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991.
Rosner JL Adam NE Alexander JP Berkelman K Cassel DG Crede V Duboscq JE Ecklund KM Ehrlich R Fields L Galik RS Gibbons L Gittelman B Gray R Gray SW Hartill DL Heltsley BK Hertz D Jones CD Kandaswamy J Kreinick DL Kuznetsov VE Mahlke-Krüger H Meyer TO Onyisi PU Patterson JR Peterson D Phillips EA Pivarski J Riley D Ryd A Sadoff AJ Schwarthoff H Shi X Shepherd MR Stroiney S Sun WM Urner D Wilksen T Weaver KM Weinberger M Athar SB Avery P Breva-Newell L Patel R Potlia V Stoeck H Yelton J Rubin P 《Physical review letters》2005,95(10):102003
The h(c)((1)P(1)) state of charmonium has been observed in the reaction psi(2S) --> pi(0)h(c) --> (gammagamma)(gammaeta(c)) using 3.08 x10(6) psi(2S) decays recorded in the CLEO detector. Data have been analyzed both for the inclusive reaction, where the decay products of the eta(c) are not identified, and for exclusive reactions, in which eta(c) decays are reconstructed in seven hadronic decay channels. We find M(h(c)) = 3524.4 +/- 0.6 +/- 0.4 MeV which corresponds to a hyperfine splitting DeltaM(hf)(1P) triple-bond pi(0)h(c)) x B(h(c) --> gammaeta(c)) = (4.0 +/- 0.8 +/- 0.7) x 10(-4). 相似文献
992.
The complexation reactions of iron(III) with 2-pyridine carboxylic acia (picolinic acid) and 2,6-pyridine dicarboxylic acid (dipicolinic acid) in aqueous solutions have been studied by spectrophotometric and stopped flow techniques. Equilibrium constants were determined for the 1 : 1 complexes at temperatures between 25 and 80°C. The values obtained are: Picolinic Acid (HL): Fe3++ H2L+? FeHL3++H+(K1 = 2.8,ΔH = 2 kcal mole?1 at 25°C, μ = 2.67 M) Dipicolinic Acid (H2D): Fe3++H2D? FeD++2H+(K1K1A= 227 M, ΔH = 3.4 kcal mole?1 at 25°C,μ = 1.0 M). The rate constants for the formation of these complexes are also given. The results are used to evaluate the effects of these two acids upon the rate of dissolution of iron(III) from its oxides. 相似文献
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996.
Harasit Kumar Mandal Biman Kumar Patel Somnath Dasmandal 《Journal of Dispersion Science and Technology》2018,39(4):552-559
The kinetic investigations on the alkaline hydrolysis of tris-(1,10–phenanthroline)iron(II) has been explored spectrophotometrically in microheterogeneous environment at 301?K and ionic strength of 0.13?mol?L?1. Guar gum, cationic amphiphiles, and their mixtures are used as the reaction environments to carry out the reaction. Guar gum decreases the rate of reaction, which indicates that Fe(II) complex may be trapped in the hydrophobic region of gum. Cationic amphiphile decreases the rate in the presence of guar gum. The extent of interaction between guar gum and amphiphile increases with the hydrophobic carbon chain length. The critical aggregation concentration (CAC) and critical micelle concentration (CMC) of the amphiphiles (cetyl trimenthyl ammonium bromide (CTAB), tetradecyl trimenthyl ammonium bromide (TTAB), dodecyl trimenthyl ammonium bromide (DTAB)) in the presence of guar gum have been determined with conductometry and tensiometry. All observations support either weak or strong interaction of cationic amphiphiles with guar gum. Activation parameters of the reaction in different environments have been determined which corroborate the rate data. 相似文献
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998.
Phenacyl bromides are used as a building blocks in synthetic organic chemistry, which serves as a key model for the development of various biologically important heterocyclic compounds and other industrially important scaffolds. This review covers recent synthetic advances in the preparation of heterocyclic compounds utilizing various phenacyl bromides. A wide range of five- and six-membered heterocyclic compounds as well as fused heterocyclic compounds were synthesized efficiently from the phenacyl bromide precursors through one-pot multicomponent reactions. 相似文献
999.
Zhang Q. Vickers M.E. Patel A. Whatmore R.W. 《Journal of Sol-Gel Science and Technology》1998,11(2):141-152
The formation and growth of polymeric particles during the hydrolysis and condensation of PbZr0.3Ti0.7 O3 (PZT 30/70) sol-gel precursor solutions have been investigated by using photon correlation spectroscopy (PCS), small angle X-ray scattering (SAXS) and by measuring their rheological properties. The measurements showed that the growth of the particles in the transition of PZT sol to gel followed a simple polymerisation process. Solution A (containing by-products) and Solution B (by-products removed) displayed a similar plot of logarithmic viscosity against logarithmic time, indicating that the particles in both solutions have similar structures after hydrolysis. The changes in viscosity and particle size with time were described by single logarithmic growth models. However, the increasing rate of logarithmic particle size in Solution B is higher than that in Solution A. A model for the form of the aggregates is discussed which is applicable to PZT organometal-particle aggregation process in systems with acetic acid as a modifier. 相似文献
1000.
Veerababurao Kavala Siva Murru Bhisma K. Patel Gopal Das 《Journal of chemical crystallography》2007,37(8):527-535
Various multi carbon homologations of 9-phenyl-9H-xanthen-9-ol (1) were obtained through a C-C bond formation by reacting it with various enolisable ketones in the presence of 1,1′-(ethane-1,2-diyl)dipyridinium
bistribromide (EDPBT). All the ten derivatives along with the starting xanthen-9-ol have been characterized by single crystal
X-ray diffraction. They all form self-assembled superstructure in the solid state. The self-assembling patterns in these supramolecular
architectures were explained based on steric and electronic nature of the pendant arm.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献