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991.
Qureshi AK Mukhtar MR Hirasawa Y Hosoya T Nugroho AE Morita H Shirota O Mohamad K Hadi AH Litaudon M Awang K 《Chemical & pharmaceutical bulletin》2011,59(2):291-293
Two new indole alkaloids, neolamarckines A and B (1, 2) were isolated from the leaves of Neolamarckia cadamba (Rubiaceae). Structural elucidation of 1 and 2 was performed by combination of 2D-NMR and circular dichroism (CD) spectra, and chemical correlations. Neolamarckine A (1) showed inhibition of inducible nitric oxide synthase (iNOS) dose dependently. 相似文献
992.
Osamu Shimabukuro 《Discrete Mathematics》2011,(12):978
In this paper, we consider algebras over a field of characteristic p, which are generated by adjacency algebras of Johnson schemes. If the algebra is semisimple, the structure is the same as that of the well-known Bose-Mesner algebras. We determine the structure of the algebra when it is not semisimple. 相似文献
993.
We have performed the heat capacity, neutron diffraction, and neutron quasielastic scattering measurements of an ionic liquid 1-octyl-3-methylimidazolium chloride (C8mimCl). The heat capacity data revealed that C8mimCl exhibits a glass transition with a large heat capacity jump at T(g) = 214 K, which is lower than T(g) of C4mimCl with a shorter alkyl-chain. In the neutron diffraction measurement for a deuterated analogue, d-C8mimCl, the peaks associated with the inter-domain, inter-ionic, and inter-alkyl-chain correlations appeared at (3, 11, and 14) nm(-1), respectively. The temperature dependence of these peaks indicates that the packing of the alkyl-chains becomes more compact and the domains become more vivid and larger as decreasing temperature. The quasielastic neutron scattering measurements using neutron spin echo and time-of-flight type instruments demonstrated that C8mimCl has faster relaxations probably owing to the alkyl-group and a slower relaxation owing to the ions. The latter relaxation, which is related to the glass transition, is of non-exponential as in the α relaxation of glass-forming molecular liquids. The relaxation of domains could not be observed in the present experiment but should have relaxation times longer than 100 ns. This is the first report to clarify temperature dependence of the hierarchical structure and relaxations simultaneously for a typical ionic liquid. 相似文献
994.
Diastereoselective introduction of phosphono groups into l-proline derivatives at the 5-position was achieved with suitable selection of N-protecting group. N-Benzoyl-l-prolinate preferentially gave trans-phosphorylated products, which could be easily transformed into (S)-(pyrrolidin-2-yl)phosphonates. On the other hand, N-benzyloxycarbonyl-l-prolinate reacted with phosphite to give cis-substituted products, which could be easily transformed into (R)-(pyrrolidin-2-yl)phosphonates. 相似文献
995.
Tatsuki Koike Yasutaka HoashiTakafumi Takai Osamu Uchikawa 《Tetrahedron letters》2011,52(23):3009-3011
The 4-aza analog of ramelteon (−)-1, a novel tricyclic 1,6,7,8-tetrahydro-2H-cyclopenta[d]furo[2,3-b]pyridine derivative, was synthesized via the intramolecular inverse electron demand Diels-Alder reaction followed by fluoride-induced desilylation-cyclization. 相似文献
996.
Yusuke Imai Hiroshi Abe Hitoshi Matsumoto Osamu Shimada Tomonori Hanasaki Yukihiro Yoshimura 《The Journal of chemical thermodynamics》2011,43(3):319-322
By a simple DTA system, the glass transition temperatures of the quaternary ammonium type ionic liquid, {N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium iodide, [DEME][I] + H2O} mixtures after quick pre-cooling were measured as a function of water concentration (x mol% H2O). Results were compared with the previous results of {[DEME][BF4] + H2O} mixtures in which double glass transitions were observed in the water concentration region of (16.5 to 30.0) mol% H2O. Remarkably, we observed the double glass transition phenomenon in {[DEME][I] + H2O} mixtures too, but the two-Tgs regions lie towards the water-rich side of (77.5 to 85.0) mol% H2O. These clearly reflect the difference in the anionic effect between and I? on the water structure. The end of the glass-formation region of {[DEME][I] + H2O} mixtures is around x = 95.0 mol% H2O, and this is comparable to that of {[DEME][BF4] + H2O} mixtures (x = 96.0 mol% H2O). 相似文献
997.
Iduru Shigeta Osamu Murayama Alexander Brinkman Yukio Tanaka Hans Hilgenkamp 《Journal of Physics and Chemistry of Solids》2011,72(5):604-607
We report spin polarization P of Ru2−xFexCrSi Heusler alloys by the Andreev reflection technique. Ru2−xFexCrSi with L21-type structure and saturation magnetic moment of per formula unit is theoretically predicted to be half-metals in the wide range of the composition x. We had clarified that the experimental results of saturation magnetic moment in Fe-rich compounds had coincided with the theoretical prediction. Therefore, we have measured the differential conductance of Ru2−xFexCrSi/Pb planar-type junctions. The P value of Ru2−xFexCrSi was determined by fitting the differential conductance with the modified Blonder-Tinkham-Klapwijk theory. We have found that the behavior of P for Ru2−xFexCrSi was independent of the composition x in the Fe-rich region; P=0.53 for both of x=1.5 and 1.7. The spin polarization is the similar value to Co-based Heusler alloys. 相似文献
998.
Osamu Yamashita 《Optics Communications》2011,284(19):4248-4253
A circularly polarized plane wave of infinite transverse extent (δ = ∞) has no spin angular momentum, while a realistic light does carry it. This paradox originates from the presence (δ = ∞) and absence (δ ≈ 0) of the surface integral in the total angular momentum J. The same holds for the torque equation of dJ/dt, so that δ is also connected with the relative Faraday rotation angle ΘF/θF when a radius (a) of a cylindrical medium with optical activity is only a little larger than that (b) of light beam, where ΘF is the Faraday rotation angle and θF is the intrinsic Faraday rotation angle of a medium. It is shown here that it is possible to estimate δ for a realistic light from the drastic variation in ΘF/θF near b/a = 1. 相似文献
999.
Tanaka M Sawaguchi T Sato Y Yoshioka K Niwa O 《Langmuir : the ACS journal of surfaces and colloids》2011,27(1):170-178
Surface modification of glassy carbon (GC) and highly oriented pyrolytic graphite (HOPG) was carried out with diazonium, amine, azide, and olefin derivatives bearing ferrocene as an electroactive moiety. Features of the modified surfaces were evaluated by surface concentrations of immobilized molecule, blocking effect of the modified surface against redox reaction, and surface observation using cyclic voltammetry and electrochemical scanning tunneling microscope (EC-STM). The measurement of surface concentrations of immobilized molecule revealed the following three aspects: (i) Diazonium and olefin derivatives could modify substrates with the dense-monolayer concentration. (ii) The surface concentration of immobilized amine derivative did not reach to the dense-monolayer concentration reflecting their low reactivity. (iii) The surface modification with the dense-monolayer concentration was also possible with azide derivative, but the modified surface contained some oligomers produced by the photoreaction of azides. Besides, the blocking effect against redox reaction was observed for GC modified with diazonium derivative and for HOPG modified with diazonium and azide derivatives, suggesting fabrication of a densely modified surface. Finally, the surface observation for HOPG modified with diazonium derivative by EC-STM showed a typical monolayer structure, in which the ferrocene moieties were packed densely at random. On the basis of those results, it was demonstrated that surface modification of carbon substrates with diazonium could afford a dense monolayer similar to the self-assembled monolayer (SAM) formation. 相似文献
1000.
Urbani M Pelado B de la Cruz P Yamanaka K Ito O Langa F 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(19):5432-5444
Unsymmetric dumbbell molecules based on N-methylpyrrolidine[60]fullerene, oligothienylenevinylenes (nTV; n=2, 4), and N-methylpyrrolidine[70]fullerene, namely, C(60) -nTV-C(70) were synthesized and their photophysical properties were studied. In nonpolar solvents, photoinduced energy-transfer process predominantly takes place from the singlet excited state of nTV to C(60) and C(70) , as was confirmed by time-resolved emission and transient absorption spectroscopy. In polar solvent, charge-separation processes take place instead of energy transfer. The generated charge-separated radical-ion pairs decay to the neutral molecules by a fast charge-recombination process; for n=4, a rate constant of 2×10(7) s(-1) and lifetime of 50 ns were evaluated. 相似文献