全文获取类型
收费全文 | 6184篇 |
免费 | 405篇 |
国内免费 | 1912篇 |
专业分类
安全科学 | 412篇 |
废物处理 | 773篇 |
环保管理 | 990篇 |
综合类 | 4324篇 |
基础理论 | 450篇 |
环境理论 | 1篇 |
污染及防治 | 1372篇 |
评价与监测 | 119篇 |
社会与环境 | 42篇 |
灾害及防治 | 18篇 |
出版年
2024年 | 16篇 |
2023年 | 88篇 |
2022年 | 116篇 |
2021年 | 166篇 |
2020年 | 171篇 |
2019年 | 145篇 |
2018年 | 122篇 |
2017年 | 145篇 |
2016年 | 194篇 |
2015年 | 214篇 |
2014年 | 347篇 |
2013年 | 396篇 |
2012年 | 458篇 |
2011年 | 447篇 |
2010年 | 364篇 |
2009年 | 420篇 |
2008年 | 327篇 |
2007年 | 540篇 |
2006年 | 632篇 |
2005年 | 479篇 |
2004年 | 411篇 |
2003年 | 405篇 |
2002年 | 336篇 |
2001年 | 297篇 |
2000年 | 261篇 |
1999年 | 247篇 |
1998年 | 173篇 |
1997年 | 137篇 |
1996年 | 100篇 |
1995年 | 92篇 |
1994年 | 80篇 |
1993年 | 55篇 |
1992年 | 31篇 |
1991年 | 25篇 |
1990年 | 10篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1986年 | 7篇 |
1984年 | 2篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1971年 | 3篇 |
1970年 | 2篇 |
排序方式: 共有8501条查询结果,搜索用时 15 毫秒
931.
This paper presents result from an economic and technical point of view evaluation study, which has sought to establish the potential for replacing well-water that is currently used at the Piaggio industrial plant in Pontedera with recycled wastewater. The study is based upon a pilot wastewater treatment plant, which has been used to test wastewater treatment processes and to compare with achieved quality of recycled waters with that of water drawn on-site from physical/chemical pre-treatment and end with a reverse osmosis and air stripping stage. However, after the physical/chemical pre-treatment, the first option uses oxidation with ozone followed by activated carbon filtration, whereas the second method uses ultrafiltration. The first method is more effective at reducing chemical oxygen demand (COD) whereas the second method is more effective in removing bacteria. Nonetheless, both methods deliver water for re-use of a quality comparable with or better than that of well-water. In principle, the reverse osmosis permeate from either process could be re-used in all production phases at the industrial plant. However, the method base upon oxidation with ozone followed by activated carbon filtration is preferred, because, the process is simpler and continuous. The economic analysis of this process gives an estimated cost of Euro 0.55 per m3 for treated water. This compares favorably with other treatment processes and with the cost of other forms of water supply, which are projected to increase in any case. 相似文献
932.
氯化法处理医院废水的研究 总被引:2,自引:0,他引:2
介绍了次氯酸钠法和液氯法2种目前常用的处理医院废水的方法.对2家医院的废水处理过程进行了测试及实验研究.结果表明,这2家医院的废水处理后细菌总数和余氯量未达到国家规定的排放标准.主要原因是加氯量不精确,加氯后的停留时间不足,不能有效杀死废水中的病菌.对加氯量和停留时间的实验研究表明,每吨医院废水中次氯酸钠和液氯的最佳投入量分别为90 g和9 g,加氯后的停留时间不少于60min. 相似文献
933.
天津市城区暴雨沥涝仿真模拟系统的研究 总被引:11,自引:3,他引:11
天津市位于黄河水系尾闾,是我国北方重要的工业和港口城市。该市历史上一直遭受洪涝灾害的威胁,加之近几年市区范围不断扩大,不透水面积增加,排水能力远远不能适应城市的发展要求,城市沥涝问题日趋严重。为了掌握天津市暴雨沥涝的规律,减轻洪涝灾害对该市的影响,作者利用二维不恒定流水动力学模型和计算机信息管理及图形技术,采用Power Station Fortran 4.0和Visual Basic5.0编程语言,在Widows98环境下开发了天津市暴雨沥涝仿真模拟系统。该系统首次实现了从城市暴雨预报、监测到城市暴雨沥涝仿真模拟的研究, 不仅能够处理实时的不均匀的降雨信息,还能处理数值预报模型的预报降雨信息。系统的信息前后处理模块用图形方式管理仿真模型的各类信息,方便用户显示、查询和修改,使系统更加完整、实用。 相似文献
934.
污水的人工湿地系统处理技术 总被引:9,自引:4,他引:9
本文通过了人工湿地系统处理技术及其发展、应用的综述介绍,并以深圳白泥坑人工湿地处理系统工程与二级生化污水处理厂相比较。结果表明,用人工湿地系统处理污水具有投资少,耗能低,运行简便等优点,提出研究、推广应用湿地系统技术处理污水的建议,可供环境保护科研及管理人员参考。 相似文献
935.
本文论了宰屠废水的水质特征,我国屠宰废水处理的主要工艺。侧重阐述了生物法与“组合法”处理屠宰废水的运行机理与处理效果。在对比了这两种方法各自优缺点的基础上,作者推荐采用“厌氧(兼氧)-好氧生物法”。 相似文献
936.
Adnan Shindala 《Journal of the American Water Resources Association》1972,8(5):987-998
ABSTRACT. A comprehensive evaluation of current techniques for nutrients, nitrogen and phosphorus, removal from wastewaters was conducted by the author under a research project supported by the Office of Water Resources Research, Department of the Interior. The object of this study was to compile and evaluate, under one cover, the available information on current techniques for removing nutrients from wastewaters with emphasis on type of treatment (physical, chemical, biological, or any combination); economics (capital and operating costs); efficiencies, and applications. Due to space limitations, only a brief summary of this work is presented in this paper. A copy of the completion report may be obtained from the author. 相似文献
937.
Jack E. McKee 《Journal of the American Water Resources Association》1971,7(4):740-749
ABSTRACT There are several possible ways in which wastewater from municipalities may be reclaimed and reused so as to minimize the need for imported water in North Central Texas. The rationale for reuse is enhanced by the fact that new water quality requirements in the Trinity River system will necessitate a very high degree of treatment at municipal sewage plants, just for discharge to surface streams. The largest potential market for municipal effluent is the steam-electric power industry. Within the next decade the generating capacity for electric power in North Central Texas will have to be more than doubled to meet increasing demand. Adequate supplies of condenser cooling water for such expansion will be difficult to obtain and assure. New large power stations might advantageously be located adjacent to municipal wastewater treatment plants, to utilize effluent as make-up water for cooling towers. Experience elsewhere has shown that well-treated wastewater can be used for cooling tower make-up with a minimum of trouble, with a considerable saving in overall cost, and with conservation of pristine water for other uses. 相似文献
938.
Clifford W. Randall Bruce S. Huloher Paul H. King 《Journal of the American Water Resources Association》1970,6(4):648-660
The activated sludge process can remove significant amounts of phosphorus from sewage, but the removal efficiency is usually significantly reduced by the release of phosphate back to solution during subsequent treatment steps. This research presents a study of soluble phosphate release from activated sludge with emphasis on defining the factors that affect such release and the actual release mechanisms. Laboratory units were used for experimental purposes. The experiments were designed to study the relationship between soluble phosphate release and various environmental factors such as redox potential (ORP), dissolved oxygen (DO), pH, solids concentration, solids destruction, and sulfate salt addition. The effect of substrate utilization on phosphate uptake and the relationship between uptake characteristics and subsequent phosphate release were also studied. The results show that some phosphate storage occurs during aerobic substrate utilization. Following substrate utilization, activated sludge phosphate release is directly related to the amount of biological stress the organisms are subjected to, and the mechanism of release is primarily cell lysis. The phosphate released per unit sludge under anoxic conditions is relatively constant. Under normal environmental conditions, neither ORP or pH change have a significant affect on phosphate release. 相似文献
939.
940.
为了探讨火电厂除灰水中的粉煤灰(含炉渣)对炼油厂含碱污水中石油类、COD(cr)等污染物的吸附处理效果,根据某单位现场情况,将炼油厂含碱污水送入火电厂除灰沟→经充分混合排入储灰场→并经长时间沉降分离的流程进行模拟试验,结果表明:由于粉煤灰的吸附作用,显著降低了炼油厂含碱污水中的石油类、COD(cr)、挥发酚、碳化匕物等污染物。 相似文献