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WANG QianXin & XU TianHe School of Information Physics Geomatics Engineering Central South University Changsha China Geodesy Department Xi'an Research Institute of Surveying Mapping Xi'an 《中国科学:物理学 力学 天文学(英文版)》2011,(6)
The truncation error and propagation error are analyzed for velocity determination through differential GPS carrier phase observations,and an approach for the choice of the best number of points for the central difference method is developed.In order to overcome the disadvantages of existing GPS velocity determination methods,a new velocity determination algorithm is presented,based on combining carrier phase and Doppler observations.The basic idea is that two types of observation are combined by adding the... 相似文献
83.
QI GuoPeng JIANG Feng SUN XueWen & ZHAO SuoQi School of Chemical Engineering Tianjin University Tianjin China State key Laboratory of Heavy Oil Processing Petroleum University of China Beijing China 《中国科学:化学》2010,(5)
The isotope exchange method was employed to investigate the catalytic mechanism of ionic liquid in alkylation of benzenes with olefins.It is proposed that alkylation was induced by the Lewis acid AlCl3 which attracted π electrons of 1-dodecene to shift toward 1-carbon,thus forming a carbonium ion.The carbonium ion further reacted with benzenes to form a complex.Due to unstabilit of the complex,a deuterated ring proton was transferred into an electronegative 1-carbon of the side chain to substitute for the A... 相似文献
84.
An efficient and mild synthesis of 2-(guaiazulen-1-yl)furans,starting from easily accessible 1-(3-aryl-2-cyanopropenoyl) guaiazulenes,tributylphosphine and acyl chlorides,is described.The strategy employs the intramolecular Wittig protocol as a key step to append the crticial furan ring,leading to the highly functional furans in good yields. 相似文献
85.
Jia Rong Li~* Li Jun Zhang Xi Quan Yang Qing Li Dong Wang Chun Xia Wang Da Xin Shi Qi Zhang School of Chemical Engineering Environment Beijing Institute of Technology Beijing China 《中国化学快报》2008,(1)
Two different skeletons of heterocyclic compounds,quinoline and quinazolinone analogs could be obtained by a novel one-pot synthesis from substituted 3-amino-1 H-benzo[f]chromene-2-carbonitrile derivatives and cyclohexanone in DMF in the catalyst of anhydrous zinc chloride under reflux.A plausible mechanism was proposed. 相似文献
86.
SHANG Jing ZHAO FengWei ZHU Tong & LI Jia State Key Joint Laboratory of Environmental Simulation Pollution Control College of Environmental Sciences Engineering Peking University Beijing China 《中国科学B辑(英文版)》2011,(1)
Perylene tetracarboxylic diimide (PTCDI),widely used in organic photovoltaic devices,is an n-type semiconductor with strong absorption in the visible-light spectrum.There has been almost no study of the PTCDI-sensitized TiO2 composite used to photocatalytically degrade pollutants.In this study,PTCDIand copper phthalocyanine tetrasulfonic acid (CuPcTs)-sensitized TiO2 composites were prepared using a hydrothermal method.The morphologies and structures of the two composites were characterized by X-ray diffrac... 相似文献
87.
WANG Jingping LI Jie & NIU Jingyang Institute of Molecular Crystal Engineering Institute of Chemistry Chemical Engineering Henan University Kaifeng China 《中国科学B辑(英文版)》2006,(5)
A two-dimensional network compound [Ce(DMF)4(H2O)][α-BW12O40]·H2O·(HDMA)2 (HDMA = protoned dimethylamine, DMF = N,N-dimethylformamide) was synthesized from α-H5BW12O40·nH2O, Ce(NO3)3·6H2O and DMF and characterized by IR, UV spectra and TG-DTA. The result of the X-ray single crystal diffraction indicates that the crystal is monoclinic, space group P21/n, with unit cell dimensional: a = 1.1983(3), b = 2.4216(5), c = 1.9517(4) nm, β = 92.91(3)°, Z = 4, R1 = 0.07710, wR2 = 0.1416. Structural analysis indicates that every [Ce(DMF)4(H2O)]3 building block is surrounded by three adjacent [α-BW12O40]5- polyanions, meanwhile, every [α-BW12O40]5- polyanion interconnects with three neighboring [Ce(DMF)4(H2O)]3 subunits, by making use of which two-dimensional network structure can be constructed. The result of thermogravimetric analysis manifests that the title compound has two-stage weight loss and the decomposition temperature of the title polyanionic framework is 560℃ . The electrochemical analysis shows the title polyanion has three-step redox processes in the pH = 4―7 media. 相似文献
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90.
铝(Ⅲ)-氧氟沙星-十二烷基硫酸钠荧光体系测定微量铝的研究 总被引:2,自引:0,他引:2
在NaAc HAc介质中,溶液中的铝(Ⅲ)能与氧氟沙星和十二烷基硫酸钠(SDS)反应生成一稳定的络合物,使氧氟沙星的内源性荧光显著增强,据此建立了铝(Ⅲ) 氧氟沙星 SDS体系测定铝(Ⅲ)的荧光分析新方法。该体系的最大激发波长λex=365nm,最大发射波长λem=480nm,铝(Ⅲ)浓度在2.0×10-7~5.0×10-5mol L范围内,与荧光增强程度成正比。该方法可直接用于水样和食品中微量铝(Ⅲ)的测定。 相似文献