全文获取类型
收费全文 | 1684篇 |
免费 | 173篇 |
国内免费 | 157篇 |
专业分类
安全科学 | 933篇 |
废物处理 | 34篇 |
环保管理 | 119篇 |
综合类 | 629篇 |
基础理论 | 40篇 |
污染及防治 | 89篇 |
评价与监测 | 30篇 |
社会与环境 | 52篇 |
灾害及防治 | 88篇 |
出版年
2024年 | 15篇 |
2023年 | 56篇 |
2022年 | 59篇 |
2021年 | 76篇 |
2020年 | 43篇 |
2019年 | 56篇 |
2018年 | 46篇 |
2017年 | 71篇 |
2016年 | 56篇 |
2015年 | 83篇 |
2014年 | 155篇 |
2013年 | 111篇 |
2012年 | 114篇 |
2011年 | 118篇 |
2010年 | 95篇 |
2009年 | 112篇 |
2008年 | 104篇 |
2007年 | 114篇 |
2006年 | 99篇 |
2005年 | 103篇 |
2004年 | 59篇 |
2003年 | 52篇 |
2002年 | 43篇 |
2001年 | 33篇 |
2000年 | 34篇 |
1999年 | 21篇 |
1998年 | 26篇 |
1997年 | 13篇 |
1996年 | 10篇 |
1995年 | 9篇 |
1994年 | 3篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 1篇 |
排序方式: 共有2014条查询结果,搜索用时 328 毫秒
101.
Denitrification potential enhancement by addition of external carbon sources in a pre-denitrification process 总被引:3,自引:0,他引:3
The aim of this study is to investigate the denitrification potential enhancement by addition of external carbon sources and to estimate the denitrification potential for the predenitrification system using nitrate utilization rate (NUR) batch tests. It is shown that the denitrification potential can be substantially increased with the addition of three external carbon sources, i.e. methanol, ethanol, and acetate, and the denitrification rates of ethanol, acetate, and methanol reached up to 9.6, 12, and 3.2 mgN/(g VSS.h), respectively, while that of starch wastewater was only 0.74 mgN/(g VSS,h). By comparison, ethanol was found to be the best external carbon source. NUR batch tests with starch wastewater and waste ethanol were carried out. The denitfification potential increased from 5.6 to 16.5 mg NO3-N/L owing to waste ethanol addition. By means of NUR tests, the wastewater characteristics and kinetic parameters can be estimated, which are used to determine the denitrification potential of wastewater, to calculate the denitrification potential of the plant and to predict the nitrate effluent quality, as well as provide information for developing carbon dosage control strategy. 相似文献
102.
动态膜-生物反应器中新型预涂剂的抗污染特性研究 总被引:1,自引:1,他引:0
对动态膜技术中的预涂剂进行了拓展研究,通过聚乙烯醇(PVA)与戊二醛(GA)的乳化交联制备新型预涂剂——PVA微球,分析交联反应机理,并通过PVA微球对产生膜污染主要物质EPS的吸附实验分析其抗污染特性.结果表明,乳化交联过程中主要发生的是半缩醛反应,PVA胶团的羟基数量实质上没有大量减少,PVA微球仍然保持良好的亲水性能,而且其表面呈现的电负性能够对活性污泥絮体产生静电排斥作用, PVA微球对活性污泥中蛋白质和多糖的吸附率稳定且较低,分别为0 .543 mg·g-1和0 .694 mg·g-1,从微观上延缓了膜污染.预涂液中微球的粒径在1 .14 μm左右,其不同浓度的Zeta电位都小于-39 mV,具有良好的稳定性,能够快速稳定地沉积在多孔底膜的表面和孔道内壁上,试验中采用SEM分析了PVA微球及其在工业滤布内部纤维丝上形成动态膜的表观形貌. 相似文献
103.
104.
以实际工作中的含油废水为研究对象,采用加压气浮处理工艺,通过多年的实际应用与对监测数据的分析,总结出气浮压力对气浮处理效果的影响,通过对溶气罐压力的调整,可得到最佳的出水水质。该项研究结果操作方便、处理效率高、易于控制、对今后的工作具有指导意义,有很好的推广价值。 相似文献
105.
106.
Water supply is the primary element of an urban system. Due to rapid urbanization and water scarcity, maintaining a stable and safe water supply has become a challenge to many cities, whereas a large amount of water is lost from the pipes of distribution systems. Water leakage is not only a waste of water resources, but also incurs great socio-economic costs. This article presents a comprehensive review on the potential water leakage control approaches and specifically discusses the benefits of each to environmental conservation. It is concluded that water leakage could be further reduced by improving leakage detection capability through a combination of predictive modeling and monitoring instruments, optimizing pipe maintenance strategy, and developing an instant pressure regulation system. The environment could benefit from these actions because of water savings and the reduction of energy consumption as well as greenhouse gas emissions. 相似文献
107.
A novel method based on the selective pressure of particle size (particle-size cultivation method, PSCM) was developed for the cultivation and operation of aerobic granular sludge in a continuous-flow reactor, and compared with the conventional method based on the selective pressure of settling velocity (settling-velocity cultivation method, SVCM). Results indicated that aerobic granules could be cultivated in continuous operation mode by this developed method within 14 days. Although in the granulation process, under particle-size selective pressure, mixed liquor suspended solids (MLSS) in the reactor fluctuated greatly and filamentous bacteria dominated the sludge system during the initial operation days, no obvious difference in profile was found between the aerobic granules cultivated by PSCM and SVCM. Moreover, aerobic granules cultivated by PSCM presented larger diameter, lower water content and higher specific rates of nitrification, denitrifieation and phosphorus removal, but lower settling velocity. Under long term operation of more than 30 days, aerobic granules in the continuous-flow reactor could remain stable and obtain good chemical oxygen demand (COD), NH4^+-N, total nitrogen (TN) and total phosphorus (TP) removal. The results indicate that PSCM was dependent on the cultivation and maintenance of the stability of aerobic granules in continuous-flow bioreactors. 相似文献
108.
污染控制的障碍到底是什么?这不只是一个技术问题或者资金问题.最核心的问题还是缺乏动力。这个动力原本应该源自严格的执法。源自司法介入的环境诉讼,但是我国现在还不具备这些。从国际经验看,环境保护需要广泛的社会参与,除了政府监管,包括立法、司法、环保行政部门的作为.还有市场手段和公众参与。在西方国家,司法手段可以起到非常重要的作用。而我国环境司法系统还需要进一步完善,这会是一个相当艰难和漫长的过程。 相似文献
109.
110.
压力强化混凝除藻工艺中藻毒素安全性研究 总被引:2,自引:1,他引:1
为了研究预压力强化混凝沉淀蓝藻水处理工艺中,外加压力是否会引起藻细胞破裂,导致细胞内藻毒素泄漏到水体中,影响供水安全,实验对比研究了预压力和预氧化含藻水后藻毒素浓度的变化,以及预压力混凝沉淀和预氧化混凝沉淀除藻工艺中藻毒素浓度的变化和藻类去除效果.结果表明,含藻水经0.4~0.8 MPa压力加压后,水中藻毒素浓度没有增加,而次氯酸钠预氧化后水中藻毒素浓度大幅度增加.在0.5~0.8 MPa压力范围内,加压后混凝沉淀取得了较好的除藻除浊效果,蓝藻去除率达到90%~93.5%,浊度1.23~1.95 NTU,而次氯酸钠预氧化混凝沉淀后,蓝藻去除率56.2%~78.8%,浊度8.01~10.7 NTU,说明压力强化混凝沉淀除藻工艺是安全有效的. 相似文献