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191.
192.
Fungicidal values of bio-oils and their lignin-rich fractions obtained from wood/bark fast pyrolysis 总被引:2,自引:0,他引:2
Pine wood, pine bark, oak wood and oak bark were pyrolyzed in an auger reactor. A total of 16 bio-oils or pyrolytic oils were generated at different temperatures and residence times. Two additional pine bio-oils were produced at the National Renewable Energy Laboratory in a fluidized-bed reactor at different temperatures. All these bio-oils were fractionated to obtain lignin-rich fractions which consist mainly of phenols and neutrals. The pyrolytic lignin-rich fractions were obtained by liquid-liquid extraction. Whole bio-oils and their lignin-rich fractions were studied as potential environmentally benign wood preservatives to replace metal-based CCA and copper systems that have raised environmental concerns. Each bio-oil and several lignin-rich fractions were tested for antifungal properties. Soil block tests were conducted using one brown-rot fungus (Gloeophyllum trabeum) and one white-rot fungus (Trametes versicolor). The lignin-rich fractions showed greater fungal inhibition than whole bio-oils for a impregnation solution 10% concentration level. Water repellence tests were also performed to study wood wafer swelling behavior before and after bio-oil and lignin-rich fraction treatments. In this case, bio-oil fractions did not exhibit higher water repellency than whole bio-oils. Comparison of raw bio-oils in soil block tests, with unleached wafers, at 10% and 25% bio-oil impregnation solution concentration levels showed excellent wood preservation properties at the 25% level. The good performance of raw bio-oils at higher loading levels suggests that fractionation to generate lignin-rich fractions is unnecessary. At this more effective 25% loading level in general, the raw bio-oils performed similarly. Prevention of leaching is critically important for both raw bio-oils and their fractions to provide decay resistance. Initial tests of a polymerization chemical to prevent leaching showed some success. 相似文献
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铬渣解毒处理处置技术综述 总被引:1,自引:1,他引:0
简要介绍了国内外铬盐生产现状和铬渣堆存现状,对铬渣解毒处理处置技术的五大类方法进行了评述,着重对铬渣干法解毒处理处置技术进行了研究。分析了各方法的优缺点和存在的主要问题,提出了铬渣治理要求及今后的发展方向。 相似文献
195.
硫酸生产中废钒催化剂回收工艺研究 总被引:2,自引:0,他引:2
采用H2SO4浸取、NH4HSO3还原、NH4NO3氧化、KOH精制的方法回收废钒催化剂中的V2O5。实验结果表明,还原反应的最佳条件为:n(NH4HSO3)/n(V2O5)=1.10,还原反应温度90℃,还原反应时间2.0h。氧化反应的最佳条件为:n(KOH)/n(VO^+)=1.10,氧化反应温度60℃,液固比8,氧化反应时间60min。该方法V2O5回收率达90.3%以上,V2O5纯度达82%以上。 相似文献
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作者把气相色谱仪(GC)与自行研制的光离子化检测器(PID)联用,实现了大气中痕量烃类化合物的直接测定,给出了仪器的构成和性能指标及测量结果. 相似文献
200.
Identification of sources of elevated concentrations of polycyclic aromatic hydrocarbons in an industrial area in Tianjin, China 总被引:2,自引:0,他引:2
Wentao Jiao Yonglong Lu Jing Li Jingyi Han Tieyu Wang Wei Luo Yajuan Shi Guang Wang 《Environmental monitoring and assessment》2009,158(1-4):581-592
The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were determined by gas chromatography equipped with a mass spectrometry detector in 105 topsoil samples from an industrial area around Bohai Bay, Tianjin in the North of China. Results demonstrated that concentrations of PAHs in 104 soil samples from this area ranged from 68.7 to 5,590 ng g???1 dry weight with a mean of ∑16PAHs 814 ± 813 ng g???1, which suggests that there exists mid to high levels of PAH contamination. The concentration of ∑16PAHs in one soil sample from Tianjin Port was exceptionally high (48,700 ng g???1). Ninety-three of the 105 soil samples were considered to be contaminated with PAHs (>200 ng g???1), and 25 were heavily polluted (>1,000 ng g???1). The sites with high PAHs concentration are mainly distributed around chemical industry parks and near highways. Two low molecular weight PAHs, naphthalene and phenanthrene, were the dominant components in the soil samples, which accounted for 22.1% and 10.7% of the ∑16PAHs concentration, respectively. According to the observed molecular indices, house heating in winter, straw stalk combustion in open areas after harvest, and petroleum input were common sources of PAHs in this area, while factory discharge and vehicle exhaust were the major sources around chemical industrial parks and near highways. Biological processes were probably another main source of low molecular weight PAHs. 相似文献