全文获取类型
收费全文 | 262篇 |
免费 | 16篇 |
国内免费 | 81篇 |
专业分类
安全科学 | 8篇 |
废物处理 | 5篇 |
环保管理 | 29篇 |
综合类 | 111篇 |
基础理论 | 139篇 |
污染及防治 | 36篇 |
评价与监测 | 3篇 |
社会与环境 | 21篇 |
灾害及防治 | 7篇 |
出版年
2023年 | 4篇 |
2022年 | 10篇 |
2021年 | 3篇 |
2020年 | 6篇 |
2019年 | 11篇 |
2018年 | 6篇 |
2017年 | 8篇 |
2016年 | 11篇 |
2015年 | 7篇 |
2014年 | 14篇 |
2013年 | 45篇 |
2012年 | 15篇 |
2011年 | 19篇 |
2010年 | 25篇 |
2009年 | 28篇 |
2008年 | 17篇 |
2007年 | 19篇 |
2006年 | 11篇 |
2005年 | 14篇 |
2004年 | 20篇 |
2003年 | 11篇 |
2002年 | 16篇 |
2001年 | 10篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1986年 | 1篇 |
排序方式: 共有359条查询结果,搜索用时 17 毫秒
111.
葡萄酒副产品深度利用的研究进展 总被引:1,自引:0,他引:1
介绍了葡萄皮渣、葡萄籽、酒脚的深度利用途径:葡萄皮渣可用于酿酒、酿醋、提取色素和多酚、吸附重金属;葡萄籽可以提取葡萄籽油、葡萄籽蛋白和抗氧化物质;酒脚可以提取酒石酸盐。开展葡萄酒副产品的深度利用,不仅可以获得良好的经济效益,而且可有效减轻环保压力,获得巨大的社会效益。 相似文献
112.
113.
114.
In Chul Kong 《环境科学学报(英文版)》2013,25(5):889-894
This investigation was to assess the joint effects of metal binary mixtures on seed germination,root and shoot growth,bacterial bioluminescence,and gene mutation based on the one toxic unit(1 TU)approach.Different sensitivities and orders of toxicity of metal mixtures were observed among the bioassays.In general,mostly additive or antagonistic effects were observed,while almost no synergistic effects by the binary metal mixtures in all bioassays.Therefore,the combined effects of heavy metals in the different bioassays were difficult to generalize since they were dependent on both chemical type and the organism used in each bioassay.However, these results indicate that a battery of bioassays with mixture chemicals as opposed to just a single assay with single metal is a better strategy for the bioassessment of environmental pollutants. 相似文献
115.
采用种子萌发试验对贵阳市乌当区马背山喀斯特次生林不同干扰迹地(弃耕干扰、火烧干扰和碎石堆积干扰)土壤种子库与地上植被的关系进行研究,结果显示:弃耕地、火烧地和碎石堆积地的地面植被的物种数和生活型比土壤种子库丰富,土壤种子库中乔木种类缺乏,以菊科、禾本科和豆科植物等草本植物占优势。3种干扰迹地地上植被物种丰富度指数、均匀度指数均大于土壤种子库,弃耕地土壤种子库的生态优势度指数大于地上植被,而碎石堆积地则小于地上植被。3种干扰迹地土壤种子库与地表植被的物种相似性系数分别为0.4000、0.4274和0.3556,表明不同人为干扰方式对地表植被和土壤种子库的影响程度不同。 相似文献
116.
针对当前滨海湿地种子流在潮汐过程中种子有效沉降降低、土壤种子库分布不均、定植效率低和栖息地裸斑现象等关键问题,以黄河三角洲盐沼湿地的盐地碱蓬(Suaeda salsa)为修复物种,研发一种应用于滨海湿地盐沼植被修复的固态种子产品,阐述固态种子产品的制作过程,并开展三种不同保水材料为核心材料(聚丙烯酰胺PAM,羟乙基纤维素HEC,羟丙基甲基纤维素HPMC)的种子产品的有效性研究。研究结果表明:(1)包装制作后的盐地碱蓬种子的吸水倍率和保水持续时间显著高于普通天然种子,表现出良好的吸水保水特性;(2)包装后的盐地碱蓬种子受盐度梯度变化的影响较小,表现出良好的耐盐抗性;(3)包装后的盐地碱蓬种子具有更高的萌发潜力,而不同保水材料的种子产品包装对盐地碱蓬种子萌发的促进作用表现为PAM>HPMC>HEC>天然种子;(4)包装后的盐地碱蓬种子具有更短的悬浮时间和较快的平均沉降速度,表明了种子产品增强了盐地碱蓬种子抵抗水动力干扰的潜力,其中以PAM为保水材料的种子产品可以直接、快速地沉降。本文首次将种子产品技术应用于滨海湿地盐沼植被修复中,为种子产品技术在退化滨海湿地的植被修复领域的应用与实践提供了理论基础。 相似文献
117.
毛竹入侵对常绿阔叶林主要树种的化感作用研究 总被引:2,自引:0,他引:2
为探讨毛竹入侵对周边森林环境的影响,以毛竹浸提液处理苦槠、青冈种子,测定种子萌发效应.结果表明,两树种种子萌发与浸提液浓度和来源有关.浓度效应表现为高抑低促的作用规律,高浓度处理下苦槠的发芽率为对照的82.3%~102.2%,青冈为对照的80%~90.9%,而低浓度处理下分别为对照的101.7%~107.6%和94.9%~109.1%.除低浓度处理对苦槠发芽速度无影响外,其他处理均对两树种发芽速度有显著的延缓作用(P<0.05).高浓度浸提液对苦槠根系活力有显著的抑制作用(P<0.05),抑制率为41.1%~62.4%.不同来源浸提液处理间差异明显,根系浸提液处理的种子发芽率最低.苦槠芽苗的芽长与不同来源浸提液间差异不显著(P>0.05),而青冈芽苗芽长与不同来源浸提液间差异显著(P<0.05),茎叶、根系与枯落物浸提液高于土壤浸提液.这些结果说明毛竹具有潜在的化感作用,可能有利于其入侵周边森林,从而危害周边森林环境. 相似文献
118.
研究了不同质量浓度Cu、Cd胁迫对荻(Triarrhena sacchariflora(Maxim.)Nakai)种子萌发及其幼苗生长的影响。结果表明:随着胁迫质量浓度的增大,Cu、Cd对荻种子萌发和幼苗生长的抑制作用增强。就发芽率来看,影响荻种子萌发的Cu的临界质量浓度和极限质量浓度分别为20.81、67.37 mg·L-1,Cd的临界质量浓度和极限质量浓度分别为16.30、42.79 mg·L-1。Cu、Cd对荻幼苗根的抑制作用大于对芽的抑制作用;芽的生长表现为低促高抑。影响荻幼苗芽生长的Cu的临界质量浓度和极限质量浓度分别为52.32、96.11 mg·L-1,Cd的临界质量浓度和极限质量浓度分别为33.55、55.88 mg·L-1;影响荻幼苗根生长的Cu的临界质量浓度和极限质量浓度分别为42.33、85.03 mg·L-1,Cd的临界质量浓度和极限质量浓度分别为26.18、50.45 mg·L-1。 相似文献
119.
The chromium(VI) biosorption onto guava seeds, as an alternative method for Cr6+ removal from aqueous solutions, was investigated. The parameters affecting kinetics and equilibrium of Cr6+ adsorption onto guava seeds were studied. An external mass-transfer diffusion coefficient k and intra-particle diffusion coefficient ki were determined to measure the rate-limiting step of adsorption. A single external mass-transfer diffusion model and intra-particle diffusion models were used. The effects of initial pH, sorbent mass, and initial Cr6+ concentrations on mass-transfer coefficients were investigated. The external mass-transfer coefficient has an average value of 7.2×10-3 cm s-1, while the intra-particle mass-transfer diffusion coefficient was 0.34 mg g-1 min-0.5. This indicates that external diffusion to the guava seeds surface and intra-particle diffusion are both involved in the sorption process. The isotherm equilibrium data were well fitted by the Langmuir and Freundlich models with an average correlation coefficient R2=0.98. The maximum removal of Cr6+ was obtained at pH 1 (about 100% for adsorbent dose of 15 g l-1 and 25 mg l-1 initial concentration of Cr6+). The results indicated that the guava seeds exhibit acceptable sorption capacity. 相似文献
120.
Abstract: Introducing rare plants to new sites for conservation to offset effects of habitat destruction requires detailed knowledge of habitat requirements, plant demography, and management needs. We conducted a factorial experiment replicated at three coastal prairie sites to test the effects of clipping frequency and litter accumulation on seed germination, seedling survival, reproduction, and seedling recruitment of introduced populations of the endangered, tall-stature, annual forb, Holocarpha macradenia (DC.) E. Greene. Clipping favored H. macradenia , primarily by enhancing seed germination and flower production. Litter accumulation had no effect on seed germination, even after 5 years of treatments. Seedling recruitment was highly site specific with large numbers of recruits recorded at only one of three sites. Although recruitment of seedlings was higher in clipped plots for 2–3 years, by 4–5 years after introduction very few seedlings survived to reproduction in any treatment. We attribute this result to a combination of poor habitat quality, small population size, and lack of a seed bank. We were unsuccessful in introducing this relatively well-studied species of concern to apparently suitable habitat at multiple sites in multiple years, which suggests that translocating rare plant populations to mitigate for habitat destruction is an expensive and highly uncertain endeavor. 相似文献