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61.
我国企业信息化建设中存在三类角色分别是企业、管理咨询公司和信息化产品开发商,他们各有优势和不足.只有三方面互相影响、互相促进、改变三者之间的"挤压关系",建立新的服务、协作、监督关系,企业信息化才能顺利进行.本文通过对这三类角色各自特点的分析和比较,深刻的思考了在我国企业信息化建设中这些角色之间的关系.  相似文献   
62.
通过对三清山缺萼枫香林群落的野外调查和分析,其结果表明,(1)该群落乔木分层明显,其中第1层高达20~25m,最高可达35m。年龄结构显示,主要优势种缺萼枫香处于衰退状态。(2)群落生活型以高位芽植物占绝对优势(75.38%),地上芽植物较多(21.54%),反映出该群落具有山顶群落特征。(3)重要值计算表明,各优势种的重要值比例为缺萼枫香(52.08%)、细叶青冈(34.14%)、猴头杜鹃(31.01%)、多脉青冈(24.95%)和红花油茶(20.63%),其相应的科所占比例为壳斗科(21.9%)、金缕梅科(17.36%)、山茶科(14.86%)及杜鹃花科(12.96%),在科属地理分布区类型上群落具有从热带向温带过渡的特征,热带性科占57.84%,温带性科占42.16%。(4)多样性指数以及频度分析表明,以Shannon-Wiener公式计算,其多样性指数为4.46,介于广东鼎湖山常绿阔叶林与江西中亚热带常绿阔叶林之间;频度值分析为A>B>CE,与Raunkiaer频度定律有一定差异。整体分析表明缺萼枫香群落是中亚热带地区典型的山地常绿落叶阔叶林群落。  相似文献   
63.
Method 30B and the Ontario Hydro Method (OHM) were used to sample the mercury in the flue gas discharged from the seven power plants in Guizhou Province, southwest China. In order to investigate the mercury migration and transformation during coal combustion and pollution control process, the contents of mercury in coal samples, bottom ash, fly ash, and gypsum were measured. The mercury in the flue gas released into the atmosphere mainly existed in the form of Hg°. The precipitator shows a superior ability to remove Hgp (particulate mercury) from flue gas. The removal efficiency of Hg2+ by wet flue gas desulfurization (WFGD) was significantly higher than that for the other two forms of mercury. The synergistic removal efficiency of mercury by the air pollution control devices (APCDs) installed in the studied power plants is 66.69–97.56%. The Hg mass balance for the tested seven coal-fired power plants varied from 72.87% to 109.67% during the sampling time. After flue gas flowing through APCDs, most of the mercury in coal was enriched in fly ash and gypsum, with only a small portion released into the atmosphere with the flue gas. The maximum discharge source of Hg for power plants was fly ash and gypsum instead of Hg emitted with flue gas through the chimney into the atmosphere. With the continuous upgrading of APCDs, more and more mercury will be enriched in fly ash and gypsum. Extra attention should be paid to the re-release of mercury from the reutilization of by-products from APCDs.

Implications: Method 30B and the Ontario Hydro Method (OHM) were used to test the mercury concentration in the flue gas discharged from seven power plants in Guizhou Province, China. The concentrations of mercury in coal samples, bottom ash, fly ash, and gypsum were also measured. By comparison of the mercury content of different products, we found that the maximum discharge source of Hg for power plants was fly ash and gypsum, instead of Hg emitted with flue gas through the chimney into the atmosphere. With the continuous upgrading of APCDs, more and more mercury will be enriched in fly ash and gypsum. Extra attention should be paid to the re-release of mercury from the reutilization of by-products from APCDs.  相似文献   

64.
水相中CCl4和CHCl3的紫外光解机理   总被引:1,自引:0,他引:1  
利用瞬态吸收光谱技术研究水体污染物CCl4 和CHCl3 在紫外光照条件下的转化和归宿 ,表明在 2 4 8nm激光作用下 ,CCl4 解离为CCl3 和Cl自由基 ;CHCl3 在此条件下不解离 ,但加入少量的苯后即发生明显解离 ,产生CHCl2 和Cl自由基 .在有氧条件下 ,光解产生的CCl3 和CHCl2 自由基均与O2 反应分别生成CCl3O2 和CHCl2 O2 ;在无氧条件下 ,CCl3 和CHCl2 则发生偶合反应分别生成C2 Cl6和C2 H2 Cl4 .本研究还得出了一些微观速率常数 .  相似文献   
65.
66.
水相中CCl4和CHCl3的紫外光解机理   总被引:2,自引:0,他引:2  
利用瞬态吸收光谱技术研究水体污染物CCl4和CHCl3在紫外光照条件下的转化和归宿,表明在248nm激光作用下,CCl4解离为CCl3和Cl自由基;CHCl3在此条件下不解离,但加入少量的苯后即发生明显解离,产生CHCl2和Cl自由基.在有氧条件下,光解产生的CCl3和CHCl2自由基均与O2反应分别生成CCl3O2和CHCl2O2;在无氧条件下,CCl3和CHCl2则发生偶合反应分别生成C2Cl6和C2H2Cl4.本研究还得出了一些微观速率常数.  相似文献   
67.
Composite nucleating agent (CNA) consisting of zinc oxide as a crystallization promoter and phenylphosphonic acid zinc salt (PPZn) as an heterogeneous nucleation agent was employed to improve the crystallization behaviors of branched poly (lactic acid) (B-PLA) which was prepared by use of multi-functional epoxy-based chain extender (CE). The differential scanning calorimeter results showed that the crystallinity and crystallization temperature of prepared B-PLA/CNA were higher than that of linear poly (lactic acid) (L-PLA) and B-PLA at a high cooling rate. The corresponding phenomena of heterogeneous nucleation of B-PLA/CNA were observed by means of polarized optical microscope. The crystalline mechanism research results show that the degradation reaction and chain extending reaction were occurred simultaneously after the addition of CE and CNA into the PLA, PPZn as an effective nucleation points could increase the nucleation density and the degraded short molecular chains with higher chain mobility would improve crystal growth during the crystallization of the branched PLA. Non-isothermal cold crystallization kinetics of various B-PLA with different content of CNA was studied. The corresponding result showed that the crystallinity and crystallization rate increased obviously with the CNA content greater than or equal to 5phr, as well as the crystallization time decreased. The similar experimental results of non-isothermal and isothermal melt crystallization kinetics also showed that CNA had a significant impact on crystallization behavior of B-PLA.  相似文献   
68.
大气环境红线划定技术研究   总被引:1,自引:0,他引:1  
大气环境质量安全底线是环境质量安全底线的重要内容,其划定工作能够更好地为环境管理提供服务.本研究旨在建立大气环境质量安全底线划定技术方法,为国家和地方大气环境质量安全底线划分和管控措施设计提供导引,为建立国家环境质量安全底线提供技术支撑.  相似文献   
69.
党的十八大把生态文明建设列入中国特色社会主义事业五位一体的总体布局,提出大力推进生态文明建设,努力建设美丽中国,实现中华民族永续发展。随着市场经济的持续增长,环境污染、扰民问题愈加突出,人民群众对环境问题日益关注,环境保护工作面临的形势越来越严峻,任务和责任越来越繁重和艰巨,给基层环境保护工作提出更高的要求。基层环境监管在思想观念更新,工作思路调整,能力建设加强,管理机制完善等方面需进一步提高和发展。  相似文献   
70.
为探究绝缘油污染土壤微波热脱附的影响条件,考察了温度、停留时间、土壤含水率、污染物初始浓度和微波功率对土壤中绝缘油去除效果的影响.结果表明,温度和停留时间显著影响土壤中绝缘油的去除率,在400℃、微波处理时间5 min的条件下,土壤中绝缘油的去除率为98.6%.当土壤含水率为5%时,土壤中绝缘油的去除率达到最佳.在微波处理15 min内,土壤中绝缘油的去除率随着绝缘油初始浓度的升高逐渐降低.微波功率越高,土壤中绝缘油的微波热脱附效率越高,综合考虑能耗和去除率,微波功率为1 000 W时较优.绝缘油污染土壤微波热脱附机理研究表明,脂肪烃主要通过蒸汽蒸馏和热解吸两种方式从土壤中脱除.本研究结果可为高浓度绝缘油污染土壤微波热脱附技术应用提供参考.  相似文献   
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