全文获取类型
收费全文 | 2277篇 |
免费 | 201篇 |
国内免费 | 862篇 |
专业分类
安全科学 | 217篇 |
废物处理 | 139篇 |
环保管理 | 163篇 |
综合类 | 1488篇 |
基础理论 | 318篇 |
环境理论 | 1篇 |
污染及防治 | 665篇 |
评价与监测 | 98篇 |
社会与环境 | 157篇 |
灾害及防治 | 94篇 |
出版年
2024年 | 9篇 |
2023年 | 49篇 |
2022年 | 146篇 |
2021年 | 147篇 |
2020年 | 124篇 |
2019年 | 96篇 |
2018年 | 121篇 |
2017年 | 135篇 |
2016年 | 138篇 |
2015年 | 157篇 |
2014年 | 181篇 |
2013年 | 240篇 |
2012年 | 200篇 |
2011年 | 209篇 |
2010年 | 173篇 |
2009年 | 164篇 |
2008年 | 156篇 |
2007年 | 112篇 |
2006年 | 162篇 |
2005年 | 98篇 |
2004年 | 67篇 |
2003年 | 58篇 |
2002年 | 59篇 |
2001年 | 53篇 |
2000年 | 55篇 |
1999年 | 41篇 |
1998年 | 37篇 |
1997年 | 26篇 |
1996年 | 22篇 |
1995年 | 33篇 |
1994年 | 13篇 |
1993年 | 13篇 |
1992年 | 12篇 |
1991年 | 9篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有3340条查询结果,搜索用时 15 毫秒
241.
Sorption of pentachlorophenol on surficial sediments: the roles of metal oxides and organic materials with co-existed copper present 总被引:5,自引:0,他引:5
The sorption characteristics of pentachlorophenol (PCP) in the surficial sediments were investigated using a selective extraction procedure. The results show that the Gamma(max) of PCP sorption decreased from 1.60mumolg(-1) to 0.69mumolg(-1) by approximately 60% after selective removal of organic materials from the sediments. The sorption of PCP in the sediments after selective removal of Mn oxides increased nearly up to 600% (from 1.60mumolg(-1) to 11.11mumolg(-1)) and, to a less degree, the PCP sorption in the sediments after simultaneous removal of Fe/Mn oxides (Gamma(max)=3.53mumolg(-1)). The analysis of the data using an additional model indicates that the contribution of Mn oxides to PCP sorption was negative, and Fe oxides and organic materials both have greater potential for sorption of PCP with less contribution from residues including Mn and Fe oxides in the residual fractions determined by a sequential extraction procedure and clay and silicate minerals. The differences in the decreased degrees of PCP sorption with increasing of Cu suggest that competition between Cu and PCP for sorption sites mainly takes place on Fe oxides. 相似文献
242.
采用风险分类-要素分析-风险排序的思路,对北京市核与辐射恐怖事件风险进行分析。根据国际上1998—2006年该类恐怖事件的实例,从事件所涉及的材料、场所角度将核与辐射恐怖事件分为6大类。结合北京市的实际情况进行涉核恐怖事件的要素分析,将北京市各类场所划分为4类敏感区并与5类涉核恐怖事件结合起来,得到北京市核与辐射恐怖事件风险构成图。通过风险分析,笔者认为北京市发生核与辐射恐怖事件风险最大的场所为核研究机构,最容易发生的核与辐射恐怖事件类型为涉及放射源的恐怖事件,结合分析结果对从阻止、探测、响应3个层次上提出了奥运核安保工作的反核恐工作建议。 相似文献
243.
目前,已经有多种方法可以用于石油化工企业的定量风险评价,但是这些方法多数是基于二维的风险分析,不能满足当今社会日趋增长的三维空间的安全管理和风险评价要求,因此,提出了三维的风险场的评价理论,从三维风险等值面来考察风险的分布和风险变化率.该方法采用场论的基本知识,把风险场看作数量场,对不同事故的个人风险及其风险梯度进行叠加,得到个人风险及其变化率.针对同一个危险源产生的爆炸、火灾和中毒三种风险属性,给出了其叠加后的个人风险和个人风险变化率公式,在相应的坐标系中并对二维和三维个人风险的不同的空间分布进行了比较.该方法能够清晰、直观、全面地表示出个人风险场的分布情况,同时能够了解到多个风险共同作用下的风险变化情况. 相似文献
244.
结合鼓浪屿区实施ISO14001标准,探讨了其意义,实施步骤和特点,可为其它风景名胜区建立环境管理体系所借鉴。 相似文献
245.
本文应用地震学综合定量预报方法,结合区域地震活动特点,在华东地区进行了分区实际预报效能检验.结果表明该方法在华东地区有5个区域通过R值检验,效果较好,有4个区域未能通过R值检验;并对通过检验的区域地震活动趋势进行了分析. 相似文献
246.
247.
Composition and source apportionment of PAHs in sediments at river mouths and channel in Kaohsiung Harbor, Taiwan 总被引:1,自引:0,他引:1
Fifty-eight sediment samples were collected in 2009 from the bottom of river mouths near Kaohsiung Harbor (Taiwan) and the harbor channel for the analyses of polycyclic aromatic hydrocarbons (PAHs) using gas chromatography-mass spectrometry (GC-MS). Concentrations of total PAHs varied from 39 to 30,521 ng g(-1) (dry weight); samples collected from the mouths of Love River, Canon River, Jen-Gen River, and Salt River showed the highest PAHs concentrations. This indicates that the major sources of sediment PAHs come from those polluted urban rivers and the harbor channel. In samples collected from the Salt River mouth, approximately 43% of the PAHs are identified as PAHs with 2 or 3 rings. However, samples collected from other locations contain predominantly PAHs with 4 rings (32 to 42%) or 5 and 6 rings (36 to 44%). Emissions from traffic-related sources and waste incineration contribute to the majority of PAHs found in most channel and river mouth sediments. However, coal/oil combustion is the main cause of high concentrations of PAHs observed in the Salt River mouth sediments. Principal component analyses with multivariate linear regression (PCA/MLR) have been used to further quantify the source contributions, and the results show that the contributions of coal/oil combustion, traffic-related and waste incineration are 37%, 33% and 30%, respectively. 相似文献
248.
With the rapid urbanization and industrialization in China, wastewater treatment in rural areas has become an increasing national concern. The selection of appropriate treatment processes closely based on the actual local status is crucial for the prevention of water quality deterioration in rural areas of China. This study presents a full year survey on the performances of various rural wastewater treatment processes at a county level in eastern China including seven three-chamber septic tanks (ST), five micro-power biological facilities (MP), seven constructed wetlands (CW), three stabilization ponds (SP) and five centralized activated sludge treatment plants (AS). It was found that although ST could remove a notable portion of total suspended solids (TSS) and chemical oxygen demand (COD(Cr)), it was ineffective in reducing nutrients and pathogens. Reliability and stability analyses showed that the centralized AS and decentralized CW processes outperformed the SP and MP processes. There were obvious discrepancies between the mean design concentrations, which ensure that 95% of the effluents meet the discharge standards, and the actual effluent concentrations determined for each process. The expected compliance with the tentatively adopted second-grade discharge standards (GB 18918-2002) was unsatisfactory for most of the water quality parameters examined, indicating an urgent need to design more practical discharge standards for decentralized treatment processes. Based on an overall assessment of reliability, stability and cost-effectiveness, the centralized AS was suitable for densely populated towns while the decentralized CW was suitable for sparsely populated villages. 相似文献
249.
250.
超临界水氧化技术处理含油污水研究 总被引:21,自引:0,他引:21
在间歇式实验装置上对超临界水氧化技术处理含油污水进行了研究,主要考察了COD的脱除率与反应时间、温度和压力的关系。实验结果表明,超临界水中的氧化反应能有效去除污水中COD,反应时间、反应温度是影响COD脱除率的重要因素。 相似文献