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101.
Recyclable and reusable NiCl2(PPh3)2/CuI/PEG‐400/H2O system for the sonogashira coupling reaction of aryl iodides with alkynes 下载免费PDF全文
A stable and highly efficient NiCl2(PPh3)2/CuI/PEG‐400/H2O catalytic system for the Sonogashira reaction has been developed. In the presence of NiCl2(PPh3)2 and CuI, the coupling reaction of aryl iodides with terminal alkynes was carried out smoothly in a mixture of poly(ethylene glycol) (PEG‐400) and water at 100°C with K2CO3 as base to afford a variety of arylacetylenes in good to excellent yields. The isolation of the products was readily performed by extraction with petroleum ether, and the NiCl2(PPh3)2/CuI/PEG‐400/H2O system could be easily recycled and reused six times without significant loss of catalytic activity. Our system not only avoids the use of easily volatile organic solvents but also solves the basic problem of catalyst reuse. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
102.
103.
Qing-E Wu Tuo Wang Xue-Min Pang Yong-Xuan Huang Ji-Sheng Li 《Journal of Computational and Applied Mathematics》2008
With a brand-new theory, this paper not only provides the differences of attributes in concept, formula expression and function type between fuzzy rough sets and probability statistics, but also introduces their differences in algorithms on target control for better solving the control problem. Some new definitions and theorems concerning fuzzy rough sets and probability statistics are given, but this paper mainly makes a comparison of two control algorithms for the target tracking. The simulation results show that the comprehensive performance of the fuzzy rough sets algorithm is better than that of the probability statistics algorithm, but its control effect is not as good as that of the latter on multisensor target control. Finally, some problems concerning the combination of fuzzy rough sets and the probability statistics phenomenon to be solved and development trends are discussed. By these investigations, we can choose the optimal control algorithms for accomplishing better target control. 相似文献
104.
De-Hui Tuo Chao Chen Huapeng Ruan Prof. Dr. Qi-Qiang Wang Dr. Yu-Fei Ao Prof. Dr. Xinping Wang Prof. Dr. De-Xian Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(33):14144-14147
Radical pimers are the simplest and most important models for studying charge-transfer processes and provide deep insight into π-stacked organic materials. Notably, radical pimer systems with magnetic bi- or multistability may have important applications in switchable materials, thermal sensors, and information-storage media. However, no such systems have been reported. Herein, we describe a new pimer consisting of neutral N-(n-propyl) benzene triimide ([BTI-3C]) and its anionic radical ([BTI-3C]−.) that exhibits rare magnetic multistability. The crystalline pimer was readily synthesized by reduction of BTI-3C with cobaltocene (CoCp2). The transition occurred with a thermal hysteresis loop that was 27 K wide in the range of 170–220 K, accompanied by a smaller loop with a width of 25 K at 220–242 K. The magnetic multistability was attributed to slippage of the π-stacked BTI structures and entropy-driven conformational isomerization of the side propyl chains in the crystalline state during temperature variation. 相似文献
105.
106.
A BALANCED OVERSAMPLING FINITE ELEMENT METHOD FOR ELLIPTIC PROBLEMS WITH OBSERVATIONAL BOUNDARY DATA
In this paper we propose a finite element method for solving elliptic equations with observational Dirichlet boundary data which may subject to random noises. The method is based on the weak formulation of Lagrangian multiplier and requires balanced oversampling of the measurements of the boundary data to control the random noises. We show the convergence of the random finite element error in expectation and, when the noise is sub-Gaussian, in the Orlicz $\psi_2$-norm which implies the probability that the finite element error estimates are violated decays exponentially. Numerical examples are included. 相似文献
107.
Tuo Fei Li Dehong Zhou Fengqun Luo Junhua Tuo Hua Kong Xiangzhong 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(3):507-511
Roots of Astragalus membranaceus, Angelica sinensis, Glycyrrhiza uralensis and Codonopsis pilosula, which were often used as herbs in traditional Chinese medicine, were analyzed by Instrumental Neutron Activation Analysis
(INAA). The samples were collected in Gansu, northwest of China and irradiated at the 15 MW heavy water reactor in China Institute
of Atomic Energy (CIAE). The induced activities were counted by a well calibrated low background γ-spectrometer equipped with
a high efficiency coaxial high-purity germanium (HPGe) detector. The concentrations of eighteen trace elements (Ca, Fe, Na,
Zn, Ba, Rb, Ce, Cr, La, Co, Th, Cs, Sb, Sc, Sm, Hf, Eu and Tb) in the herbs were determined. Possible links between pharmacological
action of the herbs and content of some elements were also discussed in this paper. The measured results were compared with
the reported values in literature. 相似文献
108.
Junhua Luo Xinxing Wang Zhenlai Liu Fei Tuo Xiangzhong Kong 《Radiation Physics and Chemistry》2010,79(10):1018-1021
The cross-sections for formation of metastable state of 195Pt (195mPt, 98.85 keV, 4.02 d) through natPt(n,x)195mPt reaction induced by 13.5–14.6 MeV neutrons were measured. Measurements were corrected for gamma-ray attenuations, random coincidence (pile-up), dead time and fluctuation of neutron flux. The data for natPt(n,x)195mPt reaction cross-sections are reported to be 438±46, 399±44 and 372±43 mb at 13.5±0.2, 14.1±0.1 and 14.6±0.2 MeV incident neutron energies, respectively. 相似文献
109.
110.
Liming Tang Teng Qiu Xinlin Tuo Hu You Deshan Liu Xianlai Tang 《Colloid and polymer science》2006,284(9):957-964
Amphiphilic hyperbranched polyester (P2) consisting of a hydrophobic core, surrounded by aromatic carboxylic acids, is self-assembled into aggregates in aqueous solution at pH region of 3.8–4.7 and in THF–water mixed solution at THF/water volume ratio of 1/100–1/10. With P2 in both aqueous and THF–water mixed solution as polyanion and linear poly(diallydimethylammonium chloride) (PDAC) as polycation, self-assembled films were successfully formed by layer-by-layer dipping. The solution condition of P2, including the pH of aqueous solution and the THF/water volume ratio, affected not only the absorption behavior of P2 but also the surface morphology and hydrophilicity of the films with P2 as the outmost layer. At lower pH or higher THF/water volume ratio the aggregation of P2 in solution was enhanced, thus resulting in higher adsorption rate for P2, more rough and less hydrophilic surface for the films. 相似文献