全文获取类型
收费全文 | 382篇 |
免费 | 23篇 |
国内免费 | 104篇 |
专业分类
安全科学 | 20篇 |
废物处理 | 28篇 |
环保管理 | 52篇 |
综合类 | 201篇 |
基础理论 | 67篇 |
污染及防治 | 91篇 |
评价与监测 | 16篇 |
社会与环境 | 11篇 |
灾害及防治 | 23篇 |
出版年
2023年 | 4篇 |
2022年 | 22篇 |
2021年 | 14篇 |
2020年 | 21篇 |
2019年 | 10篇 |
2018年 | 14篇 |
2017年 | 14篇 |
2016年 | 23篇 |
2015年 | 18篇 |
2014年 | 29篇 |
2013年 | 41篇 |
2012年 | 32篇 |
2011年 | 43篇 |
2010年 | 30篇 |
2009年 | 27篇 |
2008年 | 27篇 |
2007年 | 27篇 |
2006年 | 16篇 |
2005年 | 13篇 |
2004年 | 8篇 |
2003年 | 10篇 |
2002年 | 8篇 |
2001年 | 12篇 |
2000年 | 11篇 |
1999年 | 9篇 |
1998年 | 3篇 |
1997年 | 5篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1993年 | 5篇 |
1990年 | 3篇 |
排序方式: 共有509条查询结果,搜索用时 203 毫秒
141.
Phosphorus (P) is a key biological element and limiting nutrient in aquatic environments. Phosphate (+5) is traditionally associated with the P nutrient supply. However, phosphite (+3) has recently generated a great deal of interest, because of the possibility that it is a P source based on recognition of its vital role in the original life of the early earth. This study investigated whether phosphite can be an alternative P source for Microcystis aeruginosa PCC 7806, one of the predominant bloom species in freshwater systems. The results indicated that M. aeruginosa could not utilize phosphite as a sole P-nutrient directly for cell growth at any concentration, but that phosphite could boost cell numbers and chlorophyll a (Chl-a) content as long as phosphate was provided simultaneously. Specifically, Chl-a production increased sharply when 5.44 mg P L−1 phosphite was added to 0.54 mg P L−1 phosphate medium. Analysis of the maximum yield of PSII indicated that phosphite may stimulate the photosynthesis process of cells in phosphate-phosphite medium. In addition, phosphite failed to support cell growth, even though it more readily permeated the cells in P-deficient medium than in P-sufficient medium. Alkaline phosphatase activity (APA) analysis indicated that, unlike organic P, phosphite inhibits the response of cells to deficient P status, especially under P-deprived conditions. 相似文献
142.
144.
调查分析了胜利采油厂特种作业人员培训持证工作现状,查找了管理中存在的问题,结合实际提出加强特种作业人员安全管理的建议。 相似文献
145.
安全和治安防卫有很多的共同特征,分析和研究治安防卫达到最佳效果的方法同样可应用于安全和事故防范方面。虽然通常安全不必考虑蓄意的破坏活动,但可以应用治安的脆弱性评估技术来进行安全分析。笔者旨在从另一个角度来讨论安全分析的方法,换一个切入点来辨识安全的脆弱性:将治安防卫中的脆弱性评估方法应用于安全脆弱性分析中,以期达到转换思维模式的目的。为此,讨论了“对立面”分析的人员组成、考虑范围和对该方法的理解,并运用实例,说明从“对立面”来考虑安全脆弱性是可行的。 相似文献
146.
147.
The circular economy (CE) concept was introduced in China to address environmental degradation and resource scarcity associated with rapid economic development. Chosen as a demonstration city, Dalian has implemented the CE strategy as a means of conserving water, materials, energy and land. This paper outlines some of the regional CE initiatives that have been successful to date in Dalian, including those focusing on conserving energy and water resources and others focusing on reduced industrial emissions. The paper details the approach used in implementing the CE concept in Dalian, tracing the foci and goals of the program, and the sectoral approach used to implement a CE. Although Dalian municipality has achieved many successes in implementing a CE, our paper identifies several challenges that, until recently, have held back complete implementation. These include: the lack of incentives for older industries to 'green' their operations, the lack of financial support to expand the CE concept, and a broad-based need for heightened public awareness and participation in CE initiatives. Our paper then identifies several responses by Dalian municipality to overcome these challenges, including pricing and tax reforms that serve as conservation incentives, the provision of financial support for CE promotion through budget reorganization, and the organization of CE training programs. Our paper concludes that, although CE initiatives have been successful in Dalian, more is possible and more is needed before Dalian can be designated a true 'eco-city'. The approach used by Dalian can provide guidance for other Chinese cities, although it is recognized that each city must tailor its own approach for differing contexts and conditions. 相似文献
148.
采用过滤法与吸收法联用的采样方法,测定燃煤电厂烟气中Pb,并通过试验考察4种不同的吸收液和4种不同采样流量对测定的影响。结果表明:0.1 mol/L HNO_3、体积分数为5%的HNO_3+10%的H_2O_2和体积分数为1.6%的HNO_3+2.5%的HCl 3种吸收液均对Pb起到良好的捕集作用,且测定结果相近。采样流量控制在20 L/min吸收效果最好。 相似文献
149.
Environmental and Ecological Statistics - The results show that a comprehensive evaluation system consisting of natural resources, pollution response, government management, and legal involvement... 相似文献
150.
除草剂阿特拉津生物降解研究进展 总被引:4,自引:0,他引:4
本文综述了近年来国内外在阿特拉津降解菌及降解途径方面的研究进展 ,及在微生物产生的阿特拉津降解酶、其操作基因方面的研究现状 ,并提出了阿特拉津生物降解的研究趋势 相似文献