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51.
Mohammed ElKaoutit Ignacio Naranjo-Rodríguez Khalid Riffi Temsamani Manuel Domínguez José Luis Hidalgo-Hidalgo-de-Cisneros 《Journal of Sol-Gel Science and Technology》2008,45(2):157-163
Structural characteristics an cyclic voltammetry of three amperommetric biosensors based on immobilization of tyrosinase on
a Sonogel-Carbon electrode for detection of phenols are described. Cyclic voltammetry was applied to study the electrochemical
behaviour of the electrode and the electrochemical reaction on the electrode surface. Scanning electron microscopy, X-ray
energy dispersive spectroscopy and atomic force microscopy were used for the structure characterization of the electrode surface,
enzyme film and polymers coatings. The influence of additive-protective polymers, such as polyethylene glycol and perfluorinated-Nafion
ion-exchanger on the surface of the biosensor were explored. 相似文献
52.
动力学荧光法测定对苯二酚的研究 总被引:2,自引:0,他引:2
基于在稀H2SO4介质中,对苯二酚对H2O2氧化罗丹明B产生的荧光猝灭有显著的催化作用,建立了测定对苯二酚的动力学荧光分析法。反应在80℃的水浴中进行12 min,方法的线性范围为4.0~600.0μg/L,检出限为3.7μg/L。该方法用于水样中对苯二酚的测定,加标回收率在96.4%~101.3%之间,相对标准偏差为2.2%。 相似文献
53.
在La-TiO2催化剂上由苯酚直接氧化制取邻苯二酚的研究 总被引:7,自引:2,他引:5
以La-TiO2作为苯酚选择氧化催化剂,用过氧化氢氧化,得到邻苯二酚选择性高达90%的良好结果,讨论了溶剂,反应温度,反应时间,过氧化氢浓度,催化剂用量,过氧化氢用量等工艺条件对苯酚羟基化作用的影响。 相似文献
54.
Platinum(II) chloride can selectively be coordinated to the 2,2′-bipyridine moiety of the alkyl bridged sequential catechol/2,2′-bipyridine ligand 1 a-H2 and of the related ligands 1 a/b-Me2 and 2 . Reaction of ( 1 b-Me2 )PtCl2 with BBr3 produces the platinum(II) complex ( 1 b-H2 )PtCl2 while ether cleavage of the uncoordinated ligand 1 b-Me2 fails. Under basic conditions ( 1 a-H2 )PtCl2 forms polymeric/oligomeric species [( 1 a )Pt]n besides traces of the dinuclear complex [( 1 a )Pt]2. 相似文献
55.
溶胶-凝胶法制备了高HC比(10~40,对苯二酚与催化剂(Na2CO3/sub>)的物质的量之比)的对苯二酚-甲醛有机气凝胶,并经高温碳化处理得到其碳气凝胶。借助有机气凝胶的红外光谱研究了其化学结构,说明其网孔结构形成的可能性;研究了有机气凝胶的扫描电镜图像、比表面积及孔径分布等,并得到碳化前后的一些对比数据:有机气凝胶颗粒大小30~50 nm,碳化后约为10 nm,比表面积从341.77 m2/g增大到452.75 m2/g,密度从0.170 8 g/cm3/sup>增大到0.335 6 g/cm3/sup>。 相似文献
56.
Shiju Thomas 《Proceedings of the Combustion Institute》2009,32(1):615-622
In order to better understand the reactions responsible for the formation and growth of polycyclic aromatic hydrocarbons (PAH) from solid fuels, we have performed pyrolysis experiments in an isothermal laminar-flow reactor (at temperatures of 600-1000 °C and a fixed residence time of 0.3 s) with catechol, a model fuel representative of the aromatic moieties in coal and biomass fuels; 1,3-butadiene, a major product of biomass pyrolysis; and with catechol and 1,3-butadiene together (in a catechol-to-1,3-butadiene molar ratio of 0.83). No PAH of ?3 rings are produced at temperatures <700 °C, but PAH production becomes significant at temperatures ?800 °C. Analysis of the higher-temperature reaction products by high-pressure liquid chromatography with diode-array ultraviolet-visible absorbance detection has led to the identification of over 100 PAH (ranging in size to 10 fused aromatic rings) - 47 of which have never before been reported as products of any phenol-type fuel. Quantification of the product yields shows that a much higher percentage of fed carbon is converted to PAH in the catechol-only pyrolysis experiments than in the 1,3-butadiene-only pyrolysis experiments - a result attributable to catechol’s relatively labile O-H bond and capacity for generating oxygen-containing radicals, which accelerate both fuel conversion and the pyrolysis reactions leading to 1- and 2-ring aromatics and PAH. When the two fuels are co-pyrolyzed, the percentage of the total fed carbon converting to PAH is more than two times higher than the amount calculated for the hypothetical case of the two fuels together behaving as a linear combination of the two fuels individually. This elevated production of PAH from the co-pyrolysis experiments reflects not only the reaction-accelerating role of the oxygen-containing radicals but also the efficacy, as growth agents, of the C2 - and especially the C4 - species abundantly present in the catechol/1,3-butadiene co-pyrolysis environment. 相似文献
57.
58.
Combination of CuI and Catechol violet (CuI-CV) was employed as catalyst for the first time in the C-S coupling reaction of a wide variety of aromatic halides, such as aryl iodides, bromo pyridines, activated aryl chlorides, and vinyl iodide with thiols to afford the corresponding thioethers in good to excellent yields. Broad range of functional group tolerance present in both the coupling partners has been observed in this reaction protocol. 相似文献
59.
基于多壁碳纳米管/壳聚糖多层膜修饰玻碳电极邻苯二酚的测定 总被引:1,自引:0,他引:1
改进了碳纳米管在壳聚糖溶液中的分散方法,制备了多壁碳纳米管/壳聚糖多层膜修饰玻碳电极,对比了不同修饰层数膜电极的循环伏安和电化学阻抗行为,5层多壁碳纳米管/壳聚糖膜修饰玻碳电极的电化学性能优良.在最优实验条件下,该修饰玻碳电极对邻苯二酚(CAT)有灵敏的响应,CAT浓度在3.99×10-6~9.09×10-4mol/L范围内与氧化峰电流呈良好的线性关系,检出限为2.39×10-6mol/L(S/N=3).该修饰玻碳电极性能稳定,测定4×10-5mol/LCAT溶液,RSD(n=10)为2.1%;15周后,该电极的响应值仅降低1.9%. 相似文献
60.
The Mobil Composition of Matter No. 41 (MCM-41) containing Cu and Al with Si/Al ratios varying from 100 to 10 and 1 to 6 wt.% of Cu was synthesized under hydrothermal and impregnation conditions, respectively. The samples were characterized by nitrogen adsorption–desorption measurements, X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS), temperature-programmed reduction (TPR), temperature-programmed desorption (TPD), and 29Si and 27Al magic-angle spinning–nuclear magnetic resonance (MAS–NMR) spectra. X-ray diffraction patterns indicate that the modified materials retain the standard MCM-41 structure. TPR patterns show the two-step reduction of Cu species. TPD study shows that Cu-impregnated Al-MCM-41 samples are more acidic than Al-MCM-41. From the MAS–NMR it was confirmed that most of the Al atoms are present tetrahedrally within the framework and some are present octahedrally in extraframework position. Impregnation of Cu shifted Al to the extraframework position. The catalytic activity of the samples toward hydroxylation of phenol in aqueous medium was evaluated using H2O2 as the oxidant at 80 °C. The effects of reaction parameters such as temperature, catalyst amount, amount of H2O2, and solvent were also investigated. Sample containing 4 wt.% copper-loaded Al-MCM-41-100 showed high phenol conversion (78%) with 68% catechol and 32% hydroquinone selectivity. 相似文献