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   72篇
  免费   3篇
  国内免费   7篇
安全科学   2篇
废物处理   3篇
环保管理   1篇
综合类   32篇
基础理论   15篇
污染及防治   16篇
评价与监测   12篇
社会与环境   1篇
  2020年   4篇
  2019年   2篇
  2016年   4篇
  2014年   1篇
  2013年   5篇
  2012年   4篇
  2011年   2篇
  2010年   2篇
  2009年   5篇
  2008年   3篇
  2007年   11篇
  2006年   4篇
  2005年   3篇
  2004年   2篇
  2003年   8篇
  2002年   3篇
  2001年   4篇
  2000年   2篇
  1999年   2篇
  1998年   3篇
  1997年   1篇
  1996年   1篇
  1994年   1篇
  1993年   1篇
  1992年   3篇
  1990年   1篇
排序方式: 共有82条查询结果,搜索用时 31 毫秒
51.
In a study of fetal cells from a series of 12 pregnancies in ten families at risk for the ultraviolet light-sensitive, DNA repair-deficient diseases xeroderma pigmentosum (XP) and Cockayne syndrome (CS), we detected one XP and two CS homozygote fetuses. The diagnoses were confirmed by analysis of fetal skin fibroblasts or second amniotic samples after termination of the pregnancies. The measurement of ultraviolet light sensitivity and DNA repair depended on properties common to the seven excision repair-deficient XP complementation groups (A-G) and the two CS complementation groups (A, B). No XP variant families were included in the study, because the variant requires different testing techniques. Reliable and rapid diagnosis proved possible in all but one of the 12 pregnancies, supporting the use of these methods until the spectrum of mutations in the various XP and CS genes of the U. S. population is fully characterized and a DNA sequence-based diagnostic procedure becomes available.  相似文献   
52.
王斌  富江  周志刚 《环境科技》2007,20(2):18-20
本研究利用UV-US-O3联用处理废水.结果表明,UV-US-O3联用的处理效果大大高于单一紫外、单一臭氧及单一超声波处理的去除效率之和,UV-US-O3联用具有极好的协同效应.另外,本研究还考察了pH值、臭氧流量、超声波声能密度、处理时间的变化对处理效果的影响.  相似文献   
53.
紫外线杀菌效能的研究   总被引:8,自引:0,他引:8  
自来水的消毒目前普遍采用氯及含氯化合物药剂,消毒过程中产生三卤甲烷等致癌或致突变物质,从而造成水体的二次污染,许多国家已经禁止在消毒中使用含氯药剂。因此,具有安全可靠高效杀菌作用的紫外线消毒技术逐渐发展起来,并越来越受到人们的关注。但是紫外线的使用也有一定的限制,通过紫外线照射时间及进水浊度的变化,研究了具有一定照射强度的紫外灯的杀菌效能变化,并得出了紫外线具有最佳杀菌效果的进水极限浊度和照射时间。同时还研究了紫外线对具有不同抗性的细菌的系灭效率,为饮用水和污水的消毒处理提供了实验基础。  相似文献   
54.
光化学氧化技术去除水中有机污染物的试验研究   总被引:25,自引:0,他引:25  
以自来水为试验对象,对紫外-臭氧和紫外-二氧化钛两种光化学氧化技术对水中微量有机污染物的去除进行了试验研究,结果表明两种工艺的UVA(紫外吸光度)去除率均达到80%以上,对氯仿的去除也均能达到国家饮用水标准。在此基础上,自制了一种催化剂膜,并取得了预期的处理效果,有望在新型净水技术及设备的研制和开发上得到应用。  相似文献   
55.
Both males and females of many avian species maintain elaborate plumage traits, and elaborate monomorphic plumage may convey adaptive benefits to one or both sexes as inter- or intraspecific signals. Both sexes of the turquoise-browed motmot (Eumomota superciliosa) are elaborately plumed with long racket-tipped tail. I investigated whether the racketed tail functions as a sexually selected signal in one or both sexes by testing the predictions that males and/or females with the largest tails have: (1) greater pairing success, (2) greater reproductive performance (clutch-initiation date, clutch size, and hatching success), and (3) greater reproductive success. Yearling males with longer denuded rachises (wires) on the central tail feathers had greater pairing success. In addition, adult males with longer wires paired with females who laid larger clutches, had greater hatching success independent of clutch size, and fledged more young. There was no relationship between female tail plumage and pairing success, reproductive performance, or fledgling success. These results are consistent with the hypothesis that male tail plumage functions as a mate choice or status signal, but that the tail of the female does not function in a sexually selected context. I discuss alternative hypotheses for the evolutionary maintenance of the elaborate female tail plumage.  相似文献   
56.
地表水中石油类红外法与紫外法测定结果的比对   总被引:3,自引:1,他引:3  
进行了红外光度法与紫外分光光度法测定混合油样、闽江干流水样和内河水样中石油类的比对试验 ,试验表明 ,两法所测结果相差较大 ,以红外法所得结果较符合水体实际情况 ,提出了红外光度法测定时的注意事项  相似文献   
57.
Scytonemin, located in the extracellular polysaccharide sheath of some cyanobacterial species is considered an efficient natural photoprotectant against lethal doses of ultraviolet (UV) radiations. In the present study, scytonemin from the cyanobacterium Rivularia sp. HKAR-4 was partially characterized and investigated for its induction by UV radiation as well as its role in photoprotection. High-performance liquid chromatography (HPLC) with photodiode-array detection studies revealed the presence of an UV-absorbing compound with absorption maximum at 386 nm. Based on its absorption spectrum and ion trap liquid chromatography/mass spectrometry (LC/MS) analysis, the compound was confirmed as scytonemin. In comparison to photosynthetically active radiation, a significant induction in the synthesis of scytonemin was found under UV-stress. Scytonemin also exhibited efficient photoprotective ability by detoxifying the in vivo reactive oxygen species (ROS) generated by UV radiation and by reducing the formation of thymine dimers. To the best of our knowledge this is the first report on the UV-screening effects of scytonemin on in vivo ROS generation and thymine dimer formation in any cyanobacterial strain. Based on these findings, we conclude that scytonemin may play a vital role in the survival and sustainability of cyanobacterial life in adverse environmental conditions such as under high solar irradiances.  相似文献   
58.
Dimer formation was observed during ultraviolet (UV) photolysis of the anti-inflammatory drug diclofenac, and confirmed with mass spectrometry, NMR and fluorescence analysis. The dimers were combinations of the two parent molecules or of the parent and the product of photolysis, and had visible color. Radical formation during UV exposure and dissolved oxygen photosensitized reactions played a role in dimer formation. Singlet oxygen formed via photosensitization by photolysis products of diclofenac. It reacted with diclofenac to form an epoxide which is an intermediate in some dimer formation pathways. Quantum yield of photolysis for diclofenac was 0.21 ± 0.02 and 0.19 ± 0.02 for UV irradiation from medium pressure and low pressure mercury vapor lamps, respectively. Band pass filter experiments revealed that the quantum yield is constant at wavelengths >200 nm. The same dimers formed in laboratory grade water when either of the two UV sources was used. Dimers did not form in wastewater effluent matrix, and diclofenac epoxide molecules may have formed bonds with organic matter rather than each other Implications for the importance of dimer formation in NOM are discussed.  相似文献   
59.
分光光度法测定废水中草甘膦的探讨   总被引:3,自引:0,他引:3  
探讨了亚硝基衍生化紫外分光光度法测定废水中草甘膦的适用性,考察了硫酸加入体积对亚硝化反应的影响,提出应根据样品碱度调整硫酸用量。方法与高效液相色谱法测定值的重现性较好,应用于实际废水中草甘膦测定的加标回收率为95%~105%,平行测定的RSD≤1.3%,检出限为0.069 mg/L,检测上限为50.0 mg/L,废水中可能存在的伯胺和叔胺类物质对测定无明显干扰。  相似文献   
60.
双波长分光光度法测定含硝酸盐水样中二甲基乙酰胺   总被引:1,自引:1,他引:0  
紫外分光光度法是目前水中N,N-二甲基乙酰胺(DMAC)的常用分析方法。研究结果表明,硝酸盐对紫外分光光度法测定DMAC具有很强的干扰。本研究中提出一种双波长法用于消除水中硝酸盐的干扰作用,所采用的波长对为194.0nm和219.0nm。精密度实验及加标回收实验表明,方法的相对标准偏差在4%以内,回收率为95%~102%,可有效消除硝酸盐的干扰作用。  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