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1.
In our previous two works, we studied the blow-up and lifespan estimates for damped wave equations with a power nonlinearity of the solution or its derivative, with scattering damping independently. In this work, we are devoted to establishing a similar result for a combined nonlinearity. Comparing to the result of wave equation without damping, one can say that the scattering damping has no influence. 相似文献
2.
《Wave Motion》2020
Analytical solutions are reported for the scattering coefficients of a solid elastic sphere suspended in a viscous fluid for arbitrary partial wave order. Expressions are derived for incident compressional and shear wave modes, taking into account the viscosity of the surrounding fluid and resultant wave mode conversion. The long compressional wavelength limit is employed to simplify the derivation, whereas no restriction is placed on the shear wavelength in the fluid compared to the particle dimension. The analytical approximations are compared with numerical results obtained from matrix inversion of the boundary equations and agree within the validity domain of the solutions. 相似文献
3.
本文通过反应力场来研究中性双甘氨肽与高取向热解石墨的碰撞动力学过程,分别模拟初始入射角度为0o、20o、45o和70o以及入射能量为481.5 kJ/mol和表面温度为677 K的情况,并且确定和分析了散射产物的角度分布、平动能分布、内能分布和表面滞留时间分布. 双甘氨肽是一种多原子分子,具有较多的低频振动模式和较强的表面吸附相互作用,这些使得碰撞过程的表面滞留时间较长和容易造成能量损失,尤其是表面法线方向. 由于碰撞分子的动量沿表面法线方向上明显地发生损失,而沿表面平行方向上的动量则会大部分保留,因此,其散射角通常会呈现出超镜面反射分布,并且末态的平动能要远小于所谓硬立方模型的预测值. 本文加深了多肽分子与高取向热解石墨碰撞及其能量转移过程的认识和理解,有助于设计在稀薄大气中收集这类大分子的中性气体浓缩器. 相似文献
4.
《Annales de l'Institut Henri Poincaré (C) Analyse Non Linéaire》2020,37(2):417-456
We study the energy-critical nonlinear wave equation in the presence of an inverse-square potential in dimensions three and four. In the defocussing case, we prove that arbitrary initial data in the energy space lead to global solutions that scatter. In the focusing case, we prove scattering below the ground state threshold. 相似文献
5.
6.
Shuang Guo Dr. Yeonju Park Eungyeong Park Dr. Sila Jin Prof. Lei Chen Prof. Young Mee Jung 《Angewandte Chemie (International ed. in English)》2023,62(34):e202306709
π-Conjugated organic semiconductors are promising materials for surface-enhanced Raman scattering (SERS)-active substrates based on the tunability of electronic structures and molecular orbitals. Herein, we investigate the effect of the temperature-mediated resonance-structure transitions of poly(3,4-ethylenedioxythiophene) (PEDOT) in poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT : PSS) films on the interactions between substrate and probe molecules, thereby affecting the SERS activity. Absorption spectroscopy and density functional theory calculations show that this effect occurs mainly due to delocalization of the electron distribution in molecular orbitals, effectively promoting the charge transfer between the semiconductor and probe molecules. In this work, we investigate for the first time the effect of electron delocalization in molecular orbitals on SERS activity, which will provide new design ideas for the development of highly sensitive SERS substrates. 相似文献
7.
Feifan Li Xinyang Mu Xueqing Tang Ge Song Hongzhao Sun Xiuling Zha Peiyan Sun Jianhui Fang Dongmei Hu Shan Cong Zhigang Zhao 《Angewandte Chemie (International ed. in English)》2023,62(12):e202218055
Non-metallic materials have emerged as a new family of active substrates for surface-enhanced Raman scattering (SERS), with unique advantages over their metal counterparts. However, owing to their inefficient interaction with the incident wavelength, the Raman enhancement achieved with non-metallic materials is considerably lower with respect to the metallic ones. Herein, we propose colourful semiconductor-based SERS substrates for the first time by utilizing a Fabry-Pérot cavity, which realize a large freedom in manipulating light. Owing to the delicate adjustment of the absorption in terms of both frequency and intensity, resonant absorption can be achieved with a variety of non-metal SERS substrates, with the sensitivity further enhanced by ≈100 times. As a typical example, by introducing a Fabry-Pérot-type substrate fabricated with SiO2/Si, a rather low detection limit of 10−16 M for the SARS-CoV-2S protein is achieved on SnS2. This study provides a realistic strategy for increasing SERS sensitivity when semiconductors are employed as SERS substrates. 相似文献
8.
Dr. Shi Xuan Leong Dr. Ya-Chuan Kao Dr. Xuemei Han Dr. Zhong Wei Poh Jaslyn Ru Ting Chen Emily Xi Tan Yong Xiang Leong Dr. Yih Hong Lee Dr. Wei Xuan Teo Prof. George W. Yip Prof. Yulin Lam Prof. Xing Yi Ling 《Angewandte Chemie (International ed. in English)》2023,62(44):e202309610
Molecular recognition of complex isomeric biomolecules remains challenging in surface-enhanced Raman scattering (SERS) spectroscopy due to their small Raman cross-sections and/or poor surface affinities. To date, the use of molecular probes has achieved excellent molecular sensitivities but still suffers from poor spectral specificity. Here, we induce “charge and geometry complementarity” between probe and analyte as a key strategy to achieve high spectral specificity for effective SERS molecular recognition of structural analogues. We employ 4-mercaptopyridine (MPY) as the probe, and chondroitin sulfate (CS) disaccharides with isomeric sulfation patterns as our proof-of-concept study. Our experimental and in silico studies reveal that “charge and geometry complementarity” between MPY's binding pocket and the CS sulfation patterns drives the formation of site-specific, multidentate interactions at the respective CS isomerism sites, which “locks” each CS in its analogue-specific complex geometry, akin to molecular docking events. Leveraging the resultant spectral fingerprints, we achieve > 97 % classification accuracy for 4 CSs and 5 potential structural interferences, as well as attain multiplex CS quantification with < 3 % prediction error. These insights could enable practical SERS differentiation of biologically important isomers to meet the burgeoning demand for fast-responding applications across various fields such as biodiagnostics, food and environmental surveillance. 相似文献
9.
Neville Murphy Dr. William J. Tipping Henry J. Braddick Dr. Liam T. Wilson Prof. Nicholas C. O. Tomkinson Prof. Karen Faulds Prof. Duncan Graham Dr. Pau Farràs 《Angewandte Chemie (International ed. in English)》2023,62(48):e202311530
Multiplex optical detection in live cells is challenging due to overlapping signals and poor signal-to-noise associated with some chemical reporters. To address this, the application of spectral phasor analysis to stimulated Raman scattering (SRS) microscopy for unmixing three bioorthogonal Raman probes within cells is reported. Triplex detection of a metallacarborane using the B−H stretch at 2480–2650 cm−1, together with a bis-alkyne and deuterated fatty acid can be achieved within the cell-silent region of the Raman spectrum. When coupled to imaging in the high-wavenumber region of the cellular Raman spectrum, nine discrete regions of interest can be spectrally unmixed from the hyperspectral SRS dataset, demonstrating a new capability in the toolkit of multiplexed Raman imaging of live cells. 相似文献
10.
Visible and Near Infrared (Vis–NIR) Spectroscopy is a powerful non destructive analytical method used to analyze major compounds in bulk materials and products and requiring no sample preparation. It is widely used in routine analysis and also in-line in industries, in-vivo with biomedical applications or in-field for agricultural and environmental applications. However, highly scattering samples subvert Beer–Lambert law's linear relationship between spectral absorbance and the concentrations. Instead of spectral pre-processing, which is commonly used by Vis–NIR spectroscopists to mitigate the scattering effect, we put forward an optical method, based on Polarized Light Spectroscopy to improve the absorbance signal measurement on highly scattering samples. This method selects part of the signal which is less impacted by scattering. The resulted signal is combined in the Absorption/Remission function defined in Dahm's Representative Layer Theory to compute an absorbance signal fulfilling Beer–Lambert's law, i.e. being linearly related to concentration of the chemicals composing the sample. The underpinning theories have been experimentally evaluated on scattering samples in liquid form and in powdered form. The method produced more accurate spectra and the Pearson's coefficient assessing the linearity between the absorbance spectra and the concentration of the added dye improved from 0.94 to 0.99 for liquid samples and 0.84–0.97 for powdered samples. 相似文献