全文获取类型
收费全文 | 142篇 |
免费 | 9篇 |
国内免费 | 14篇 |
专业分类
废物处理 | 3篇 |
环保管理 | 93篇 |
综合类 | 39篇 |
基础理论 | 11篇 |
污染及防治 | 13篇 |
评价与监测 | 4篇 |
灾害及防治 | 2篇 |
出版年
2024年 | 1篇 |
2022年 | 3篇 |
2021年 | 2篇 |
2020年 | 8篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 6篇 |
2013年 | 1篇 |
2012年 | 4篇 |
2011年 | 6篇 |
2010年 | 7篇 |
2009年 | 9篇 |
2008年 | 4篇 |
2007年 | 9篇 |
2006年 | 6篇 |
2005年 | 7篇 |
2004年 | 7篇 |
2003年 | 1篇 |
2002年 | 6篇 |
2001年 | 5篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1973年 | 1篇 |
1972年 | 3篇 |
1971年 | 4篇 |
排序方式: 共有165条查询结果,搜索用时 265 毫秒
161.
Eric G. Reichard John D. Bredehoeft 《Journal of the American Water Resources Association》1984,20(6):929-939
This study describes and demonstrates two alternate methods for evaluating the relative costs and benefits of artificial groundwater recharge using percolation ponds. The first analysis considers the benefits to be the reduction of pumping lifts and land subsidence; the second considers benefits as the alternative costs of a comparable surface delivery system. Example computations are carried out for an existing artificial recharge program in Santa Clara Valley in California. A computer groundwater model is used to estimate both the average long term and the drought period effects of artificial recharge in the study area. For the example problem, the benefits of reduced average annual pumping lifts and reduced incremental subsidence are greater than the total costs of continuing the existing artificial recharge program. Benefits for reduced subsidence are strongly dependent on initial aquifer conditions. The second analysis compares the costs of continuing the artificial recharge program with the costs of a surface system which would achieve the same hydraulic effects. Results indicate that the costs of artificial recharge are considerably smaller than the alternative costs of an equivalent surface system. In evaluating a particular program, consideration should also be given to uncertainties in future supplies and demands for water as well as to the probability of extreme events such as droughts. 相似文献
162.
南水北调水进京后部分水源将通过潮白河河道人工回灌至地下储存,以涵养严重亏损的地下水资源.为研究回灌过程中的水岩相互作用,本研究在潮白河河道开展了现场淋溶试验,通过测试分析K+、Na+、Ca2+、Mg2+、HCO-3、Cl-、SO2-4、NH3-N、NO2-N、NO3-N、F-、溶解性总固体、总硬度、p H值等水质指标的变化特征,从水岩相互作用的角度探讨了水质变化机理,为南水北调水资源的合理利用提供技术支撑.试验结果表明,回灌水源在包气带介质运移过程中物理淋溶现象显著,试验过程中发生了阳离子交换吸附作用、氨氮解析和硝化作用等一系列的化学反应. 相似文献
163.
城市污水地下回灌深度处理技术 总被引:11,自引:0,他引:11
以城市污水地下回灌为回用目的,研究了不同的污水深度处理工艺,并着重研究了去除二级生物处理出水中有机物的处理工艺.研究结果表明,采用臭氧氧化和粉末活性炭预处理后再经土壤渗滤回灌,可大大改善水质,水中溶解性有机碳浓度可降至3mg/L以下,通过静态吸附实验选出了适于处理二级出水的粒状活性炭,并运用ADSA软件对有机物在活性炭上的吸附行为进行分析.将活性炭的动态实验同混凝、过滤结合起来,研究不同组合工艺对有机物的去除效果,筛选出了适于城市污水处理厂二级出水地下回灌的预处理工艺,其出水溶解性有机碳浓度低达3~4.5mg/L以下. 相似文献
164.
Tony Falkland 《Natural resources forum》1999,23(3):245-260
The water resources of most small island developing states (SIDS) are often very limited and require special consideration to ensure that they are developed and managed in a sustainable manner. Many small islands, typically located in the humid tropics, have no surface water resources and rely on limited groundwater resources in the form of thin freshwater lenses. The exposed location of small islands makes them particularly vulnerable to natural disasters such as cyclones, floods and droughts. Pollution from population centres and from agricultural and other activities is an increasing problem. This article provides an overview of the water resources of small islands, and the main problems and issues related to water resources. Some suggested solutions, based on practical experiences, are offered for water resource assessment and monitoring programmes, and water resource development. Water resource policy, planning and management issues are also addressed, and suggested approaches for resolving some of the major water resource problems presented. 相似文献
165.
Wei Fan Qi Li Mingxin Huo Xiaoyu Wang Shanshan Lin 《Frontiers of Environmental Science & Engineering》2020,14(4):63