全文获取类型
收费全文 | 63篇 |
免费 | 4篇 |
国内免费 | 15篇 |
专业分类
安全科学 | 1篇 |
废物处理 | 1篇 |
环保管理 | 10篇 |
综合类 | 36篇 |
基础理论 | 20篇 |
污染及防治 | 11篇 |
评价与监测 | 1篇 |
社会与环境 | 1篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 5篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 6篇 |
2013年 | 9篇 |
2012年 | 5篇 |
2011年 | 6篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 7篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2002年 | 5篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1994年 | 1篇 |
排序方式: 共有82条查询结果,搜索用时 437 毫秒
1.
牛粪-化肥配施对水稻田氮磷迁移转化的影响 总被引:1,自引:0,他引:1
在控制外源N输入量相同的前提下,通过田间小区实验,探讨有机肥与化肥不同施用量(牛粪施用量:5,10,20t/hm2)对稻田田间土-水界面氮磷迁移转化特征的影响.结果表明:控制稻田水中NH4+-N、NO3--N、TN和TP输出的最佳时期分别为施肥后的第5,30,7,20d,且TN和TP浓度随时间变化符合单指数衰减方程(0.7444≤R2≤0.9724;1.1×10-6≤F≤0.0055).采用牛粪部分代替化肥的施肥方式,在一定范围内能降低稻田退水中TN、TP输出负荷(41.8%、36.0%、64.3%;20.3%、39.1%、48.9%),还可以降低稻田水中N/P,降低水体富营养化风险.同时,牛粪的施用可提高土壤中脲酶和磷酸酶的含量,促进氮磷向植物可吸收形态转化.综合经济成本和生态效益核算,采用10t有机肥代替无机肥的处理是相对经济环保的施肥方法,该施肥方式下,氮磷年输出负荷分别为17.70,1.26kg/hm2. 相似文献
2.
以糖、淀粉、蛋白质、纤维素培养基及菌株增殖倍数、菌株性能等为筛选方法,从牛粪低温堆肥中筛选不同原料重要功能菌并组成功能菌剂;以不同类别原料菌及单菌株发酵实验对升温机制进行研究。结果表明,芽孢杆菌、假单胞菌、纤维单胞菌及小孢霉菌等为重要功能菌;菌剂起温快,升温效果好,48 h堆体即由低温进入中温,5 d达到高温,腐熟时间可缩短至约17~18 d;糖功能菌升温效果最为显著,淀粉及蛋白质功能菌次之,纤维素功能菌升温能力较弱;菌株利用各种原料能力越强,增殖速度越快,对升温作用越大。各菌株充分利用基质各成分,紧密协同和促进,是低温堆体发酵升温的主要作用机制。 相似文献
3.
Recycling of plant materials and agricultural residues for biomethanation was attempted in vials. The methanogenic activities of certain sewage samples have also been tested. Both sterilized and non-sterilized biomasses were used. Biomethanation was carried out with dung samples (cow, goat, buffalo, piggery wastes and poultry wash) as wild populations of microbes and in combination with other microbial isolates (isolated in the laboratory).Biomethanation had been observed to be good in most cases and particularly with the sterilized biomass. Mixed inoculum (dung samples and poultry wash) was found to be best for biomethanation. Of the microbe isolates, isolates from buffalo, pig and paper mill wastes appear to be most effective. Pretreated sawdust and rice straw were found to be good subtrates for biomethanation. Of the different plant biomass used Spirogyra (algae), Ipomea and water hyacinth were most effective whereas Jatropa gossypifolia and Parthenium sp. were the least effective. Biomethanation of Spirogyra was carried out both in anoxic and oxic conditions. Though methane production decreased enormously under oxic conditions, definite methane production continued indicating that the biomethanation process is not exclusively anoxic. Similarly, biomethanation of sewage samples from different sewage treatment plants were carried out with and without isolated methanogens and methane production was found to be moderate. 相似文献
4.
Abstract: Anthropogenic disturbances such as fragmentation are rapidly altering biodiversity, yet a lack of attention to species traits and abundance patterns has made the results of most studies difficult to generalize. We determined traits of extinction‐prone species and present a novel strategy for classifying species according to their population‐level response to a gradient of disturbance intensity. We examined the effects of forest fragmentation on dung beetle communities in an archipelago of 33 islands recently created by flooding in Venezuela. Species richness, density, and biomass all declined sharply with decreasing island area and increasing island isolation. Species richness was highly nested, indicating that local extinctions occurred nonrandomly. The most sensitive dung beetle species appeared to require at least 85 ha of forest, more than many large vertebrates. Extinction‐prone species were either large‐bodied, forest specialists, or uncommon. These explanatory variables were unrelated, suggesting at least 3 underlying causes of extirpation. Large species showed high wing loading (body mass/wing area) and a distinct flight strategy that may increase their area requirements. Although forest specificity made most species sensitive to fragmentation, a few persistent habitat generalists dispersed across the matrix. Density functions classified species into 4 response groups on the basis of their change in density with decreasing species richness. Sensitive and persistent species both declined with increasing fragmentation intensity, but persistent species occurred on more islands, which may be due to their higher baseline densities. Compensatory species increased in abundance following the initial loss of sensitive species, but rapidly declined with increasing fragmentation. Supertramp species (widespread habitat generalists) may be poor competitors but strong dispersers; their abundance peaked following the decline of the other 3 groups. Nevertheless, even the least sensitive species were extirpated or rare on the smallest and most isolated islands. 相似文献
5.
Summary. We report field and laboratory evidence indicating that the defensive compounds secreted by the millipedes Amplinus bitumidus (Diplopoda: Polydesmida) and Anadenobolus putealis (Diplopoda: Spirobolida) attract the carrion scarab Canthon morsei (Scarabaeidae: Scarabaeinae). In a Mexican tropical rain forest, C. morsei was mostly caught in pitfall traps baited with the carcasses of both millipede species. Only a few beetles were attracted
to fish carrion. Experimental evidence indicates that C. morsei is attracted to freshly dead millipedes. Benzaldehyde and HCN were identified from Amplinus bitumidus; but 2-methyl-1,4-benzoquinone (toluquinone) and 2-methoxy- 3-methyl-1,4-benzoquinone from Anadenobolus putealis. Benzaldehyde attracted significantly more C. morsei individuals than fish meat, or millipedes of both species did after rinsing in hexane. This is the first report of Polydesmida
attracting dung beetles. 相似文献
6.
7.
8.
9.
黄军 《环境保护与循环经济》2021,41(1)
将某种同位素发生器用于示踪测井的贮存、运输、淋洗及现场测井各阶段,通过开展不同阶段放射性水平调查,对调查结果进行剂量估算与现状评价,掌握113Sn-113mIn同位素发生器用于示踪测井过程对环境及人员造成的辐射危害。 相似文献
10.
采用室内接种法,以赤子爱胜蚓(Eisenia fetida)构建生物反应器,研究猪粪、木屑混合物的蚯蚓堆制处理中,蚓体的生长状况及影响其Cu、Zn富集的主要因素。结果表明,接种密度为40 mg.g-1、湿度为75%同时有利于蚯蚓生长和基质消耗;温度为15℃对蚓体质量增加最有利,而温度为20℃最利于基质消耗;m(猪粪)∶m(木屑)为6∶4可同时利于蚓体质量增加和基质消耗。适宜的接种密度(48 mg.g-1)、湿度(70%)、温度(15℃)及较高比例的碳源辅料〔m(猪粪)∶m(木屑)为6∶4〕有利于蚓体对Cu的吸收和富集;低接种密度和高比例碳源辅料有利于蚓体对Zn的吸收,湿度和温度对蚓体Zn含量无显著影响,但蚓体Zn富集量分别在接种密度48 mg.g-1、m(猪粪)∶m(木屑)为6∶4、湿度75%和温度15℃条件下达最大。 相似文献