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Seasonal features of aerosol particles recorded in snow from Mt. Qomolangma (Everest) and their environmental implications 总被引:5,自引:1,他引:4
To assess the seasonality of aerosol deposition and anthropogenic effects on central Himalayas, a 1.85-m deep snow pit was dug on the northern slope of Mr. Qomolangma (Everest). Based on the morphology and energy dispersive X-ray (EDX) signal, totally 1500 particles were classed into 7 groups: soot; aluminosilicates; fly ash; calcium sulfates; Ca/Mg carbonates; metal oxides; and biological particles and carbon fragments. The size distribution and number fractions of different particle groups exhibited distinct seasonal variations between non-monsoon and monsoon periods, which are clearly related to the differences in air mass pathways. Specifically, the relative abundance of soot in non-monsoon period (25%) was much higher than that in monsoon period (14%), indicating Mr. Qomolangma region received more anthropogenic influence in non-monsoon than monsoon period. 相似文献
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三维电极电催化氧化处理邻氯苯胺废水的研究 总被引:1,自引:0,他引:1
文章用粉末状活性炭作为三维电极电化学反应器的粒子电极,选择石墨板和不锈钢板分别作为阳极和阴极,组成三维电极电化学反应器。文章研究了三维电极电化学反应器对邻氯苯胺废水的电催化氧化效果,探讨了槽电压、溶液初始pH、电解时间、支持电解质浓度、电极极板间距等影响因素对邻氯苯胺废水COD的去除效果。实验结果表明:当槽电压为15.0 V,溶液初始pH为3.0,支持电解质浓度为0.10 mol/L,极板间距为2 cm,电解时间为30 min时,邻氯苯胺废水的COD去除率达到97.50%。通过紫外-可见光光谱扫描发现,由于三维电极电催化氧化作用,邻氯苯胺的苯环断裂,生成一些脂肪族物质。谱图在250~350 nm波长范围内并无其他吸收峰出现,说明溶液在降解过程中并没有生成其他大分子物质。从而证实了三维电极电化学反应器对邻氯苯胺有很好的降解效果。 相似文献
686.
Rico等人2009年展示了1种创造一次性传感器的简单方法,这种传感器以碳电极条为基础,由微量锌、镉和铅量子化的铋纳米粒子修饰.这种传感器的检测范围为0.9~4.9ng/mL,并具有良好的精度和线性反应.对于分布式处理系统控制而言,相对增益矩阵(RGA)分析算法是1种有潜力的方法,该方法应用于模拟污水控制器来确定设备 相似文献
687.
Effective in situ remediation of Cr(VI) in groundwater requires the successful delivery of reactive iron particles to the subsurface.
Fe0 nanoparticles (20–110 nm diameter) supported on silica fume were synthesized by borohydride reduction of an aqueous iron salt
in the presence of a support material. The experimental result showed that attachment of Fe0 nanoparticles on the commercial available
sub-micrometer silica fume prevented them from aggregation while maintaining the particle reactivity. When the Fe0 concentration
was 0.4 g/L, 88.00% of 40 mg/L Cr(VI) was removed by silica fume-supported Fe0 nanoparticles (SF-Fe0) in 120 min, 22.55% higher
than unsupported Fe0. Furthermore, transport experiments confirmed that almost all unsupported Fe0 was retained, whereas 51.50%
and 38.29% of SF-Fe0 were eluted from the vertical and horizontal sand column, respectively. Additionally, the effect of solution ionic
strength on the transport ability of SF-Fe0 was evaluated. The result showed that increase in the salt concentration led to a decrease in
the mobility and also the divalent ion Ca2+ had a greater effect than that of monovalent ion Na+. 相似文献
688.
The activities of CeO2 nanocubes calcined at di erent temperatures were tested for catalytic oxidation of o-xylene. Using
CeO2 nanocubes as catalysts, complete catalytic oxidation of o-xylene was achieved below 210°C. The CeO2 nanomaterials were
characterized by means of BET, X-ray di raction (XRD), transmission electron microscopy (TEM), and high-resolution transmission
electron microscopy (HRTEM). From the TEM images, all CeO2 nanocubes displayed cubic morphology irrespective of calcination
temperature. The HRTEM images revealed that these nanocubes were enclosed by reactive f001g planes, which may contribute to the
intrinsically catalytic property of o-xylene oxidation. The higher activity of CeO2 nanocubes calcined at 550°C than those calcined
at above 550°C was attributed to their smaller crystallite size and larger surface area. The influences of reaction conditions were also
studied, which found that a higher reaction temperature was necessary for complete catalytic oxidation of o-xylene at higher weight
hourly space velocity (WHSV) and o-xylene concentration. 相似文献
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