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421.
G. C. Samanta 《International Journal of Theoretical Physics》2013,52(11):4015-4024
Two-fluid anisotropic Bianchi type-III cosmological model is investigated with variable gravitational constant G and cosmological constant Λ in the framework of Einstein’s general relativity. In the two-fluid model, one fluid represents the matter content of the universe and another fluid is chosen to model the cosmic microwave background radiation. The dynamics of the anisotropic universe with variable G and Λ are discussed. We also discussed in detail the behavior of associated fluid parameters and kinematical parameters. 相似文献
422.
Five Dimensional Bulk Viscous String Cosmological Models in Saez and Ballester Theory of Gravitation
G. C. Samanta S. K. Biswal P. K. Sahoo 《International Journal of Theoretical Physics》2013,52(5):1504-1514
LRS Bianchi type-I bulk viscous string cosmological models are obtained in scalar tensor theory of gravitation proposed by Saez and Ballester (Phys. Lett. A 113:467, 1986). It is shown that cosmic string does not survive for ρ+λ=0 whereas it survives for the equations of state ρ=(1+ω)λ (Takabayasi string) and ρ=λ (Geometric string). Some physical and geometrical properties of the exhibited model are discussed. 相似文献
423.
Alakes Maiti Bibek Patra G. P. Samanta 《Journal of Applied Mathematics and Computing》2006,22(3):71-86
Recently non-conventional approaches of pest control are getting much more importance in different parts of the world. The main reason behind this is the long list of side effects of conventional approaches (use of pesticides etc.). The present paper focuses on one such extremely useful method of insect pest control, namely the Sterile Insect Release Method (SIRM), by using a mathematical model. A blend of dynamical behaviours of the model is studied critically, which, in turn, indicates the relevance of the method. The effect of uncertain environmental fluctuations on both fertile and sterile insects is also investigated. Our analytical findings are verified through computer simulation. Some important restrictions on the parameters of the system are mentioned, which may be implemented for a better performance of SIRM. 相似文献
424.
A combination of a catalytic amount of indium (III) chloride and sodium borohydride in acetonitrile reduces selectively the carbon-carbon double bonds in conjugated alkenes such as α,α-dicyano olefins, α,β-unsaturated nitriles, cyanoesters, cyanophosphonate and dicarboxylic esters. However, reduction of chalcones is little different. They are reduced to a mixture of saturated ketones and alcohols if the reaction mixture is quenched with H2O, whereas quenching with MeOH leads to saturated alcohols only. 相似文献
425.
Drillstring dynamics is highly non-linear in nature and its model can only be described by a set of non-linear differential equations. In addition to this complexity, the drillstring dynamics are not linearly controllable and thus linear control methods are not suitable for suppressing the coupled torsional and lateral vibrations of a rotating drillstring. In this paper a non-linear dynamic inversion control design method is used to suppress the lateral and the torsional vibrations of a non-linear drillstring. It was found that the designed controller is effective in suppressing the torsional vibrations and reducing the lateral vibrations significantly. 相似文献
426.
Enhancing Selectivity and Kinetics in Oxidative Photocyclization by Supramolecular Control
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Dr. Ritesh Haldar Dr. Stéphane Diring Dr. Pralok K. Samanta Marius Muth William Clancy Antoine Mazel Dr. Sabine Schlabach Frank Kirschhöfer Dr. Gerald Brenner‐Weiß Prof. Dr. Swapan K. Pati Prof. Dr. Fabrice Odobel Prof. Dr. Christof Wöll 《Angewandte Chemie (International ed. in English)》2018,57(41):13662-13665
Photochemical reactions typically proceed via multiple reaction pathways, yielding a variety of isomers and products. Enhancing the selectivity is challenging. Now, the potential of supramolecular control for oxidative photocyclization of a tetraarylethylene, containing a stereogenic ?C=C? bond, is demonstrated. In solution, this photochemical reaction produces three constitutional isomers (substituted phenanthrenes), with slow kinetics. When the reactant is assembled into a crystalline framework, only one product forms with accelerated kinetics. Key to this selectivity enhancement is the integration into a surface grown metal–organic framework (SURMOF); the dramatic gain in selectivity is ascribed to the hindrance of the rotational freedom of the ?C=C? double bond. The structure of the MOF is key; the corresponding reaction in the solid does not result in such a high increase in selectivity. A striking change of luminescence properties after photocyclization is observed. 相似文献
427.
428.
A Diradical Approach towards BODIPY‐Based Dyes with Intense Near‐Infrared Absorption around λ=1100 nm
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Dr. Yong Ni Sangsu Lee Minjung Son Prof. Dr. Naoki Aratani Masatoshi Ishida Dr. Animesh Samanta Prof. Dr. Hiroko Yamada Prof. Dr. Young‐Tae Chang Prof. Dr. Hiroyuki Furuta Prof. Dr. Dongho Kim Prof. Dr. Jishan Wu 《Angewandte Chemie (International ed. in English)》2016,55(8):2815-2819
A diradical approach to obtain stable organic dyes with intense absorption around λ=1100 nm is reported. The para‐ and meta‐quinodimethane‐bridged BODIPY dimers BD‐1 and BD‐2 were synthesized and were found to have a small amount of diradical character. These molecules exhibited very intense absorption at λ=1088 nm (?=6.65×105 M ?1 cm?1) and 1136 nm (?=6.44×105 M ?1 cm?1), respectively, together with large two‐photon‐absorption cross‐sections. Structural isomerization induced little variation in their diradical character but distinctive differences in their physical properties. Moreover, the compounds showed a selective fluorescence turn‐on response in the presence of the hydroxyl radical but not with other reactive oxygen species. 相似文献
429.
Brajagopal Samanta Joy Chakraborty Dilip Kumar Dey Volker Gramlich Samiran Mitra 《Structural chemistry》2007,18(3):287-293
A new diorganotin(IV) complex, Me2Sn[5-Br-(2-OC6H4CH=N–N=C(O)Ph)] (1) has been synthesised from dimethyltin(IV) dichloride and a Schiff base derived from 5-bromosalicylaldehyde and benzoyl hydrazide. The complex has been characterised by elemental analysis, and FT-IR and NMR spectroscopies. Molecular structure has been confirmed by single-crystal X-ray diffraction analysis. Complex 1 crystallises in triclinic system, space group P-1 (no. 2) with a=7.562(6), b=9.980(8), c=11.899(8) Å; α=81.08(6)°, β=72.71(5)°, γ=79.64(6)°; Z=2. The ligand N′-(5-bromo-2-hydroxybenzylidene)benzoylhydrazone (H2L) coordinates to the metal centre in enolate form via the phenolic O, imino N and enolic O atoms. The central tin atom is in distorted trigonal bipyramidal geometry with two oxygen atoms of the ligand in axial positions, while the imino nitrogen atom of the ligand and two methyl groups on tin occupy the equatorial sites. 相似文献
430.
A general method for the synthesis of β-(2-furyl)-α,β-unsaturated aldehydes is described using the Suzuki coupling reaction of furan-2-boronic acids and β-bromo-α,β-unsaturated aldehyde derivatives. 相似文献