流场影响明显:夜间为山风,白天为谷风。夜间山风与偏西北气流及偏东气流在武汉及周边地区辐合,形成气流汇聚带,在武汉地区形成一个反复污染带,即由地形引起的局地流场对污染物扩散的贡献就大;(2)武汉地区发生空气污染时,地面湿度较高,边界层呈上干下湿状态,其特征为暖而干且有偏东小风,这导致污染物不断堆积和重污染过程的形成。  相似文献   
8.
Through the MGU – Useful Plants Project (2007–2015) led by the Royal Botanic Gardens Kew, high-quality seed collections and research information have been gathered on useful indigenous plants selected by communities in Botswana, Kenya, Mali, South Africa, and Mexico. Local communities were trained in seed conservation, plant propagation, and planting activities, while revenue generation was promoted directly through the sustainable use of plants and plant products and indirectly through wider environmental and cultural services. The success of this project was determined by its participative approach, involving local communities in plant conservation activities and using plant research to support it. However, the promotion of sustainable use and income generation highlighted issues that confirmed the importance of using a ‘holistic approach’ to address the objective of poverty reduction and contribute to improved livelihoods in the communities.  相似文献   
9.
Using meteorological and electricity demand data for a 4-year period, electricity demand in Shetland was modeled to provide an estimate of the demand over a 30-year period from 1 January 1981. That modeled demand was then compared to estimated wind power output over the same period using the WAsP model. The wind farm output was estimated for a range of sizes of wind farm up to the consented 370 MW Viking Wind Farm in Shetland. Some wind power was available for 94% of the time and the 370 MW wind farm would meet 100% of demand for nearly 80% of the time. The statistics of single and accumulated deficits were calculated for a range of wind farms and estimates of the amount of additional generation capacity and additional power requirements were assessed. The study suggests that with storage, wind power in Shetland could meet all electricity demand in Shetland at around £130 to £150/MWh (excluding subsidy) and with a grid connection allowing the sale of excess power, those costs could be reduced.  相似文献   
10.
Patterson, Lauren A., Jeffrey Hughes, Glenn Barnes, and Stacey I. Berahzer, 2012. A Question of Boundaries: The Importance of “Revenuesheds” for Watershed Protection. Journal of the American Water Resources Association (JAWRA) 48(4): 838‐848. DOI: 10.1111/j.1752‐1688.2012.00655.x Abstract: Watersheds transcend jurisdictional boundaries; raising important questions of who should pay for watershed protection, and how can watershed governance be funded? The responsibility and cost for watershed protection has progressively devolved to local governments, resulting in additional negative externalities and financing challenges. Watershed governance structures have formed at the scale of the watershed, but they often lack the financing mechanisms needed to achieve policy goals. Financing mechanisms via local governments provide a reliable source of revenue and the flexibility to address watershed specific issues. We develop a “revenueshed” approach to access the initial challenges local governments face when seeking to finance trans‐jurisdictional watershed governance. The revenueshed approach engages local governments into discussion and implementation of financial strategies for collaborative watershed governance. Legislation places water quality regulations primarily on local governments inside the watershed. The revenueshed approach extends the financial and stewardship discussion to include local governments outside the watershed that benefit from the watershed. We applied the revenueshed approach to the Mills River and Upper Neuse watersheds in North Carolina. Mills River had a partnership governance seeking revenue for specific projects, whereas the Upper Neuse sought long‐term financial stability to meet new water quality legislation.  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