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221.
自然环境的优劣,会直接影响人体的健康。在良好的环境中,人们所依赖的物质是不受污染的,自然环境的物质中所含微量元素和微量元素对维持人类生命、保护人体健康起到了一定的基础作用。 相似文献
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224.
Theory into Practice: Implementing Ecosystem Management Objectives in the USDA Forest Service 总被引:5,自引:1,他引:5
In the United States and around the world, scientists and practitioners have debated the definition and merits of ecosystem management as a new approach to natural resource management. While these debates continue, a growing number of organizations formally have adopted ecosystem management. However, adoption does not necessarily lead to successful implementation, and theories are not always put into practice. In this article, we examine how a leading natural resource agency, the United States Department of Agriculture Forest Service, has translated ecosystem management theory into concrete policy objectives and how successfully these objectives are perceived to be implemented throughout the national forest system. Through document analysis, interviews, and survey responses from 345 Forest Service managers (district rangers, forest supervisors, and regional foresters), we find that the agency has incorporated numerous ecosystem management components into its objectives. Agency managers perceive that the greatest attainment of such objectives is related to collaborative stewardship and integration of scientific information, areas in which the organization has considerable prior experience. The objectives perceived to be least attained are adaptive management and integration of social and economic information, areas requiring substantial new resources and a knowledge base not traditionally emphasized by natural resource managers. Overall, success in implementing ecosystem management objectives is linked to committed forest managers. 相似文献
225.
泸州市城市空气自然降尘和硫酸盐化速率的探讨 总被引:1,自引:0,他引:1
本文以1992-2001年泸州市城市空气质量数据为依据,指出了该市自然降尘和硫酸盐化速率的变化规律,并对防治对策进行了探讨。 相似文献
226.
Kaniye S.A. Ebeku 《Natural resources forum》2003,27(4):291-299
This article discusses the decision of the Supreme Court of Nigeria on the constitutional provision dealing with the sharing of revenues derived from natural resources located within the states of the Federation, the ‘derivation principle.’ Although the case relates to the interpretation of a constitutional provision, the arguments of the parties suggest that the real battle was — and still is — about the ownership and control of Nigeria's offshore oil. The article details the legal history and precedents as well as constitutional provisions relevant to the case. Disagreements arose over legal questions such as the seaward boundaries of littoral states (from which oil revenues are derived), and whether a distinction can be made between offshore and onshore oil revenues in applying a 13% constitutionally prescribed derivation principle. The article shows that, in its judgment, Nigeria's Supreme Court relied heavily on rules of international law, while failing to apply existing Nigerian laws and constitutional provision, and argues that the decision might have been different had the court investigated and invoked the legislative history of the provision in question, as required in Nigerian law. Furthermore, it is argued that the court was wrong to disregard the provision of the law which had abolished any distinction between onshore and offshore natural resources in the application of the derivation principle. The article concludes that the legal tug of war is set to continue for some years. 相似文献
227.
The environmental performance of hemp based natural fiber mat thermoplastic (NMT) has been evaluated in this study by quantifying carbon storage potential and CO2 emissions and comparing the results with commercially available glass fiber composites. Non-woven mats of hemp fiber and polypropylene matrix were used to make NMT samples by film-stacking method without using any binder aid. The results showed that hemp based NMT have compatible or even better strength properties as compared to conventional flax based thermoplastics. A value of 63 MPa for flexural strength is achieved at 64% fiber content by weight. Similarly, impact energy values (84–154 J/m) are also promising. The carbon sequestration and storage by hemp crop through photosynthesis is estimated by quantifying dry biomass of fibers based on one metric ton of NMT. A value of 325 kg carbon per metric ton of hemp based composite is estimated which can be stored by the product during its useful life. An extra 22% carbon storage can be achieved by increasing the compression ratio by 13% while maintaining same flexural strength. Further, net carbon sequestration by industrial hemp crop is estimated as 0.67 ton/h/year, which is compatible to all USA urban trees and very close to naturally, regenerated forests. A comparative life cycle analysis focused on non-renewable energy consumption of natural and glass fiber composites shows that a net saving of 50 000 MJ (3 ton CO2 emissions) per ton of thermoplastic can be achieved by replacing 30% glass fiber reinforcement with 65% hemp fiber. It is further estimated that 3.07 million ton CO2 emissions (4.3% of total USA industrial emissions) and 1.19 million m3 crude oil (1.0% of total Canadian oil consumption) can be saved by substituting 50% fiber glass plastics with natural fiber composites in North American auto applications. However, to compete with glass fiber effectively, further research is needed to improve natural fiber processing, interfacial bonding and control moisture sensitivity in longer run. 相似文献
228.
试论我国环境税制的完善 总被引:1,自引:0,他引:1
董丽 《中国环境管理干部学院学报》2003,13(1):33-36
在商品经济高度发达的今天,环保事业也逐步走向市场。越来越多的国家开始重视运用经济手段来解决环境危机问题,环境税就是其中倍受青睐的一种手段。我国目前虽已意识到环境税的重要性,但环境税仍是极其薄弱的环节。本文试从分析我国环境税的现状着手,参考国外的先进经验,对完善我国环境税制提出几点建议。 相似文献
229.
Alternating nitrification-denitrification via nitrite for nitrogen removal from soybean wastewater by SBR with real-time control 总被引:3,自引:0,他引:3
A novel treating technology for nitrogen removal from soybean wastewater was studied. The process for nitrogen removal was achieved by alternating aeration and mixing, combined with real\|time control strategies. Results showed that the COD and total nitrogen removal rates are more than 90% and 92% at COD and total nitrogen loads of 1.0-1.2 kg COD/(kgMLSS·d) and 0.20-0.27 kg TN/(kgMLSS·d), respectively. In addition, it could improve sludge settling property. SVI value is less than 70 g/ml during the whole cycles. The method not only may be adapted to treat soybean wastewater with high nitrogen, but also may be applied to treat other high nitrogen wastewater. 相似文献
230.
Valiollah Raufirad Richard Hunter Reza Khalili Setareh Bagheri 《Local Environment》2017,22(7):880-893
The driving forces behind natural resource management (NRM) vary among countries. Most NRM programmes focus on biophysical drivers such as soil, water and vegetation, with little attention directed towards the nuanced sociocultural and religious drivers of sustainable natural resource management (SNRM) practices. This paper explores those understudied drivers that influence local people’s participation (LPP) in SNRM in Isfahan, Iran. Using a multi-stage stratified sampling method, we selected 200 natural resource experts and natural resource users to complete a questionnaire about their perceptions of SNRM. Results reveal that sociocultural and religious beliefs are the major drivers of SNRM. The results also indicate that subsidiary drivers include: a sense of responsibility towards SNRM; the conviction that natural resources belong to God and should therefore be preserved; participation to preserve natural resources because of training courses and media influence; a long-established custom of preserving natural resources; and the specific impact of environmental television programmes. Demographic analysis finds a significant relationship between educational level and LPP in SNRM. This study’s results therefore suggest that natural resource managers would benefit from a deeper understanding of the local sociocultural and religious contexts that motivate people to participate in SNRM. 相似文献