全文获取类型
收费全文 | 5284篇 |
免费 | 717篇 |
国内免费 | 3066篇 |
专业分类
安全科学 | 683篇 |
废物处理 | 235篇 |
环保管理 | 622篇 |
综合类 | 5041篇 |
基础理论 | 841篇 |
环境理论 | 2篇 |
污染及防治 | 1137篇 |
评价与监测 | 314篇 |
社会与环境 | 136篇 |
灾害及防治 | 56篇 |
出版年
2024年 | 17篇 |
2023年 | 125篇 |
2022年 | 245篇 |
2021年 | 334篇 |
2020年 | 297篇 |
2019年 | 326篇 |
2018年 | 306篇 |
2017年 | 281篇 |
2016年 | 398篇 |
2015年 | 437篇 |
2014年 | 495篇 |
2013年 | 622篇 |
2012年 | 671篇 |
2011年 | 619篇 |
2010年 | 469篇 |
2009年 | 475篇 |
2008年 | 332篇 |
2007年 | 505篇 |
2006年 | 446篇 |
2005年 | 318篇 |
2004年 | 256篇 |
2003年 | 226篇 |
2002年 | 159篇 |
2001年 | 146篇 |
2000年 | 125篇 |
1999年 | 104篇 |
1998年 | 52篇 |
1997年 | 57篇 |
1996年 | 37篇 |
1995年 | 42篇 |
1994年 | 32篇 |
1993年 | 19篇 |
1992年 | 22篇 |
1991年 | 13篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有9067条查询结果,搜索用时 31 毫秒
141.
142.
详细介绍了唐钢3#高炉干法煤气净化系统。该系统与湿式高炉煤气净化系统相比,提高了煤气质量,节能效果显著,具有广泛的推广使用价值。 相似文献
143.
144.
CMK-3 and C-FDU-15 samples were synthesized using hard-templating and evaporationinduced self-assembly(EISA) methods,respectively.The pore structures of CMK-3 and CFDU-15 as well as commercial activated carbon were characterized by means of X-ray diffraction,field emission scanning electron microscopy,transmission electron microscopy,and N_2 adsorption–desorption.Adsorption of NO was investigated by means of thermogravimetric analysis,temperature-programmed desorption of NO + O_2,and in situ diffuse reflectance Fourier transform infrared spectroscopy.The results show that the CMK-3 and C-FDU-15 materials possessed ordered and uniform structures.The coadsorption capacity of NO and O_2 decreased in the sequence CMK-3(88.6 mg/g) C-FDU-15(71.7 mg/g) AC(25.3 mg/g).There were two main adsorption species on CMK-3 and CFDU-15:nitrite and nitrate.Nitrite is converted to nitrate easily.However,the adsorption species were more complex on AC,with nitrite being the main species.Moreover,CMK-3 and C-FDU-15 exhibit excellent regeneration efficiency compared with AC.The excellent NO adsorption performance of CMK-3 and C-FDU-15 was associated with their ordered mesoporous structures and high surface areas.The research provides more options for NO adsorption in the future. 相似文献
145.
电晕氧化结合化学吸收脱除烟气中NO2实验研究 总被引:2,自引:0,他引:2
实验研究了直流电晕湿空气自由基簇射结合25%的NaOH溶液吸收的NOx脱除过程.结果表明:通过调节流过喷嘴电极中的空气流量,可以得到稳定的流光电晕;空气中水蒸汽对NOx脱除效率有影响;在反应器内同时有HNO2和HNO3生成;实验工况下,反应器NOx转化率45%以上,经吸收液吸收后系统总脱氮效率可达70%. 相似文献
146.
以一座处理量为60m3·d-1的SBR法中试系统为研究对象,将三层网络智能控制技术引入SBR工艺中,并对该智能控制系统的深度脱氮效果和稳定性进行了中试研究.在SBR法硝化反硝化过程中,pH、DO、ORP曲线上会出现反映生物脱氮进程的特征点,以pH、DO、ORP为控制参数建立的智能控制策略可以准确判断反应的终点,避免了过度曝气,在保证深度脱氮的前提下节省了能耗.经过10个月的稳定运行,即使在温度较低的情况下,该SBR法智能控制中试系统出水的各项指标完全能够达到国家污水排放一级标准,并且达到了深度脱氮的效果,出水COD低于50 mg·L-1,总氮低于5 mg·L-1. 相似文献
147.
148.
149.
IntroductionAtmosphericnitrousoxide (N2 O)isaveryradioactivelyactivegreenhousegas,alsocontributingtothedepletionofozonelayerofstratosphere .AtmosphericN2 Omainlyoriginatedfromnitrificationanddenitrificationinterrestrialecosystems.Grasslandecosystem ,accoun… 相似文献
150.
SUN Zhi-gao~ 《环境科学学报(英文版)》2007,(8)
The nitrogen(N)distribution and cycling of atmosphere-plant-soil system in the typical meadow Calamagrostis angustifolia wetland (TMCW)and marsh meadow Calamagrostis angustifolia wetland(MMCW)in the Sanjiang plain were studied by a compartment model.The results showed that the N wet deposition amount was 0.757 gN/(m~2.a),and total inorganic N(TIN)was the main body (0.640 gN/(m~2.a)).The ammonia volatilization amounts of TMCW and MMCW soils in growing season were 0.635 and 0.687 gN/m~2, and the denitrification gaseous lost amounts were 0.617 and 0.405 gN/m~2,respectively.In plant subsystem,the N was mainly stored in root and litter.Soil organic N was the main N storage of the two plant-soil systems and the proportions of it were 93.98% and 92.16%, respectively.The calculation results of N turnovers among compartments of TMCW and MMCW showed that the uptake amounts of root were 23.02 and 28.18 gN/(m~2.a)and the values of aboveground were 11.31 and 6.08 gN/(m~2.a),the re-translocation amounts from aboveground to root were 5.96 and 2.70 gN/(m~2.a),the translocation amounts from aboveground living body to litter were 5.35 and 3.38 gN/(m~2.a),the translocation amounts from litter to soil were larger than 1.55 and 3.01 gN/(m~2.a),the translocation amounts from root to soil were 14.90 and 13.17 gN/(m~2.a),and the soil(0-15 cm)N net mineralization amounts were 1.94 and 0.55 gN/(m~2.a), respectively.The study of N balance indicated that the two plant-soil systems might be situated in the status of lacking N,and the status might induce the degradation of C.angustifolia wetland. 相似文献