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841.
L.Q. Cao 《Journal of Mathematical Analysis and Applications》2008,343(2):1103-1118
In this paper, we study the optimal control on the boundary for parabolic equations with rapidly oscillating coefficients arising from the heat transfer problems and the optimal control on the boundary of composite materials or porous media. The multiscale asymptotic expansion of the solution for the problem in the case without any constraints is presented. We derive the proofs of all convergence results. 相似文献
842.
光声光谱(Photoacoustic Spectroscopy,PAS)是研究凝聚态和表面吸附物振动光谱的1种新方法。近几年来PAS发展很快,它与FT-IR技术结合,已成为1种新的固体样品和表面分析的有力工具。本文应用FT-IR/PAS方法研究了金属卟啉配合物及其与NO的表面吸附物。卟啉及其金属配合物具有平面大π体系共轭环的结构特点,在光 相似文献
843.
844.
A conceptual model for microscopic-macroscopic slow-fast stochastic systems is considered. A dynamical reduction procedure is presented in order to extract effective dynamics for this kind of systems. Under appropriate assumptions, the effective system is shown to approximate the original system, in the sense of a probabilistic convergence. 相似文献
845.
L.Z. Cao H. Jiang H. Song X. Liu W.G. Guo S.Z. Yu Z.M. Li G.Q. Miao 《Solid State Communications》2010,150(15-16):794-798
Three different shapes of SiC/SiO2 core–shell nanowires were synthesized on Si substrates through a reaction between methane and silica using iron as catalyst. Analysis of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results indicated that catalyst morphology was the key factor for the formation of these three different products. The field emission properties of these three nanowires were investigated. Comparing the field emission results of these three nanowires, we can obtain a conclusion that a vertically well-aligned orientation to the substrate played a very significant role in improving the field emission properties when the emitters are up to a considerable number. 相似文献
846.
Min Cao Jian‐Qi Wang Peng‐Cheng Chen Jun‐Ting Xu Zhi‐Qiang Fan 《Journal of polymer science. Part A, Polymer chemistry》2010,48(17):3834-3840
In this work, the polystyrene‐b‐poly(ethylene oxide) (PS‐b‐PEO) block copolymers with a trithiocarbonate group between the blocks were prepared by polymerization of styrene in the presence of a trithiocarbonate reversible addition fragmentation chain transfer (RAFT) agent connected with PEO. Decomposition of the trithiocarbonate group by UV irradiation was investigated in three different types of solvent: tetrahydrofuran (THF, common solvent for both blocks), cyclohexane/dioxane mixture (selective solvent for the PS block) and N,N‐dimethylformamide (DMF)/ethanol mixture (selective solvent for the PEO block). It is found that cleavage of the block copolymers can take place in all these three solvents and the cleavage ratio ranges from 76 to 86%. The micellar morphologies in selective solvents before and after cleavage were examined. It is observed that the size of the micelles is reduced after cleavage and sometimes aggregation of the micelles occurs due to removal of the corona of micelles. It shows that this work provides a facile and general method for synthesis of cleavable block copolymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3834–3840, 2010 相似文献
847.
848.
849.
Yong Wang Xinyi Cao Jingfei Ji Xiuling Cui Chao Pi Leyao Zhao Yangjie Wu 《中国化学快报》2021,32(5):1696-1700
A green tandem reaction, including insertion/aerobic oxidation/bisindolylation, starting from indoles and diazo compounds has been developed. The combination of water and fluorinated alcohol plays dual roles as solvent and promoter in this chemical transformation. Molecular oxygen in the air acts as an oxidant. 3,3′-Bis(indolyl)methanes with quaternary carbon were produced under metal-free conditions. No any catalyst and additive were required. N2 and water were released as sole by-products. Absence of water and fluorinated alcohol resulted in Wolff rearrangement product. 相似文献
850.
Gao‐Juan Cao Qing‐Lu Li Cheng Rong Yu‐Lin Wang 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(7):712-715
A new 3d–4f heterometallic polymer, poly[[aqua‐μ3‐chlorido‐[μ3‐4‐(pyridin‐4‐yl)benzoato]tris[μ2‐4‐(pyridin‐4‐yl)benzoato]dicopper(I)erbium(III)] dihydrate], {[Cu2Er(C12H8NO2)4Cl(H2O)]·2H2O}n, was synthesized by the hydrothermal reaction of Er2O3, CuCl2·2H2O and 4‐(pyridin‐4‐yl)benzoic acid in the presence of HClO4. The asymmetric unit contains one Er3+ cation, two Cu+ cations, one Cl− anion, four deprotonated 4‐(pyridin‐4‐yl)benzoate ligands, one coordinated aqua ligand and two solvent water molecules. This tubular one‐dimensional polymer is constructed from alternating clusters of europium(III)–water and copper(I) chloride bridged by 4‐(pyridin‐4‐yl)benzoate ligands. Extensive hydrogen‐bonding interactions involving both the coordinated and the solvent water molecules provide further stabilization to the structure. 相似文献