全文获取类型
收费全文 | 1013篇 |
免费 | 193篇 |
国内免费 | 559篇 |
专业分类
安全科学 | 69篇 |
废物处理 | 62篇 |
环保管理 | 56篇 |
综合类 | 969篇 |
基础理论 | 329篇 |
污染及防治 | 209篇 |
评价与监测 | 55篇 |
社会与环境 | 12篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 18篇 |
2022年 | 48篇 |
2021年 | 74篇 |
2020年 | 38篇 |
2019年 | 60篇 |
2018年 | 126篇 |
2017年 | 55篇 |
2016年 | 66篇 |
2015年 | 57篇 |
2014年 | 60篇 |
2013年 | 97篇 |
2012年 | 98篇 |
2011年 | 110篇 |
2010年 | 77篇 |
2009年 | 95篇 |
2008年 | 72篇 |
2007年 | 79篇 |
2006年 | 70篇 |
2005年 | 61篇 |
2004年 | 54篇 |
2003年 | 65篇 |
2002年 | 43篇 |
2001年 | 39篇 |
2000年 | 42篇 |
1999年 | 29篇 |
1998年 | 19篇 |
1997年 | 20篇 |
1996年 | 18篇 |
1995年 | 24篇 |
1994年 | 11篇 |
1993年 | 15篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有1765条查询结果,搜索用时 789 毫秒
951.
952.
953.
This paper focused on the factors affecting the respiration rate of the digestate taken from a continuous anaerobic two-stage process treating the organic fraction of municipal solid waste (OFMSW). The process involved a hydrolytic reactor (HR) that produced a leachate fed to a submerged anaerobic membrane bioreactor (SAMBR). It was found that a volatile solids (VS) removal in the range 40-75% and an operating temperature in the HR between 21 and 35 °C resulted in digestates with similar respiration rates, with all digestates requiring 17 days of aeration before satisfying the British Standard Institution stability threshold of 16 mg CO2 g VS−1 day−1. Sanitization of the digestate at 65 °C for 7 days allowed a mature digestate to be obtained. At 4 g VS L−1 d−1 and Solid Retention Times (SRT) greater than 70 days, all the digestates emitted CO2 at a rate lower than 25 mg CO2 g VS−1 d−1 after 3 days of aeration, while at SRT lower than 20 days all the digestates displayed a respiration rate greater than 25 mg CO2 g VS−1 d−1. The compliance criteria for Class I digestate set by the European Commission (EC) and British Standard Institution (BSI) could not be met because of nickel and chromium contamination, which was probably due to attrition of the stainless steel stirrer in the HR. 相似文献
954.
以钛酸四丁酯为原料,空心微珠为载体,采用溶胶-凝胶法制备TiO2/beads光催化剂载体,然后浸渍法制备出H4SiW12O40/TiO2/beads表面负载修饰型复合光催化剂,并运用SEM、XRD、FT-IR和DRS对催化剂进行表征和分析.研究了H4SiW12O40/TiO2/beads对亚甲基蓝降解的光催化活性,考察了光强度、pH值、曝气量、底物浓度和催化剂用量等对催化效率的影响.实验结果表明,在中性条件下,H4SiW12O40/TiO2/beads催化剂的投加量为0.25 g/L,浓度为7.5 mg/L的亚甲基蓝溶液在250 W的紫外灯和600 W的可见光灯下光照60 min降解率分别可达到94.5%和55%. 相似文献
955.
混凝法处理含铜电镀废水的实验研究 总被引:2,自引:0,他引:2
以FeSO4、PAC作为絮凝剂去除低浓度电镀废水中的Cu2+,考察了絮凝剂投加量、溶液pH值、搅拌速度和时间等影响因素,结果表明,在各自最佳条件下,PAC和FeSO4对Cu2+的去除可达到99.37%和99.20%,达到《污水综合排放标准》(GB 8978-1996)中一级排放标准。最后通过对FeSO4、PAC和NaOH 3种药剂的综合分析和比较,发现FeSO4絮凝处理低浓度电镀废水中的铜比PAC絮凝、NaOH沉淀法操作简单,污泥产生量少、工业应用性强而且去除率高。 相似文献
956.
对碱激胶凝材料(碱-偏高岭土、碱-矿渣和碱-粉煤灰)与水-水泥体系固化Pb2+进行了试验研究,其中水-水泥体系为对比样。结果表明:对于相同稠度的碱激发胶凝材料,即使Pb2+含量达到2.4%,除了碱-粉煤灰的抗压强度略低外,其他都达到30 MPa以上,满足填埋或做建筑基材的使用要求;与水泥相比,碱激发胶凝材料能显著降低重金属离子(Pb2+)浸出浓度,其规律性与其NH+4交换容量大小的规律性一致,与其固化体的抗压强度的大小没有相关性。 相似文献
957.
MAP沉淀法处理高NH3-N废水,操作简便,处理效果好。本试验以NH3-N浓度为1 000 mg/L的模拟废水为研究对象,研究结果表明,在Mg2+∶PO3-4∶NH+4=1.2∶1.2∶1(摩尔比)、NaOH投加量为675 g/L的条件下NH3-N去除率高达98%以上。试验选择出水pH作为控制反应进程的参数,并建立了出水pH与NH3-N去除率之间的关系。通过调整NaOH投加量控制出水pH在7.5~8之间时,NH3-N去除率最高,可达98%以上。X-衍射图谱及定量分析表明,沉淀物中MAP的纯度较高,具有一定的回收价值。 相似文献
958.
TiO_2/NiFe_2O_4磁性纳米光催化剂的制备及其光催化性能研究 总被引:1,自引:0,他引:1
先用水热法制备了纳米级NiFe2O4磁核,然后采用均匀沉淀法在NiFe2O4磁核表面包覆TiO2,制备了一种新型磁性纳米光催化剂TiO2/NiFe2O4。通过实验确定了制备TiO2/NiFe2O4的最佳Ti/Ni(摩尔比)为30/1,用X射线衍射(XRD)、透射电子显微镜(TEM)、紫外—可见(UV—Vis)漫反射、热重—差示扫描量热分析(TG—DSC)、磁力学测试等手段对其进行了表征。以甲基橙的水溶液为模拟污染物,评价了TiO2/NiFe2O4的光催化性能,在光照2h后,甲基橙的脱色率可达98.5%。研究结果表明,TiO2/NiFe2O4是一种可重复使用的高效光催化剂。 相似文献
959.
Mohammad A. Al-Ghouti Yehya S. Al-Degs Majeda A.M. Khraisheh Mohammad N. Ahmad Stephen J. Allen 《Journal of environmental management》2009,90(11):3520-3527
The investigations into structural changes which occur during adsorbent modification and the adsorption mechanisms are essential for an effective design of adsorption systems. Manganese oxides were impregnated onto diatomite to form the type known as δ-birnessite. Initial investigations established the effectiveness of manganese oxides-modified diatomite (MOMD) to remove basic and reactive dyes from aqueous solution. The adsorption capacity of MOMD for methylene blue (MB), hydrolysed reactive black (RB) and hydrolysed reactive yellow (RY) was 320, 419, and 204 mg/g, respectively. Various analytical techniques were used to characterise the structure and the mechanisms of the dye adsorption process onto MOMD such as Fourier transform infrared (FTIR), X-ray diffraction (XRD) and atomic absorption spectrometry (A.A.). A small shift to higher values of the d-spacing of dye/MOMD was observed indicating that a small amount of the dye molecules were intercalated in the MOMD structure and other molecules were adsorbed on the external surface of MOMD. Two mechanisms of dye adsorption onto MOMD were proposed; intercalation of the dye in the octahedral layers and adsorption of the dye on the MOMD external surface. Moreover, the results demonstrated that the MOMD structure was changed upon insertion of MB and RY with an obvious decrease in the intensity of the second main peak of the MOMD X-ray pattern. 相似文献
960.
Braj B. Singh Jitendra Kumar Virendra S. Rana Anuradha Mishra 《Journal of environmental science and health. Part. B》2016,51(8):558-570
A new series of halogenated Schiff bases was synthesized by the condensation of 5-fluoro-2-hydroxy acetophenone and 3,5-dichloro-2-hydroxy acetophenone with different alkyl amines, namely propyl, pentyl, hexyl, heptyl, octyl, nonyl, dodecyl, tetradecyl, hexadecyl, and octadecyl amines, under microwave irradiation. Newly formed molecules were characterized by Infrared and nuclear magnetic resonance (1H NMR and 13C NMR) spectroscopic techniques. Further, the Schiff bases were screened for antifungal bioassay, and the results showed potential fungicidal activity against two very important plant infecting fungi, viz. Rhizoctonia solani and Sclerotium rolfsii. Among the screened compounds, 2,4-dichloro-2-[1-(propylimino)ethyl]phenol was found to be the most active compound against both R. solani (ED50 8.02 mg L?1) and S. rolfsii (ED50 21.51 mg L?1) followed by 2,4-dichloro-2-[1-(pentylimino) ethyl]phenol (ED50 13.02 and 29.57 mg L?1, respectively). The synthesized compounds were also screened for antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH)-free radical scavenging technique. All the compounds showed very low to moderate activity as compared with Gallic acid. 相似文献