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991.
Shao Su Xinpan Wei Yuanyuan Guo Yiling Zhong Yuanyuan Su Qing Huang Chunhai Fan Yao He 《Particle & Particle Systems Characterization》2013,30(4):326-331
A new kind of silicon nanowire (SiNWs)‐based nanoelectrode assembly, a gold‐nanoparticle‐decorated silicon nanowire array (AuNPs@SiNWsAr), is employed for the construction of high‐performance electrochemical sensors. Significantly, the electrochemical nanosensors are capable of sensitive detection of various electroactive molecules (e.g., dopamine (DA), ascorbic acid (AA), hydrogen peroxide (H2O2), and glucose). Further, DA molecules loaded on the surface of AuNPs@SiNWsAr preserve stable high electroactivity overnight without special protection, while free DA molecules may lose their biological activity due to severe oxidization in ambient environment. These findings may offer new opportunities for the design of high‐performance electrochemical nanosensors with high sensitivity and robust stability. 相似文献
992.
Cathode materials Li[CoxNiyMn1-x-y]O2 for lithium secondary batteries have been prepared by a new route using layered double hydroxides (LDHs) as a precursor. The resulting layered phase with the α-NaFeO2 structure crystallizes in the rhombohedral system, with space group R-3m having an interlayer spacing close to 0.47 nm. X-ray photoelectron spectroscopy (XPS) was used to measure the oxidation states of Co, Ni and Mn. The effects of varying the Co/Ni/Mn ratio on both the structure and electrochemical properties of Li[CoxNiyMn1-x-y]O2 have been investigated by X-ray diffraction and electrochemical tests.The products demonstrated a rather stable cycling behavior, with a reversible capacity of 118 mAh/g for the layered material with Co/Ni/Mn = 1/1/1. 相似文献
993.
Adriaan M. H. van der Veen Thomas P. J. Linsinger Andree Lamberty Jean Pauwels 《Accreditation and quality assurance》2001,6(6):257-263
To serve as a measurement standard, a (certified) reference material must be stable. For this purpose, the material should
undergo stability testing after it has been prepared. This paper looks at the statistical aspects of stability testing. Essentially,
these studies can be described with analysis of variance statistics, including variant regression analysis. The latter is
used in practice for both trend analysis and for the development of expressions for extrapolations. Extrapolation of stability
data is briefly touched upon, as far as the combined standard uncertainty of the reference material is concerned. There are
different options to validate the extrapolations made from initial stability studies, and some of them might influence the
uncertainty of the reference material and/or the shelf-life. The latter is the more commonly observed consequence of what
is called ’stability monitoring’.
Received: 6 October 2000 Accepted: 4 December 2000 相似文献
994.
995.
S. Radhakrishnan N. Somanathan T. Narasimhaswamy 《Journal of Polymer Science.Polymer Physics》2008,46(14):1463-1477
Liquid crystalline materials display unique properties, which can be exploited in organic light emitting diodes. Polythiophene model compounds containing phenyl groups linked with azomethine, ester, and alkoxy groups [thiophene‐3‐alkyloxy benzoyloxy aniline series (N series) and thiophene‐3‐alkoxy phenoxy amino benzoate series (R Series)] were synthesized. Molecular orbital calculations were performed and the predicted band gaps compared to understand the effects of spacer length and linkage. The experimental photoabsorption characteristics are compared with the theoretically predicted band gap. Photoabsorption and emission studies on N series and R series polymers as the function of polarizer angle suggest that polymers of both series emit polarized light in all base color ranges. The electroemission characteristics of the above‐synthesized polymers were also recorded as the function of polarizer angle. The results show that the compounds also emit polarized electroemission, and the EL polarization ratio decreases with the increase of alkoxy chain length for N and R polymers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1463–1477, 2008 相似文献
996.
997.
The three water‐free calcium carbonate polymorphs calcite, aragonite and vaterite were prepared from aqueous solutions without additives using standard laboratory equipment in a continuous process. Variation parameters were the way of mixing, the solution concentrations, and the reactor residence time. The samples were crystallographically and chemically pure, but a thorough elemental analysis revealed the presence of small amounts of sodium carbonate which was not detectable by X‐ray powder diffraction. The continuous process avoids the inherent variability of batch syntheses. By adapting the crystallization parameters, magnesium‐substituted amorphous calcium carbonate (molar ratio of Mg:Ca of 1:2.68) was prepared in this continuous process. 相似文献
998.
Microfluidic systems promise solutions for high throughput and highly specific analysis for biology, medicine and chemistry while consuming only tiny amounts of reactants and space. On these lab‐on‐a‐chip platforms often multiple physical effects such as electrokinetic, acoustic or capillary phenomena from various disciplines are exploited to gain the optimal functionality. The fluidics on these small length scales differ significantly from our experience of the macroscopic world. In this Review we survey some of the approaches and techniques to handle minute amounts of fluid volumes in microfluidic systems with special focus on surface acoustic wave driven fluidics, a technique developed in our laboratory. Here, we outline the basics of this technique and demonstrate, for example, how acoustic mixing and fluid actuation is realized. Furthermore we discuss the interplay of different physical effects in microfluidic systems and illustrate their usefulness for several applications. 相似文献
999.
S. P. Meenakshisundaram S. Parthiban G. Madhurambal S.C. Mojumdar 《Journal of Thermal Analysis and Calorimetry》2008,94(1):21-25
The influence of a new organic additive, chelating agent 1,10-phenanthroline (Phen) (∼5.0·10−3 M L−1) on potassium hydrogen phthalate (KHP) single crystals at 30° is investigated. The crystals were grown from the aqueous solutions
of pH ∼4.5 at constant temperature by solvent evaporation technique. The chelating agent leads to an increase in metastable
zone width and assists the bulk growth process. The growth rate of crystals in the presence of Phen decreases considerably
with an increase in impurity concentration. Not much variation is observed in FTIR and cell parameter values, determined by
XRD analysis. It appears that the growth promoting effect (GPE) of Phen is caused by the adsorption of the organic additive
on the prism of KHP crystals. Differential scanning calorimetry (DSC) and TG-DTA studies reveal the purity of the sample and
no decomposition is observed up to the melting point. Scanning electron microscope (SEM) photographs exhibit the effectiveness
of the impurity in changing the surface morphology of KHP crystals. Contrary to expectations, Phen depresses the NLO efficiency
of KHP, suggesting that the molecular alignments in the presence of Phen results in cancellation effects disturbing the non-linearity. 相似文献
1000.
Thermal properties of organoindium thiolates were investigated by means of thermogravimetric (TG) and differential thermal (DT) analysis. Dibutyl-indium propylthiolates (Bun2InSPrn, Bun2InSPri, Bui2InSPrn and Bui2InSPri) decomposed up to 280°C along with an exothermic DT peak and gave indium(I) sulfide (InS) powders. Although the arylthiolate Bun2InSPh also afforded InS powders, it decomposed at a slightly higher temperature. In contrast, the dithiolate and the dithiocarbamate complexes [BunIn(SPri)2 and In (S2CNBu2)3] gave indium(III) sulfide (In2S3) powders. 相似文献