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   19篇
  完全免费   22篇
  评价与监测   41篇
  2022年   1篇
  2021年   3篇
  2020年   1篇
  2019年   2篇
  2018年   4篇
  2017年   3篇
  2016年   3篇
  2015年   3篇
  2014年   5篇
  2013年   3篇
  2012年   1篇
  2010年   1篇
  2009年   1篇
  2008年   1篇
  2007年   1篇
  2005年   1篇
  2004年   1篇
  2003年   1篇
  2002年   1篇
  2001年   2篇
  2000年   1篇
  1998年   1篇
排序方式: 共有41条查询结果,搜索用时 290 毫秒
1.
大连市近岸海域赤潮状况、预测及防治对策   总被引:6,自引:0,他引:6  
在揭示大连市近岸海域赤潮生物与生态环境关系的基础上,通过大量的调查监测资料对赤潮发生及增殖阶段13项环境因子统计分析,经多元回归得出大连市近岸海域春夏季赤湖预测模式,并在以后的赤湖中得到验证.其春季符合率为83%,夏季的符合率为92%.文章提出了物理、化学法治理的技术参数.同时探讨了生物治理的前景.  相似文献
2.
催化光度法测定痕量铬(Ⅵ)的研究   总被引:5,自引:0,他引:5  
基于在稀磷酸介质中,铬(Ⅵ)对溴酸钾氧化结晶紫有催化作用,提出了测定痕量铬(Ⅵ)的新催化光度法,检出限为25×10-9g/L,线性范围为02~40μg/27ml。应用于测定地面水及地下水的铬(Ⅵ),结果满意。  相似文献
3.
植物性食品中拟除虫菊酯类农药测定方法的改进   总被引:3,自引:0,他引:3  
基于色素和含水率两方面的考虑,选用了大米、荼叶和西红柿作为实验介质,在植物性食品中拟除虫菊酯类农药提取条件和净化条件等方面均进行了改进和优化.结果发现,采用正己烷/丙酮混合液(97.5∶2.5,V/V)提取植物性食品中菊酯类农药,40~50℃下超声萃取40min;选用弗罗里硅土和活性炭混合填充物制作层析柱;选用石油醚/乙酸乙酯(9∶1,V/V)作为洗脱溶剂,实验回收率达70%以上,结果令人满意.  相似文献
4.
城市颗粒物污染来源与特性分析   总被引:3,自引:0,他引:3  
吴雷  王慧 《干旱环境监测》2003,17(3):157-159
简述了颗粒物的性质、来源及对人体健康和大气质量的影响等,并对有关的各种研究方法进行了介绍。  相似文献
5.
Whether to use artificial restoration or to allow natural recovery of degraded land has been an important topic in restoration ecology because of the need to determine the most appropriate way to restore degraded lands that have suffered from serious soil erosion. To identify the threshold between a need for artificial restoration and the possibility of natural recovery, we analyzed the vegetation cover, soil fertility parameters, erosion modulus, and runoff coefficient in 32 plots with different vegetation covers in China’s Fujian province from 1999 to 2009. In our study, 20 % vegetation cover appeared to be the threshold between natural recovery and artificial restoration. When vegetation cover dropped below 20 %, it was difficult to stabilize the original ecological structure and functions based on natural recovery mechanisms, and artificial restoration was needed. By monitoring sites to detect when vegetation cover is approaching this threshold, local managers could determine whether natural or assisted recovery represents the most appropriate strategy for ecological restoration.  相似文献
6.
水中多种酚类化合物同步提取方法研究   总被引:1,自引:1,他引:0  
对水中14种酚类化合物的液液萃取过程进行研究,选取不同萃取溶剂体系、水样pH和盐析条件等多个对萃取效率有决定性影响的参数进行优化。通过上述条件的优化选择,实现了同步对包括低沸点的苯酚、一氯代酚及较难提取的甲基酚和硝基酚等14种不同类型酚类化合物最优的萃取,提取效率达到75.2%~110.3%。  相似文献
7.
采用吹扫捕集-气相色谱/质谱联用法测定地表水中氯丁二烯。当进样体积为20mL时,方法在0.100μg/L~50.0μg/L范围内线性良好,检出限为0.05μg/L,标准溶液平行测定的RSD≤3.7%,地表水样加标回收率为91.0%~101%,方法可用于地表水中卤代烃、苯系物等其他21种挥发性有机物的同时测定。  相似文献
8.
食品生产企业周边空气中的异味监测   总被引:1,自引:0,他引:1       下载免费PDF全文
简述了食品生产企业产生的异味无机物、有机物的种类,指出其异味主要来源于食品加工、原料贮存以及废物处理等环节,分析了异味物质的产生机理。介绍了空气中异味物质的监测方法包括,嗅辨法、气相色谱-质谱联用法、傅里叶红外光谱法以及气相色谱/气相色谱-质谱与嗅闻联用法等,及其适用性,以及测定结果的评价方法。  相似文献
9.
主要论述了分布式实时在线可控大气监测网的总体设计、技术要点及解决途径。通过软件的设计策略和数据流图阐明了当前大气监测控制技术向网络化、分布性和互操作性方向发展的特点,结合开发的实例介绍了网络监测技术的应用效果。  相似文献
10.
Fomesafen is a diphenyl ether herbicide that has an important role in the removal of broadleaf weeds in bean and fruit tree fields. However, very little information is known about the effects of this herbicide on soil microbial community structure and activities. In the present study, laboratory experiments were conducted to examine the effects of different concentrations of fomesafen (0, 10, 100, and 500 μg/kg) on microbial community structure and activities during an exposure period of 60 days, using soil enzyme assays, plate counting, and denaturing gradient gel electrophoresis (DGGE). The results of enzymatic activity experiments showed that fomesafen had different stimulating effects on the activities of acid phosphatase, alkaline phosphatase, and dehydrogenase, with dehydrogenase being most sensitive to fomesafen. On the tenth day, urease activity was inhibited significantly after treatment of different concentrations of fomesafen; this inhibiting effect then gradually disappeared and returned to the control level after 30 days. Plate counting experiments indicated that the number of bacteria and actinomycetes increased in fomesafen-spiked soil relative to the control after 30 days of incubation, while fungal number decreased significantly after only 10 days. The DGGE results revealed that the bacterial community varied in response to the addition of fomesafen, and the intensity of these six bands was greater on day 10. Sequencing and phylogenetic analyses indicated that the six excised DGGE bands were closely related to Emticicia, Bacillus, and uncultured bacteria. After 10 days, the bacterial community exhibited no obvious change compared with the control. Throughout the experiment, we concluded that 0–500 μg/kg of fomesafen could not produce significant toxic effects on soil microbial community structure and activities.  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