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排序方式: 共有1086条查询结果,搜索用时 656 毫秒
961.
John W. Labadie John M. Shafer Robert Aukerman 《Journal of the American Water Resources Association》1980,16(3):477-485
ABSTRACT: There is considerable misconception about the dangers of opening to a recreating public in great need of additional open areas. A systematic procedure for identifying the factors essential to the selectio, planning, and management of reservoirs for recreation is described. A detailed case study conducted by an interdisciplinary project team is presented to demonstrate the feasibility fo maintaining storage levels in recreation-conductive high country reseroirs without unduly injuring downstram water users. The idea is to trade water with reservoirs having less recreation potential. The optimal means of doing this is found via a river basin simulation model with quasi-optimizing capability. Results of the case study show that this strategy is indeed feasible. Applicable to other areas may require analysis of tradeoffs if at least some damage to downstream users is unavoidable. 相似文献
962.
Thomas C. Brown Benjamin L. Harding William B. Lord 《Journal of the American Water Resources Association》1988,24(4):801-814
ABSTRACT: This study examined the disposition of streamflow increases that could be created by vegetation management on forest land along the upper reaches of the Colorado River. A network optimization model was used to simulate water flow, storage, consumptive use, and loss within the entire Colorado River Basin with and without the flow increases, according to various scenarios incorporating both current and future consumptive use levels as well as existing and potential institutional constraints. Results indicate that very little of the flow increases would be consumptively used at current use levels, or even at future use levels, if water allocation institutions remain unchanged. Given future use levels and economically based water allocation institutions, up to one-half of the flow increases could be consumptively used. The timing of streamflow increases, and the institutional constraints on water allocation, often limit the potential for consumptive use of flow increases. 相似文献
963.
M. B. Bayer 《Journal of the American Water Resources Association》1974,10(2):311-317
ABSTRACT: This paper explores the use of nonlinear programming in river basin water quality modelling. Applications recently reported in the literature, along with the author's experience with nonlinear programming, are reviewed. Results obtained using nonlinear programming are compared with the results obtained by other researchers using linear and dynamic programming to solve river basin water quality optimization problems. These water quality models have objective functions with continuous first partial derivatives, several inequality and variable bound constraints, and are of the form: minizie Σj=nj=1Yj(Xj) subject to Σj=nj=1aijXjbi, i=1,2, …, m cjXjdj, j= 1,2, …, n The variable Xi is the maximum allowable ratio of the BOD (biochemical oxygen demand) of the effluent outflow to the BOD of the wastewater inflow for treatment plant j, in the range cj to dj. The aijd and bi are constants in the DO (dissolved oxygen) and BOD constraints. The resuks show, given certain assumptions about the data, that nonlinear programming is a better solution method for these problems than is either linear programming or dynamic programming. 相似文献
964.
中国七大流域水系与洪涝的分维及其关系研究 总被引:9,自引:1,他引:9
本文在GIS技术的支持下,应用分形理论首先系统地计算了中国七大流域水系以及各流域洪涝的分维,其次对七大流域水系分维与各流域洪涝分维之间的可能关系进行了探讨。主要结论如下:(1)分维是表征洪涝发生特征的较好的参量,其蕴涵着洪涝发生次数,周期等丰富信息。(2)一般而言,在研究时段某流域洪涝发生的次数较多,则相应该流域洪涝的分维较大,反之亦然;(3)一般而言,当某一流域水系分维相对较小时,则相应该流域洪涝的分维相对较大,反之亦然。 相似文献
965.
本文采用建造与构造相互作用的观点,从沉积学、构造学和锰质来源三个方面研究了位于滇西北地区的优质富锰矿的唯一矿床——鹤庆锰矿。鹤庆锰矿产出于晚三叠世卡尼一诺利期剧烈下陷的一个台沟环境。该台沟盆地的生成与西缘台褶带卡尼一诺利中期区域性南北向深大断裂带的右行走滑拉张活动有直接的关系。成矿经由以玄武岩浆活动为代表的地热系统对盆地基底矿源层中锰质的萃取、生物吸收以热水喷流形式进入盆地的矿质而成矿的多阶段过程;区域性深大断裂、玄武岩浆活动、矿源层三者的有效时空组合是形成扬子地块西缘卡尼一诺利期优质富锰矿的控制因素。结合区域地史资料分析,认为在滇西北成群产出优质富锰矿的可能性很小。 相似文献
966.
遂昌柘岱口一湖山北东向断裂带在晚侏罗世至晚白垩世晚期经历了多期次、不同性质的活动,断裂活动与该地区两个大规模萤石矿田的形成关系密切。晚侏罗世晚期到早白垩世早期断裂活动表现为拉张松驰作用,为黄沙腰萤石矿田的形成提供了导矿和容矿构造空间,萤石矿主体赋存于北东向断裂带内。晚白垩世晚期,断裂活动表现为挤压环境,断裂带具有导矿作用,矿体受控于派生之北西向次级断裂内,湖山萤石矿田的形成具有此特征。 相似文献
967.
云南小江流域的泥石流灾害 总被引:7,自引:0,他引:7
云南东北部的小江流域是我国泥石流灾害严重地区。本文就其形成原因、运动特征、灾害简况和防治实例作了阐述,并结合生物措施与工程措施的情况,概括出“稳”、“拦”、“排”的治理对策。 相似文献
968.
This paper discusses the development and use of the first version of the WFD Explorer (WFDE), a decision support system (DSS) for the implementation of the Water Framework Directive in the Netherlands. The paper's aim is to increase our understanding of the development process of DSSs and the impact the development process has on the perceived validity and usefulness of the DSS. In other words, whether the DSS is seen as representing reality correctly and as fit for purpose and user-friendly. Contrary to the expectations, the WFDE was not used much. Tensions in the development process over the intended users, the level of analysis, the level of ambition and the type of expertise to be included have contributed to doubts over its usefulness and validity. These tensions reflect general tensions in river basin management: different actors will prefer different approaches, and none of these is objectively the best. Whereas guidelines for the development of DSSs can increase awareness of these tensions, resolving these tensions is beyond the power of the developers to control. Guidelines have their use, but also their limitations, simply because they are general and circumstances differ from case to case. 相似文献
969.
太湖流域农村公众环境意识案例研究 总被引:14,自引:1,他引:13
环境意识属上层建筑范畴,对环境行为具有指导意义。针对太湖流域日益严重的农业非点源污染,提高农村公众环境意识是控制该区水污染的主要措施之一。首次选取无锡市大浦镇14个行政村2.7万人为抽样框进行农村公众环境意识调查。结果表明:①居民对水环境污染的原因有了初步的认识,但与实际有明显偏差;②浅层次的局部的“日常生活环保型”环境意识依然存在;③居民在环保行为上为“政府依赖型”,整体参与环保意识不强;④居民获取环保信息渠道单一,政府对主要的信息发布渠道重视不足;⑤2003年该镇居民总支付意愿为55.3~98.2万元。 相似文献
970.