全文获取类型
收费全文 | 378篇 |
免费 | 23篇 |
国内免费 | 145篇 |
专业分类
安全科学 | 30篇 |
废物处理 | 26篇 |
环保管理 | 30篇 |
综合类 | 204篇 |
基础理论 | 80篇 |
污染及防治 | 131篇 |
评价与监测 | 13篇 |
社会与环境 | 13篇 |
灾害及防治 | 19篇 |
出版年
2024年 | 1篇 |
2023年 | 8篇 |
2022年 | 25篇 |
2021年 | 13篇 |
2020年 | 15篇 |
2019年 | 12篇 |
2018年 | 13篇 |
2017年 | 17篇 |
2016年 | 24篇 |
2015年 | 31篇 |
2014年 | 25篇 |
2013年 | 43篇 |
2012年 | 33篇 |
2011年 | 28篇 |
2010年 | 17篇 |
2009年 | 20篇 |
2008年 | 33篇 |
2007年 | 21篇 |
2006年 | 22篇 |
2005年 | 11篇 |
2004年 | 3篇 |
2003年 | 16篇 |
2002年 | 13篇 |
2001年 | 17篇 |
2000年 | 13篇 |
1999年 | 9篇 |
1998年 | 5篇 |
1997年 | 14篇 |
1996年 | 4篇 |
1995年 | 8篇 |
1994年 | 6篇 |
1993年 | 2篇 |
1992年 | 8篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1982年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有546条查询结果,搜索用时 234 毫秒
201.
Yifan Liu Qiongfang Zhang Ainiwaer Sidike Nuerla Ailijiang Anwar Mamat Guangxiao Zhang Miao Pu Wenhu Cheng Zhengtao Pang 《Frontiers of Environmental Science & Engineering》2022,16(11):141
202.
Algae community and trophic state of subtropical reservoirs in southeast Fujian, China 总被引:5,自引:0,他引:5
Yang J Yu X Liu L Zhang W Guo P 《Environmental science and pollution research international》2012,19(5):1432-1442
Background,
aim, and scope Fujian reservoirs in southeast China are important water resources for economic and social sustainable development, although few have been studied previously. In recent years, growing population and increasing demands for water shifted the focus of many reservoirs from flood control and irrigation water to drinking water. However, most of them showed a rapid increase in the level of eutrophication, which is one of the most serious and challenging environmental problems. In this study, we investigated the algae community characteristics, trophic state, and eutrophication control strategies for typical subtropical reservoirs in southeast Fujian.Materials and methods
Surface water samples were collected using polyvinyl chloride (PVC) plastic bottles from 11 Fujian reservoirs in summer 2010. Planktonic algae were investigated by optical microscopy. Water properties were determined according to the national standard methods.Results and discussion
Shallow reservoirs generally have higher values of trophic state index (TSI) and appear to be more susceptible to anthropogenic disturbance than deeper reservoirs. A total of 129 taxa belonging to eight phyla (i.e., Bacillariophyta, Chlorophyta, Chrysophyta, Cryptophyta, Cyanophyta, Euglenophyta, Pyrrophyta, Xanthophyta) were observed and the most diverse groups were Chlorophyta (52 taxa), Cyanophyta (20 taxa), Euglenophyta (17 taxa), Chrysophyta (14 taxa). The dominant groups were Chlorophyta (40.58%), Cyanophyta (22.91%), Bacillariophyta (21.61%), Chrysophyta (6.91%). The species richness, abundance, diversity, and evenness of algae varied significantly between reservoirs. TSI results indicated that all 11 reservoirs were eutrophic, three of them were hypereutrophic, six were middle eutrophic, and two were light eutrophic. There was a strong positive correlation between algal diversity and TSI at P?0.05. Our canonical correspondence analysis (CCA) results illustrated that temperature, transparency, conductivity, DO, TC, NH4-N, NO x -N, TP, and chlorophyll a were significant environmental variables affecting the distribution of algae communities. The transparency and chlorophyll a were the strongest environmental factors in explaining the community data. Furthermore, the degradation of water quality associated with excess levels of nitrogen and phosphorus in Fujian reservoirs may be impacted by interactions among agriculture and urban factors. A watershed-based management strategy, especially phosphorus control, should be developed for drinking water source protection and sustainable reservoirs in the future.Conclusion and recommendations
All investigated reservoirs were eutrophicated based on the comprehensive TSI values; thus, our results provided an early warning of water degradation in Fujian reservoirs. Furthermore, the trophic state plays an important role in shaping community structure and in determining species diversity of algae. Therefore, long-term and regular monitoring of Euglenophyta, Cyanophyta, TN, TP and chlorophyll a in reservoirs is urgently needed to further understand the future trend of eutrophication and to develop a watershed-based strategy to manage the Cyanophyta bloom hazards. 相似文献203.
204.
205.
Physiological aspects of vetiver grass for rehabilitation in abandoned metalliferous mine wastes 总被引:16,自引:0,他引:16
Physiological aspects of why vetiver grass (Vetiveria zizanioides L.) can be tolerant to heavy metals and be used as an alternative method for rehabilitation of abandoned metalliferous mine wastelands have been investigated. The results showed that high proportions of lead and zinc (Pb/Zn) tailing greatly inhibited the leaf growth, dry matter accumulation, and photosynthesis of leaves, but stimulated the accumulation of proline and abscisic acid (ABA), and enhanced the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), implying that different mechanisms to detoxify active oxygen species (AOS) existed in different parts of plants. Physiological responses to heavy metal treatments differed greatly between roots and shoots. Nitrogen fertilizer application could greatly alleviate the adverse effects of high proportions of Pb/Zn tailing on vetiver grass growth. 相似文献
206.
分别在300、500、700℃下限氧热解稻草、小麦和玉米秸秆制备生物炭,并以制备的生物炭为载体固定化硫酸盐还原菌(SRB),对比不同类型生物炭固定化SRB对Cd2+的吸附效果,筛选出吸附效果最佳的固定化SRB菌剂,并采用SEM、FTIR和BET对其进行表征分析;同时,研究溶液pH、吸附时间、生物炭添加量、Cd2+浓度对吸附效应的影响,并结合吸附动力学和等温吸附模型探究其对Cd2+的吸附过程及作用机理.结果表明,700℃限氧热解小麦秸秆生物炭固定化SRB菌剂(IBXM700)对Cd2+的吸附效果最佳;在pH=8、生物炭添加量为0.6 g(每50 mL溶液)、吸附时间为8 h、Cd2+初始浓度为40 mg·L-1条件下,IBXM700对Cd2+的吸附效果最佳,其吸附符合拟一级动力学模型,以离子交换和表面物理吸附为主,以化学吸附作用为辅,且符合Langmuir模型,表明是单分子层吸附;离子交换、沉淀可能是IBXM700吸附Cd2+... 相似文献
207.
208.
通过对某铜矿水平矿柱回采中的结构稳定性问题的研究,探讨了有限元计算结合结构可靠性分析的研究方法。研究表明,这对矿山工程的可靠性分析提供了新的思路和方法。 相似文献
209.
高精度模具加工除了与机床本身精度有关外电火花电源起重要作用。电极损耗性能与生产率、粗糙度等性能相比更起关键作用。此文论述了在保证同样的电极损耗下,性能优良的电极损耗将使粗糙度更细、放电间隙更小、生产率更高。在例举若干较高的电极损耗指标后提出了评审某电源的电极损耗性能高低的标准。 相似文献
210.
黔北地区土壤中活性铝的分布调查 总被引:2,自引:0,他引:2
本研究对黔北地区土壤中活性铝的分布进行了分析,结果表明该地区目前土壤活性铝含量的平均水平较低,对于农田及森林系统尚不致有严重影响,但酸性降水对该地区黄壤中铝的溶出有潜在性危害作用。 相似文献