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   46篇
  免费   0篇
  国内免费   1篇
废物处理   9篇
环保管理   3篇
综合类   7篇
基础理论   8篇
污染及防治   13篇
社会与环境   2篇
灾害及防治   5篇
  2022年   1篇
  2020年   1篇
  2017年   1篇
  2014年   4篇
  2013年   4篇
  2012年   1篇
  2011年   2篇
  2010年   4篇
  2009年   1篇
  2008年   2篇
  2007年   4篇
  2006年   1篇
  2005年   3篇
  2004年   5篇
  2003年   1篇
  2002年   2篇
  2000年   1篇
  1994年   1篇
  1992年   1篇
  1990年   1篇
  1989年   2篇
  1988年   1篇
  1982年   1篇
  1979年   1篇
  1975年   1篇
排序方式: 共有47条查询结果,搜索用时 15 毫秒
41.
应用电子自旋探针(Electoron spin probe,简ESP)Mn^2+离子的超精细结构(hyperfine structure,简称hfs),揭示了水泥固化土壤中Cd^2+离子的化学反应,研究发现:由于水泥水化产生高的PH值,Cd^2+离子与OH^-离子反应生成Cd(OH)2沉‘当有CO2气体存在时,Cd^2+离子会与CO2和水泥水化的OH^-离子反应生成CdCO3、Cd(OH)2,这些  相似文献   
42.
Ozonated soil-humic acid induced direct mutagenicity on TA98, TA100 and TA104, while not the ozonated reagent- and wastewater-humic acids. Oxygen radicals generated from mutagens such as glyoxal and hydrogen peroxide identified as the ozonation products might, in part, contribute to the mutagenicity of ozonated soil-humic acid.  相似文献   
43.
The seasonal successions of standing crop and floral assemblage were studied for oceanic coccolithophores at 5 weather stations in the western North Atlantic Ocean. The coccolithophores were less populous during winter at the northern stations, whereas they became scarce during summer at the southern stations. The average standing crop in the surface water was quite consistent throughout all climatic regions, being a few tens of thousand cells per liter. The average standing crop at the 100 m level showed a clear trend of increasing southwards. The population at this depth was only one-tenth as large as that of the surface level at the northernmost station, whereas it was almost two-thirds as large as the surface levels at the southernmost station. Many of the major species exhibited seasonally biased occurrences. The trend was mostly repeated in consecutive years, although the magnitude of their abundances fluctuated from year to year in some case. The average species composition was obtained for the 5 weather stations at the surfacewater (surface and 20 m levels combined) and 100 m levels; Emiliania huxleyi dominated the flora at all stations. The relationship between occurrences of major species and ambient water temperature was also studied. Although some species were stenothermal, the majority exhibited eurythermal characteristics; this accounts for the high specific diversity of the coccolithophore community throughout the wide range of waters studied.Contribution No. 2899 of the Lamont-Doherty Geological Observatory of Columbia University.  相似文献   
44.
This study, based on a questionnaire survey and workshops, and with a focus on the impact of an earthquake on the Nagata Elementary School Community in Kobe City, Japan, develops a collaborative model to assess the allocation of residents to shelters. The current official allocation plan is compared with three alternative allocations developed within the framework of this model. The collaborative model identifies accessibility, amenity, capacity, connectivity, continuity, security, and stability as the basic, necessary criteria for shelter planning. The three alternative allocations are very similar to the local residents’ own choice of shelters, but they are quite different from the current official allocation plan, which is supposed to be followed but has achieved relatively low satisfaction among households. The proposed collaborative approach provides an effective tool to assess the officially determined allocation plan by taking into account the viewpoints of local residents, and the results are useful for enhancing community evacuation planning.  相似文献   
45.
Poly(acrylic acid)s (PAAs) with various functional groups, such as phenolic hydroxyl, amino, and aldehyde groups, in the side-chains were treated with manganese peroxidase (MnP) prepared from the culture of lignin-degrading white rot fungi. While no change in the Mw of PAA without a functional group was observed after a 24-h MnP treatment, the Mw␣of␣PAA␣with p-aminophenol as side-chains decreased from 90,000 to 59,000, and that with␣o-aminophenol from 70,000 to 26,000. MnP treatment also decreased the Mw of PAA with a p-aminoaniline or aldehyde group. Furthermore, the MnP treatment generated a significant depolymerization of the cross-linked PAA with p-aminophenol from an insoluble polymer to water soluble products. These results suggest that functional groups generating radicals can act as elemental devices and induce degradation of the PAA main chain.  相似文献   
46.
Intraspecific variation in a resting metabolic rate (RMR) is likely to be an important determinant of energetic-resource use and may influence the resources subsequently available for allocation to traits not directly associated with somatic maintenance. The influence of RMR on resource availability could be especially important for condition-dependent sexual traits, such as cricket calls, that are themselves energetically costly to produce. RMR may also be associated with longevity, either negatively because individuals with a high RMR burn resources faster and die young, or positively as individuals with high RMR are more able to accrue resources to fuel survival. Additionally, the associations between RMR and other characters may vary across populations if differential selection or drift shapes these traits. Here we tested for differences in RMR, body mass, calling effort, and longevity in two populations of cricket Gryllodes sigillatus and then evaluated the potential influence of RMR on calling and longevity. We find that RMR, calling effort, and longevity varied across populations, but mass did not. Controlling for population and mass, RMR was not significantly associated with calling effort, but was negatively associated with longevity. These findings suggest that male crickets that live fast die young.  相似文献   
47.
The objective of this study is to find metal ions that enhance the ozone decomposition of chlorinated organic substances in acetic acid. Although the pseudo-first order degradation rate constant for 2,4-DCP by ozone in acetic acid in addition of Ca2+, Mg2+, Al3+ and Fe2+ were almost the same as that with no metal ion, the degradation rate in addition of Mn2+ and Fe3+ were 2.4 and 4.5 times as high as that with no metal ion, respectively. The presence of Fe3+ enhanced the degradation of 2,4-DCP by ozone in acetic acid because Fe3+-phenolate complex which have high reactivity with ozone was produced by the reaction between 2,4-DCP and Fe3+ in acetic acid.  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