全文获取类型
收费全文 | 499篇 |
免费 | 64篇 |
国内免费 | 149篇 |
专业分类
安全科学 | 94篇 |
废物处理 | 19篇 |
环保管理 | 47篇 |
综合类 | 342篇 |
基础理论 | 75篇 |
环境理论 | 1篇 |
污染及防治 | 53篇 |
评价与监测 | 15篇 |
社会与环境 | 35篇 |
灾害及防治 | 31篇 |
出版年
2024年 | 1篇 |
2023年 | 12篇 |
2022年 | 21篇 |
2021年 | 22篇 |
2020年 | 21篇 |
2019年 | 21篇 |
2018年 | 22篇 |
2017年 | 19篇 |
2016年 | 23篇 |
2015年 | 31篇 |
2014年 | 23篇 |
2013年 | 35篇 |
2012年 | 40篇 |
2011年 | 43篇 |
2010年 | 41篇 |
2009年 | 25篇 |
2008年 | 24篇 |
2007年 | 32篇 |
2006年 | 34篇 |
2005年 | 31篇 |
2004年 | 28篇 |
2003年 | 17篇 |
2002年 | 16篇 |
2001年 | 18篇 |
2000年 | 21篇 |
1999年 | 15篇 |
1998年 | 21篇 |
1997年 | 12篇 |
1996年 | 10篇 |
1995年 | 8篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 7篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1981年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有712条查询结果,搜索用时 31 毫秒
61.
Fe2+EDTA溶液络合-铁还原脱除烟气中NO 总被引:1,自引:0,他引:1
提出了“Fe2 螯合剂络合-铁粉还原-酸吸收”回收法脱除烟气中NO的新工艺,重点研究了模拟烟气中O2体积分数对NO络合量的影响,以及铁粉用量、铁粉粒径、搅拌速度对NO脱除效率的影响,确定了最佳的铁粉脱氮工艺条件,并对铁粉和铁屑的脱氮效果进行了比较。结果表明,烟气中O2的体积分数从0%增加到4.2%,NO络合量下降90.2%;NO脱除效率随铁粉用量和反应器搅拌速度的增加而增加,随铁粉粒径的增加而降低;过程的最佳工艺参数为,铁粉用量0.8g,铁粉粒径≤0.077mm,搅拌速度900r·min-1,在此条件下,对O2体积分数为5%的模拟烟气在搅拌反应器中可取得90%以上的NO脱除效率;用铁粉在1台搅拌反应器中取得的NO脱除效率和用铁屑在2个鼓泡反应器串联时所取得的效率相当。 相似文献
62.
阎伍玖 《生态与农村环境学报》1994,(3)
本文简要分析了环境质量评价中目前广泛应用的各种评价方法与模型。在此基础上提出环境质量综合评判-灰色关联优势分析复合模型,应用于黄山风景区景观生态环境质量的综合评价,取得了满意的结果。 相似文献
63.
选择17种不同结构的园林绿地复合系统,对光照、温度、湿度和防尘效应进行测定,综合评价这17种园林绿地复合系统在改善城市气候方面的作用.结论是:乔、灌、草园林绿地复合系统在改善城市气候方面的作用最大,表4参7 相似文献
64.
Summary The ripe fruit of the Indian mulberry,Morinda citrifolia, is the host plant forDrosophila sechellia but is highly toxic for three closely related species (D. melanogaster, D. simulans, D. mauritiana). A simple bioassay is described with which a clear dose response to the fruit was found for these species. Significant differences in reactivity to the ripe fruit were found among species. Tested strains ofD. simulans andD. mauritiana adults were more sensitive to the toxic properties of the fruit thanD. melanogaster. A marked intraspecific variability was shown inD. melanogaster. Reciprocal interspecific hybridizations betweenD. sechellia andD. mauritiana suggested an autosomal dominant control of resistance. MoreoverD. melanogaster intraspecific crossings suggested the influence of an additional X-linked factor. Responses of flies toMorinda fruit in different states were tested in a T olfactometer. The less resistant strains ofDrosophila generally showed less preference for the ripe fruit. 相似文献
65.
Summary In four fruit-eating bats sniff-rate analysis revealed the threshold value for natural banana odour to be 1 × 10–4 vol% of head-space while the threshold values for its major components were found to be 3–6 orders of magnitude higher; even the total of molecules present at the threshold dilution of banana odour was 2 orders of magnitude below the lowest threshold values obtained for single components. Thus, the responsiveness of the bats to threshold concentration of natural banana odour is discussed as an example of synergism of stimuli. 相似文献
66.
生物有机无机复合肥对土壤微生物活性的影响 总被引:3,自引:0,他引:3
进行了化肥、有机肥、生物堆肥、有机无机复合肥和生物有机无机复合肥的田间比较试验。结果表明 :生物有机无机复合肥显著提高土壤微生物活性。与不施肥处理比较 ,土壤细菌增加了 1 6 5 .3 8% ,真菌增加了1 89.4 7% ,放线菌增加了 4 8.72 % ,总量增加了 1 0 4 .0 7% ,其增加量高于其他处理。土壤蔗糖酶、脲酶、磷酸酶活性也都有明显提高 ,促进了土壤有机质的分解转化和速效养分的释放。 相似文献
67.
Frode Skarstein Ivar Folstad Ståle Liljedal Mats Grahn 《Behavioral ecology and sociobiology》2005,57(4):374-380
Genes of the major histocompatibility complex (MHC) are remarkably polymorphic. Several selection mechanisms have been invoked to account for this diversity, including disassortative mating preferences. In addition, eggs may discriminate between sperm based on MHC. To investigate the effects of MHC-genotype on fertilization success, we obtained mature gametes from ripe Arctic charr (Salvelinus alpinus) males and females captured on spawning grounds. The eggs of each female were divided into two batches, and by letting each of 2 males fertilize 1 of the batches, we obtained a total of 36 half-sibling batch-pairs. The semen was diluted to ensure that the two males in each half-sibling batch-pair contributed with the same number of sperm cells. We found that MHC-heterozygous males had significantly higher fertilization success than MHC-homozygous males and neither initial spermatocrit, sperm motility nor swimming velocity co-varied with difference in fertilization success. There was no effect of female genotype or female-male MHC-similarity on fertilization success. However, one MHC-allele was associated with increased fertilization success. It seems plausible that the difference in fertilization success between homo- and heterozygous males may be due to MHC-dependent sperm selection by the ovum.Communicated by M. Abrahams 相似文献
68.
Paul Harvey 《Disasters》1998,22(3):200-217
The paper examines the challenge of rehabilitation from complex political emergencies (CPEs) and identifies a strategy that is characterised as a civil society rebuilding approach. It focuses on Somalia and a case study of a CARE project that aims to build the capacity of local NGOs. The paper argues that civil society in CPEs is simultaneously being undermined and contested by warring parties and emerging after state collapse. The scope of the paper is limited to one case study and that case study examines only a single aspect of civil society: national and international NGOs. The paper therefore presents tentative and preliminary results based on limited research. However, in reviewing the literature and presenting a way of approaching the subject, it aims to suggest a starting-point for developing a theoretical framework for such research. The paper finds that international agencies have tended to focus on civil society institutions simply as conduits for aid money and that this has tended to create organisations which lack downward accountability, are dependent on donors and are not addressing the wider roles for civil society envisaged in the approach. Rebuilding civil society does hold out the promise of giving non-military interests a stronger voice and starting a process of changing the aid delivery culture. Achieving these objectives, however, will be a slow and largely indigenous process and there is a need for lowered expectations about what outside assistance can achieve 相似文献
69.
70.