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101.
The paper reviews the current situation regarding a new theory of brain dynamics put forward by the authors in an earlier publication. Motivation for the theory is discussed in terms of two issues: the long-standing problem of accounting for the stability and nonlocal properties of memory, and the experimental and theoretical evidence against the classical theory of brain action. It is shown that the new theory provides an explanation and a conceptually unifying framework for phenomena of brain action that resist classical explanation. Further independent experiments provide strong additional support for the theory. The fact that this theory incorporates quantum mechanisms in an essential way is considered to be of wide scientific interest in view of the unique status of the brain in relation to the physical, biological, and mental orders in nature. 相似文献
102.
Setsuko Niitsuma Kuniki Kato Tomohisa Takita Hamao Umezawa 《Tetrahedron letters》1985,26(47):5785-5786
The synthesis of 3-deazaoxanosines, C-nucleoside isosteres of oxanosine, is described. 相似文献
103.
Keitaro Umezawa Dr. Akihiro Matsui Yuki Nakamura Daniel Citterio Prof. Dr. Koji Suzuki Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(5):1096-1106
A new series of high-performance fluorophores named Keio Fluors (KFL), which are based on borondipyrromethene (BODIPY), are reported. The KFL dyes cover a wide spectral range from the yellow (547 nm) to the near-infrared (NIR, 738 nm) region, and their emission wavelength could be easily and subtly controlled based on simple molecular modifications only, without losing their optical properties. This “tailor-made” synthetic strategy for tuning the emission wavelength enabled the creation of fourteen KFL dyes with well-controlled emission colors (yellow, orange, red, far-red, and NIR). Moreover, these KFL dyes also retain their excellent optical properties, such as spectral bands sharper than quantum dots, high extinction coefficients (140 000–316 000 M −1 cm−1), and high quantum yields (0.56–0.98), without any critical solvent polarity dependent decrease of their brightness. These advantageous characteristics make the KFL dyes potentially useful as new candidates of fluorescent standard dyes to substitute or to complement existing long-wavelength fluorescent dyes, such as cyanines, oxazines, rhodamines, or other BODIPY dyes. 相似文献
104.
Water-soluble near-infrared (NIR) fluorescent labeling probes, named KSQ-3 and -4, which are based on a squaraine backbone, were synthesized and applied to biological labeling. The presented results demonstrate that the large, planar and hydrophobic squaraine dye becomes fully soluble in aqueous solution by the introduction of several sulfo group terminated alkyl substituents. Especially KSQ-4, which is substituted with four sulfo groups, exhibited perfect water solubility and significant fluorescence emission at the NIR region (817 nm) in the presence of bovine serum albumin (BSA). BSA was covalently labeled with KSQ-4, and the conjugate showed a strong absorption peak at 787 nm, which indicates compatibility with commercially available NIR laser diodes used for exciting the fluorophore. Furthermore, strong fluorescence emission was observed at 812 nm (phi = 0.08). 相似文献
105.
106.
In ferromagnetic superconductors, the spin-spiral phase and the self-induced vortex phase have been predicted to be caused by the interplay between the persistent current and the magnetic moments. Along with these two phases, the Meissner phase, the ferromagnetic normal phase, and the paramagnetic normal phase are also expected to appear in the system. From the calculation of the free energies, the phase-diagrams for these phases are obtained in the planes of temperature-the Landau parameter, -magnetization, and -the concentration of magnetic ions. 相似文献
107.
108.
Iguchi S Kawasaki K Okamoto H Umezawa C Okada Y 《Chemical & pharmaceutical bulletin》1999,47(3):423-427
Some pseudo-peptide analogs of thiol proteinase inhibitors were synthesized by a conventional solution method. Among them, Suc-Ala-Val-Val-Ala-psi-(CH2-NH)-Ala-pNA (peptide 1) and Suc-Ala-Val-Val-psi-(CH2-NH)-Ala-Ala-pNA (peptide 2) showed a stronger inhibitory activity compared with parent peptide such as Suc-Ala-Val-Val-Ala-Ala-pNA. In particular, peptide 2 was about 10-fold as active as the parent peptide (IC50 = 8 microM). Inserting psi-(CH2-NH) possibly makes the inhibitor less susceptible to papain and, as a result, produces more potent inhibition. 相似文献
109.
[chemical reaction: see text]. A novel fluorescence-based assay for serine/threonine kinases is described. Base-mediated beta-elimination of the phosphate moiety and the Michael addition of a thiol-containing fluorescent molecule allows convenient and efficient detection of the enzyme activity. This approach may be broadly applicable to various serine/threonine kinases. 相似文献
110.
The effect of substitution of rare earth elements (R) on superconductivity and crystal structure is investigated for the samples
of (La1−xRx)1.82Sr0.18CuO4, R=Pr,Nd,Eu through the measurements of electrical resistivity and lattice parameters. It is revealed thatT
c
suppression due to R-elements is not due to their magnetism but can be attributed to two contributions; the reduction of
the Madelung site potential at apex sites and the random potential scattering on CuO2 plane which in effective for pair-breaking in d-wave superconductors, both of which are brought about by the displacement
of apex oxygens due to the substitution of R-elements. 相似文献