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排序方式: 共有872条查询结果,搜索用时 93 毫秒
1.
基于序批式活性污泥法(SBR)工艺,将镁盐改性活性炭(MgO-PAC)与传统活性炭(PAC)混合而成MPAC材料,用于处理生活与工业混合污水。通过连续30 d的运行实验,探讨了MPAC材料对生活与工业混合污水中COD、NH4^+-N和TP的去除效果以及对污泥的比耗氧速率、沉降性能和微生物多样性的影响。结果表明,投加MPAC材料对污水中COD的去除率提升了12.7百分点,对TP的去除率提升了17.5百分点,对NH4^+-N的去除率超过86.4%。投加MPAC后处理效果更好的重要原因,在于MPAC使得活性污泥的沉降性能和比耗氧速率得到明显改善,也提升了污泥的微生物丰度。MPAC对活性污泥处理生活与工业混合污水具有强化作用。 相似文献
2.
《Engineering Applications of Artificial Intelligence》2007,20(6):735-744
Harmful algal blooms, which are considered a serious environmental problem nowadays, occur in coastal waters in many parts of the world. They cause acute ecological damage and ensuing economic losses, due to fish kills and shellfish poisoning as well as public health threats posed by toxic blooms. Recently, data-driven models including machine-learning (ML) techniques have been employed to mimic dynamics of algal blooms. One of the most important steps in the application of a ML technique is the selection of significant model input variables. In the present paper, we use two extensively used ML techniques, artificial neural networks (ANN) and genetic programming (GP) for selecting the significant input variables. The efficacy of these techniques is first demonstrated on a test problem with known dependence and then they are applied to a real-world case study of water quality data from Tolo Harbour, Hong Kong. These ML techniques overcome some of the limitations of the currently used techniques for input variable selection, a review of which is also presented. The interpretation of the weights of the trained ANN and the GP evolved equations demonstrate their ability to identify the ecologically significant variables precisely. The significant variables suggested by the ML techniques also indicate chlorophyll-a (Chl-a) itself to be the most significant input in predicting the algal blooms, suggesting an auto-regressive nature or persistence in the algal bloom dynamics, which may be related to the long flushing time in the semi-enclosed coastal waters. The study also confirms the previous understanding that the algal blooms in coastal waters of Hong Kong often occur with a life cycle of the order of 1–2 weeks. 相似文献
3.
Incorporating of hydrous ferric oxide(HFO) inside porous supports with large sizes has become an effective way to decontaminate the water from heavy metals. Ubiquitous anions like sulfate are usually present in high concentrations in water, and might greatly affect adsorption behavior of hybrid HFO. Here, a polymer-based HFO-CPS was fabricated by encapsulating nano-HFO inside a chloromethylated polystyrene polymer(CPS) and the reactivity of HFO-CPS with Cu(Ⅱ) was evaluated in the presence of sulfate ions.Surface complexation theory was firstly employed to describe the effect of sulfate on Cu(Ⅱ) adsorption edges of hybrid HFO-CPS, where constant capacitance model(CCM) was adopted. The available weak adsorption site Fe_((2))OH of hybrid HFO-CPS was found to decrease from 20% Fe to 5% Fe, which might be caused by the pore plugging effect after HFO encapsulation. With the assumption that a ternary complex was formed, the effect of sulfate on Cu(Ⅱ) adsorption by HFO-CPS were successfully described by CCM using the optimized Fe_((2))OH site under different sulfate concentrations(1 or 10 mmol·L~(-1)) and Cu/Fe ratios(0.0042 or 0.0252). It is confirmed that the formation of Fe OHCu SO_4 ternary surface complexes played an important role in enhancing Cu(Ⅱ) adsorption on HFO-CPS in the presence of sulfate. 相似文献
4.
垃圾焚烧厂渗滤液生化出水混凝处理及其模型的建立 总被引:1,自引:0,他引:1
对采用聚合氯化铝、硫酸铝和氯化铁等混凝剂处理焚烧厂垃圾渗滤液生化出水的混凝效果及其模型进行了研究.结果表明:聚合氯化铝对焚烧厂垃圾渗滤液中CODCr、色度和浊度的去除效果比硫酸铝和氯化铁要好,且投加量相对也较少.在投加量500 mg/L、中性条件下,CODCr、浊度和色度的去除率可分别达到28.9%、91.6%和77.6%.在不同投药量、pH和搅拌速度下,PAC保持了良好的污染物去除效果,而对硫酸铝和氯化铁的处理效果影响较大.各种混凝剂的最佳投药量与起始CODCr浓度之间的关系可采用指数关系式表达.通过对PAC在各条件下混凝效果的统计分析,采用Matlab优化工具软件,建立了垃圾焚烧厂垃圾渗滤液PAC混凝处理的处理效果数学模式方程,其与试验结果的相关系数可达到0.982,表明建立的模型与混凝处理效果较为一致. 相似文献
5.
以醋酸锌和氯氧化锆为原料,采用化学沉淀法制备了纳米氧化锆/氧化锌光催化剂。在中性条件下研究了催化剂煅烧温度,锆复合量,催化剂用量,染料初始质量浓度,过氧化氢质量浓度,各种阴、阳离子等条件对酸性红B脱色反应的影响。结果表明,该催化剂最佳制备条件为煅烧温度350℃,锆复合量2.5%(物质的量分数)。催化剂最佳用量0.9g/L。提高染料初始质量浓度会降低反应脱色率。适量过氧化氢可提高反应脱色率,当其质量浓度超过300mg/L会起负作用。NO3^-对反应影响不大;Fe^3+和Ag^+对反应起促进作用;SO4^2-,Cl^-,NO2^-等阴离子和Fe^2+,Mn^2+等阳离子对反应起抑制作用。 相似文献
6.
《Catalysis communications》2007,8(3):241-246
A simple method for evaluating the surface acidity of different cation-exchanged montmorillonite (mont) clay catalysts, Mn+-mont (Mn+=Al3+, Fe3+, Cr3+, Zn2+, Ni2+, Cu2+, and H+), involving treatment with pyridine is described. After treating with pyridine, the samples were heated at 120 °C and the FT-IR spectra were directly recorded in the region 1650 and 1350 cm−1. The data obtained show the presence of both Lewis and Brønsted acid sites. The activities of the catalysts to bring about Brønsted acid catalysed esterification of succinic acid with iso-butanol to yield di-(iso-butyl) succinate have been studied. The Brønsted acidity data obtained for Mn+-mont correlated well with activity in the esterification reaction. The activities of the catalysts were found to decrease in the order of exchange ions Al3+ > Fe3+ > Cr3+ > Zn2+ > Ni2+ > Cu2+ > Na+-mont. They also correlated well with the charge to radius ratio of the cations. The catalysts exchanged with trivalent cations showed stronger absorption bands attributed to Brønsted acidity (1540 cm−1) whereas those exchanged with divalent cations showed an increased Lewis acidity (1450 cm−1) and reduced Brønsted acidity along with charge to radius ratio. Zn2+-, Cu2+- and Ni2+-exchanged clays showed an additional peak around 1605 cm−1 which is attributed to the pyridine adsorption on surface sites through its π electrons. The method suggested here to evaluate the acidity is suitable for active sites which are thermally unstable such as water molecules in the hydration shell of a cation in exchanged clay. 相似文献
7.
以硅酸钠、硫酸、硫酸铝和三氯化铁为原料制备了聚硅铝铁复合絮凝剂,对低温低浊水进行处理研究,并与硫酸铝、PAC进行了对比。结果表明,聚硅铝铁复合絮凝荆对低温低浊水有较好的处理效果,投加量为4mg/L时,出水浊度在0.5NTU以下。 相似文献
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10.
《Microporous and mesoporous materials》2007,98(1-3):16-20
Deprotonation of 4,4′-biphenyldicarboxylic acid (H2BPDC) with triethylamine followed by the copolymerization with Y(III) in N,N-dimethylformamide (DMF) at room temperature yields a new three-dimensional (3-D) porous metal–organic coordination network, [Y2(BPDC)3(DMF)2(H2O)2]n · (DMF)n · (H2O)n (1). Compound 1 (C24.50H19N1.50O9Y) crystallizes in the triclinic P-1 space group (a = 8.220 (2), b = 13.998 (4), c = 14.212 (4) Å, α = 111.058 (5)°, β = 90.187 (5)°, γ = 94.318 (5)°, V = 1520.9 (7) Å3, and Z = 2). X-ray crystallography reveals that 1 consists of a 3-D framework contained open 1-D channels with the dimension of 5 × 10 Å along the crystallographic a axis. The adsorption measurements show that compound 1 can adsorb N2, Ar and CO2 into its pores. The adsorption isotherms for MeOH and H2O were also measured. 相似文献