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981.
982.
983.
Belma Imamovi Polonca Trebe Elma Omeragi Ervina Be
i Andrej Pe
et Mirza Dedi 《Molecules (Basel, Switzerland)》2022,27(6)
Benzophenone (BP) type UV filters are common environmental contaminants that are posing a growing health concern due to their increasing presence in water. Different studies have evidenced the presence of benzophenones (BP, BP-1, BP-2, BP-3, BP-4, BP-9, HPB) in several environmental matrices, indicating that conventional technologies of water treatment are not able to remove them. It has also been reported that these compounds could be associated with endocrine-disrupting activities, genotoxicity, and reproductive toxicity. This review focuses on the degradation kinetics and mechanisms of benzophenone-type UV filters and their degradation products (DPs) under UV and solar irradiation and in UV-based advanced oxidation processes (AOPs) such as UV/H2O2, UV/persulfate, and the Fenton process. The effects of various operating parameters, such as UV irradiation including initial concentrations of H2O2, persulfate, and Fe2+, on the degradation of tested benzophenones from aqueous matrices, and conditions that allow higher degradation rates to be achieved are presented. Application of nanoparticles such as TiO2, PbO/TiO2, and Sb2O3/TiO2 for the photocatalytic degradation of benzophenone-type UV filters was included in this review. 相似文献
984.
碳纳米管结构对碳纳米管载Pt催化剂电催化性能的影响 总被引:1,自引:0,他引:1
在制备单、双壁及不同管径的多壁碳纳米管(CNTs)的基础上, 用液相还原法把Pt沉积到单、双壁和管径不同的多壁CNTs上. 发现制得的CNTs载Pt(Pt/CNTs)催化剂对甲醇氧化的电催化活性随CNTs管径减小而增加. 这归结于管径小的CNTs的比表面积较大, 含氧基团多, 有利于提高Pt粒子分散度, 加上管径小的单壁CNTs具有更高的导电性, 这些因素都有利于提高Pt/CNTs催化剂对甲醇氧化的电催化活性. 相似文献
985.
锰卟啉/钒取代杂多酸配合物的合成、表征和性能研究 总被引:1,自引:0,他引:1
利用碘化四对(4-三甲氨基苯基)锰卟啉与钒取代杂多酸H5 PMo10 V2O40,在水溶液中,室温下反应合成了锰卟啉/钒取代杂多酸配合物,用红外和紫外光谱技术对其结构进行了表征,发现该配合物中包含着金属卟啉的环状结构与杂多酸的笼状结构,并且二者以化学键的形式键合在一起.以该化合物作为催化剂,以过氧化氢水溶液为氧化剂,在温和的条件下研究了锰卟啉/钒杂多酸配合物对苯的羟基化反应的影响,考察了催化剂的催化活性,探讨了催化剂对苯羟基化反应的活性中心.研究结果表明,杂多酸中的钒原子是其主要的催化活性中心,锰卟啉的存在可以有效地提高其催化活性. 相似文献
986.
采用高温漫反射红外光谱考察了钛硅分子筛TS-1的稳定性,发现960 cm-1吸收峰在673 K时没有变化,表明所表征的骨架钛具有一定的高温稳定性,而表征分子筛骨架振动的两个吸收峰在673 K下向低波数位移了约13 cm-1。探讨了H2O2吸附对TS-1分子筛骨架钛的影响,发现960 cm-1处的吸收峰在吸附H2O2后强度减弱,并且向高波数位移了11 cm-1;抽真空或加热,吸收峰又复原,表明骨架钛可能存在TiO结构,H2O2与分子筛中的TiO作用,使相应的960 cm-1吸收峰向高波数位移。原位漫反射红外光谱考察了TS-1催化苯乙烯氧化反应,谱图分析表明,苯甲醛是主要产物,TS-1催化氧化的关键是H2O2吸附在TS-1的骨架钛上形成活性中心。 相似文献
987.
文章以水溶性碘化四对(4-三甲氨基苯基)铁卟啉和钒取代杂多酸H5PMo10V2O40为原料,采用离子交换方法在水溶液中合成了一种铁卟啉/钒取代杂多酸新型无机-有机复合催化剂,并使用红外和紫外光谱技术对其结构进行了表征,结果表明,这种新型复合催化剂仍然保持着卟啉的大环共轭结构和杂多酸的笼状多电子结构。同时研究了以30%过氧化氢水溶液为绿色氧化剂,初步探讨了这种铁卟啉杂多酸催化剂对苯的羟基化反应的的影响,考察了催化剂的催化活性。催化氧化实验表明,制备的铁卟啉/杂多酸配合物可用作苯直接氧化羟基化成苯酚的催化剂,并且表现出较高的催化活性。 相似文献
988.
An effective and environmentally benign benzylic oxidation for transition of alkylarenes into the corresponding carbonyl compounds was reported.Alkylarenes were mixed and stirred with potassium bromide,m-chloroperbenzoic acid and a catalytic amount of iodobenzene in water at 60 8C for several hours,a series of the corresponding carbonyl compounds was obtained in moderate to good yields.In the reaction,iodobenzene was first oxidized by m-chloroperbenzoic acid into the hypervalent iodine intermediate which then reacted with potassium bromide to form the key radical initiator for the benzylic oxidation. 相似文献
989.
《Physics and Chemistry of Liquids》2012,50(3):297-303
Kinetic studies on the photochemical oxidation of 1,3-diphenylisobenzofuran have been carried out in binary liquid mixtures of N,N-dimethylformamide (DMF) with 1-propanol (PrOH). The strongest influence of solvating effects upon the course of this reaction was observed for compositions of the studied mixture corresponding respectively to ca. 50?mol% of PrOH. Additionally, we have carried out analogous studies of photooxidation of cis-cyclooctene. Similarly as previously, the noticeable influence of solvating effects upon the course of this reaction corresponded to ca. 50?mol% of DMF. We suspect that the mechanism of this effect is associated with the formation of the polar intermediate during the ene reaction being easier. 相似文献
990.
Ragunatharaddi R. Hosamani Nagaraj P. Shetti Sharanappa T. Nandibewoor 《Journal of Physical Organic Chemistry》2009,22(3):234-240
The kinetics of oxidation of antibiotic drug, ampicillin (AMP) by diperiodatoargentate (III) (DPA) in alkaline medium at a constant ionic strength of 0.25‐mol dm?3 was studied spectrophotometrically. The reaction between DPA and AMP in alkaline medium exhibits 1:2 stoichiometry (AMP:DPA). The reaction is of first order in [DPA] and has less than unit order in both [AMP] and [alkali]. Added periodate retarded the rate of reaction and intervention of free radicals was observed in the reaction. The oxidation reaction in alkaline medium has been shown to proceed via a DPA–AMP complex, which decomposes slowly in a rate‐determining step followed by other fast steps to give the products. The main products were identified by spot test, IR and NMR studies. The reaction constants involved in the different steps of the mechanism are calculated. The activation parameters with respect to slow step of the mechanism were computed and discussed and thermodynamic quantities were also determined. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献