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101.
W. Huang Z. L. Li Y. D. Peng S. Chen J. F. Zheng Z. J. Niu 《Journal of Solid State Electrochemistry》2005,9(5):284-289
A film of Ni(OH)2 deposited cathodically on a roughened nickel substrate consists of even nanoparticles, which were characterized by atomic-force microscopy (AFM). The mechanism of potential oscillations in the electrocatalytic oxidation of methanol on this film electrode in alkaline medium was studied in situ by means of Raman spectroscopy in combination with electrochemical measurements. The redox change of the nickel hydroxide film, the concentration distribution of methanol in the diffusion layer, and the oxidation products of methanol were characterized in situ by time-resolved, spatial-resolved, and potential-dependent Raman spectroscopy, respectively. Electrochemical reactions, i.e. methanol oxidation and periodic oxygen evolution, coupling with alternately predominant diffusion and convection mass transfer of methanol, account for the potential oscillations that occur during oxidation of methanol above its limiting diffusion current. This mechanism is totally different from that of methanol oxidation on platinum electrodes, for which surface steps, i.e. formation and removal of COad, are essential.This work is dedicated to Professor Gyorgy Horanyi on the occasion of his 70th birthday in recognition of his numerous contributions to field of electrochemical oscillations and electrocatalysis at Ni-hydroxide electrodes. 相似文献
102.
Ailong Li Hideshi Ooka Nadge Bonnet Toru Hayashi Yimeng Sun Qike Jiang Can Li Hongxian Han Ryuhei Nakamura 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(15):5108-5112
Efficient, earth‐abundant, and acid‐stable catalysts for the oxygen evolution reaction (OER) are missing pieces for the production of hydrogen via water electrolysis. Here, we report how the limitations on the stability of 3d‐metal materials can be overcome by the spectroscopic identification of stable potential windows in which the OER can be catalyzed efficiently while simultaneously suppressing deactivation pathways. We demonstrate the benefits of this approach using gamma manganese oxide (γ‐MnO2), which shows no signs of deactivation even after 8000 h of electrolysis at a pH of 2. This stability is vastly superior to existing acid‐stable 3d‐metal OER catalysts, but cannot be realized if there is a deviation as small as 50‐mV from the stable potential window. A stable voltage efficiency of over 70 % in a polymer–electrolyte membrane (PEM) electrolyzer further verifies the availability of this approach and showcases how materials previously perceived to be unstable may have potential application for water electrolysis in an acidic environment. 相似文献
103.
Jiai Hua Xiang Ma Pengtao Ma Jingping Wang Jingyang Niu 《Journal of Cluster Science》2013,24(3):689-700
A new compound H8[NaCu5Cl(H2O)3(B-α-AsW9O33)2] 24H2O (1) is synthetized by the reaction of the CuCl2 2H2O and Na27[NaAs4W40O140] 60H2O in aqueous solution, which is constructed from a {Cu5Na} hexagon moiety sandwiched by two trilacunary [B-α-AsW9O33]9? units. The structure is determined by single-crystal X-ray diffraction technique and further characterized by IR spectroscopy. Single-crystal X-ray diffraction analysis reveals that 1 is built by two trilacunary [B-α-AsW9O33]9? units incorporating a {Cu5Na} hexagon moiety and further linked to each other to form an infinitely extended 2-D network via Cu–O–W bridges. Notably, magnetic measurement demonstrates that the occurrence of intramolecular ferromagnetic Cu–Cu interactions within {Cu5Na} hexagon moiety. 相似文献
104.
Many quantum mechanical calculations indicate water molecules in the gas and liquid phase have much larger quadrupole moments than any of the common site models of water for computer simulations. Here, comparisons of multipoles from quantum mechanical∕molecular mechanical (QM∕MM) calculations at the MP2∕aug-cc-pVQZ level on a B3LYP∕aug-cc-pVQZ level geometry of a waterlike cluster and from various site models show that the increased square planar quadrupole can be attributed to the p-orbital character perpendicular to the molecular plane of the highest occupied molecular orbital as well as a slight shift of negative charge toward the hydrogens. The common site models do not account for the p-orbital type electron density and fitting partial charges of TIP4P- or TIP5P-type models to the QM∕MM dipole and quadrupole give unreasonable higher moments. Furthermore, six partial charge sites are necessary to account reasonably for the large quadrupole, and polarizable site models will not remedy the problem unless they account for the p-orbital in the gas phase since the QM calculations show it is present there too. On the other hand, multipole models by definition can use the correct multipoles and the electrostatic potential from the QM∕MM multipoles is much closer than that from the site models to the potential from the QM∕MM electron density. Finally, Monte Carlo simulations show that increasing the quadrupole in the soft-sticky dipole-quadrupole-octupole multipole model gives radial distribution functions that are in good agreement with experiment. 相似文献
105.
H. L. Cheng D. Y. Shi J. W. Zhao Z. D. Geng L. J. Chen P. T. Ma J. Y. Niu 《Russian Journal of Coordination Chemistry》2011,37(4):302-308
A novel 3D 3d–4f heterometallic polymer Pr4(H2O)9Cu3.5Cl0.5(Bpdc)6.5(OH)2 · 5H2O (I) (H2Bpdc = 2,2′-bipyridyl-5,5′-dicarboxylic acid) has been hydrothermally synthesized by the reaction of CuCl2 · 2H2O, PrCl3, H2Bpdc, TAA (TAA = 1H-tetrazolyl-1-acetic acid) and glacial acetic acid and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. Single-crystal structural analysis shows that I displays an interesting heterometallic 3D coordination framework constructed from 2D praseodymium-oxygen layers and [Cu(Bpdc)2]3? and [CuCl(Bpdc)]2? pillars. The photofluorescence properties of I have been investigated. 相似文献
106.
Simultaneous determination of carbohydrates and organic acids in beer and wine by ion chromatography 总被引:3,自引:0,他引:3
The simultaneous determination of mono-organic acids and carbohydrates by ion chromatography with both conductometric and pulsed amperometric detection is described. The carbohydrates, such as mannitol, arabinose, glucose, fructose, lactose, sucrose, raffinose, and maltose, as well as monoorganic acids including acetate, glycolate, formate, pyruvate, and fluoride are separated as anions by ion-exchange chromatography with 0.080 mol/L sodium hydroxide eluent at 1 mL/min within 12 min. Carbohydrates are determined by pulsed amperometric detection and mono-organic acids are determined by suppressed conductivity detection. The species in beverages are determined. 相似文献
107.
多相催化反应原位红外系统及其应用 总被引:1,自引:0,他引:1
设计和建立了一套能耐高温的用于多相催化反应研究的原位红外系统,反应温度从室温到1150K,系统真空为1.0*10^5-1.0-10^-4Pa,红外光谱检测范围为4800-200cm^-1。此系统扩展了原仪器的功能,提高了仪器利用率和效率。 相似文献
108.
Effect of environmental conditions on the sorption of radiocobalt from aqueous solution to treated eggshell as biosorbent 总被引:1,自引:0,他引:1
Shouwei Zhang Zhiqiang Guo Junzheng Xu Haihong Niu Zhesheng Chen Jinzhang Xu 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(1):121-130
Carbonate hydroxylapatite (CHAP), prepared from eggshell waste, was used to remove 60Co(II) from aqueous solutions. The sorption of 60Co(II) on CHAP as a function of contact time, pH, ionic strength and foreign ions in the absence and presence of humic acid
and fulvic acid under ambient conditions was studied. The sorption of 60Co(II) on CHAP was strongly dependent on pH and ionic strength. The thermodynamic parameters (ΔH
0, ΔS
0, ΔG
0) of 60Co(II) sorption on CHAP were calculated from the temperature-dependent sorption isotherms, and the results indicated that
the sorption process of 60Co(II) on CHAP was endothermic and spontaneous. At low pH, the sorption of 60Co(II) was dominated by outer-sphere surface complexation and ion exchange with Na+/H+ on CHAP surfaces, whereas inner-sphere surface complexation was the main sorption mechanism at high pH. Experimental results
also indicated that CHAP was a suitable low-cost adsorbent for pre-concentration and solidification of 60Co(II) from large volumes of aqueous solutions. 相似文献
109.
Bing Niu Yuhuan Jin Lin Lu Kaiyan Fen Lei Gu Zhisong He Wencong Lu Yixue Li Yudong Cai 《Molecular diversity》2009,13(3):313-320
The knowledge of whether one enzyme can interact with a small molecule is essential for understanding the molecular and cellular
functions of organisms. In this paper, we introduce a classifier to predict the small molecule– enzyme interaction, i.e.,
whether they can interact with each other. Small molecules are represented by their chemical functional groups, and enzymes
are represented by their biochemical and physicochemical properties, resulting in a total of 160 features. These features
are input into the AdaBoost classifier, which is known to have good generalization ability to predict interaction. As a result,
the overall prediction accuracy, tested by tenfold cross-validation and independent sets, is 81.76% and 83.35%, respectively,
suggesting that this strategy is effective. In this research, we typically choose interactions between small molecules and
enzymes involved in metabolism to ultimately improve further understanding of metabolic pathways. An online predictor developed
by this research is available at .
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
110.
R. M. Niu J. Zhang Z. J. Wang G. Liu G. J. Zhang X. D. Ding J. Sun 《Applied Physics A: Materials Science & Processing》2009,97(2):369-374
This letter reports an experimental investigation into the direct current (DC) induced reduction in the yield strength of
60∼700-nm-thick Cu films. Results show that the larger the current density and the thinner the film, the greater the reduction
when the film thickness is below about 340 nm. This reduction could be described on the basis of dislocation buckling, which,
caused by the electron wind of the current flow, induces an increase in the dislocation length and a decrease in the critical
stress for multiplying the dislocation. 相似文献