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   461篇
  免费   52篇
  国内免费   167篇
安全科学   53篇
废物处理   16篇
环保管理   52篇
综合类   266篇
基础理论   65篇
环境理论   6篇
污染及防治   105篇
评价与监测   11篇
社会与环境   71篇
灾害及防治   35篇
  2024年   1篇
  2023年   17篇
  2022年   21篇
  2021年   19篇
  2020年   11篇
  2019年   30篇
  2018年   49篇
  2017年   38篇
  2016年   30篇
  2015年   33篇
  2014年   31篇
  2013年   59篇
  2012年   36篇
  2011年   34篇
  2010年   30篇
  2009年   33篇
  2008年   18篇
  2007年   31篇
  2006年   32篇
  2005年   22篇
  2004年   16篇
  2003年   14篇
  2002年   17篇
  2001年   12篇
  2000年   9篇
  1999年   9篇
  1998年   4篇
  1997年   5篇
  1996年   6篇
  1994年   1篇
  1993年   3篇
  1990年   2篇
  1987年   3篇
  1982年   1篇
  1978年   1篇
  1974年   1篇
  1971年   1篇
排序方式: 共有680条查询结果,搜索用时 31 毫秒
21.
曝气生物滤池Biostyr处理微污染水源   总被引:7,自引:1,他引:6  
采用曝气生物滤池Biostyr对浙江省T市某水厂微污染水源水进行生物预处理,现场试验研究表明:在气水比为2∶1,滤速6m/h,水温24~32℃的运行条件下,其对水中各污染物的平均去除率为:高锰酸盐指数24.1%,氨氮81.7%,亚硝酸盐氮79.9%,浊度49.0%。完全能达到生物预处理目的。  相似文献   
22.
悬浮填料活性污泥法优化填料投配比试验   总被引:1,自引:1,他引:0  
悬浮填料活性污泥法中试试验系统,利用某城市污水厂生产工艺回流污泥为系统悬浮污泥,探讨了悬浮填料投配比、投配方式和中试硝化效果之间的关系。试验结果表明,悬浮填料最小投配比为15%即可满足系统硝化功能的要求;悬浮填料的投配方式宜采用集中投配并布置于曝气池的末端,这样既可提高系统的生物膜量,又有利于硝化反应的实现。而且,控制适当的溶解氧浓度,悬浮填料的投加有助于同步硝化反硝化更充分的进行。  相似文献   
23.
在利用电化学反应器单独脱硝脱卤的电催化实验基础上,对电化学催化方法同步脱硝脱卤进行研究.试验采用化学沉积法负载钯-铜合金(4∶ 1)的多孔钛板作为电解反应器阴极,电解硝酸盐氮(NO-3-N)和五氯酚(PCP)的混合溶液.结果表明: PCP的脱卤效果与单独脱卤时相似,但PCP的存在对NO-3-N的还原脱除有明显影响.PCP在钯原子上的竞争性吸附抑制了NO-3-N还原反应的中间产物NO-2-N继续还原,导致在反应初期出现NO-2-N的积累;随着PCP的充分还原,前期积累的副产物NO-2-N可以逐渐被降解.分批试验和推流试验结果表明,利用多孔钛板负载的钯-铜二元合金电极,选择合适的反应参数,可有效地脱除水中的硝酸盐氮和卤代有机物.  相似文献   
24.
This essay identifies and examines scapegoat ecology, an emergent genre in online environmental discourse. In scapegoat ecology, a public of environmentally minded individuals focuses attention and vitriol on a single person for being particularly harmful to the environment. This essay argues that such discourse deflects attention from more complex and systemic environmental factors and implicitly exonerates the broader community, assuring it of its own environmental commitments while excusing it from further ecological action. The essay describes the form and appeal of scapegoat ecology, then provides a series of illustrative case examples before highlighting the implications of such discourse for both environmental communication and broader social/political conversations.  相似文献   
25.
This study addresses the use of message carriers to convey corporate social responsibility information to promote eco-purchasing involvement. The work tests various media formats transmitted via social media. The effects of corporate vs. peer communication in a corporate social responsibility campaign in stimulating self-reported eco-purchasing involvement are indicated. The research varies communication dimensions of a fictional corporate social responsibility campaign sent through social media. Multiple media formats; new release; article; and advertisement were tested, as was the inclusion of social media persuasive sentiment. The analysis of source/format combinations and source/format/sentiment combinations found statistically significant differences for consumer-to-consumer communication in stimulating eco-purchasing involvement in certain circumstances. This research suggests an emerging role for the consumer communicator as a content co-creator and validates the effective use of articles and news releases instead of advertising on social media, yielding managerial and scholarly implications.  相似文献   
26.
程刚  周孝德  王静  仝攀瑞 《化工环保》2007,27(4):319-322
介绍了纳米晶粒TiO2多孔微球的主要制备方法、主要参量及表征、光催化性能研究进展,指出了纳米晶粒TiO2多孔微球制备过程的技术关键与基本参量的功能。针对目前存在的问题,提出了今后的主要研究方向,并展望了纳米晶粒TiO2多孔微球在水处理领域的应用前景。  相似文献   
27.
在Biot饱和多孔介质动力学理论的基础上,利用Fourier-Bessel级数展开法,通过对含有衬砌洞室的局部场地进行波场分析,得到饱和土半空间中圆柱形衬砌洞室对平面SV波的散射问题的解析解。经验证,本文得到的解可以退化为半空间单相介质的情况。通过与已有的单相弹性介质半空间中圆柱形衬砌洞室对平面SV波散射问题的解析解的对比,验证了此解的正确性。在解析解的基础上,数值计算给出洞口动应力集中放大系数,分析了入射频率和孔洞埋深对柱面上的应力集中因子的影响。  相似文献   
28.
Social movements often amalgamate otherwise diffuse public political interests. In recent years, social media use has allowed both groups and individuals to engage with political issues both online and offline. How do organizations use Twitter to mobilize networked publics? To what extent do groups promote both ‘connective action’ online and traditional activism offline? How do their strategies differ according to whether they seek to promote or combat the status quo? And how do they balance encouraging and reinforcing individualized expression through group messaging? The ways pro-Keystone XL pipeline and anti-Keystone XL groups differed in their Keystone-related action on Twitter from January 2010 until October 2014 are analyzed. Boolean searching and Natural Language processing are used to analyze more than three million tweets. The results demonstrate that the frames within Twitter conversations have significant implications for how communities understand, develop, and mobilize around environmental issues.  相似文献   
29.
This paper examines ideologies about nature and the environment in popular, animated Hollywood films—including The Lorax, Wall-E, and Ice Age 2—through a symptomatic reading. The primary goal of the analysis is to elucidate key omissions in these texts through an assessment of the problematic—defined in this research as an a-priori answer to perceived audience concerns regarding the role of consumerism and corporate culture in environmental problems. Silences in the films revolve around: how environmental problems are defined; what the consequences are; who the responsible parties are; and what potential solutions exist to mitigate them. The significance of the research is underscored by the formation of an increasingly intimate relationship between children, consumer culture, and commercial media in the USA, as well as the increasingly dire information emerging about global environmental issues. This analysis reveals the dual, often conflicting, messages that commercial film provides for its young audiences about pivotal environmental problems and their potential resolution.  相似文献   
30.
The boundary between preferential flow and Richards-type flow is a priori set at a volumetric soil water content θ at which soil water diffusivity D (θ) = η (= 10− 6 m2 s− 1), where η is the kinematic viscosity. First we estimated with a hydrostatic approach from soil water retention curves the boundary, θK, between the structural pore domain, in which preferential flow occurs, and the matrix pore domain, in which Richards-type flow occurs. We then compared θK with θ that was derived from the respective soil hydrological property functions of same soil sample. Second, from in situ investigations we determined 96 values of θG as the terminal soil water contents that established themselves when the corresponding water-content waves of preferential flow have practically ceased. We compared the frequency distribution of θG with the one of θ that was calculated from the respective soil hydrological property functions of 32 soil samples that were determined with pressure plate apparatuses in the laboratory. There is support of the notion that θK θ≈ θ, thus indicating the potential of θ to explain more generally what constitutes preferential flow. However, the support is assessed as working hypothesis on which to base further research rather than a procedure to a clear-cut identification of preferential flow and associated flow paths.  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