全文获取类型
收费全文 | 1891篇 |
免费 | 269篇 |
国内免费 | 839篇 |
专业分类
安全科学 | 77篇 |
废物处理 | 65篇 |
环保管理 | 276篇 |
综合类 | 1687篇 |
基础理论 | 305篇 |
污染及防治 | 232篇 |
评价与监测 | 258篇 |
社会与环境 | 91篇 |
灾害及防治 | 8篇 |
出版年
2024年 | 4篇 |
2023年 | 41篇 |
2022年 | 73篇 |
2021年 | 69篇 |
2020年 | 101篇 |
2019年 | 73篇 |
2018年 | 82篇 |
2017年 | 114篇 |
2016年 | 120篇 |
2015年 | 168篇 |
2014年 | 159篇 |
2013年 | 193篇 |
2012年 | 207篇 |
2011年 | 198篇 |
2010年 | 147篇 |
2009年 | 132篇 |
2008年 | 101篇 |
2007年 | 135篇 |
2006年 | 148篇 |
2005年 | 107篇 |
2004年 | 74篇 |
2003年 | 107篇 |
2002年 | 69篇 |
2001年 | 56篇 |
2000年 | 56篇 |
1999年 | 52篇 |
1998年 | 35篇 |
1997年 | 35篇 |
1996年 | 27篇 |
1995年 | 30篇 |
1994年 | 19篇 |
1993年 | 8篇 |
1992年 | 6篇 |
1991年 | 11篇 |
1990年 | 5篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有2999条查询结果,搜索用时 562 毫秒
941.
根据青海湖流域土壤类型图采集了49 个表土样品,研究了这些样品的有机碳和黑碳的
含量特征及其储量。研究得出:六类土壤的有机碳含量都比较高,说明青海湖流域土壤的储碳能
力比较强;总体来说,六类土壤的黑碳含量都不高,但是焦炭的含量是相当高的,而烟炱的含量
较低;焦炭和黑碳的相关性极高,说明焦炭是黑碳的主要组成部分,并且说明二者具有相同的来
源;由于焦炭主要是由生物质燃烧生成的,故而这六类土壤的黑碳也多是由生物质燃烧生成的;
六类土壤总面积为18416.15 km2 (占流域土壤总面积的78%),有机碳总储量为119.56×106 t,
黑碳总储量为4.36×106 t。 相似文献
942.
943.
对邻菲哕啉分光光度法测定水中总铁的方法进行了改进:采用50ml比色管水浴还原水样--分光光度计比色测定水中总铁。测试结果表明,改进法精密度和准确度均优于标准方法,是测定水中总铁较为理想的方法 相似文献
944.
945.
用浓硝酸和高氯酸混酸体系在超声波作用下消解滤膜,加入稳定剂琼脂,用超声波震荡15min制成悬浮液,用火焰原子吸收光谱法测定TSP中的锌、铅和铁的含量,并以传统浓HNO3-H2O2湿法消解-原子吸收光谱法的测定结果为参考对测定值进行t检验,结果表明:RSD≤3.27%(n=6),两种方法的相对误差<±0.85%,且两种方法无显著性差异,说明悬浮液进样法的测定结果准确、可靠。 相似文献
946.
947.
Evaluation of ambient air quality in Guangzhou, China 总被引:5,自引:0,他引:5
On the basis of the reported air quality index (API) and air pollutant monitoring data provided by the Guangzhou Environment Monitoring Stations over the last twenty-five years, the characteristics of air quality, prominent pollutants, and variation of the average annual concentrations of SOE, NOE, total suspended particulate (TSP), fine particulates (PM10), CO and dustfall in Guangzhou City were analyzed. Results showed that TSP was the prominent pollutant in the ambient air environment of Guangzhou City. Of the prominent pollutants, TSP accounted for nearly 62%, SOE 12.3%, and NOx 6.4%, respectively. The average API of Guangzhou over 6 years was higher than that of Beijing, Tianjin, Nanjing, Hangzhou, Suzhou and Shanghai, and lower than that of Shenzhen, Zhuhai and Shantou. Concentrations of air pollutants have shown a downward trend in recent years, but they are generally worse than ambient air quality standards for USA, Hong Kong and EU. SOE and NOx pollution were still serious, impling that waste gas pollution from all kinds of vehicles had become a significant problem for environmental protection in Guangzhou. The possible causes of worsening air quality were also discussed in this paper. 相似文献
948.
The pollutant loads of surface runoff in an urban tourist area have been investigated for two years in the Wuhan City Zoo, China. Eight sampling sites, including two woodlands, three animal yards, two roofs and one road, were selected for sampling and study. The results indicate that pollutants ranked in a predictable order of decreasing load (e.g. animal yard〉roof〉woodland〉road), with animal yards acting as the key pollution source in the zoo. Pollutants were transported mainly by particulate form in runoff. Particulate nitrogen and particulate phosphorous accounted on average for 61%, 78% of total pollutant, respectively, over 13 monitored rainfall events. These results indicate the treatment practices should be implemented to improve particulate nutrient removal. Analysis of the M(V) curve indicate that no first flush effect existed in the surface runoff from pervious areas (e.g. woodland, animal ground yard), whereas a first flush effect was evident in runoff from impervious surfaces (e.g. animal cement yard, roof, road). 相似文献
949.
Distribution of PBDEs in air particles from an electronic waste recycling site compared with Guangzhou and Hong Kong, South China 总被引:4,自引:0,他引:4
Air samples of total suspended particles (TSP, particles less than 30-60 microm), and particles with aerodynamic diameter smaller than 2.5 microm (PM(2.5)) were collected simultaneously at Guiyu (an electronic waste recycling site), three urban sites in Hong Kong and two urban sites in Guangzhou, South China from 16 August to 17 September 2004. Twenty-two PBDE congeners (BDE-3, -7, -15, -17, -28, -49, -71, -47, -66, -77, -100, -119, -99, -85, -126, -154, -153, -138, -156, -184, -183, -191) in TSP and PM(2.5) were measured. The results showed that the overall average concentrations of TSP and PM(2.5) collected at Guiyu were 124 and 62.1 microg m(-3), respectively. The monthly concentrations of the sum of 22 BDE congeners contained in TSP and PM(2.5) at Guiyu were 21.5 and 16.6 ng m(-3), with 74.5 and 84.3%, contributed by nine congeners (BDE-28, -47, -66, -100, -99, -154, -153, -183 and -191 respectively). This pattern was similar to Tsuen Wan site of Hong Kong. Two urban sites of Guangzhou had the same congener pattern, but were different from Yuen Long and Hok Tsui sites of Hong Kong. The results also showed that the amount of mono to penta brominated congeners, which are more toxic, accounted for 79.4-95.6% of Sigma(22)PBDEs from all sites. All congeners tested in Guiyu were up to 58-691 times higher than the other urban sites and more than 100 times higher than other studies reported elsewhere. The higher concentration in the air was due to heating or opening burning of electronic waste since PBDEs are formed when plastics containing brominated flame retardants are heated. 相似文献
950.
河口滨岸悬浮颗粒物中多环芳烃分布与风险评价 总被引:4,自引:0,他引:4
通过收集长江口滨岸13个典型采样点上覆水中的悬浮颗粒物,分析了悬浮颗粒中多环芳烃(PAHs)的含量水平,探讨了PAHs的来源,并进行了生态风险评价。研究结果显示,EPA14种优控PAHs的总量在600~12 308 ng/g 之间,平均值为5 373 ng/g,其组成主要以3环和4环PAH为主。受附近陆源输入的影响,顾路采样点的PAHs含量最高,此外,临近城市排污、滨岸工业开发区及河道排污口的采样点PAHs含量也较高,如石洞口、金山、白茆、浏河口等。结合PAHs不同环数的相对丰度与同分异构体荧蒽/芘、芘/苯并[a]蒽比值,初步推断出人类油污染及矿物燃料的不完全燃烧是悬浮颗粒物中PAHs的主要来源。此外,参照有关环境质量标准,发现悬浮颗粒物中萘、菲、芴、蒽/苯并[b]荧蒽和苯并[k]荧蒽等化合物已经产生不同程度的生物影响效应。 相似文献