全文获取类型
收费全文 | 2096篇 |
免费 | 123篇 |
国内免费 | 103篇 |
专业分类
安全科学 | 119篇 |
废物处理 | 28篇 |
环保管理 | 572篇 |
综合类 | 755篇 |
基础理论 | 222篇 |
环境理论 | 1篇 |
污染及防治 | 36篇 |
评价与监测 | 30篇 |
社会与环境 | 457篇 |
灾害及防治 | 102篇 |
出版年
2024年 | 5篇 |
2023年 | 28篇 |
2022年 | 28篇 |
2021年 | 48篇 |
2020年 | 42篇 |
2019年 | 39篇 |
2018年 | 32篇 |
2017年 | 83篇 |
2016年 | 82篇 |
2015年 | 72篇 |
2014年 | 52篇 |
2013年 | 109篇 |
2012年 | 143篇 |
2011年 | 171篇 |
2010年 | 118篇 |
2009年 | 96篇 |
2008年 | 80篇 |
2007年 | 127篇 |
2006年 | 120篇 |
2005年 | 96篇 |
2004年 | 88篇 |
2003年 | 80篇 |
2002年 | 82篇 |
2001年 | 49篇 |
2000年 | 59篇 |
1999年 | 46篇 |
1998年 | 53篇 |
1997年 | 42篇 |
1996年 | 22篇 |
1995年 | 38篇 |
1994年 | 24篇 |
1993年 | 23篇 |
1992年 | 24篇 |
1991年 | 10篇 |
1990年 | 14篇 |
1989年 | 3篇 |
1988年 | 9篇 |
1983年 | 5篇 |
1982年 | 12篇 |
1980年 | 10篇 |
1979年 | 9篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 6篇 |
1975年 | 4篇 |
1974年 | 6篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1971年 | 7篇 |
1970年 | 2篇 |
排序方式: 共有2322条查询结果,搜索用时 827 毫秒
551.
Anthony Donigian W. Henry Waggy 《Journal of the American Water Resources Association》1974,10(2):229-244
ABSTRACT: Proper economic evaluation of alternative plans will maximize the utility achieved from the resources available for water resource management. A knowledge of the frequency of occurrence of the events under study is necessary to fully utilize the advantages of economic evaluation in planning. Frequency information is widely used in flood control and water supply, but relatively unknown in water quality planning. A continuous, dynamic hydrologic and water quality model is presented to develop frequency curves for various water quality criteria. Results from the Denver Regional Water Quality Management Study are discussed as an example of the use of frequency analysis for economic evaluation of water quality management. 相似文献
552.
Robert R. Criss 《Journal of the American Water Resources Association》1971,7(4):639-643
ABSTRACT The growing social consciousness and concern with human well-being has resulted in numerous water resource use and control programs, the results of which must be measured not in the customary monetary terms, but rather in terms of social and human welfare. Interdisciplinary research offers the greatest promise of yielding fruitful results in establishing planning methodology that would result in a maximum utilization of funds available for water resource programs. Working with the various social science disciplines, accountants have begun research in social measurement thus opening the door to a new field of accountancy known as socio-economic accounting. The development of social accounting systems will improve water resource management by projecting heretofore unmeasureable social values into the management decision making process. 相似文献
553.
Courtland L. Smith Thomas C. Hogg 《Journal of the American Water Resources Association》1971,7(4):652-660
ABSTRACT Attitudes toward the development of the American West have undergone important changes over the past century just as the nature of water resources as factors in development have changed. Viewing these changes processually, stages for water resources definition and use can be identified in the total process of western cultural development. The first stage involves the value of water resource development as a stimulus to population and economic growth in the West. The second stage, still in process', adopts a dominant cultural norm which sees water resource development as inevitable if not necessary to keep up with growth. A third stage to this evolutionary process is incipient. Future cultural values and thinking with respect to water resource development will be to look at development as a means for controlling or managing both the location and quantity of population and economic growth. To this end planners will have to become concerned with the questions of human adaptation. Concern will have to be given to the problems of getting a living which enables individuals to meet the subsistence needs of self and family, to establishing community which provides for cooperation among individuals and the management of conflict, to establishing improved communication which promotes interpersonal interaction, and for fostering innovation which provides the new ideas necessary to adapt to new environmental situations., 相似文献
554.
Elwyn S. Krous Joseph P. Wagner Harold L. Parkinson Milton S. Sachs 《Journal of the American Water Resources Association》1971,7(4):810-822
ABSTRACT .A case study was performed to evaluate potential applications of desalted saline water for agriculture using 2 distillation type processes and 2 membrane type processes. The investigation determined the costs and benefits associated with desalting saline water at concentrations of 1,500, 900, 400, 200, and 50 ppm. Benefits from desalting are generated by shifts to more profitable crops, reduced costs for drainage, and reduction in fertilizer and labor requirements with better quality water. Costs are based on the project features such as desalting plants, raw water diversion facilities, storage reservoirs, conveyance and distribution systems, brine disposal, blending facilities, and gypsum addition systems. Hydrologic studies determined the crop irrigation requirements, water demand schedules, desalted water storage requirements, brine disposal requirements, and size of facilities required. Reconnaissance design layouts were made for producing desalted water using a combination of 14 schemes. The study also included a review of irrigation practices. The benefit-cost ratios range from 0.4 to 1.0 for 1,500 ppm irrigation water to 0.8 to 1.0 for 50 and 200 ppm water. Investment costs per acre are high, ranging from $12,900 to $20,900. Irrigation benefits are based on the increase in production from a desert condition with no water supply to the irrigation conditions studied. 相似文献
555.
Martin T. Farris 《Journal of the American Water Resources Association》1971,7(6):1128-1136
While the science of economics is widely used in Federal water resource development projects, the usual procedure of applying an analytical discipline to arrive at a conclusion is reversed. The “answer” is usually provided ahead of time and economics is assigned the task of justifying the preconceived conclusion. This leads to a series of mitigatory effects in which economics as a science is not allowed to freely function. This article attempts to illustrate some of these “unusual” uses of economics in Federal water projects and note the “answers” we would logically expect from the economic discipline. Even though the theory of economics is often subverted, there are positive aspects to the role of economics in evaluating Federal water projects. 相似文献
556.
James A. Seagraves K. William Easter 《Journal of the American Water Resources Association》1983,19(4):663-672
ABSTRACT Alternative combinations of water pricing and regulations are possible in allocating irrigation water. The best combination will depend on the value of water, ability to control deliveries, desire to subsidize agriculture, ownership traditions, crops grown, return flows, drainage problems, staff training, ability to collect fees, the number of farmers involved, etc. Marginal cost pricing is just one possible alternative and it is more a way of thinking about prices rather than a set system. The possibilities for achieving an equitable and efficient distribution of water are improved if some form of marginal cost pricing is included in the system of water charges. 相似文献
557.
Katharina Rietig 《Journal of Environmental Policy & Planning》2019,21(3):228-241
ABSTRACTLearning among actors within the United Nations Framework Convention on Climate Change (UNFCCC) negotiations helped transferring climate policies across countries and changed negotiation positions. Together with group pressure and leadership by key governments and non-national actors, experience, knowledge and belief-based learning types altered the UNFCCC negotiation dynamics and facilitated the Paris Agreement. Governments, the UNFCCC secretariat and NGOs created opportunities for government representatives to explore policy options and learn from each other’ successes of designing and implementing low carbon policies. These experience exchanges during and beyond the UNFCCC meetings were established to help countries share their experiences with low carbon economic development plans to address climate change while decoupling economic growth. Based on elite interviews, participant observation and document analysis, this contribution examines how learning facilitated breakthroughs in international climate negotiations. It finds that structured experience exchange of and reflection on other countries’ and non-national actors’ successful policy experiences can modify national interests as policymakers increasingly understand that climate action can support economic growth. This resulted in a higher willingness to take on more ambitious climate action commitments. Sharing experiences with climate policies can facilitate other actor’s learning how they can adapt successful policies to their specific framework conditions. 相似文献
558.
通过对辽西北部半干旱地区秸秆资源的分析,提出了其开发与利用途径,为农业资源开发与利用提供了重要依据。 相似文献
559.
煤炭企业清洁生产的中/高费方案评述 总被引:1,自引:0,他引:1
简述了煤炭企业在清洁生产审核过程中如何产生中/高费方案,分析了中/高费方案所占的比例。通过3个工程实例的分析证明,中/高费方案的实施给煤炭企业带来良好的环境效益和经济效益。 相似文献
560.
我国城市周边规划建设用地利用探讨 总被引:2,自引:0,他引:2
随着我国城市面积的不断扩大,大量的郊区耕地成为或即将成为城市的建设用地,同时与城市建设相伴相随的建筑渣土的堆放已成为城市的一大问题,本文按照循环经济原则,提出利用规划期内即将建设的城市周边耕地资源建立供应城市建筑的制砖企业,同时利用取土坑填埋建筑渣土,建立城市物质的有效循环,实现城市建筑的循环经济。并对此物质循环方式做了生态经济的分析,也对此物质循环中存在的障碍提出了解决的方法。 相似文献