全文获取类型
收费全文 | 494篇 |
免费 | 20篇 |
国内免费 | 118篇 |
专业分类
安全科学 | 46篇 |
废物处理 | 25篇 |
环保管理 | 33篇 |
综合类 | 229篇 |
基础理论 | 94篇 |
污染及防治 | 149篇 |
评价与监测 | 21篇 |
社会与环境 | 17篇 |
灾害及防治 | 18篇 |
出版年
2023年 | 3篇 |
2022年 | 28篇 |
2021年 | 17篇 |
2020年 | 11篇 |
2019年 | 15篇 |
2018年 | 21篇 |
2017年 | 21篇 |
2016年 | 20篇 |
2015年 | 19篇 |
2014年 | 29篇 |
2013年 | 58篇 |
2012年 | 38篇 |
2011年 | 38篇 |
2010年 | 42篇 |
2009年 | 26篇 |
2008年 | 37篇 |
2007年 | 32篇 |
2006年 | 30篇 |
2005年 | 16篇 |
2004年 | 13篇 |
2003年 | 13篇 |
2002年 | 14篇 |
2001年 | 15篇 |
2000年 | 19篇 |
1999年 | 9篇 |
1998年 | 4篇 |
1997年 | 10篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有632条查询结果,搜索用时 639 毫秒
581.
Estimating soil salinity in different landscapes of the Yellow River Delta through Landsat OLI/TIRS and ETM+ Data 总被引:2,自引:0,他引:2
Soil salinization has increasingly become a serious issue in coastal zone due to global climate changes and human disturbances. Assessment of soil salinity, especially at the landscape scale, is critical to coastal management and restoration. Two data from OLI/TIRS and ETM+ sensors of Landsat satellite were used to compare their ability to invert the spatial pattern of soil salinity in both farmland and salt marsh landscapes in the Yellow River Delta, China, respectively. The results showed that the in situ electrical conductivity (EC a ) of soil, representing soil salinity, were closely related with spectral parameters and salinity indices calculated by the remote sensing data. The results of multiple regression models have showed that nearly all the spectral parameters and salinity indices calculated by OLI/TRIS data were more sensitive to soil salinity than those by ETM+ data. Therefore, the models based on OLI/TIRS data are superior to those on ETM+ data in estimating the spatial pattern of soil salinity in farmland and salt marsh landscapes. Our results were very helpful to evaluate the levels of soil salinization in the Yellow River Delta. 相似文献
582.
Gaoling Wei Jinhua Zhang Jinqiu Luo Huajian Xue Deyin Huang Zhiyang Cheng Xinbai Jiang 《Frontiers of Environmental Science & Engineering》2019,13(4):61
583.
Biochemical responses and DNA damage of earthworm (Eisenia fetida) exposed to various concentrations of fomesafen (0, 10, 100, and 500 μg kg?1) for 3, 7, 14, 21, and 28 days were investigated in vivo. Glutathione S-transferase (GST) activity was significantly stimulated upon treatment with 500 μg kg?1 fomesafen for 21 days, while the cellulase activity was markedly inhibited after 14 days of treatment. On day 28, the activities of GST and cellulase had recovered to the level similar to that of controls. Low or mild DNA damage in earthworm was induced within 14 days of exposure, and the damage was reduced or disappeared with the extension of exposure. 相似文献
584.
Yongliang ZHANG Bing ZHANG Jun BI Pan HE 《Frontiers of Environmental Science & Engineering》2013,7(2):231-241
The various forms of uncertainty that firms may face in bankable emission permit trading markets will affect firms’ decision making as well as their market performance. This research explores the effect of increased uncertainty over future input costs and output prices on the temporal distribution of emission. In a dynamic programming setting, the permit price is a convex function of stochastic prices of coal and electricity. Increased uncertainty about future market conditions increases the expected permit price and causes a risk neutral firm to reduce ex ante emissions in order to smooth out marginal abatement costs over time. Finally, safety valves, both low-side and high-side, are suggested to reduce the impact of uncertainty in bankable emission trading markets. 相似文献
585.
对兰坪铅锌尾矿区自然发生的植物进行调查,共发现18种植物,分属于10科。对野豇豆(Vigna vexiauata(Linn.)Bench.)、长波叶山蚂蝗(Desmodium sequax Wall.)、三叶草(Trifolium pratense Linn.)、白刺花(Sophora davii(franch.)Skeels)、密花序黄芪(Astragalus forrestii Simpson.)、美丽胡枝子(Lespedeza Formosa(Vog.)Koehne.)6种8株豆科植物根瘤进行根瘤菌的分离纯化,共得到419株细菌,经镜检初步确定有94株为根瘤菌。对其中31株根瘤菌的淀粉水解、糖发酵等12项生理生化指标进行测定,并以平均连锁法进行聚类分析。结果表明,兰坪铅锌尾矿区31株根瘤菌在50%的相似水平上可分为6个类群,其表型特性存在明显差异,同一种植物中可能存在不同代谢类型的根瘤菌,同一种代谢类型的根瘤菌也可与不同植物共生。抗逆性测定结果表明,菌株(4G.7、5.4.3、7.4.3)对温度、(4A.12、4G.7、4G.10、5.4.3)对pH、(3.7.9、5.4.3)对盐、(3.7.19、4A.12、6.1.2、6.1.13)对抗生素有较强耐受性或抗性,大多数菌株能在较宽的温度、盐度和pH范围内生长。 相似文献
586.
Yanbiao Liu Jinhua Li Baoxue Zhou Jing Bai Qing Zheng Jialing Zhang Weimin Cai 《Environmental Chemistry Letters》2009,7(4):363-368
Self-organized, well-crystallized and high aspect-ratio TiO2 nanotube arrays (TNAs) have been prepared by anodic oxidation in dimethyl sulfoxide (DMSO) containing 5 wt% HF at 40 V (vs.
Pt). A 50 h anodization results in a nanotube arrays approximately 19.4 μm in length, referred as long tube. As a comparison,
the short titania nanotube arrays, about 500 nm in length, was obtained by anodization in HF aqueous solution, referred as
short tube. Different characterization techniques (viz. FESEM, TEM, XRD and DRS) are used to study the nanotubular microstructure.
The morphology of the nanotube electrodes shows an evident influence on their photocatalytic (PC) and photoelectrochemical
reactivity. The long tube reveals enhanced photocurrent response and PC degradation efficiency of organic compounds. The kinetic
constant of PC degradation of methylic orange (MO) for long tube electrode is found 1.55 times as high as the short tube.
A significant photoelectrochemcial synergetic effect in MO degradation was observed on the long tube electrode and the photoelectrocatalytic
(PEC) degradation of MO on long tube is 27% higher than its PC process. 相似文献
587.
以重庆市四面山4种森林群落为研究对象,选取林冠截留率、林地土壤毛管孔隙度、林地土壤非毛管孔隙度和林地0~20 cm土壤抗冲刷系数为分析指标,运用灰色关联度法对4种森林群落的面源污染控制功能进行研究.结果表明:在4种森林群落中作为天然林的楠竹林灰关联度值最大为0.887 7,面源污染控制功能最好,其次是人工阔叶林(0.7794)和人工混交林(0.6992),人工针叶林(0.636 1)面源污染防控能力相对较弱.在人工林方面,阔叶林灰关联度值最大为0.7794,面源污染防控能力最好,其次是针阔混交林(0.699 2),针叶林灰关联度值最低为0.636 1,其面源污染防控能力较弱. 相似文献
588.
循环经济与低碳经济都是要求人类在考虑生产和消费时,还需考虑自然生态系统的承载能力,尽可能地节约自然资源,不断提高固体废物的利用效率,在固体废物减量化、资源化、无害化过程中,降低化石能源消耗,减少温室气体排放活动,建设资源节约型、环境友好型社会,促进人与自然的和谐发展。 相似文献
589.
自2016年《土壤污染防治行动计划》实施以来,随着污染土壤修复工作的推进,因场地污染类型、污染程度以及土地规划类型等因素的不同,如何筛选出科学、合理、高效、低耗的修复技术显得尤为重要。在此背景下场地修复决策系统应运而生,即通过输入修复过程所有要素并结合专家判断,修复决策系统运算得出最佳修复模式,为管理者提供决策依据。本文在分析国内外修复决策系统的发展现状、特点以及优势和劣势基础上,以焦化污染场地为例拟开发基于WebGIS的污染场地修复辅助决策系统,以找出适合我国污染场地修复决策的模式,为从事相关工作的研究者和决策者提供参考。 相似文献
590.