全文获取类型
收费全文 | 2232篇 |
免费 | 180篇 |
国内免费 | 412篇 |
专业分类
安全科学 | 545篇 |
废物处理 | 56篇 |
环保管理 | 290篇 |
综合类 | 1412篇 |
基础理论 | 145篇 |
污染及防治 | 158篇 |
评价与监测 | 85篇 |
社会与环境 | 52篇 |
灾害及防治 | 81篇 |
出版年
2024年 | 36篇 |
2023年 | 87篇 |
2022年 | 112篇 |
2021年 | 159篇 |
2020年 | 143篇 |
2019年 | 87篇 |
2018年 | 83篇 |
2017年 | 59篇 |
2016年 | 84篇 |
2015年 | 108篇 |
2014年 | 286篇 |
2013年 | 121篇 |
2012年 | 125篇 |
2011年 | 133篇 |
2010年 | 95篇 |
2009年 | 109篇 |
2008年 | 117篇 |
2007年 | 134篇 |
2006年 | 105篇 |
2005年 | 86篇 |
2004年 | 90篇 |
2003年 | 72篇 |
2002年 | 76篇 |
2001年 | 44篇 |
2000年 | 48篇 |
1999年 | 44篇 |
1998年 | 22篇 |
1997年 | 23篇 |
1996年 | 18篇 |
1995年 | 21篇 |
1994年 | 26篇 |
1993年 | 12篇 |
1992年 | 19篇 |
1991年 | 19篇 |
1990年 | 10篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 2篇 |
排序方式: 共有2824条查询结果,搜索用时 15 毫秒
871.
Removal of citrate and hypophosphite binary components using Fenton,
photo-Fenton and electro-Fenton processes 总被引:1,自引:0,他引:1
Both citrate and hypophosphite in aqueous solution were degraded by advanced oxidation processes (Fe2+/H2O2, UV/Fe2+/H2O2, and electrolysis/ Fe2+/H2O2) in this study. Comparison of these techniques in oxidation efficiency was undertaken. It was found that Fenton process could not degrade completely citrate in the presence of hypophosphite since it caused a series inhibition. Therefore, UV light (photo-Fenton) or electron current (electro-Fenton) was applied to improve the degradation efficiency of the Fenton process. Results showed that both photo-Fenton and electro-Fenton processes could overcome the inhibition of hypophosphite, especially the electro-Fenton. 相似文献
872.
873.
水体中污染物的排放必须与水体的水环境容量相适应.在综合考虑城市经济发展与水资源利用状况前提下,首先,通过监测资料对九寨沟县辖区内主要污水受纳水体--白水江的地表水环境质量现状进行了评价,同时,结合对白水江流域污染源的现场调查,明确了河道水体的主要污染因子为CODCr和NH3-N,并预测了其在远、近规划期内的排放量;其次,在对河段进行功能分区基础上,采用一维稳态模型下的段首控制法计算了水环境容量.结果表明,2005年白水江CODCr与NH3-N的理论水环境容量分别为39.44 T/d和2.32 T/d,2005年其实际水环境容量分别为26.42 T/d和1.55 T/d.白水江水环境容量在近、远期内均能满足城市发展要求,但鉴于九寨沟县的旅游定位功能,应采取更为严格的控制标准;最后,结合九寨沟城镇生活污染源、农村面源与工业污染源的相应特点,提出了全面提升九寨沟县水环境质量的规划方案,为白水江实施污染总量控制与水环境管理提供了科学依据. 相似文献
874.
875.
在热泵蒸发过程中,二次蒸汽压缩比是个至关重要的参数,它直接关系到热泵蒸发的经济程度。对热泵蒸发中的传热过程及可利用的余热作了全面分析。最后对热泵蒸发在浓缩垃圾渗滤液中的应用进行了探讨。 相似文献
876.
The article investigated the adsorption of Hg(II) on Macrocystis pyrifera and Undaria pinnatifida in monometallic system and in the presence of Zn(II), Cd(II) and Ni(II). 相似文献
877.
Material conversion from paper sludge ash (PSA) in NaOH solution was attempted to synthesize the adsorbent for removal of
inorganic pollutants, such as Pb2+, NH4
+ and PO4
3?? from aqueous solution. PSA of 0.5 g was added into 10 mL of 3 mol/L NaOH
solution, and then heated at 80, 120, and 160°C for 6–48 hr to obtain the product. PSA mainly composed of two crystalline phases,
gehlenite (Ca2Al2SiO7) and anorthite (CaAl2Si2O8), and amorphous phase. Hydroxysodalite (Na6Al6Si6O24 8H2O) was formed at
80°C, and anorthite dissolved, whereas gehlenite remained una ected. Katoite (Ca3Al2SiO4(OH)8) was formed over 120°C, and
hydroxycancrinite (Na8(OH)2Al6Si6O24 2H2O) was formed at 160°C, due to the dissolution of both gehlenite and anorthite. Specific
surface areas of the products were almost same and were higher than that of raw ash. Cation exchange capacities (CECs) of the products
were also higher than that of raw ash, and CEC obtained at lower temperature was higher. Removal abilities of products for Pb2+, NH4
+,
and PO4
3?? were higher than that of raw ash.With increasing reaction temperature, the removal e ciencies of Pb2+ and NH4
+ decreased
due to the decrease of CEC of the product, while removal e ciency for PO4
3?? was almost same. The concentrations of Si and Al in the
solution and the crystalline phases in the solid during the reaction explain the formation of the product phases at each temperature. 相似文献
878.
The experimental study on ozonation of ethylenethiourea(ETU) is conducted.The reaction of gas-phase ETU with 0.63 × 10-6 mol/L ozone is carried out in a 200-L reaction chamber.The secondary organic aerosol(SOA) resulted from the ozonation of gas-phase ETU is observed with a scanning mobility particle size(SMPS).The rapid exponential growth of SOA reveals that the atmospheric lifetime of ETU vapor towards ozone reaction is less than four days.The ozonation of dry ETU particles,ETU-contained water droplets an... 相似文献
879.
880.
分布式电源改变了配电网的运行模式,对配电网的运行管理提出了新的挑战和要求。针对这种情况,运用一、二次融合的设计理念,提出了一种适用于分布式电源管理的新型智能开关设计,应用结果表明:该智能开关采用电子式互感器采集全部运行数据,具备三段式过流方向保护、零序方向保护、电能量计量等功能,可以很好地解决分布式电源管理及多电源线路的故障判断与故障隔离等问题。 相似文献