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101.
Kazutoshi Haraguchi Kazuhisa Uyama Hisashi Tanimoto 《Macromolecular rapid communications》2011,32(16):1253-1258
Polymer hydrogels with characteristics distinct from those of solid materials are one of the most promising candidates for smart materials. Here, we report that a nanocomposite hydrogel (NC gel) consisting of a unique polymer/clay network structure, can exhibit complete self‐healing through autonomic reconstruction of crosslinks across a damaged interface. Mechanical damage in NC gels can be repaired without the use of a healing agent, and even sections of NC gels separated by cutting, from whichever the same or different kinds of NC gel, perfectly (re‐)combine by just contacting the cut surfaces together at mildly elevated temperatures. In NC gels, the autonomic fusion of cut surfaces as well as the self‐healing could be achieved not only immediately after being cut but also after a long waiting time.
102.
Takayuki Tanimoto Assoc. Prof. Mineto Uchiyama Prof. Masami Kamigaito 《Angewandte Chemie (International ed. in English)》2023,62(43):e202307791
A series of exo-olefin compounds ((CH3)2C(PhY)−CH2C(=CH2)PhY) were prepared by selective cationic dimerization of α-methylstyrene (αMS) derivatives (CH2=C(CH3)PhY) with p-toluenesulfonic acid (TsOH) via β-C−H scission. They were subsequently used as reversible chain transfer agents for sulfur-free cationic RAFT polymerization of αMS via β-C−C scission in the presence of Lewis acid catalysts such as SnCl4. In particular, exo-olefin compounds with electron-donating substituents, such as a 4-MeO group (Y) on the aromatic ring, worked as efficient cationic RAFT agents for αMS to produce poly(αMS) with controlled molecular weights and exo-olefin terminals. Other exo-olefin compounds (R−CH2C(=CH2)(4-MeOPh)) with various R groups were prepared by different methods to examine the effects of R groups on the cationic RAFT polymerization. A sulfur-free cationic RAFT polymerization also proceeded for isobutylene (IB) with the exo-olefin αMS dimer ((CH3)2C(Ph)−CH2C(=CH2)Ph). Furthermore, telechelic poly(IB) with exo-olefins at both terminals was obtained with a bifunctional RAFT agent containing two exo-olefins. Finally, block copolymers of αMS and methyl methacrylate (MMA) were prepared via mechanistic transformation from cationic to radical RAFT polymerization using exo-olefin terminals containing 4-MeOPh groups as common sulfur-free RAFT groups for both cationic and radical polymerizations. 相似文献
103.
104.
105.
用两波混频方法在514.5nm(氩离子激光器)对BSO晶体中光折变增益与入射面情况的依赖关系进行了研究,由于BSO晶体围绕<110>轴旋转时受主能级状态的影响,从而光折变增益将取决于衍射效率的改变。 相似文献
106.
Aldose reductase and aldehyde reductase from the medulla of the rat kidney have been purified to homogeneity by using affinity chromatography, gel filtration and chromatofocusing. The molecular weights of aldose reductase and aldehyde reductase by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis were found to be 37000 and 39000, respectively. The isoelectric points of aldose reductase and aldehyde reductase were found to be 5.4 and 6.2 by chromatofocusing, respectively. The major differences of amino acid compositions between both enzymes were found in serine, alanine and aspartic acid. Substrate specificity studies showed that aldose reductase utilized aldo-sugars such as D-glucose and D-galactose, but aldehyde reductase did not use them. The Km values of aldose reductase for various substrates were lower than those of aldehyde reductase. Aldose reductase utilized both reduced nicotinamide adenine dinucleotide phosphate (NADPH) and reduced nicotinamide adenine dinucleotide (NADH) as coenzymes, whereas aldehyde reductase utilized only NADPH. The presence of the sulfate ion resulted in a dramatic activation of aldose reductase whereas it did not affect aldehyde reductase activity. These enzymes were strongly inhibited by the known aldose reductase inhibitors. However, aldose reductase was more susceptible than aldehyde reductase to inhibition by the aldose reductase inhibitors. 相似文献
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108.
Yonezo Morino Mitsutoshi Tanimoto Shuji Saito Eizi Hirota Ryoichi Awata Takehiko Tanaka 《Journal of Molecular Spectroscopy》1983,98(2):331-348
Microwave spectra were observed for 14NO2 in the vibrationally excited ν1, ν2, ν3, and 2ν2 states, as well as for 15NO2 in the ν1 and ν2 states. The rotational constants, spin-rotation coupling constants and hyperfine interaction constants were precisely determined. Second-order change of the spin-rotation coupling constants with respect to the bending vibrational quantum number v2 was also determined. Combined use of the rotational constants obtained by the present microwave investigation and those reported in high-resolution infrared spectroscopic studies leads to the determination of all the vibration-rotation interaction constants αs and γss′ and the equilibrium structure of nitrogen dioxide, and θe (ONO) = 133°51.4′ ± 0.2′, in the second-order approximation with respect to the vibrational quantum numbers. 相似文献
109.
110.
Microwave spectra of the anti rotamer of vinyl mercaptan and its SD isotopic species have been studied in the frequency range 12–60 GHz. For the normal species rotational and centrifugal distortion constants have been obtained for the ground and first three excited states of the SH torsional mode, the ground state values being A = 49 422.75(5) MHz, B = 5 897.215(9) MHz, C = 5 279.436(9) MHz, DJ = 3.12(11) kHz, DJK = ?38.50(1.71) kHz, and δJ = 0.498(51) kHz. An approximate potential function for the SH torsion in the vicinity of the anti conformation, derived using the observed variation of rotational constants with vibrational quantum number, reveals the presence of a small potential barrier of 19 cm?1 at the planar conformation. The v = 0 state lies above this barrier so the molecule is essentially planar in the ground state in spite of the observed negative value for the inertia defect (?0.1976(2) a.m.u.Å2). The anti rotamer is found to be 50 ± 25 cm?1 less stable than the syn rotamer. The dipole moment has the ground state values μa = 0.425(10), μb = 1.033(10), and μtotal = 1.117(14) D and is shown to vary considerably with vibrational quantum number. Evidence for significant structural changes in going from the syn rotamer to the anti rotamer is also presented. 相似文献