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211.
W. Z. Khan 《Environmental monitoring and assessment》2001,71(2):123-142
The reduction of SO2 by ammonia gas additionduring staged combustion of bituminous coal has beenstudied in a 2 m high fluidized bed combustor of 30 cmstatic bed height and a freeboard height of 100 cm.The coal was introduced to the combustor at 42 cmabove the distributor and the ammonia gas was injectedat 52 cm above the distributor by an uncooledstainless steel injector. Experiments were carriedout to investigate effects of ammonia gas injection onSO2 emissions of (i) air staged levels, (ii) excess air levels, (iii) primary air factor, PAF(ratio of primary to stoichiometric air), (iv) NH3:SO2 molar ratio, and (v) fluidizingvelocity. Experiments were carried out under a newtechnique of air staging called Pseudo-stagedCombustion, maintaining the excess air level andfluidizing velocity between 17 and 70% and between0.7 and 2.0 m sec-1, respectively. A maximum reduction of92% was obtained at 37% excess air, at NH3:SO2 molar ratio of 5.5. The effective NH3:SO2 molar ratio was found to be between 3.0 and5.5, which is true for all staging and excess air levels.A greater removal of SO2 with NH3 injectionduring staged combustion is probably due to this newstaging technique. The Pseudo-staging reducestemperature through the freeboard and flue for theoccurance of as NH3 + SO2 reactions. Thesereactions are reported to be low temperaturereactions. The NH3 carry over was less than 83 ppm for all operating conditions. The present studydemonstrates that staged combustion coupled withammonia injection can reduce SO2 emissions. 相似文献
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214.
介绍了国内燃煤电厂"烟塔合一"技术的应用现状,结合实际情况阐述了"烟塔合一"环境防护距离设置的必要性,列举工程实例说明现阶段大气环境防护距离估算方法。 相似文献
215.
针对高瓦斯易自燃厚煤层开采时所引发的系列安全问题,以研究煤层超前注水为切入点,以义马耿村矿12200综放工作面为研究背景,展开煤层注水工艺参数及效果的研究。研究发现,采用"多排扇形立体注水"可使煤体含湿率显著增加。对煤体注水前后相关参数的实测数据分析表明,"多排扇形立体注水"的超前压注工艺措施对降低工作面及进回风顺槽粉尘浓度、预防采空区浮煤自燃及抑制工作面瓦斯涌出的作用显著。此研究对高瓦斯易自燃综放面的综合灾害防治具有一定的理论及现实意义。 相似文献
216.
A HPLC-MS/MS method is presented for the simultaneous determination of frequently used artificial sweeteners (ASs) and the main metabolite of aspartame (ASP), diketopiperazine (DKP), in environmental water samples using the direct-injection (DI) technique, thereby achieving limits of quantification (LOQ) of 10 ng L−1. For a reliable quantification of ASP pH should be adjusted to 4.3 to prevent formation of the metabolite. Acesulfame (ACE), saccharin (SAC), cyclamate (CYC) and sucralose (SUC) were ubiquitously found in water samples. Highest concentrations up to 61 μg L−1 of ACE were found in wastewater effluents, followed by surface water with concentrations up to 7 μg L−1, lakes up to 600 ng L−1 and groundwater and tap water up to 70 ng L−1. The metabolite DKP was only detected in wastewater up to 200 ng L−1 and at low detection frequencies. 相似文献
217.
喷射系统是水泥窑烟气SNCR脱硝技术的重要组成部分,对日产5 kt新型干法水泥烟气SNCR脱硝项目中的喷射系统进行了设计和实验研究.结果表明,系统压力设计、分配调节设计、喷枪布置和喷枪雾化能力是影响烟气脱硝效率的关键因素.在氨水质量分数为13.5%,喷入点温度904℃,n(NH3) /n(NH3)为1.2条件下,系统压力能够稳定运行在0.3~0.6 MPa之间、喷枪雾化颗粒度平均直径在50μm左右、喷枪在分解炉上的垂直安装角度为75°时烟气NOx浓度由原来的720 mg/Nm3降低到206 mg/Nm3,脱硝效率能达到70%,远低于水泥工业大气污染物排放标准的限定要求.对同类新型干法水泥熟料生产线SNCR脱硝技术有一定的参考意义. 相似文献
218.
Increasing petroleum prices, increasing threat to the environment from exhaust emissions and global warming have generated intense international interest in developing renewable and alternative non-petroleum fuels for engines. Evolving technology and a recurring energy crisis necessitates a continuous investigation into the search for sustainable and clean-burning renewable fuels. In this paper, cottonseed oil methyl ester (COME) was used in a four-stroke, single-cylinder variable compression ratio diesel engine. Tests were carried out to study the effects of fuel injection timing, fuel injector opening pressure (IOP) and injector nozzle geometry on the performance and combustion of COME biodiesel fuel used in a compression ignition engine with a single fuel mode. Fuel injection timing varied from 19° to 27° before top dead centre (bTDC) in incremental steps of 4° bTDC; fuel IOP varied from 210 to 240 bar in incremental steps of 10 bar. Fuel nozzle injectors with three, four and five holes, each of 0.3 mm size, were selected for the study. The results suggested that with retarded injection timing of 19° bTDC, increased IOP of 230 bar and a four-hole nozzle injector of 0.3 mm size resulted in overall better engine performance with an increased brake thermal efficiency and reduced HC, CO and smoke emission levels. 相似文献
219.
油田注空气工艺防爆实验的研究 总被引:3,自引:1,他引:2
通过实验,研究可燃气体(甲烷)的爆炸极限规律和加入惰性气体(氮气)后可燃气体临界氧含量的变化规律,测定在特定条件下甲烷的爆炸极限范围和安全氧含量,根据实验结果,确定氧含量的安全标准并提出相应的事故预防与控制措施,确保注空气采油技术实施过程中的风险处于可控制范围内,使注空气采油技术得到更广泛的应用。 相似文献
220.
利用PreVent预排/切割气相色谱进样技术,对多种多环芳烃致突变物质进行大体积进样分析,并与常规毛细管色谱进样方式进行比较,最大进样量为125μl,检测灵敏度可提高0.5-2个数量级以上,检测精度一般〈5%。 相似文献