全文获取类型
收费全文 | 281篇 |
免费 | 33篇 |
国内免费 | 55篇 |
专业分类
安全科学 | 36篇 |
废物处理 | 4篇 |
环保管理 | 58篇 |
综合类 | 170篇 |
基础理论 | 36篇 |
污染及防治 | 28篇 |
评价与监测 | 7篇 |
社会与环境 | 7篇 |
灾害及防治 | 23篇 |
出版年
2023年 | 5篇 |
2022年 | 13篇 |
2021年 | 9篇 |
2020年 | 13篇 |
2019年 | 6篇 |
2018年 | 8篇 |
2017年 | 8篇 |
2016年 | 13篇 |
2015年 | 13篇 |
2014年 | 7篇 |
2013年 | 18篇 |
2012年 | 28篇 |
2011年 | 23篇 |
2010年 | 23篇 |
2009年 | 18篇 |
2008年 | 19篇 |
2007年 | 19篇 |
2006年 | 17篇 |
2005年 | 9篇 |
2004年 | 5篇 |
2003年 | 9篇 |
2002年 | 8篇 |
2001年 | 12篇 |
2000年 | 12篇 |
1999年 | 5篇 |
1998年 | 10篇 |
1997年 | 7篇 |
1996年 | 8篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
排序方式: 共有369条查询结果,搜索用时 15 毫秒
301.
DING Yu MIAO Jin-lai LI Guang-you WANG Quan-fu KAN Guang-feng WANG Guo-dong 《环境科学学报(英文版)》2005,17(4):667-671
Glutathione(GSH) and GSH-related enzymes play a great role in protecting organisms from oxidative damage. The GSH level and GSH-related enzymes activities were investigated as well as the growth yield and malonyldialdehyde(MDA) content in the Antarctic ice microalga Chlamydomonas sp. ICE-L exposure to the different cadmium concentration in this paper. The results showed that the higher concentration Cd inhibited the growth of ICE-L significantly and Cd would induce formation of MDA. At the same time, it is clear that GSH level, glutathione peroxidases(GPx) activity and glutathione S-transferases(GST), activity were higher in ICE-L exposed to Cd than the control. But GR activity dropped notably when ICE-L were cultured in the medium containing Cd. Increase of GSH level, GPx and GST activities acclimate to oxidative stress induced by Cd and protect Antarctic ice microalga Chlamydomonas sp. ICE-L from toxicity caused by Cd exposure. These parameters may be used to assess the biological impact of Cd in the Antarctic pole region environment. 相似文献
302.
303.
作用于斜坡结构物上海冰荷载的三维计算 总被引:2,自引:0,他引:2
作用于斜坡结构物上的海冰荷载包括两部分:使冰板发生弯曲破坏的分力和使破裂冰块沿斜面上爬的分力。当结构物迎冰面的宽度小于冰的宽度时,冰与结构物之间的相互作用为三维问题。本文分析冰板作用于结构物时的三维破坏机理,建立一个通用的三维计算模式,并计算了给定的海冰条件作用于斜坡结构物上的冰荷载。 相似文献
304.
305.
利用电子显微镜和银染技术研究HTO对莱哈衣藻核仁纤维区的辐射效应。结果显示:分裂间期衣藻核仁纤维区为由细线样结构组成的索状结构;衣藻细胞在含低剂量HTO(370kBq/mL)培养基培养1400h以后,间期核仁纤维区索状结构变得膨松,体积增大;经含中剂量HTO(3700kBq/mL)培养1400h以后,纤维区索状结构明显解体,轮廓变得不清晰;经含高剂量HTO(37000kBq/mL)培养基培养1400h后,纤维区索状结构完全解体,呈现出松散的细线样结构,同时参与rRNA合成的一种酸性蛋白明显减少,结果表明,衣藻细胞分裂间期的核仁纤维区对HTO的辐射作用是敏感的。 相似文献
306.
307.
纳米材料以其独特的性质,在光学、化工、环保、陶瓷、生物和医药等诸多方面具有广泛的应用价值。而纳米金属材料的表面包覆和修饰是21世纪纳米材料科学的一个新的研究方向。文中比较系统地综述了核-壳型纳米双金属微粒制备方法的研究进展,包括还原化学镀法、共沉淀法等,简要分析了各类制备方法的基本原理、特点及适用的范围,并在此基础上讨论了核-壳型纳米双金属粉末的未来研究发展方向。 相似文献
308.
Photodegradation of halobenzenes in water ice 总被引:3,自引:0,他引:3
Klán P Del Favero D Ansorgová A Klánová J Holoubek I 《Environmental science and pollution research international》2001,8(3):195-200
Results from the photolysis of o, p-dichlorobenzene, bromobenzene, and p-dibromobenzene in water ice are reported. All phototransformations appeared to be based on dehalogenation, coupling, and rearrangement reactions in ice cavities. No photosolvolysis products, i.e. products from intermolecular reactions between organic and water molecules, were found. Many of the products were very toxic substances of a high environmental risk, such as PCBs. The results support our model, in which secondary, very toxic, pollutants can be formed in ice, snow, and atmospheric ice particles from primary pollutants through the action of solar irradiation. The photoproducts may be released to the environment by ice melting and evaporation. 相似文献
309.
ABSTRACT: The simple, empirical degree-day approach for calculating snowmelt and runoff from mountain basins has been in use for more than 60 years. It is frequently suggested that the degree-day method be replaced by the more physically-based energy balance approach. The degree-day approach, however, maintains its popularity, applicability, and effectiveness. It is shown that the degree-day method is reliable for computing total snowmelt depths for periods of a week to the entire snowmelt season. It can also be used for daily snowmelt depths when utilized in connection with an adequate snowmelt runoff model for computing the basin runoff. The degree-day ratio is shown to vary seasonally as opposed to being constant as is often assumed. Additionally, in order to evaluate the degree-day ratio correctly, the changing snow cover extent in a basin during the snowmelt season must be taken into account. It is also possible to combine the degree-day approach with a radiation component so that short time interval (<24 hours) computations of snowmelt depth can be made. When snowmelt input is transformed to basin output (runoff) by a snowmelt runoff model, there is little difference between the degree-day approach and a radiation-based approach. This is fortuitous because the physically-based energy balance models will not soon displace the degree-day methods because of their excessive data requirements. 相似文献
310.
Christopher R. Ellis Heinz G. Stefan 《Journal of the American Water Resources Association》1991,27(6):903-914
ABSTRACT: Artificial aeration is used to prevent winter fish kills due to oxygen depletion in ice-covered lakes. Conventional aeration by air bubble plumes and other techniques usually mixes the water column and produces hazardous open water in the ice cover. A non-mixing winter lake aeration system which creates a fish refuge was designed and field tested to oxygenate the water and maintain water temperature stratification in a lake such that no open water is created. The system uses a cascade aerator and has a design discharge and dissolved oxygen input rate of 85 1/s and 70 kg/d, respectively. Aerated water is discharged near mid-depth with minimum disturbance of the ambient water through a specially designed diffuser. The system was tested in a shallow 3 m deep lake of 17 ha surface area during two winters and was found to perform as expected. Significant photosynthetic production of dissolved oxygen under the ice-cover was also observed during snow-free periods. 相似文献