全文获取类型
收费全文 | 6013篇 |
免费 | 420篇 |
国内免费 | 2227篇 |
专业分类
安全科学 | 526篇 |
废物处理 | 328篇 |
环保管理 | 430篇 |
综合类 | 3720篇 |
基础理论 | 1013篇 |
环境理论 | 1篇 |
污染及防治 | 1771篇 |
评价与监测 | 286篇 |
社会与环境 | 314篇 |
灾害及防治 | 271篇 |
出版年
2024年 | 25篇 |
2023年 | 121篇 |
2022年 | 340篇 |
2021年 | 286篇 |
2020年 | 285篇 |
2019年 | 225篇 |
2018年 | 245篇 |
2017年 | 290篇 |
2016年 | 284篇 |
2015年 | 381篇 |
2014年 | 417篇 |
2013年 | 573篇 |
2012年 | 532篇 |
2011年 | 556篇 |
2010年 | 402篇 |
2009年 | 412篇 |
2008年 | 449篇 |
2007年 | 372篇 |
2006年 | 316篇 |
2005年 | 237篇 |
2004年 | 183篇 |
2003年 | 198篇 |
2002年 | 174篇 |
2001年 | 153篇 |
2000年 | 166篇 |
1999年 | 152篇 |
1998年 | 162篇 |
1997年 | 140篇 |
1996年 | 148篇 |
1995年 | 104篇 |
1994年 | 79篇 |
1993年 | 71篇 |
1992年 | 64篇 |
1991年 | 35篇 |
1990年 | 21篇 |
1989年 | 18篇 |
1988年 | 12篇 |
1987年 | 10篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1975年 | 1篇 |
排序方式: 共有8660条查询结果,搜索用时 836 毫秒
491.
MCM-41介孔分子筛的合成及其对铜离子的吸附性能简 总被引:1,自引:0,他引:1
以微硅粉为硅源,CTAB和PEG-6000为模板剂,合成MCM-41介孔分子筛。采用XRD、N2吸附-脱附曲线、FTIR以及TEM表征了其结构、比表面积、孔径分布及晶体形貌,并且以该样品为吸附剂,对含Cu2+的溶液进行了静态吸附实验。结果表明,以微硅粉为硅源成功合成了具有典型六方排列孔道结构的MCM-41,其比表面积为869.5 m2/g,孔容为0.97 cm3/g,平均孔径为3.3 nm;溶液pH为5~6时,MCM-41对Cu2+的去除效果最好;MCM-41对Cu2+的最大吸附吸附容量36.3 mg/g;MCM-41对Cu2+的吸附性能符合Langmuir吸附方程的特征。动力学研究表明,该过程符合准二级动力学模型。 相似文献
492.
493.
采用酸碱预处理乌梁素海典型沉水植物龙须眼子菜和挺水植物芦苇,通过厌氧发酵动力学分析、还原糖变化及微观结构解析,研究酸碱预处理对水生植物厌氧发酵联产氢气-甲烷的影响。实验结果表明,酸碱预处理后水生植物厌氧发酵联产氢气-甲烷两阶段累积产气量、氢气及甲烷含量均显著提高,酸处理效果优于碱处理。采用0.5 mol/L HCl预处理龙须眼子菜效果最佳,最大氢气、甲烷含量分别达42.65%和52.82%,产氢气速率为4.118 mL/h,产甲烷速率最高达14.199 mL/h。芦苇经1 mol/L HCl预处理效果最佳,最高氢气、甲烷含量分别为32.22%和65.26%。扫描电镜微观结构分析表明,酸碱预处理可显著破坏芦苇、龙须眼子菜的纤维素结构,有效增加植物与微生物接触面积,有利于厌氧发酵联产氢气-甲烷工艺的快速启动和稳定运行。 相似文献
494.
Dian Yu Jing Yang Ting Li Jianfang Feng Qiming Xian Jiping Zhu 《Environmental science and pollution research international》2015,22(9):6601-6609
The occurrence and spatial distribution of dechloranes including mirex, dechlorane plus (DP), dechlorane (Dec) 602, Dec 603, and Dec 604 in surficial sediments of Lake Taihu were investigated in this study. The concentrations of mirex and DP ranged from below detection limit (BDL) to 1.29 ng g?1 dw and 0.051 to 2.10 ng g?1 dw, respectively. Dec 602, Dec 603, and Dec 604 on the other hand, were BDL in any of the samples. The contamination levels of DP were higher than that of Mirex at 21 of all 22 sampling sites. Levels of mirex and DP in the lake sediments were correlated when an extremely high mirex value was removed. Both mirex and DP levels were correlated with the amount of organic matters in the sediment samples. Spatial distribution of mirex and DP suggested that these two chemicals in the lake had similar input sources except for one site. Comparison to previously reported flame retardants’ levels in the sediments shows that DP levels were similar with the levels of tetrabromobisphenol A, hexabromocyclododecane but lower than PBDEs and organophosphates levels in Lake Taihu. The higher levels in the north-east part of Lake Taihu adjacent to two major cities: Wuxi and Suzhou, indicated that city effluent might be a major source for DP contamination in the lake. 相似文献
495.
496.
497.
498.
强化垂直流可渗透反应墙处理渗滤液污染物 总被引:1,自引:0,他引:1
针对垃圾渗滤液污染物组分多、处理难度大、可生化性差的特点,基于可渗透反应墙(PRB)被动修复技术,通过多种填料的组合构建三重垂直流PRB强化的砂箱模型,对垃圾渗滤液进行连续动态处理研究。实验结果表明,填料的组合顺序对强化PRB系统净化能力有较大的影响,由无烟煤、沸石、钢渣依次组成的强化垂直流PRB系统(2#砂箱)对NH+4-N、NO-3-N、NO-2-N、COD、PO3-4-P的平均去除率分别为96.12%、30.36%、75.24%、39.03%和30.47%,处理效果明显好于相同条件下依次由无烟煤、钢渣、沸石组成的强化垂直流PRB系统(1#砂箱)。与常规PRB处理系统相比,强化垂直流可渗透反应墙系统可实现垃圾渗滤液中多种污染物同步有效去除,是极具发展潜力的新型技术。 相似文献
499.
Guangyong Zhu Xian Zhu Zuobing Xiao Rujun Zhou Yalun Zhu Xueliang Wan 《Journal of Material Cycles and Waste Management》2014,16(3):546-556
Biomass is recognized as an important solution to energy and the environmental problems related to fossil fuel usage. The rational utilization of biomass waste is important not only for the prevention of environmental issues, but also for the effective utilization of natural resources. Pyrolysis and hyrolysis in subcritical water are promising processes for biomass waste conversion. This paper deals with hydrolysis and pyrolysis of peanut shells. Hydrolysis and pyrolysis kinetics of peanut shell wastes were investigated for the in-depth exploration of process mechanisms and for the control of the reactions. Hydrolysis kinetics was conducted in a temperature range of 180–240 °C. A simplified kinetic model to describe the hydrolysis of peanut shells was proposed. Hydrolysis activation energy as well as the pre-exponential factor was determined according to the model. The target products of peanut shell hydrolysis, reducing sugars, can reach up to 40.5 % (maximum yield) at 220 °C and 180 s. Pyrolysis characteristics were investigated. The results showed that three stages appeared in this thermal degradation process. Kinetic parameters in terms of apparent pyrolysis activation energy and pre-exponential factor were obtained by the Coats–Redfern method. 相似文献
500.
The quantity of vehicles has increased rapidly in recent years in China; however, the recycling of End of Life Vehicles (ELV) faces several problems and barriers including the collection difficulty and the environmental pollution caused by improper dismantling. In this paper, based on analysis of the basic situation regarding management and recycling of ELV in China, the ELV flow was introduced, and the potential ELV quantity was estimated. The current management regulations and policies were summarized, and dismantling and pollution control technologies for ELV recycling were introduced, too. It was suggested that with the rapid growth of ELV quantities, more regulations will be enacted, and the recycling network will be more effective; the dismantling technology and pollution control measures will be upgraded, and the recycling and remanufacturing industries will be more combined. The government should pay more attention to improve the management and supervision of, and encourage the development of, high level enterprises. 相似文献