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221.
Copper(II) oleate was coated on a piezoelectric quartz crystal, and the copper removed by passing EDTA solution. The remaining coating reacted with aluminium, copper(II), iron(III) and lead ions in a flowing acidic solution, to form absorbed compounds which changed the frequency of the crystal. Lead (3–40 μM) could be determined at pH 5.5–5.8 with good reproducibility. Interfering metal ions (Al3+, Cu2+, Fe3+) were masked with acetylacetone. 相似文献
222.
M. Nomura A. Yamada S. Fujita A. Sugimoto J. Ikoma K. Fujita 《Journal of polymer science. Part A, Polymer chemistry》1991,29(7):987-994
In order to clarify the general kinetic behavior of emulsion polymerization initiated by oilsoluble initiators, the emulsion polymerization of styrene initiated by 2,2′-azoisobutyronitrile was as a typical example, investigated thoroughly. The variations of the polymerization rate and the number of polymer particles produced with changes in emulsifier (sodium lauryl sulfate), initiator, and monomer concentrations initially charged and the reaction temperature were determined. It is shown from these experimental results that the kinetic behavior of this emulsion polymerization system is quite similar to that of styrene emulsion polymerization initiated by the water-soluble initiator, potassium persulfate despite the difference in the principal loci of radical production in both systems. 相似文献
223.
Tetsuji Kametani Keiichiro Fukumoto Takuo Nakano 《Journal of heterocyclic chemistry》1972,9(6):1363-1366
The indisputable benzyne reaction of 1-(5-bromo-3,4-dimethoxybenzyl)-1,2,3,4-tetrahydro-7-hydroxy-6-metlioxy-2-methylisoquinoline (II) with sodium amide in liquid ammonia afforded the following compounds, (±)-cryptaustoline iodide (VI), (±)-thaliporphine (VIII), 1 -(3,4-dimeth-oxybenzyl)- (III), and 1 -(2-amino-4,5-dimethoxybenzyl)-l,2,3,4-tetrahydro-7-hydroxy-6-meth-oxy-2-methylisoquinoline (IV). 相似文献
224.
225.
Many metal ions are spontaneously adsorbed onto a piezoelectric quartz crystal and change the oscillation frequency. The pH ranges in which the metal ions adsorbed were just below that of precipitate formation as the ‘hydroxides’; frequency changes caused by adsorption were not observed in these pH ranges where the ‘hydroxides’ formed. Cationic organic reagents, such as crystal violet and methylene blue, were also adsorbed on the piezoelectric quartz crystal but non-ionic and anionic organic compounds were not. These results showed that the crystal was negatively charged on the surface. 相似文献
226.
Observation of cerium isotope fractionation in ion-exchange chromatography of Ce(III)-malate complex
The cerium isotope fractionation between Ce(III)-malate complex in aqueous solution and cerium ions in a cation-exchange resin was conducted by displacement chromatography. The pH and the chemical composition of the eluent were optimized for maintaining the self-sharpening band boundaries and the 21 m chromatographic migration of the Ce band underwent. Graphite slurry was coated on the tantalum filament prior to sample loading for reducing the isobaric interferences in cerium isotopic ratio determination by mass spectrometry. From the experimental results, it was found that the heavier isotope was enriched in the front boundary part of the cerium adsorption band, which meant that the heavier isotope was preferentially fractionated into the Ce3+ malate complex rather than simply hydrated Ce3+ ions. The isotope separation coefficient for the 136Ce/140Ce and 142Ce/140Ce was 5.2 x 10(-5) and -1.9 x 10(-5), respectively, at 298 K. 相似文献
227.
Kotohiro Nomura 《Catalysis Surveys from Asia》1998,2(1):59-69
This review describes recent progresses in the selective reduction of aromatic nitro-groups to amines catalyzed by homogeneous ruthenium or rhodium catalysts under CO/H2O conditions. These catalytic reactions are useful from both synthetic and industrial viewpoints, because the after-treatment of by-products can be simplified in comparison to the conventional methods, since the reaction proceeds with extremely high selectivity. Efficient and convenient palladium–phosphine catalysts for hydrocarbonylation of chlorobenzenes affording benzoic acid derivatives in high yields are also described. 相似文献
228.
A computer simulation by a molecular dynamics method at constant volume has been performed on a model material that is composed
of accumulating two different fluoride conductors: ⋯BaF2–CaF2–BaF2–CaF2⋯. The average value of CaF2 and BaF2 for the lattice constant of the new layered material is prepared to hold its mechanical strength. The CaF2 region is compressed and the BaF2 region is stretched along the c axis (z axis) in the thermal equilibrium state. It is obtained that the diffusion coefficient and ionic conductivity of F − ions in the layered fluoride conductors increases with decreasing periods, more specifically with the number of interfaces.
The layer depth dependence on transport coefficients approximately coincides with the experiment. 相似文献
229.
Yukio Imanishi Kotohiro Nomura 《Journal of polymer science. Part A, Polymer chemistry》2000,38(Z1):4613-4626
Olefin polymerizations catalyzed by Cp′TiCl2(O‐2,6‐iPr2C6H3) ( 1 – 5 ; Cp′ = cyclopentadienyl group), RuCl2(ethylene)(pybox) { 7 ; pybox = 2,6‐bis[(4S)‐4‐isopropyl‐2‐oxazolin‐2‐yl]pyridine}, and FeCl2(pybox) ( 8 ) were investigated in the presence of a cocatalyst. The Cp*TiCl2(O‐2,6‐iPr2C6H3) ( 5 )–methylaluminoxane (MAO) catalyst exhibited remarkable catalytic activity for both ethylene and 1‐hexene polymerizations, and the effect of the substituents on the cyclopentadienyl group was an important factor for the catalytic activity. A high level of 1‐hexene incorporation and a lower rE · rH value with 5 than with [Me2Si(C5Me4)(NtBu)]TiCl2 ( 6 ) were obtained, despite the rather wide bond angle of Cp Ti O (120.5°) of 5 compared with the bond angle of Cp Ti N of 6 (107.6°). The 7 –MAO catalyst exhibited moderate catalytic activity for ethylene homopolymerization and ethylene/1‐hexene copolymerization, and the resultant copolymer incorporated 1‐hexene. The 8 –MAO catalyst also exhibited activity for ethylene polymerization, and an attempted ethylene/1‐hexene copolymerization gave linear polyethylene. The efficient polymerization of a norbornene macromonomer bearing a ring‐opened poly(norbornene) substituent was accomplished by ringopening metathesis polymerization with the well‐defined Mo(CHCMe2Ph)(N‐2,6‐iPr2C6H3)[OCMe(CF3)2]2 ( 10 ). The key step for the macromonomer synthesis was the exclusive end‐capping of the ring‐opened poly(norbornene) with p‐Me3SiOC6H4CHO, and the use of 10 was effective for this polymerization proceeding with complete conversion. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4613–4626, 2000 相似文献
230.
Nomura H Koda S Matsuoka T Hiyama T Shibata R Kato S 《Journal of colloid and interface science》2000,226(1):22-28
Spreading of a tiny macroscopic droplet of a nonvolatile, completely wetting liquid over a flat solid is considered. A liquid in creeping is subjected to capillary forces and long-range molecular forces. The droplet may be surrounded with a precursor wetting film. This paper deals with the problem of determining of the microscopic parameter that influences the interface shape near the apparent line of wetting; this is regarded as the inverse problem in the hydrodynamics of wetting. If the system includes a precursor film, the microscopic parameter coincides with the maximum thickness of the film. A series of inverse equations for the microparameter is obtained, which relate it to, first, the current geometric parameters of the macroscopic drop part and, second, the spreading time. A method for determining how the microparameter depends on the wetting line speed is proposed. The theory expands the opportunity to perform macroscopic measurements and reveals additional parameters. The inverse relations may be used to experimentally study the growth of the maximum thickness of a precursor film during drop spreading. Copyright 2000 Academic Press. 相似文献