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101.
Kunio Kimura Shin‐ichiro Kohama Satomi Kondoh Tetsuya Uchida Yuhiko Yamashita Takeshi Oohazama Yoshimitsu Sakaguchi 《Journal of polymer science. Part A, Polymer chemistry》2005,43(8):1624-1634
Polymerization of 4‐acetoxybenzoic acid (ABA) with 3,5‐diacetoxybenzoic acid (DABA) was examined to control the morphology of poly(p‐oxybenzoyl) (POB). Polymerizations were carried out at a concentration of 1.0% in an aromatic solvent Therm S‐1000® (mixture of dibenzyltoluene) at 320 °C. Polymerization of ABA yielded the POB fibrillar crystals, but the polymerization with DABA at a concentration in the feed (χf) of 0.10–0.15 afforded novel network structures comprised of spheres connected by fibrillar crystals. The diameter of the spheres prepared at χf of 0.15, which were 0.7 and 5.0 μm, showed bimodality. The network distance, fibril length, and fibril width were 6.1, 2.6, and 0.1 μm, respectively. They possessed high crystallinity. The network structure was formed as follows. Co‐oligomers were first precipitated in the beginning of the polymerization by liquid–liquid phase separation to form the microdroplets. The fibrillar crystals were formed in the coalesced spheres by the crystallization of oligomers induced by the increase of molecular weight. The fibrillar crystals connecting the spheres gradually appeared owing to the shrinkage of the spheres. The fibrillar crystals grew from the surface of the spheres with the crystallization of homo‐oligomers of 4‐oxybenzoyl units, and finally the network structure was completed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1624–1634, 2005 相似文献
102.
Factors influencing bubble coalescence in surfactant-free aqueous electrolyte solutions are considered in this compilation of literature results. These factors include viscous and inertial thin film drainage, surface deformation, surface elasticity, mobility or otherwise of the air-water interface, and disjoining pressure. Several models from the literature are discussed, with particular attention paid to predictions of transitions between regions where behaviour is qualitatively different. The transitions are collated onto a single chart with salt concentration and bubble approach speed as the axes. This creates a map of the regions in which different mechanisms operate, giving an overall picture of bubble coalescence behaviour over a wide range of concentration and speed. Only mm-size bubbles in water and NaCl solutions are discussed in this initial effort at creating such a map. Data on bubble coalescence or non-coalescence are collected from the literature and plotted on the same map, generally aligning well with the predicted transitions and thus providing support for the theoretical reasoning that went into creating the coalescence map. 相似文献
103.
Satomi HagiwaraYohei Ishida Dai MasuiTetsuya Shimada Shinsuke Takagi 《Tetrahedron letters》2012,53(43):5800-5802
Novel tetracationic pyrene derivative (1,3,6,8-tetrakis(N-methylpyridinium-4-yl)pyrene, Py4+) was synthesized. Photochemical properties such as fluorescence quantum yield and fluorescence lifetime were observed for Py4+ and Py4+/clay complexes. Judging from Lambert-Beer plot analysis, Py4+ molecules adsorb on the clay surface without aggregation up to 69% versus cation exchange capacity of the clay. Py4+ molecule emits strong fluorescence from an excited state of monomer, while the emission from excimer was not detected, in spite of high density adsorption condition on the solid surface. It is supposed that strong interaction between host and guest by the ‘Size-Matching Effect’ inhibits the formation of excimer on the clay surface. 相似文献
104.
Yoshiharu Tsujita Noboru Satomi Akira Takizawa 《Journal of Macromolecular Science: Physics》2013,52(5-6):619-632
The side-chain molecular motion of the α helix, ω helix, and β form of copoly(butyl-L-aspartate-benzyl-L-aspartate) with degrees of butylation 0%, 25%, and 43% was investigated by means of dielectric relaxation. Copoly(butyl-L-aspartate-benzyl-L-aspartate) with butylation 0% and 25% has a left-handed α helix, and, on the contrary, that of the 43% copolymer is a right-handed α helix. These two a helices transformed into the left-handed ω helix, with stacking between the benzyl groups, or between benzyl and butyl groups, or between butyl groups when heated to 140°C. The dielectric constant decreased at the α-ω transition temperature, irrespective of frequency. In particular, a remarkable decrease of dielectric constant was observed to accompany the reversal in helix sense. The ω-β transformation was observed at about 180°C by further heating, accompanied by an abrupt increase in dielectric constant. The side-chain dispersion temperature was in the following order: T(ω) ? T(β) < T(α). Relatively free rotation of the side chain for the ω helix is possible, although the side-chain molecular motion, the side-chain dispersion, is restricted by the stacking of the side chain in the ω helix. The side-chain molecular motion of the α helix, rotation of the benzene ring, is hindered by the presence of δ O and ? CH2 atoms of the residue above and below the benzene ring. 相似文献
105.
Fujimoto H Okamoto Y Sone E Maeda S Akiyama K Ishibashi M 《Chemical & pharmaceutical bulletin》2005,53(8):923-929
In a screening study on immunomodulatory fungal constituents, eleven new 2-pyrones tentatively named TT-1 (1), and TT-2-11 (2-11) have been isolated from a Fungi Imperfecti, Trichurus terrophilus, and designated rasfonin (1), and trichurusin B-K (2-11), respectively. Compounds 1-4 exhibited considerably high immunosuppressive activities, and compounds 8-11 have shown moderate ones. The structure-activity relationships of these constituents have also been discussed. 相似文献
106.
Sha Y Tashima T Mochizuki Y Toriumi Y Adachi-Akahane S Nonomura T Cheng M Ohwada T 《Chemical & pharmaceutical bulletin》2005,53(10):1372-1373
We found that a variety of compounds containing partial structures of tamoxifen showed activity as chemical modulators of large-conductance calcium-activated K+ channels (BK channels). 相似文献
107.
Sabu A Kondo S Saito R Kasai Y Hashimoto K 《The journal of physical chemistry. A》2005,109(9):1836-1842
The intermolecular potential energy surface of O(2)-H(2)O was investigated at ab initio MP2 and MRSDCI levels using the aug-cc-pVTZ basis set. The vibrational levels were evaluated by numerically solving the Schr?dinger equations for the nuclear motions with the ab initio potential functions using one- to three-dimensional finite-element methods. On the basis of the calculated partition functions, the equilibrium constant of the complex, K(p), was studied. The K(p) values at atmospheric temperatures of 200-300 K were found to be 1-2 orders of magnitude less than previous estimates from the harmonic oscillator approximation. 相似文献
108.
Oxidation of phenol, anisole and toluene with permonophosphoric acid in acetonitrile or water gives the corresponding ortho and para hydroxylated aromatics (HO-C6H4-X, X = OH, OMe, Me). The observed ortho :para ratio in a solvent acetonitrile are as follows: 5·0 with phenol, 3·5 with anisole and 2·0 with toluene. The oxidation rates for phenol and anisole in acetonitrile are expressed as: v = k″[ArH][H3PO5]2ho, where ho is the Hammett's acidity function and ArH is phenol or anisole. A mechanism involving a rate-determining attack of protonated dimeric perphosphoric acid 4 on aromatic carbon is presented and discussed. 相似文献
109.
Satomi Y Kudo Y Sasaki K Hase T Takao T 《Rapid communications in mass spectrometry : RCM》2005,19(4):540-546
An electrospray dual sprayer, which generates separate sample and reference sprays by alternately switching the high voltage between the two sprayers, is described. The technique permits accurate mass measurements in nano-electrospray ionization mass spectrometry (ESI-MS) to be obtained using a quadrupole/orthogonal acceleration time-of-flight mass spectrometer (Q-TOF). Similar to the method employed with a dual ESI source (Wolff JC et al., Anal. Chem. 2001; 73: 2605), the two sprays are orthogonal with respect to each other, but can be independently sampled without any baffle between these sprays. The reference sprayer is used in the original configuration of the ESI source and was optimized for a 1-2 muL/min flow, whereas the sample sprayer can be either a conventional glass capillary or a borosilicate tip of the type used for nano-ESI. Both sprayers can be positioned close to the cone so as to give maximum ion currents. The sample and reference sprays are independently generated by raising the potentials on the sample and reference sprayers to 1.4 and 3.0 kV, respectively; the high voltages can be rapidly turned on and off in ca. 1 ms. A nano-ESI-MS or nano-flow LC/ESI-MS experiment using a Q-TOF coupled with the above system gave mass accuracies within 3 ppm for measurements of ions up to m/z 1000 using subpicomole samples. 相似文献
110.
Electrode behavior of Sb-doped poly-crystalline tin oxide electrodes has been investigated by means of current and differential capacity measurements in molten chloroaluminate melts (AlCl3+NaCl) with different pCl values. The SnO2 is stable in the melts consisting of near equimolar composition, being used as an indicator electrode possessing a polarizable potential region between chlorine evolution and its cathodic decomposition. The differential capacity is assigned to the space charge layer capacity of the electrode side and its potential dependence is explained by using the Mott-Schottky equation. It is found that the flat band potential does depend on pCl (=?log aCl?) at a rate of 2(2.3kT/e) per pCl unit. This anomaly is attributed to the specific adsorption of Cl? ions on the oxide electrode. 相似文献