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631.
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Ryunosuke Hata Dr. Hiroshi Nonaka Dr. Yoichi Takakusagi Prof. Dr. Kazuhiro Ichikawa Prof. Dr. Shinsuke Sando 《Angewandte Chemie (International ed. in English)》2016,55(5):1765-1768
Aminopeptidase N (APN) is an important enzyme that is involved in tumor angiogenesis. Detection of APN activity can thus lead to early diagnosis and elucidation of tumor development. Although some molecular probes for APN have been developed, the detection of APN activity in opaque biological samples remains a challenge. To this end, we designed a hyperpolarized NMR probe [1‐13C]Ala‐NH2 which satisfies the prerequisites for APN detection, namely, sufficient retention of the hyperpolarized state, a high reactivity to APN, and an APN‐induced chemical shift change. The [1‐13C]Ala‐NH2 probe allowed sensitive detection of APN activity using 13C NMR spectroscopy. 相似文献
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635.
Lszl Temleitner Takanori Hattori Jun Abe Yoichi Nakajima Lszl Pusztai 《Molecules (Basel, Switzerland)》2021,26(5)
Total scattering structure factors of per-deuterated methanol and heavy water, CD3OD and D2O, have been determined across the entire composition range as a function of pressure up to 1.2 GPa, by neutron diffraction. The largest variations due to increasing pressure were observed below a scattering variable value of 5 Å−1, mostly as shifts in terms of the positions of the first and second maxima. Molecular dynamics computer simulations, using combinations of all-atom potentials for methanol and various water force fields, were conducted at the experimental pressures with the aim of interpreting neutron diffraction results. The peak-position shifts mentioned above could be qualitatively reproduced by simulations, although in terms of peak intensities, the accord between neutron diffraction and molecular dynamics was much less satisfactory. However, bearing in mind that increasing pressure must have a profound effect on repulsive forces between neighboring molecules, the agreement between experiment and computer simulation can certainly be termed as satisfactory. In order to reveal the influence of changing pressure on local intermolecular structure in these “simplest of complex” hydrogen-bonded liquid mixtures, simulated structures were analyzed in terms of hydrogen bond-related partial radial distribution functions and size distributions of hydrogen-bonded cyclic entities. Distinct differences between pressure-dependent structures of water-rich and methanol-rich composition regions were revealed. 相似文献
636.
To study the ion‐conductive and dielectric properties of polymer electrolytes based on poly(ethylene carbonate) (PEC) with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), the complex permittivity and conductivity were measured using broadband dielectric spectroscopy. The temperature dependence of the relaxation frequency and ionic conductivity for PEC‐LiTFSI electrolytes (1 – 200 mol%) indicates that the segmental motion of PEC chains decreases with the addition of just 1 mol% of Li salt and increases with increasing concentration above 10 mol%. According to the Walden rule for PEC‐based electrolytes, the value of deviation from the reference line increased, and the fragility and decoupling exponents decreased with increasing salt concentration. These results indicate that there are large numbers of ion pairs and aggregated ions, which imply low ionicity and reduced fragility in highly concentrated PEC‐based electrolytes. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
637.
Yoichi Ogata Munetaka Iwano Takeshi Mogi Yutaka Makita 《Journal of Polymer Science.Polymer Physics》2011,49(23):1651-1659
Aggregation behavior including dilute solution property and surface‐activity of the amphiphilic random copolymer composed of 2‐(acrylamido)‐2‐methylpropanesulfonic acid and tris(trimethylsiloxy)silylpropylmethacrylate (AMPS/TRIS copolymer) in aqueous solution were studied by static light scattering (SLS), dynamic light scattering (DLS), surface tension measurement, and transmission electron microscopy (TEM). The surface tension measurement made it clear that AMPS/TRIS copolymer exhibited weaker surface‐activity than a typical low‐molecular weight surfactant sodium dodecyl sulfate in water, that is, there were no plateau of surface tension γ versus concentration and no critical micelle concentration (CMC) in the whole concentration studied. SLS and DLS analyses, and TEM revealed that AMPS/TRIS copolymer self‐associated into imperfect core‐shell micelles having hydrophobic TRIS core surrounded by hydrophilic AMPS shell in water. AMPS shell was considered as a hard shell due to the stiffness of AMPS chain in water. TRIS chain could not densely aggregate in water due to the large steric hindrance between bulky trimethylsiloxy groups despite its hydrophobic nature, thereby providing TRIS core with less‐dense structure. The balance between the spreading force of stiff AMPS chain and the cohesion force of bulky TRIS chain provides the driving force for forming the unique micelle having less‐dense TRIS core and hard AMPS shell. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011 相似文献
638.
Antonella Amore Yoichi Honda Vincenza Faraco 《Applied biochemistry and biotechnology》2012,168(4):761-769
The laccase family of Pleurotus ostreatus has been widely characterized, and studies of the genes coding for laccase isoenzymes in P. ostreatus have so far led to the identification of four different genes and the corresponding cDNAs, poxc, pox1, poxa1b and poxa3. Analyses of P. ostreatus laccase promoters poxc, pox1, poxa1b and poxa3 have allowed identification of several putative response elements, and sequences of metal-responsive elements involved in the formation of complexes with fungal proteins have been identified in poxc and poxa1b promoters. In this work, development of a system for in vivo analysis of P. ostreatus laccase promoter poxc by enhanced green fluorescent protein expression is performed, based on a poly ethylene glycol-mediated procedure for fungal transformation. A quantitative measurement of fluorescence expressed in P. ostreatus transformants is hereby reported for the first time for this fungus. 相似文献
639.
Takashi Moriyama Yoichi Takanishi Ken Ishikawa Hideo Takezoe Atsuo Fukuda 《Liquid crystals》2013,40(4):639-643
Abstract We have observed the diffusion constants of a dye in several liquid crystals by forced Rayleigh scattering. In a liquid crystal which has a standard phase sequence of N-SA-SC, the diffusion anisotropy changes at the N-SA phase transition and increases with decreasing temperature in SA and SC phases. The diffusion constants exhibit a rather smooth decrease with decreasing temperature except an anomaly at the SA-Sc phase transition. In a liquid crystal which has the antiferroelectric SCA phase, however, the diffusion constants show discontinuous increase and decrease at the SA-Sc and the Sc-ScA phase transition temperatures, respectively: the diffusion constant in SC is larger than that in the higher temperature SA phase. Anomalous signal increase and profile were observed at the phase transition temperatures, and were ascribed to the complementary transient grating due to the coexistence of two phases. 相似文献