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   4661篇
  免费   443篇
  国内免费   600篇
安全科学   296篇
废物处理   37篇
环保管理   829篇
综合类   2114篇
基础理论   1447篇
环境理论   3篇
污染及防治   152篇
评价与监测   213篇
社会与环境   437篇
灾害及防治   176篇
  2024年   12篇
  2023年   127篇
  2022年   161篇
  2021年   208篇
  2020年   181篇
  2019年   166篇
  2018年   161篇
  2017年   185篇
  2016年   228篇
  2015年   228篇
  2014年   226篇
  2013年   285篇
  2012年   308篇
  2011年   342篇
  2010年   282篇
  2009年   283篇
  2008年   257篇
  2007年   327篇
  2006年   230篇
  2005年   212篇
  2004年   189篇
  2003年   139篇
  2002年   127篇
  2001年   122篇
  2000年   125篇
  1999年   84篇
  1998年   77篇
  1997年   60篇
  1996年   59篇
  1995年   63篇
  1994年   40篇
  1993年   41篇
  1992年   26篇
  1991年   19篇
  1990年   15篇
  1989年   6篇
  1988年   12篇
  1987年   14篇
  1986年   7篇
  1985年   5篇
  1984年   4篇
  1983年   10篇
  1982年   9篇
  1981年   9篇
  1980年   8篇
  1979年   6篇
  1978年   7篇
  1975年   3篇
  1972年   2篇
  1971年   4篇
排序方式: 共有5704条查询结果,搜索用时 15 毫秒
991.
杨士  刘祖文  龙焙  毕永顺  林苑  左华伟 《环境科学》2022,43(3):1567-1576
以脐橙皮渣和天然石墨为原料,采用改进Hummer-共热解法制备了生物炭负载氧化石墨烯(BGO)材料,利用土壤钝化实验考察了 BGO复合材料对稀土矿区土壤重金属形态的影响,土柱淋溶实验探讨了淋滤液重金属含量变化特征以及土壤重金属垂向迁移规律,确定了淋溶条件下重金属的累积释放模型.结果表明,添加BGO复合材料提高了土壤pH...  相似文献   
992.
科技飞速发展的今天,射频及微波技术已经广泛应用于国民经济的各个领域,这使得越来越多的从业人员在工作场所受到电磁辐射污染的影响。本文总结归纳了我国电磁辐射职业危害状况,分析了现代企业电磁辐射防护的新特点,并提出企业电磁辐射防护对策。  相似文献   
993.
This paper examines the transformation of open space and how it compares to older residential development. A study has been conducted at the residential level because neighbourhoods have been a basic unit of city design throughout the recent history of urban settlements. Furthermore, the neighbourhood is a more humanly relevant scale of urban development. The method adopted for this research was a comparative urbanism by comparing old and new residential areas. This study found that incremental redevelopment of old residential areas through both re-subdivision and intensification of development on existing allotments has resulted in a progressive loss of open space. However, the study also confirmed that the current supplies of open space across all the study areas (old and new residential areas) are relatively similar. The main difference between the open space supply in older and newer residential areas comes down to the ownership of land (i.e. the proportion of public versus private open space). The study demonstrated that older residential areas with large allotments have experienced a significant loss of private open space – originally from 50%, to current levels of 23–30%. The paper concludes that there is a need for a holistic approach to the provision of public and private open spaces to improve the quality of life at a residential level.  相似文献   
994.
Domestic energy practices are a topical policy issue, with implications for climate change, energy security and fuel poverty. Accordingly, a growing body of literature examines ways of promoting energy conservation and generation by individuals. However, there has been relatively little discussion of how status and stigma are implicated in these practices, and may act as facilitators or barriers to “behaviour change”. To help address this gap, this article draws both on existing literature and a new UK-based study of people who are attempting to live sustainable lives, to provide insights into how domestic energy practices may be status-enhancing or stigmatising, and how these risks and opportunities can be managed. While energy practices are often understood as “inconspicuous”, it is argued here that in some circumstances individuals may actively manage the visibility of their energy practices. The discussion considers these findings with regard to social power relations, and identifies issues warranting further exploration within the emerging research agenda on energy and equity.  相似文献   
995.
Lu, Haorong, S. Samuel Li, and Jinsong Guo, 2012. Modeling Monthly Fluctuations in Submersion Area of a Dammed River Reservoir: A Case Study. Journal of the American Water Resources Association (JAWRA) 1‐13. DOI: 10.1111/jawr.12003 Abstract: Fluctuations in water submersion of the Three Gorges Reservoir in China have not been explored in spite of their important implications for shoreline erosion and other undesirable consequences. This article aims to quantify the monthly fluctuations in response to changing hydraulic parameters and regional climatic factors. Flow velocity and water levels distributed along the 609‐km long dammed river reservoir are calculated with a one‐dimensional hydrodynamics model. Evaporation of water from the surface of the reservoir is determined using mass transfer‐based methods. Calculated flow velocities and water levels compare well with field data. We show that the water surface slope decreases with rising water level at the dam, and decreases to almost zero during the winter months of water storage when the downstream water level reaches the normal pool level. The submersion area varies between 830 and 1,070 km2 over the year or over 20% of the reservoir zone will experience the annual cycle of dry land and partial or complete submersion. These fluctuations are of relevance to shoreline management and to the prevention and restoration of shoreline erosion. Evaporation is estimated to fluctuate between 1,240 and 26,110 tons of water per month per kilometer length of reservoir channel; this can possibly affect the hydrological budget of the reservoir region. The simple methodologies discussed in this article can easily be applied to other dammed river reservoirs for submersion estimates.  相似文献   
996.
本文采用自主设计的强化预处理人工湿地装置进行处理低浓度农村生活污水的研究,针对人工湿地堵塞问题,考察了运用强化预处理装置(海绵装置和滤布装置)对污水进行预处理来预防湿地的堵塞,并且在水力停留时间为1d的工况下,研究了湿地装置对污水的净化效果.结果表明:运用强化预处理装置后,不仅能有效防止湿地堵塞而且不影响湿地对污水的净化效果,强化预处理湿地装置对CODCr、SS、NH4+-N、TN、TP的平均去除率分别为67.14%,90.39%,64.12%,70.13%和67.98%,出水CODCr、SS、NH4+-N、TN、TP均可满足《城镇污水处理厂污染物排放标准》 (GB18918-2002)的一级B要求,在我国广大农村地区的分散式污水处理中具有良好的应用前景.  相似文献   
997.
This article uses experiences from South Africa to argue that, despite progress made in making biodiversity conservation compatible with social, political and economic changes, progress could still be limited by reluctance of social actors to acknowledge and engage with the issue of race. The article argues that acknowledging the history of conservation in Africa, including close ties to racially charged colonialism, could be a positive impetus in the transformation of conservation to make it more socially, economically and politically justifiable.  相似文献   
998.
This study presents the contributions of materials, earth engineering machines and construction techniques to potential environmental impacts from the main items of typical road earthworks. To achieve this goal, the overall activity at a 1.9-km long French earthworks project site for a heavily trafficked highway was surveyed during its 2007–2009 construction period. Using data collected and a numerical model of road life cycle assessment (LCA), i.e. ECORCE, six indicators could be evaluated, namely: energy consumption, global warming potential, acidification, eutrophication, photochemical ozone creation, and human chronic toxicity. When available, several life cycle inventories were implemented in order to appraise indicator sensitivity with respect to the considered panel of pollutants. Results also allowed estimating from an LCA point of view: (i) the conservation of both aggregates and soil as induced by quicklime treatment and (ii) the duration necessary for projected traffic levels to offset the potential environmental impacts of the earthworks stage.  相似文献   
999.
分析油罐区危险特性和事故模式,将三维GIS系统、日常管理、监控预警、应急指挥与辅助决策等功能进行集成,建立基于三维GIS的油罐区一体化应急管理平台。该平台利用数据融合技术,将液位、可燃气体、温度等多参数进行了融合,提高了报警可靠性。同时构建了DEA-BP应急资源配置模型,结合罐区事故类型,实现了罐区重大事故应急资源的优化配置。平台还提供数字化预案和三维应急演练,为油罐区员工提高应急安全技能提供了培训环境。  相似文献   
1000.
为探究热场对深部倾斜采空区煤自燃区域划分的影响,通过对采场空隙结构和耗氧速率进行分析,利用Fluent软件模拟不同通风方式下热环境对采空区流场及自燃带影响。结果表明:受倾角工作面、采空区空隙率及地温梯度综合影响,下行冷风与受采空区浮升力作用的热风在工作面中下部汇合并涌向工作面,使工作面局部温度升高;上行通风方式采空区蓄热范围大于下行风,回风侧温度更高;上行通风自燃带进风侧范围25~40 m,回风侧范围21~52 m;下行通风自燃带进风侧范围15~40 m,回风侧范围15~24 m;结合工作面实测参数,上行风回风侧自燃带范围19~47 m,与实际误差较小。研究结果可为倾角采空区热场条件对自燃带划分影响分析提供参考。  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