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681.
为了研究城市砷污染的现状及不同区域砷污染的空间差异性,以吉林市表层土壤为研究对象,在交通干道的绿化带和磨盘山保护区采集35个土壤样本,进行pH、有机质及砷含量的测定。采用单项污染指数、污染累计指数法等对土壤砷污染进行评价,并运用方差分析的方法对不同区域的砷污染进行了差异比较。研究表明:吉林市街道砷含量为26.43 mg/kg,为磨盘山自然土壤砷含量的4.08倍,为吉林市砷土壤背景值7.26倍;吉林市砷总体超标率12.9%。江北工业区、吉林大街和解放大路的单项污染指数分别为1.34、0.95、0.87,整体达到轻微污染水平。江北工业区和吉林大街、解放大路的变异系数相差不大,依次为0.13、0.11、0.17。土壤砷的污染累积指数为3.21,且由北向南递减,因此,砷污染主要来自于江北工业区的工业"三废"污染。 相似文献
682.
Dubravka Relić Dragana Đorđević Sanja Sakan Ivan Anđelković Ana Pantelić Ratomir Stanković Aleksandar Popović 《Environmental monitoring and assessment》2013,185(9):7627-7645
In this paper, the main objective was fractionation of Cd, Cu, Ni, Pb, Zn, Ca, Fe, and K in certificate material and sediment samples gathered from and around the Petrochemical Industry using the conventional, microwave and ultrasonic sequential extraction. Microwave oven and ultrasound bath were used as an energy source for achieving faster extraction. Additional heating and boiling of samples were avoided by using lower power and shorter time for microwave and ultrasound extraction. Precision and accuracy of procedure were evaluated by using certificate material (BCR701). Acceptable accuracy of metals (87.0–111.3 %) was achieved for all three-step sequential of conventional extraction protocol. An accuracy of the fourth step has been verified with two certificate materials: BCR143R and 146R. The range of total extracted metal concentrations from sediments was similar for all three extraction techniques. A significant high percentage of Cd, Cu, and Zn were obtained after extraction of the exchangeable and acid soluble sediment fraction. Principal component analysis of values obtained after determination of risk assessment code using conventional and ultrasound sequential extraction show similarity of these values. Accuracy, recovery, and risk assessment code values imply that ultrasound sequential extraction is a more suitable, accelerated sequential extraction procedure (30 min per extraction step) than microwave extraction in applied conditions. 相似文献
683.
Characterizations of volatile organic compounds during high ozone episodes in Beijing,China 总被引:3,自引:0,他引:3
Air samples were collected in Beijing from June through August 2008, and concentrations of volatile organic compounds (VOCs)
in those samples are here discussed. This sampling was performed to increase understanding of the distributions of their compositions,
illustrate the overall characteristics of different classes of VOCs, assess the ages of air masses, and apportion sources
of VOCs using principal compound analysis/absolute principal component scores (PCA/APCS). During the sampling periods, the
relative abundance of the four classes of VOCs as determined by the concentration-based method was different from that determined
by the reactivity approach. Alkanes were found to be most abundant (44.3–50.1%) by the concentration-based method, but aromatic
compounds were most abundant (38.2–44.5%) by the reactivity approach. Aromatics and alkenes contributed most (73–84%) to the
ozone formation potential. Toluene was the most abundant compound (11.8–12.7%) during every sampling period. When the maximum
incremental reactivity approach was used, propene, toluene, m,p-xylene, 1-butene, and 1,2,4-trimethylbenzene were the five
most abundant compounds during two sampling periods. X/B, T/B, and E/B ratios in this study were lower than those found in
other cities, possibly due to the aging of the air mass at this site. Four components were extracted from application of PCA
to the data. It was found that the contribution of vehicle exhaust to total VOCs accounted for 53% of VOCs, while emissions
due to the solvent use contributed 33% of the total VOCs. Industrial sources contributed 3% and biogenic sources contributed
11%. The results showed that vehicle exhausts (i.e., unburned vehicle emissions + vehicle internal engine combustion) were
dominant in VOC emissions during the experimental period. The solvent use made the second most significant contribution to
ambient VOCs. 相似文献
684.
685.
介绍了生物修复的概念、水产养殖存在的自身污染问题及其主要生物修复技术.营养物污染、药物污染和底泥富集污染是水产养殖存在的主要自身污染问题;微生物修复、水生植物修复和水生动物修复是污染养殖水域生物修复的3种主要形式;微生物的有效性、生物入侵、二次污染、修复生物的季节性和非水生植物的利用等方面是实施生物修复应注意的主要方面.最后指出,推行清洁生产、实行生态养殖是水产养殖业可持续发展的出路. 相似文献
686.
Jin-Young An Joong-Chun Kwon Deog-Won Ahn Hang-Sik Shin Sung-Ho Won Byung-Woo Kim 《Water environment research》2008,80(8):757-765
To enhance nitrogen removal in an existing microbial contact oxidation (MCO) system with a treatment capacity of 900 m3/d, an upflow multilayer bioreactor (UMBR) was chosen as a preanoxic reactor for the removal of organic matter and nitrate. The removal performance of the retrofitted plant was evaluated during the startup phase at a low temperature in winter. The high removal (>80%) of organic matter and suspended solids in the UMBR provided stable nitrification conditions in the MCO system, as a result of the substantial reduction in organic matter and solids loaded onto the MCO system. This treatment system showed a stable nitrogen removal efficiency of 75.3%, even in the low temperature range 7 to 10 degrees C. Phosphorus was completely removed by chemical precipitation. Production rates of excess sludge, as a function of the loads of influent flowrate and biological oxygen demand (BOD), were 0.022 kg dry solid/m3 wastewater and 0.132 kg dry solid/kg BOD. 相似文献
687.
688.
可见光催化剂BiVO_4 降解废水中直接耐酸大红4BS 总被引:4,自引:3,他引:1
以直接耐酸大红4BS模拟染料废水为目标污染物,研究了BiVO_4对直接耐酸大红4BS(简称4BS)的吸附效果以及废水初始质量浓度、废水pH和BiVO_4的加入量对光催化降解效果的影响.实验结果表明:当废水初始质量浓度为40 mg/L、废水pH为6.38、BiVO_4加入量为1.0 g/L时,4BS的降解率可达98.9%;BiVO_4重复使用5次后4BS的降解率可达80.0%以上;COD的变化趋势说明4BS被催化剂吸附和光催化降解的过程是循序渐进的. 相似文献
689.
探讨了武汉某工业园电镀厂污泥酸浸、除杂提磷的工艺及条件。当H2SO4(浓度为72%)用量为4mL/g污泥,在液固比为5:1,常温搅拌浸出时间为1h,用碱液调节浸出液pH为4后沉淀1h,过滤,磷的浸出率为86%,铁的沉淀率达到94.2%,除铁后的浸出液进一步用NH4HCO3净化,并制取磷铵产品,总养分(N+P2O5)为52%。产品达到国家合格品的标准。 相似文献
690.
Jae-Seong Kim Dae-Hwan An Sang-Yul Lee Bo-Young Lee 《Journal of Loss Prevention in the Process Industries》2009,22(6):845-849
This paper has studied failure of an oil storage tank. During operation, several cracks were observed at the fillet weldment between reactor shell and annular plates in the bottom of oil storage tank. Extreme stresses in the structure during its operation were determined taking into account shape and geometry imperfections as well as corrosion influence. Both reactor shell and annular plates are made of carbon steel (SM53C). In this study, in order to identify the causes for the fillet weldment cracking, failure analysis such as fractography, tensile test, hardness test, corrosion test(SSRT), chemical analysis was performed. The failure of oil storage tank is the result of the combined and synergistic interaction of mechanical stress and corrosion reactions. Although cracks were initiated by corrosion, failure was generated by propagation of crack caused by stresses concentration. It was recommended that (1) the local stresses be reduced by improved weld toe geometry, and (2) the reinforcement be used in order to avoid failure by stresses concentration. 相似文献