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排序方式: 共有108条查询结果,搜索用时 15 毫秒
91.
Masanao Shibui 《International Journal of Solids and Structures》1975,11(3):357-375
A finite deformation theory of plane strain is formulated for transversely isotropic, homogeneous bodies with nonlinear stress-strain law. A new set of simplified field equations, which is valid in the case of some deviations from Hooke's law, is derived systematically with the help of the method of order estimation. For illustration purposes, a circular hole in a body under generalized plane strain is considered, together with the solution of an example problem by perturbation techniques. 相似文献
92.
The following document covers the determination of the diffusion coefficient of two powder materials: LiFePO4 and LiMn2O4 by using potentiostatic intermittent titration technique (PITT) and impedance spectroscopy methodology and compares relevant
results with the following relation: , which is obtained by solving Fick’s spherical coordinate equation (where I
0 is the initial step current in the PITT experiment, R is the particle radius, Q is the charge that intercalated during the step, and α is the percentage of the theoretical intercalated charge). This procedure allowed the verification of the validity of the
spherical model for the powder materials, the accuracy of the expression proposed for the diffusion coefficient determination,
and the correctness of the measures that had been taken. 相似文献
93.
Fast enantiomeric analysis of a complex essential oil with an innovative multidimensional gas chromatographic system 总被引:1,自引:0,他引:1
Mondello L Casilli A Tranchida PQ Furukawa M Komori K Miseki K Dugo P Dugo G 《Journal of chromatography. A》2006,1105(1-2):11-16
The present research is focussed on the evaluation of a recently developed high performance multidimensional gas chromatographic (MDGC) system employed in the fast analysis of a series of chiral compounds contained in rosemary essential oil. The heart of the MDGC system consists in a simple transfer device for the rapid sequential re-injection of analyte "heart-cuts" from the first to the second dimension. The transfer system has no temperature restrictions, presents very low dead volumes and achieves multidimensional analysis through a pressure-balance mechanism. The MDGC set-up is characterized by two GC ovens (enabling independent temperature programming) and the possibility of mass spectrometric (MS) and/or flame ionization detection (FID). Multiple-cut conventional and fast MDGC-FID methods were developed and the results obtained compared, in order to evaluate the effectiveness of the system. In this respect, the rapid method provided the same analytical result in a greatly reduced time (approximately five times less). Furthermore, quali/quantitative data reproducibilty was very good. Fast MDGC was achieved by using micro-bore (0.1mm I.D.) columns in both dimensions. 相似文献
94.
95.
Hiroko Kyotani Hisaaki Kanetsuna Masanao ya 《Journal of Polymer Science.Polymer Physics》1977,15(6):1029-1036
Conditions that affect the conformation of poly(β-benzyl L-aspartate) in films have been studied. A slow transition from the left-handed to the right-handed α-helical form is observed under certain conditions in half-dried film cast from chloroform solutions and after exposure of amorphous films of the left-handed β-helical form to chloroform vapor. This transition is caused by adsorption of moisture. Thermal transitions of these films were examined by differential scanning calorimetry and infrared spectroscopy. The right-handed α-helices change to left-handed ω-helices around 140°C, and sharp exothermic peak is observed in this region for some films. 相似文献
96.
A key intermediate, a substituted cyclopentanonitrile () with correct stereochemistry, was prepared from D-mannitol and converted to the Corey's intermediate () without a C15-epimer, which was finally transformed to (+)-brefeldin A. 相似文献
97.
Masanao Oya Keikichi Uno Yoshio Iwakura 《Journal of polymer science. Part A, Polymer chemistry》1970,8(7):1851-1862
Various kinds of NCA's were polymerized in dimethyl sulfoxide (DMSO). DL -Alanine NCA polymerized at a fast rate without initiator, the rate being represented by Rp1 = k[M]1/2. When the polymerization was carried out in chloroform in the presence of DMSO, the rate was represented by the equation, Rp2 = K2[M][DMSO]1/2. Glycine NCA and DL -α-amino-n-butyric acid NCA also polymerized at a fast rate in DMSO without initiator. On the other hand, N-methylglycine NCA, DL - and L -valine NCA and DL - and L -leucine NCA did not polymerize in DMSO without initiator. 相似文献
98.
Masayuki Kuzuya Eiichi Mano Masanao Ishikawa Takachiyo Okuda Harold Hart 《Tetrahedron letters》1981,22(17):1613-1616
Polar substituent effects on the aromatic ring emerge in the regioselectivity of the di-π-methane rearrangement of the title compounds when they possess the structural feature of including the bridgehead carbon in a saturated ring; the importance of the environment at the bridgehead carbon is pointed out. 相似文献
99.
Yoshio Iwakura Kiekichi Uno Masanao Oya 《Journal of polymer science. Part A, Polymer chemistry》1968,6(8):2165-2177
The polymerization of L - and DL -alanine NCA initiated with n-butylamine was carried out in acetonitrile which is a nonsolvent for polypeptide. The initiation reaction was completed within 60 min.; there was about 10% of conversion of monomer. The number-average degree of polymerization of the polymer obtained increased with the reaction period, and it was found to agree with value of W/I, where W is the weight of the monomer consumed by the polymerization and I is the weight of the initiator used. The initiation reaction of the polymerization was concluded as an attack of n-butylamine on the C5 carbonyl carbon of NCA. The initiation, was followed by a propagation reaction, in which there was attack by an amino endgroup of the polymer on the C5 carbonyl carbon of NCA. The rate of polymerization was observed by measuring the CO2 evolved, and the activation energy was estimated as follows: 6.66 kcal./mole above 30°C. and 1.83 kcal./mole below 30°C. for L -alanine NCA; 15.43 kcal./mole above 30°C., 2.77 kcal./mole below 30°C. for DL -alanine NCA. The activation entropy was about ?43 cal./mole-°K. above 30°C. and ?59 cal./mole-°K. below 30°C. for L -alanine NCA; it was about ?14 cal./mole-°K. above 30°C. and ?56 cal./mole-°K. below 30°C. for DL -alanine NCA. From the polymerization parameters, x-ray diffraction diagrams, infrared spectra, and solubility in water of the polymer, the poly-DL -alanine obtained here at a low temperature was assumed to have a block copolymer structure rather than being a random copolymer of D - and L -alanine. 相似文献
100.
Masanao ya Tomoko Takahashi 《Journal of polymer science. Part A, Polymer chemistry》1982,20(2):529-539
Copolymerization of N-carboxy N?-carbobenzoxy L -lysine anydride with N-carboxy β-benzyl L -aspartate anhydride was initiated with n-butylamine in acetonitrile. The copolymerization proceeded almost homogeneously except for the initial stage, when the proportion of N-carboxy anhydride (NCA) in the polymerization mixture varied from 25 to 75 mol %. This was due to the fact that the copolypeptides formed were soluble or highly swollen in the solvent, in contrast to the homopolymerization of NCAs such as N?-carbobenzoxy L -lysine NCA and β-benzyl L -aspartate NCA in acetonitrile, which proceeds heterogeneously. The compositions of the copolymers obtained were, within experimental error, the same as their monomer feed compositions. The initial rates of copolymerization were almost the same as the rate of homopolymerization of β-benzyl L -aspartate NCA, which propagates with a nonhelical polypeptide, but were slower than the rate of homopolymerization of N?-carbobenzoxy L -lysine NCA, which propagates with a helical polypeptide. 相似文献