全文获取类型
收费全文 | 8824篇 |
免费 | 1405篇 |
国内免费 | 2886篇 |
专业分类
安全科学 | 1449篇 |
废物处理 | 213篇 |
环保管理 | 823篇 |
综合类 | 7088篇 |
基础理论 | 1248篇 |
污染及防治 | 601篇 |
评价与监测 | 520篇 |
社会与环境 | 666篇 |
灾害及防治 | 507篇 |
出版年
2024年 | 68篇 |
2023年 | 170篇 |
2022年 | 530篇 |
2021年 | 586篇 |
2020年 | 657篇 |
2019年 | 409篇 |
2018年 | 446篇 |
2017年 | 506篇 |
2016年 | 421篇 |
2015年 | 544篇 |
2014年 | 546篇 |
2013年 | 713篇 |
2012年 | 835篇 |
2011年 | 832篇 |
2010年 | 772篇 |
2009年 | 758篇 |
2008年 | 699篇 |
2007年 | 718篇 |
2006年 | 741篇 |
2005年 | 546篇 |
2004年 | 365篇 |
2003年 | 256篇 |
2002年 | 246篇 |
2001年 | 209篇 |
2000年 | 184篇 |
1999年 | 134篇 |
1998年 | 46篇 |
1997年 | 37篇 |
1996年 | 42篇 |
1995年 | 32篇 |
1994年 | 20篇 |
1993年 | 10篇 |
1992年 | 17篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 7篇 |
1984年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Changpeng Zhang Hua Zhao Lifeng Ping Xiaoming Cai Min Wu Hongmei He 《Journal of environmental science and health. Part. B》2013,48(5):319-323
This study investigated the degradation of rizazole in water-sediment systems (West Lake system, WL; Beijing–Hangzhou Grand Canal system, BG) with two different types of sediments under aerobic and anaerobic conditions. The half-lives of rizazole in the WL water phase (14.59–15.13 d) were similar to those in the BG water phase (15.90–16.46 d). Within 3–7 d, the rizazole concentration in the sediments reached the maximum values, i.e., equilibrium. Rizazole dissipation was faster in the WL sediment phase with higher organic matter content (T1/2 = 18.99–19.09 d) compared with the BG sediment phase (T1/2 = 31.08–33.32 d). Rizazole degradation was slightly faster in the West Lake water-sediment system (WL system) (T1/2 = 17.11–18.05 d) than in the Beijing–Hangzhou Grand Canal water—sediment system (BG system) (T1/2 = 20.51–25.02 d). The aerobic degradation of rizazole was similar to its anaerobic degradation in the water-sediment system. The findings are useful to understand the behavior of pesticide in environment. 相似文献
992.
Occurrence, distribution, and sources of six phenolic endocrine disrupting chemicals in the 22 river estuaries around Dianchi Lake in China 总被引:1,自引:0,他引:1
Bin Wang Bin Huang Wei Jin Shimin Zhao Farong Li Ping Hu Xuejun Pan 《Environmental science and pollution research international》2013,20(5):3185-3194
The objectives of this study are to track the occurrence, distribution, and sources of phenolic endocrine disrupting compounds (EDCs) in the 22 rivers around Dianchi Lake in China, to estimate the input and output amounts of phenolic EDCs in the water system, and to provide more comprehensive fundamental data for risk assessment and contamination control of phenolic EDCs in aquatic environment. Six phenolic EDCs were systematically evaluated in water and surface sediment in the estuaries of those rivers. The water and sediment samples were preconcentrated by solid-phase extraction system and microwave-assisted extraction system, respectively. Phenolic EDCs were analyzed by GC-MS (Thermo Fisher Scientific, USA) after derivatization. Phenolic EDCs were found ubiquitously in the aquatic environment. The total concentrations ranged from 248 to 4,650 ng/L in water, and 113 to 3,576 ng/g dry weight in surface sediment. The residue amount of phenolic EDCs in Dianchi Lake was 258 kg/a. Concentrations of the phenolic EDCs in the Lake decreased with increase in distance to the estuaries of those rivers which run through urban and industrial areas. The rivers seriously contaminated by phenolic EDCs were Xin River, Yunliang River, Chuanfang River, Cailian River, Jinjia River, Zhengda River, and Daqing River which run through the old area of Kunming City. Satisfying correlations were observed between the concentrations of the target compounds in water and in surface sediment. NP1EO, NP2EO, and BPA were identified as the three predominant phenolic EDCs. There were significant correlations between phenolic EDCs and many basic water quality parameters. Urban and industrial areas are the major contributors for phenolic EDCs, especially in Kunming City. Compositional profiles of phenolic EDCs in surface sediment were similar to those in river water. The concentrations of phenolic EDCs in the rivers located in the northwest part of the valley were very high, and posed a potential risk to aquatic organisms and even human. The concentrations of NP2EO, NP1EO, and BPA were at moderate levels of other areas. The basic water quality parameters (TOC, TN, DO, and pH) play important roles on the distribution, fate, and behavior of phenolic EDCs in the valley. 相似文献
993.
PPP模式作为公共部门与私人企业合作的一种模式,可以有效地缓解基础设施建设资金紧张的状况,是一种基于双赢或多赢理念基础上而形成的模式,目前已被许多国家广泛采用。在我国推行公用事业市场化改革的背景下,该模式具有广阔的应用前景。本文分析了该模式在我国城市污水处理行业中应用的主要形式,以及该模式在我国现实环境下面临的风险、存在的问题和相应的解决办法,并为政府推进PPP模式的应用提供了相关的建议。 相似文献
994.
环境监督管理全覆盖移动执法系统,是利用现代无线通信技术、计算机技术等先进技术手段,利用手持终端(PDA)、手提电脑等设备,通过无线数字通信网的支持,实现在任何执法地点都可从后台业务系统中获取所需的业务数据、文字、图片、视频等信息,同时将现场执法的信息及时回传至后台系统中。本文介绍了移动执法系统的建设以及应用的情况。 相似文献
995.
996.
采用压汞法(MIP)和扫描电镜(SEM)法,在自由和侧限状态下,试验研究了高压实新疆阿尔泰膨润土在不同吸力条件下的微观结构变化特征。吸力的控制采用了气相法和渗析(液相)法。研究结果表明:(1)低吸力范围内,自由膨胀和侧限条件下的高压实膨润土土水特征存在明显差异;(2)膨润土在自由和侧限状态下的水化过程中呈现出了截然不同的微结构变化特征。自由膨胀条件下,土的吸水膨胀量主要来自土中大孔隙的逐渐膨胀。侧限状态下,随着控制吸力的降低,膨润土的大孔隙逐渐被压缩,较小孔隙的数量不断增加,土中孔隙分布变得更加均匀。 相似文献
997.
998.
999.
根据煤炭产业发展的实际状况,提出了煤炭产业竞争力评价的指标体系。采用探索性数据分析—投影寻踪法,结合遗传算法,建立了遗传—投影寻踪综合评价模型。以全球11个主要产煤国为对象进行了实证研究,验证了该方法的科学性和实践的可行性,提出提升我国煤炭产业竞争力的对策建议。 相似文献
1000.
水利旅游是水利经济的新兴增长点,吸引力评价是旅游开发的基础性研究。借鉴引力理论,构建了由25个指标组成的水利旅游吸引力评价指标体系,运用AHP—PCA—Borda主客观组合评价法,对我国水利旅游吸引力进行了实证评价。结果表明,水利旅游吸引力地区不平衡,江苏、广东、山东、湖北、河南、浙江、湖南、北京和江西等省水利旅游吸引力较强,西部省份和处于我国版图中轴线附近的省份水利旅游吸引力较弱。 相似文献