全文获取类型
收费全文 | 5890篇 |
免费 | 346篇 |
国内免费 | 2009篇 |
专业分类
安全科学 | 507篇 |
废物处理 | 336篇 |
环保管理 | 460篇 |
综合类 | 3289篇 |
基础理论 | 929篇 |
环境理论 | 1篇 |
污染及防治 | 1975篇 |
评价与监测 | 251篇 |
社会与环境 | 245篇 |
灾害及防治 | 252篇 |
出版年
2024年 | 14篇 |
2023年 | 109篇 |
2022年 | 304篇 |
2021年 | 248篇 |
2020年 | 191篇 |
2019年 | 177篇 |
2018年 | 234篇 |
2017年 | 268篇 |
2016年 | 288篇 |
2015年 | 349篇 |
2014年 | 448篇 |
2013年 | 618篇 |
2012年 | 476篇 |
2011年 | 550篇 |
2010年 | 416篇 |
2009年 | 361篇 |
2008年 | 381篇 |
2007年 | 330篇 |
2006年 | 346篇 |
2005年 | 246篇 |
2004年 | 195篇 |
2003年 | 182篇 |
2002年 | 195篇 |
2001年 | 190篇 |
2000年 | 176篇 |
1999年 | 158篇 |
1998年 | 162篇 |
1997年 | 121篇 |
1996年 | 109篇 |
1995年 | 87篇 |
1994年 | 70篇 |
1993年 | 63篇 |
1992年 | 54篇 |
1991年 | 29篇 |
1990年 | 37篇 |
1989年 | 13篇 |
1988年 | 9篇 |
1987年 | 12篇 |
1986年 | 7篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 1篇 |
排序方式: 共有8245条查询结果,搜索用时 539 毫秒
671.
672.
Haiying Lu Linzhang Yang Sadaf Shabbir Yonghong Wu 《Environmental science and pollution research international》2014,21(14):8782-8791
To explain the detailed process involved in phosphorus removal by periphyton, the periphyton dominated by photoautotrophic microorganisms was employed in this study to remove inorganic phosphorus (P i ) from wastewater, and the removal kinetics and isotherms were then evaluated for the P i removal process. Results showed that the periphyton was capable of effectively removing P i that could completely remove the P i in 24 h at an initial P i concentration of 13 mg P L?1. Furthermore, the P i removal process by the periphyton was dominated by adsorption at initial stage (~24 h), which involved physical mechanistic process. However, this P i adsorption process was significantly influenced by environmental conditions. This work provides an insight into the understanding of phosphorus adsorption by periphyton or similar microbial aggregates. Graphical Abstract
? 相似文献
673.
Defu Xu Yinjuan Wu Yingxue Li Alan Howard Xiaodong Jiang Yidong Guan Yongxia Gao 《Environmental science and pollution research international》2014,21(17):10108-10119
A surface- and vertical subsurface-flow-constructed wetland were designed to study the response of chlorophyll and antioxidant enzymes to elevated UV radiation in three types of wetland plants (Canna indica, Phragmites austrail, and Typha augustifolia). Results showed that (1) chlorophyll content of C. indica, P. austrail, and T. augustifolia in the constructed wetland was significantly lower where UV radiation was increased by 10 and 20 % above ambient solar level than in treatment with ambient solar UV radiation (p?0.05). (2) The malondialdehyde (MDA) content, guaiacol peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) activities of wetland plants increased with elevated UV radiation intensity. (3) The increased rate of MDA, SOD, POD, and CAT activities of C. indica, P. australis, and T. angustifolia by elevated UV radiation of 10 % was higher in vertical subsurface-flow-constructed wetland than in surface-flow-constructed wetland. The sensitivity of MDA, SOD, POD, and CAT activities of C. indica, P. austrail, and T. augustifolia to the elevated UV radiation was lower in surface-flow-constructed wetland than in the vertical subsurface-flow-constructed wetland, which was related to a reduction in UV radiation intensity through the dissolved organic carbon and suspended matter in the water. C. indica had the highest SOD and POD activities, which implied it is more sensitive to enhanced UV radiation. Therefore, different wetland plants had different antioxidant enzymes by elevated UV radiation, which were more sensitive in vertical subsurface-flow-constructed wetland than in surface-flow-constructed wetland. 相似文献
674.
Abdullah Mofarrah Tahir Husain Bing Chen 《Journal of Material Cycles and Waste Management》2014,16(3):482-490
In order to explore the beneficial utilization of heavy oil fly ash (HOFA) generated in the power plants, the present study is intended to optimize the chromium(VI) [Cr(VI)] adsorption on activated carbon produced from HOFA. The raw HOFA obtained from a power plant was washed by nitric/hydrochloric acid and activated at 800 °C with a holding time of 60 min to produce fly ash activated carbon (FAC). Phosphoric acid was used as a chemical agent to improve the surface characteristics of the HOFA during the activation process. Batch adsorption experiments were employed to evaluate the effects of different parameters such as initial Cr(VI) concentration, pH, and FAC dose on the removal of Cr(VI) from aqueous solution. A total of 17 adsorption experimental runs were carried out employing the detailed conditions followed the response surface methodology based on the Box–Behnken design. The results indicate that developed FAC has the potential for removing Cr(VI) from wastewater. Under the test conditions, a maximum of 91.51 % Cr(VI) removal efficiency was achieved. 相似文献
675.
南京大气细粒子中重金属污染特征及来源解析 总被引:2,自引:0,他引:2
利用2011年1月、4月、7月和10月在南京市区和北郊采集的气溶胶样品,研究了南京大气细粒子中zn、Ph、Hg、As和cd5种重金属的污染水平,通过元素相关性分析和因子分析方法,对细粒子中这些重金属的污染来源进行了初步解析。结果表明,南京大气细粒子及其重金属污染严重,北郊普遍比市区严重;As严重超标,cd在南京北郊超标约5倍,zn在市区与北郊的质量浓度均高于其他重金属元素。每种重金属的浓度均随季节而变化。市区细粒子中,As和zn可能主要与燃煤、轮胎灰尘和建筑扬尘等有关,Pb、Hg和cd主要来自交通尘、城市垃圾焚烧等。北郊细粒子中,As、Hg和zn主要来源于燃煤、钢铁冶炼等工业,Pb和cd主要与农作物秸秆燃烧、汽车尾气、道路扬尘等影响有关。 相似文献
676.
以氯化铁为铁源,硼氢化钠为还原剂,壳聚糖为稳定剂,采用液相还原法制备壳聚糖稳定纳米铁(CS-nZⅥ);研究了印染废水中常见助剂NaNO3、Na2SO4、NaH2PO4、K2Cr2O7、EDTA二钠盐存在下,超声波辅助CS-nZⅥ对酸性品红(AF)降解的影响。结果表明,反应15 min,0.01 g CS-nZⅥ对25 mL、100 mg/L AF的去除率高达99.9%;各种助剂的存在使得纳米铁表面不同程度失活,阻碍反应的进行,使得AF的去除率下降。NaNO3、K2Cr2O7、EDTA二钠盐与纳米铁发生反应,与AF存在明显的竞争作用。重复利用实验表明,CS-nZⅥ重复利用7次仍具有一定的反应活性。此外,CS-nZⅥ对加标(50 mg/L)实际废水中AF的去除率达到99%以上,表明CS-nZⅥ是一种潜在的环境修复材料。 相似文献
677.
采用两级氧化法处理油田压裂返排液。在次氯酸钠、次氯酸钙、过氧化氢、高锰酸钾4种氧化剂中,次氯酸钠的氧化效果最好。以次氯酸钠作为一级氧化剂,进行一级氧化处理;再分别采用次氯酸钙、过氧化氢、高锰酸钾进行二级氧化处理。在次氯酸钠加入量为40mL/L、一级氧化反应时间为30min、二级氧化反应时间为30min、初始废水COD为3976mg/L的条件下,二级氧化剂过氧化氢、次氯酸钙、高锰酸钾的最佳加入量分别为80,40,40mL/L,对应的COD去除率分别为82.60%,71.50%,83.50%。 相似文献
678.
采用自制的负载型CuO-ZnO-CeO2/γ-Al2O3催化剂,常温常压下通过紫外辐照-催化湿式氧化技术处理酸性大红GR模拟染料废水。考察了催化剂加入量、H2O2加入量、废水pH、反应时间、初始酸性大红GR质量浓度等对废水脱色率的影响。实验得到最佳工艺条件为初始酸性大红GR质量浓度200mg/L,催化剂加入量10.0g/L,H2O2加入量2.0mL/L,废水pH4,反应时间2h。最佳工艺条件下废水脱色率达99.33%。 相似文献
679.
以堇青石蜂窝陶瓷(CC)为载体,采用浸渍法制备了堇青石负载Pd和过渡金属混合氧化物催化剂,记作Pd-M-Mn(M=Cu,Co,Fe,Ni)/CC。实验结果表明:Pd-Co-Mn/CC催化剂的催化活性最高;随着Pd负载量的增加,CO转化率提高;当Pd负载量为1.00%时,反应温度为150℃时CO转化率达到98%,200℃时CO转化率达到100%;在反应温度150℃条件下,Pd-Co-Mn/CC催化剂(Pd负载量1.00%)的CO转化率在前30h内小幅度下降,随后稳定在90%以上,反应100h后,催化剂表面颜色由黑色变为棕褐色。 相似文献
680.