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131.
Hou J Chen HY Zhang S Li G Yang Y 《Journal of the American Chemical Society》2008,130(48):16144-16145
A new low band gap silole-containing conjugated polymer, PSBTBT, was designed and synthesized. Photovoltaic properties of PSBTBT were initially investigated, and an average power conversion efficiency (PCE) of 4.7% with a best PCE of 5.1% was recorded under illumination (AM 1.5G, 100 mW/cm(2)). The response range of the device covers the whole visible range from 380 to 800 nm. These results indicate that PSBTBT is a promising polymer material for applications in polymer solar cells. 相似文献
132.
Qiuyu Ding Zhen Lu Rui Zhao Longqiang Xiao Linxi Hou 《Journal of polymer science. Part A, Polymer chemistry》2024,62(9):1842-1852
Photo-induced reversible complexation-mediated polymerization (RCMP) is a green and economical method to prepare polymers with precise molecular weights, narrow molecular weight distributions and functionally active chain ends. Covalent organic frameworks (COFs) are a promising heterogeneous photocatalyst for mediating RCMP due to their adjustable structure, band gap, and porosity. In this work, 1,3,5-triformylphloroglucinol (Tp) and p-azoaniline (Azo) were selected to construct 2D β-ketoenamine linked Tp-Azo-COF as a heterogeneous photocatalyst to trigger RCMP under white light irradiation. A series of polymers with controllable molecular weight and narrow molecular weight distribution were successfully prepared by using Tp-Azo-COF as photocatalysis. On/off light experiments confirmed the good spatiotemporal control feature, and chain expansion experiments demonstrated the high “activity” of polymer chain ends. Furthermore, the mechanistic research elucidated that electron transfer between Tp-Azo-COF and initiator occurred, allowing the formation of reactive radicals to mediate RCMP. Density functional theory calculations revealed that the coordination of iodine on the initiator to catalyst obviously reduced the bond dissociation energy, leading to enhance in the polymerization rate. This work provides a platform for constructing heterogeneous photocatalysts with more efficient and stable to mediate RCMP. 相似文献
133.
The plasma copolymerization of pyrrole with hexamethyldisiloxane, hexamethyldisilane and hexamethyldisilazane was investigated with regard to the polymer deposition characteristics and the properties of the product films. Deposition rates were evaluated by monitoring the weight increase of the deposits over time, and the effect of varying the experimental set up parameters was determined. The results of deposition rates and quantitative IR analysis suggested that the increasing amounts of Si-components were incorporated into the polymer matrix as the supply ratio of the Si-monomer was increased. The Si-component in the copolymer brought some dramatic effects on the physical properties of the films and changed the hydrophobicity of the surfaces, as reflected in the advancing and receding contact angle measurements. The experimental results obtained are discussed in terms of the contribution of the polar and dispersion components of surface energy. 相似文献
134.
The upper-rim 1,3-alternate tetraoxacalix[2]arene[2]triazine azacrowns were constructed effectively by macrocyclic condensation reaction of diamines with dichlorinated tetraoxacalix[2]arene[2]triazine intermediates that were synthesized from the stepwise fragment coupling reactions of 3,5-dihydroxybenzoic acid esters with cyanuric chlorides. Because of the formation of conjugation of amino groups with triazine rings, tetraoxacalix[2]arene[2]triazine azacrowns existed in a mixture of syn- and anti-isomeric forms. Both fluorescence titration and 1H NMR spectroscopic study showed that tetraoxacalix[2]arene[2]triazine azacrowns interacted with fluoride anion, leading to cavity changes of the host molecules. 相似文献
135.
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137.
Sun Y Zheng Y Lei WH Zhou QX Hou YJ Zhang BW Wang XS 《Dalton transactions (Cambridge, England : 2003)》2012,41(2):651-657
Hypocrellin B (HB), a naturally occurring photosensitizer, has been extensively and intensively studied as a promising photodynamic therapy (PDT) agent. In this work, three new oxovanadium(IV) complexes were designed and synthesized with HB as a bridging ligand and phen (1,10-phenanthroline, complex 1), tmp (3,4,7,8-tetramethyl-1,10-phenanthroline, complex 2) and dpq (dipyrido[3,2-f:2'3'-h]quinoxaline, complex 3) as terminal ligands. The use of a diimine terminal ligand avoids the formation of polymeric complexes and ensures the three VO(2+)-HB complexes possess a definite molecular formula and molecular weight to meet the single component requirement for an ideal PDT agent. Compared to HB, the VO(2+)-HB complexes exhibit improved water solubility, enhanced absorptivity in the phototherapeutic window, increased binding affinity toward dsDNA, and similar singlet oxygen quantum yield, therefore advanced DNA photocleavage activity. Both the DNA binding constants and photo nuclease activities of the complexes follow the order 2 (tmp) > 3 (dpq) > 1 (phen), demonstrating the importance of the binding affinity to biomolecules, which improves the bioavailability of reactive oxygen species. Our work opens a new avenue for the development of HB-based PDT agents. 相似文献
138.
The reaction of propionyl radical with oxygen has been studied using the full coupled cluster theory with the complete basis set. This is the first time to gain a conclusive insight into the reaction mechanism and kinetics for this important reaction in detail. The reaction takes place via a chemical activation mechanism. The barrierless association of propionyl with oxygen produces the propionylperoxy radical, which decomposes to form the hydroxyl radical and the three-center alpha-lactone predominantly or the four-center beta-propiolactone. The oxidation of propionyl radical to carbon monoxide or carbon dioxide is not straightforward rather via the secondary decomposition of alpha-lactone and beta-propiolactone. Kinetically, the overall rate constant is almost pressure independent and it approaches the high-pressure limit around tens of torr of helium. At temperatures below 600 K, the rate constant shows negative temperature dependence. The experimental yields of the hydroxyl radical can be well reproduced, with the average energy transferred per collision -DeltaE=20-25 cm(-1) at 213 and 295 K (helium bath gas). At low pressures, together with the hydroxy radical, alpha-lactone is the major product, while beta-propiolactone only accounts for about one-fifth of alpha-lactone. At the high-pressure limit, the production of the propionylperoxy radical is dominant together with a fraction of the isomers. The infrared spectroscopy or the mass spectroscopy techniques are suggested to be employed in the future experimental study of the C2H5CO+O2 reaction. 相似文献
139.
Tan S Feng H Ji Y Wang Y Zhao J Zhao A Wang B Luo Y Yang J Hou JG 《Journal of the American Chemical Society》2012,134(24):9978-9985
The water splitting reaction based on the promising TiO(2) photocatalyst is one of the fundamental processes that bears significant implication in hydrogen energy technology and has been extensively studied. However, a long-standing puzzling question in understanding the reaction sequence of the water splitting is whether the initial reaction step is a photocatalytic process and how it happens. Here, using the low temperature scanning tunneling microscopy (STM) performed at 80 K, we observed the dissociation of individually adsorbed water molecules at the 5-fold coordinated Ti (Ti(5c)) sites of the reduced TiO(2) (110)-1 × 1 surface under the irradiation of UV lights with the wavelength shorter than 400 nm, or to say its energy larger than the band gap of 3.1 eV for the rutile TiO(2). This finding thus clearly suggests the involvement of a photocatalytic dissociation process that produces two kinds of hydroxyl species. One is always present at the adjacent bridging oxygen sites, that is, OH(br), and the other either occurs as OH(t) at Ti(5c) sites away from the original ones or even desorbs from the surface. In comparison, the tip-induced dissociation of the water can only produce OH(t) or oxygen adatoms exactly at the original Ti(5c) sites, without the trace of OH(br). Such a difference clearly indicates that the photocatalytic dissociation of the water undergoes a process that differs significantly from the attachment of electrons injected by the tip. Our results imply that the initial step of the water dissociation under the UV light irradiation may not be reduced by the electrons, but most likely oxidized by the holes generated by the photons. 相似文献
140.
Liu J Hu X Hou S Wen T Liu W Zhu X Wu X 《Chemical communications (Cambridge, England)》2011,47(39):10981-10983
Nanostructured materials are a new class of enzyme mimics, the inhibitors of which have not been studied. Herein, we demonstrate the screening of inhibitors for Au@Pt nanorod (NR) oxidase mimics. In addition, based on the enzyme inhibition reaction, determination of "poisoning" inhibitors is demonstrated. 相似文献