全文获取类型
收费全文 | 1680篇 |
免费 | 180篇 |
国内免费 | 1001篇 |
专业分类
安全科学 | 227篇 |
废物处理 | 133篇 |
环保管理 | 187篇 |
综合类 | 1587篇 |
基础理论 | 131篇 |
污染及防治 | 551篇 |
评价与监测 | 37篇 |
社会与环境 | 6篇 |
灾害及防治 | 2篇 |
出版年
2024年 | 1篇 |
2023年 | 20篇 |
2022年 | 32篇 |
2021年 | 36篇 |
2020年 | 51篇 |
2019年 | 61篇 |
2018年 | 60篇 |
2017年 | 56篇 |
2016年 | 84篇 |
2015年 | 106篇 |
2014年 | 151篇 |
2013年 | 160篇 |
2012年 | 216篇 |
2011年 | 188篇 |
2010年 | 158篇 |
2009年 | 171篇 |
2008年 | 119篇 |
2007年 | 215篇 |
2006年 | 197篇 |
2005年 | 142篇 |
2004年 | 116篇 |
2003年 | 116篇 |
2002年 | 81篇 |
2001年 | 77篇 |
2000年 | 63篇 |
1999年 | 43篇 |
1998年 | 28篇 |
1997年 | 28篇 |
1996年 | 26篇 |
1995年 | 14篇 |
1994年 | 12篇 |
1993年 | 12篇 |
1992年 | 6篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1979年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有2861条查询结果,搜索用时 542 毫秒
951.
滤筒除尘器在使用过程中需要通过脉冲喷吹清灰来维持本身的正常运行,脉冲喷吹是以压缩空气为清灰动力,运行过程中势必会产生噪声,其在一些噪声有限值要求的场合,如空调净化系统中使用时,必须考虑降低噪声以达到相关噪声限值的要求。对滤筒除尘器在脉冲喷吹清灰时产生的噪声做了测试,并与空调净化系统中的噪声限值做了对比分析,提出了滤筒除尘器在空调净化系统中使用时对脉冲喷吹清灰噪声控制的具体而有效的解决办法。 相似文献
952.
在役柴油加氢装置HAZOP分析技术 总被引:2,自引:1,他引:1
柴油加氢装置属甲类火灾危险生产装置,为了保障其安全生产,实现事故早期预防,对其进行风险分析和安全评价势在必行.HAZOP分析方法是流程工业广泛使用的一种危险辨识和分析方法,具有较好的系统性和完备性.首先介绍了HAZOP分析方法的由来及应用情况,其次分析了在役装置HAZOP分析的难点,并提出了相应的建议,然后详述了在役装置HAZOP方法的分析流程.最后以中石油某石化公司在役柴油加氢装置为例进行了HAZOP分析,辨识出可能存在的安全隐患和潜在危险,对较高风险提出了必要的安全保护措施和合理的改进建议.结果表明,HAZOP分析是提高在役装置安全性的一种有效手段,其结果为装置安全管理提供了可靠的依据. 相似文献
953.
954.
一种大型低压脉冲阀的研究 总被引:2,自引:0,他引:2
脉冲阀是脉冲袋式除尘器清灰装置的核心部件,其处理能力的大小,喷吹性能的优劣,直接关系到该类除尘设备的运行能耗、设备投资及占地面积,也影响到其更为广泛的应用。介绍了一种新开发的φ120大型低压脉冲阀,在脉冲阀大型化方面作了初步研究。 相似文献
955.
956.
马凤 《湖南环境生物职业技术学院学报》2009,15(2):46-49
阐述了油浆过滤控制系统的硬件配置、分程控制及顺序控制等.通过控制系统的控制,过滤器A、B轮流进行过滤、再生步骤,将油品内51μm以上的颗粒过滤掉,达到提高油品质量、延迟装置检维修期的目标.图1,参5. 相似文献
957.
Qing XIA Rui LIANG Yuning HONG Lili DING Hongqiang REN Yuxiang MAO Mingyu ZHAO 《Frontiers of Environmental Science & Engineering》2009,3(3):369
Batch experiments were conducted to study the short-term biological effects of rare earth ions (La3+, Ce3+) and their mixture on the nitrogen removal in a sequencing batch reactor (SBR). The data showed that higher NH+4―N removal rate, total inorganic nitrogen removal efficiency, and denitrification efficiency were achieved at lower concentrations of rare earth elements (REEs) (<1mg/L). In the first hour of the aeration stage of SBR, the presence of REEs increased the total inorganic nitrogen removal efficiency and NH+4―N removal efficiency by 15.7% and 10%―15%, respectively. When the concentrations of REEs were higher than 1mg/L, the total inorganic nitrogen removal efficiency decreased, and nitrate was found to accumulate in the effluent. When the concentrations of REEs was up to 50.0mg/L, the total inorganic nitrogen removal efficiency was less than 30% of the control efficiency with a high level of nitrate. Lower concentrations of REEs were found to accelerate the nitrogen conversion and removal in SBR. 相似文献
958.
《Process Safety and Environmental Protection》2014,92(6):789-795
Human errors during operation and the resulting increase in operational risk are major concerns for nuclear reactors, just as they are for all industries. Additionally, human reliability analysis together with probabilistic risk analysis is a key element in reducing operational risk. The purpose of this paper is to analyze human reliability using appropriate methods for the probabilistic representation and calculation of human error to be used alongside probabilistic risk analysis in order to reduce the operational risk of the reactor operation. We present a technique for human error rate prediction and standardized plant analysis risk. Human reliability methods have been utilized to quantify different categories of human errors, which have been applied extensively to nuclear power plants. The Tehran research reactor is selected here as a case study, and after consultation with reactor operators and engineers human errors have been identified and adequate performance shaping factors assigned in order to calculate accurate probabilities of human failure. 相似文献
959.
《Process Safety and Environmental Protection》2014,92(6):815-821
The aim of this research was to upgrade the performance of a conventional septic tank (CST) for on-site treatment of sewage with negligible costs. Although CST is known as an inexpensive pre-treatment system, a complementary treatment is required to reuse its output effluent. In this work, the quality of treated wastewater reached to the standard level for irrigation by the innovational changes made in the structure of CST for converting it into an advanced septic reactor (ASR). The modification consists adding some pipe and trays without using any mechanical or electrical equipment.ASR was operated at ambient temperatures in laboratory and pilot-scale. The effects of up-flow velocities (Vup) of 0.4, 0.5, 0.7, 1 and 1.5 m/h and hydraulic retention times (HRT) of 36, 24 and 12 h on the ASR treatment performance were studied.For optimum Vup of 1 m/h and HRT of 24 h and biomass specific methanogenic activity (SMA) of 0.31 mg COD/g VSS d the maximum removal of chemical oxygen demand (COD), biochemical oxygen demand (BOD5) and total suspended solids (TSS) were 86.2%, 79.4% and 95%, respectively.The results showed that ASR is an appropriate alternative for CST for sewage on-site treatment by a low cost modification. 相似文献
960.