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71.
实验以MgO/MCM-22为催化剂,在气相连续流动固定床反应器上催化苯与草酸二乙酯(DEO)烷基化,合成乙苯(EB)。考察了MgO负载量变化和工艺条件的影响。以硝酸镁为前驱体通过等体积浸渍法制备了MgO/MCM-22催化剂,并以低温N_2吸附脱附、X射线衍射、NH_3-TPD、吡啶吸附IR等,对催化剂进行了表征。实验结果表明:随MgO负载量的增加,苯的转化率逐渐下降,而乙苯的选择性明显提高,这主要是由于负载MgO后催化剂的酸性位数量下降引起的。以MCM-22为催化剂,在最佳反应条件下:温度653 K,空速为2 h~(-1),原料配比n(苯):n(DEO)=4:1,苯的转化率为37.5%,乙苯选择性为80.3%。 相似文献
72.
沸石抗菌剂的研究现状与展望 总被引:1,自引:0,他引:1
介绍了目前国内外沸石抗菌剂的研究现状,重点讨论了沸石抗菌剂的原料改性、抗菌机理、持久性、变色抑制性、结构化等方面的特点,简述了沸石抗菌剂在日常生活中的应用,并对沸石抗菌剂的发展方向进行了展望. 相似文献
73.
《Journal of Nuclear Science and Technology》2013,50(4):435-441
The pressure swing adsorption (PSA) method, operating rapid desorption, has become applied to medium-massive air-component separation. In this study, with the aim of applying the PSA method to a hydrogen isotope separation process, the multi-component adsorption characteristics of H2-D2 or H2-HD-D2 on a synthetic zeolite at the liquid nitrogen temperature 77.4 K are investigated by using a volumetric apparatus, where the system effects of thermal transpiration and diffusion are taken into account. The adsorption isotherms for pure H2 and D2 are shown in a wide pressure range between 10-2 and 105Pa. The isotherms are closely approximated by an error functional expression proposed here. The separation factors resulting in adsorption are measured in a wide range of amount adsorbed. The separation factors of D2/H2 are estimated in accordance with the ideal adsorbed solution theory using the adsorption isotherms for H2 and D2. The behavior of the estimated factors agrees with that of the experimental ones. The result suggests that values around 3 are expectable for the factors of D2/H2 at amounts adsorbed roughly between 0.01 and 1 mol/kg. 相似文献
74.
75.
The adsorption of nitrogen oxides on Cu-ZSM-5 was studied by infrared spectroscopy to elucidate the species associated with the band at 2133 cm–1. The band was found for both NO and NO2 adsorption. Labeling experiments with15NO revealed that the associated surface species contained nitrogen and, most likely, an N-O bond. Co-adsorption experiments of NO and oxygen produced adsorbed nitronium, NO
2
+
, as the principal, associated species. Adsorption of nitrogen oxides on dispersed CuO and the HZSM-5 support demonstrated that the 2133 cm–1 band was not necessarily associated with copper ions. A relatively strong correlation between the bands at 2133 and 3615 cm–1 indicates that the primary adsorption sites of NO
2
+
are the strongly protic, bridging Si(OH)Al framework hydroxyls. Once these were filled, other, weaker acid sites began to adsorb NO
2
O
. 相似文献
76.
CO hydrogenation over Mn promoted Rh/NaY catalysts was studied at 10 bar and 250°C. Significant selectivity to oxygenates, mainly ethanol and ethyl acetate, was obtained after neutralizing the protons that are formed during reduction of Rh ions. Layered bed experiments show that protons act as sites catalyzing secondary reactions. Protons also convert Mn(OH)2 to Mn2+ ions; the catalysts with highest selectivity to oxygenates contain MnO particles and Rh clusters. The results suggest chemical interaction of adsorbates on Rhn clusters with those on MnO. 相似文献
77.
稻壳炭化后添加碱液和铝源分别合成了A型、A+X型和X型沸石-活性炭复合材料,加入凹凸棒石黏土成型,采用浸渍法负载V2O5制备V2O5-沸石-活性炭-凹土复合脱硝催化剂。采用XRD、SEM、N2吸附和EDX对样品进行表征,考察载体类型、V2O5含量和反应温度对催化剂低温脱硝活性的影响。结果表明,二元载体和V2O5协同催化脱硝,其脱硝率高于纯凹土制备的脱硝催化剂。催化剂脱硝活性随V2O5含量的增加而降低。反应温度越高,催化剂脱硝活性越高,最佳的反应温度为250℃,温度大于280℃后活性炭被氧化。 相似文献
78.
采用溶胶.凝胶法制备沸石负载N、Ce共掺杂的二氧化钛光催化剂,以亚甲基蓝溶液为目标降解物研究该催化剂的光催化性能,并讨论催化剂浓度、pH值以及焙烧温度等对样品光催化性能的影响.结果表明:催化剂的焙烧温度为300℃时催化剂的催化活性最高,在反应体系中,催化剂浓度为60gru,pH=7时样品的光催化效率最佳,共掺杂的样品可见光活性高于单掺杂的样品.可见光辐射共掺杂的样品3h,亚甲基蓝的去除率可以达65%. 相似文献
79.
采用正交试验法考察了m(沸石)/V(硝酸铜溶液)(g.mL-1)、硝酸铜溶液浓度(mol.L-1)、焙烧温度(℃)和焙烧时间(h)对色度和COD去除率的影响,通过直观分析、方差分析和因素趋势图分析,确定了沸石负载氧化铜的最佳工艺条件:m(沸石)/V(硝酸铜溶液)=1∶4 g.mL-1,硝酸铜溶液浓度为1.0 mol.L-1,焙烧温度为400℃,焙烧时间为5 h。用上述最佳条件下制备的催化剂样品处理酸性大红GR废水,色度和COD去除率分别达到99.97%和88.27%,相应的出水色度和COD指标分别为6稀释倍数和76 mg.L-1,达到GB 4287-92《纺织染整工业污染物排放标准》规定的一级排放标准。 相似文献
80.
Synthesis of oleyl oleate as a jojoba oil analog 总被引:2,自引:0,他引:2
N. Sánchez M. Martinez J. Aracil A. Corma 《Journal of the American Oil Chemists' Society》1992,69(11):1150-1153
Synthesis of a wax ester analog of jojoba oil was accomplished from oleic acid and oleyl alcohol with a zeolite as catalyst.
A full 23 factorial design at two levels has been used in the synthesis. The variables selected were temperature, reduced pressure
and initial catalyst concentration. The most important variable within the range studied was temperature. Reduced pressure
had a negative influence, and initial catalyst concentration showed a positive influence on the process. A response equation
has been determined for the yield of ester. The properties of the synthesized product are similar to those of natural jojoba
oil. 相似文献