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81.
Single and binary adsorption behaviors of salicylic acid and 5-sulfosalicylic acid onto hypercrosslinked polymeric adsorbents, i.e. NDA-101 and NDA-99 were investigated. The Freundlich model can successfully describe all the adsorption isotherms tested, which indicates a favorable and exothermic adsorption process. The adsorption of salicylic acid relies on π-π interaction, while the electrostatic interaction further influences the adsorption of 5-sulfosalicylic acid onto NDA-99. The adsorptive capacity of salicylic acid on NDA-99 decreases but increases on NDA-101 with 5-sulfosalicylic acid as the background component in a binary solute system. The amount of 5-sulfosalicylic acid adsorbed was decreased with the increase in initial concentration of salicylic acid on both adsorbents. The competition for the adsorption sites is considered to be predominant in the solid-to-liquid interaction process. The adsorption selectivity of salicylic acid onto NDA-101 is higher than onto NDA-99 by more than an order of magnitude. Thus, combination technique involving NDA-101 followed by NDA-99 can be effectively applied to separate and recover salicylic acid and 5-sulfosalicylic acid from wastewater. 相似文献
82.
Exfoliated polystyrene (PS)/laponite nanocomposites were prepared successfully. The characteristic doo1 diffraction peak of organo-laponite disappeared in the XRD patterns of nanocomposites, indicating that the laponite layers were exfoliated and the ordered crystal structure of laponite was destroyed because of the styrene polymerization. TEM observations showed that the exfoliated laponite primary particles were dispersed randomly in the PS matrix with lateral dimensions from 1 nm to 10 rim. SEM results showed that the PS/laponite nanocomposite particles were almost monodispersed spheres with the size of about 120 rim. Because of the interaction between PS and laponite nanolayers, the nanocomposites exhibited higher thermal stability and glass transition temperature when compared to pure PS. 相似文献
83.
Photokilling Squamous Carcinoma Cells SCCVII with Ultrafine Particles of Selected Metal Oxides 总被引:1,自引:0,他引:1
Ivanković Siniša Gotić Marijan Jurin Mislav Musić Svetozar 《Journal of Sol-Gel Science and Technology》2003,27(2):225-233
The ability of ultrafine particles of TiO2, WO3 and iron-doped TiO2 to kill cancer cells in the presence of UV irradiation was investigated. The best photokilling effect on carcinoma cells SCVII cultured in vitro showed iron-doped TiO2 ultrafine particles synthesized by the sol-gel procedure with starting chemicals Ti(IV)-isopropoxide and anhydrous Fe(II)-acetate. It was found that a small particle size and high dispersity influenced citotoxicity and photocatalytic efficiency. The remarkable photokiling effect of highly iron-doped TiO2 ultrafine particles (the molar ratio Fe/Ti = 0.136) in the presence of UV irradiation was observed. The influence of ultrafine metal oxide particles on the inhibition of cancer cell proliferation was measured using a 3H-thymidine incorporation test. The possible mechanism involved in the photokilling of carcinoma cells with ultrafine particles of selected metal oxides was discussed. 相似文献
84.
No modern theory of polymer excluded volume adequately describes the crossover from poor solvent to good solvent conditions; a fundamental difficulty is a singularity in the binary cluster integral. Mayer expansion techniques are applied to a model with a pair interaction between monomers to clarify the distinction between geometric and solvent contributions to excluded volume. Detailed calculations are undertaken for a hard-core potential and a mimic Lennard-Jones potential. The significance of the singularity in the binary cluster integral for calculations in the crossover regime is discussed. 相似文献
85.
Catherine J. Murphy 《Journal of Cluster Science》1996,7(3):341-350
One of the most exciting frontiers in materials chemistry in recent years is the optoelectronics of quantum-confined semiconductor nanoclusters. These nanoclusters are 10–200 A in diameter, and in this size regime exhibit extra-ordinarily interesting quantum mechanical effects. Cadmium sulfide is a popular semiconductor for these studies, and reviewed here is the synthesis and charac-terization of such CdS nanoclusters, with emphasis on how chemical control of the surface by thiolates influences product formation and properties. Also described are the syntheses and structures of true molecular clusters of CdS capped with thiolate ligands. 相似文献
86.
Summary Polyethylene oxide (PEO)-based polymers with hydroxy, methoxy, and aminopropoxy terminal groups were coated on diol functionalized and hexamethyldisilazane end-capped silica particles. Proton-donor and proton-acceptor test solutes, including carboxylic acids, hydroxy-containing compounds, arylamines, and alkylamines were used to evaluate the chromatographic performances of these polymer coated particles under SFC conditions with neat CO2 as mobile phase. It was found that the particles coated with hydroxy-terminated PEO were suitable for the separation of proton-donor compounds such as hydroxy-containing compounds and carboxylic acids, and the particles coated with aminopropoxy-terminated PEO could be used for the separation of amines. That is, the proton-accepting stationary phase is suitable for the separation of proton accepting solutes, including strong basic alkylamines (pKb4), using neat CO2 as mobile phase, while the protondonating stationary phase is suitable for the separation of proton-donating compounds such as carboxylic acids (pKa4). Hydrogen bond basicity was found to be a critical factor for the chromatography of basic amines. Low volatility acidic and basic drugs were chromatographed using the new stationary phases. The stability of the PEO coated particles was determined by measuring the loss of organic carbon under SFC conditions. It was found that approximately 18 % of the coating (average molecular weight of 15,000) was washed out of the particles by supercritical CO2 after 7 h at 350 atm and 50°C 相似文献
87.
88.
Zauresh S. Nurkeeva Al-Sayed Abdel Aal Vitaliy V. Khutoryanskiy Grigoriy A. Mun Aida G. Beksyrgaeva 《Radiation Physics and Chemistry》2003,67(6):717-722
Gamma-radiation grafting of vinyl ether of monoethanolamine and vinyl ether of ethyleneglycol (VEEG) on polyethylene films has been studied from binary monomer mixtures. The effect of co-monomer composition and total exposure radiation dose on the grafting process is investigated. A combination of potentiometric and gravimetric techniques is applied to determine the grafting degree of each monomer in the final graft copolymer. The presence of more active monomer VEEG in the mixture was found to enhance the grafting of both monomers because the increasing of copolymerization rate which in turn increases the total grafting degree. The modification of the hydrophilic properties of the graft copolymer is studied by examining the grafted films for water- and copper (II) ions uptake. 相似文献
89.
Recently, we reported that multi-hollow polymer particles can be prepared from carboxylated polymer particles by the stepwise
alkali/acid method. In this article, an attempt was made to prepare similar particles from acid-swellable polymer particles
by the stepwise treatment with acid and alkali, which was named the stepwise acid/alkali method. The acid-swellable particles
were produced by emulsion terpolymerization of styrene, butyl acrylate, and dimethyl 2-amino ethyl methacrylate. The effects
of initial pH value, temperature, and time in the acid and alkali treatment processes on the multi-hollow structure were examined.
Received: 18 December 1996 Accepted: 11 March 1997 相似文献
90.
A new reactor and a novel in-situ sampling technique were developed for the study of the synthesis of CeO2 powders produced from dissolved cerium nitrate salts. The conical reactor minimized particle recirculation and provided a
highly symmetrical and undisturbed plasma flow suitable for the analysis of the phenomena affecting the formation of CeO2 powders. Both a calorimetric study of the reactor and a thermodynamic analysis of CeO2 formation were conducted. The sampling probe is described and near-isokinetic sampling was achieved. The sampled particles
were collected using a miniature wet collection system, i.e. a mist atomizer and a custom-made spray chamber. A numerical
simulation of the velocity and temperature fields of the plasma gas in the reactor was done using Fluent. A comprehensive
droplet-to-particle formation mechanism presented elsewhere is revisited and expanded based on calorimetry, thermodynamics
of CeO2 formation, numerical simulations and collected particles. No traces of other oxidation states other than CeO2 were found. 相似文献