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131.
Sadakane M Tsukuma D Dickman MH Bassil B Kortz U Higashijima M Ueda W 《Dalton transactions (Cambridge, England : 2003)》2006,(35):4271-4276
We have synthesized the mono-ruthenium substituted Keggin-type silicotungstate [SiW(11)O(39)Ru(III)(H(2)O)](5-) (1a) by reaction of the mono-lacunary silicotungstate precursor [SiW(11)O(39)](8-) with Ru(acac)(3) under hydrothermal conditions and isolated as the caesium salt Cs(5)[SiW(11)O(39)Ru(III)(H(2)O)] (1). The DMSO-coordinated complex [SiW(11)O(39)Ru(III)(DMSO)](5-) (2a) was prepared by reaction of 1a with DMSO in aqueous solution at 353 K and isolated as the caesium-potassium mixed salt Cs(4.9)K(0.1)[SiW(11)O(39)Ru(III)(DMSO)] (2). Both compounds 1 and 2 were characterized by single-crystal X-ray structure analysis, powder X-ray structure analysis, UV-Vis spectroscopy, cyclic voltammetry, IR-spectroscopy and elemental analysis. 1 crystallized in the tetragonal space group P4(2)/ncm with a = 20.9299(4), c = 10.3603(4) Angstrom, Z = 4. The ruthenium atom in the Keggin unit could not be distinguished from the tungsten due to disorder. The structural analysis of 2 (monoclinic, P2(1)/c, a = 13.5850(4), b = 20.2764(7), c = 18.1326(4) Angstrom, beta = 90.8730(10) degrees , Z = 4) successfully revealed that the incorporated ruthenium atom is coordinated by DMSO through a Ru-S bond. Polyanion 2a represents the first mono-substituted Keggin ion in which the ruthenium center is not crystallographically disordered. UV-Vis spectroscopy combined with controlled potential electrolysis confirmed that the incorporated rutheniums in 1 and 2 have a valence state of +3. The IR spectra of both 1 and 2 were very similar. All these data indicate that 1 synthesized by reaction of the mono-lacunary silicotungstate K(8)[SiW(11)O(39)] with Ru(acac)(3) under hydrothermal conditions is truly the mono-ruthenium substituted Keggin-type silicotungstate. 相似文献
132.
Heat capacity measurements have been made on ANBC(18) at temperatures from 8 to 490 K by adiabatic calorimetry. All known phases were detected. The temperatures, enthalpies and entropies of transition were determined for the phase transitions observed. On the basis of the entropy of transition to the SmC phase from the D or cubic phases, it is pointed out that the D phase of ANBC and the cubic phase of BABH might be identical in nature. It is shown that the arrangement of 'molecular' cores has a higher degree of order in the isotropic (D and cubic) phases than in the SmC phase, whereas the terminal alkoxy chains are more disordered in the isotropic phases than in the SmC phase. The degrees of disorder in the D and cubic phases relative to the SmC phase are very similar in terms of the entropy of transition per methylene group. The inverted phase sequence in ANBC (SmC D on heating) and BABH (cubic SmC) can be accounted for in terms of the competing roles in the entropy between the molecular core and the chains. 相似文献
133.
Omar Foda Kenji Iohara Michio Jimbo Rinat Kedem Tetsuji Miwa Hong Yan 《Letters in Mathematical Physics》1994,32(3):259-268
An elliptic deformation of $\widehat{s1}_2 $ is proposed. Our presentation of the algebra is based on the relationRLL = LLR *, whereR andR * are eight-vertexR-matrices with the elliptic moduli chosen differently. In the trigonometric limit, this algebra reduces to a quotient of that proposed by Reshetikhin and Semenov-Tian-Shansky. Conjectures concerning highest-weight modules and vertex operators are formulated, and the physical interpretation ofR * is discussed. 相似文献
134.
Jun Akimitsu Jiro Amano Masaki Yoshinari Michio Kokubun Tatsuya Iwasaki Satoshi Okuma Nobuhiko Nishida Kusuo Nishiyama Nobuo Mori 《Hyperfine Interactions》1994,85(1):187-192
We report SR measurements of Pr2CuO4– and (Pr2–xCex)CuO4– single crystals in the temperature range 4.2K300K. Two spin reorientation phase transitions were observed, although neutron scattering experiment could not detect these phase transitions. These allow us to conclude that magnetic moments of the Cu atoms order in an antiferromagnetic noncollinear cross like structure including a hidden canting spin arrangement. 相似文献
135.
The photoelectron spectra of 1,3-diazaadamantane (1) and 1,3-diaza-6-methyleneadamantane (2) have been measured. An analysis of the spectra based on a ZDO model indicates that the ordering of the n-orbitals in 1 is b2(n?λσ) above a1(n+?λσ). The splitting of b2 and a1 in 1 is dominated by the through space interaction. These results are confirmed by semiempirical calculations of the Extended Hückel and MINDO/3 type. An analysis of the PE spectrum of 1,3-diazaadamantanone(6) (5) indicates that in 5 the inductive effect of the CO group is dominant. 相似文献
136.
The capillary electrophoretic separation was accomplished for Fe(II) and Ni(II) precomplexed with 1,10-phenanthroline (phen) in 2 M n-butyric acid/ n-butyrate buffer at pH 4.5 with direct UV detection at 260 nm. The applied voltage was 5 kV. The high concentration buffer of the n-butyrate resulted in a similar separation mechanism to that of ion-pair reversed-phase high-performance liquid chromatography. The separation would be due to the hydrophobic interaction between the ionic associates, [Fe(phen)(3)]( n-butyrate)(+) and [Ni(phen)(3)]( n-butyrate)(+), with the n-butyrate ion and n-butyric acid as background electrolyte. Linear calibration ranges were obtained for Fe(II) and Ni(II) from 100 to 500 ng ml(-1). The relative standard deviations ( n=10) for 3 g mL(-1) Fe(II) and Ni(II) were 0.090 and 0.086, respectively. Detection limits ( S/ N=3) for Fe(II) and Ni(II) were 20 ng mL(-1). The method was applied to the determination of nickel in aluminium and duralumin alloys. 相似文献
137.
Oku K Kurose M Kubota M Fukuda S Kurimoto M Tujisaka Y Okabe A Sakurai M 《The journal of physical chemistry. B》2005,109(7):3032-3040
In a previous study (Oku, K.; Watanabe, H.; Kubota, M.; Fukuda, S.; Kurimoto, M.; Tujisaka, Y.; Komori, M.; Inoue, Y.; Sakurai, M. J. Am. Chem. Soc. 2003, 125, 12739), we investigated the mechanism of the antioxidant function of trehalose against unsaturated fatty acids (UFAs) and revealed that the key factor relevant to the function is the formation of OH...pi and CH...O hydrogen bonds between trehalose and the cis double bonds of the UFA. Here, we investigate whether such intriguing interactions also occur between this sugar and cis double bonds in other unsaturated compounds. For this purpose, we selected various diene compounds (1,3-butadiene, 1,3-pentadiene, 1,4-pentadiene, and 2,5-heptadiene) as interaction partners. All NMR experiments performed, including 1H-1H NOESY measurements, indicated that trehalose selectively interacts with the cis-olefin proton pair in the above diene with a 1:1 stoichiometry, and the C-3 (C-3') and C-6' (C-6) sites of the sugar are responsible for the interaction. Similar interactions were not observed for the mixtures of the diene and other saccharides (neotrehalose, kojibiose, nigerose, maltose, isomaltose, sucrose, maltitol, and sorbitol). Quantum chemical calculations revealed that the OH-3 and OH-6 groups bind to the olefin double bonds of the diene through OH...pi and CH...O types of hydrogen bonds, respectively, and the stabilization energy of the resulting complex is 5-6 kcal mol(-1). These results strongly support the above NMR results. Finally, the activation energies were calculated for the hydrogen abstraction reactions from the activated methylene group of heptadiene. In particular, when the reaction was initiated by a methyl radical, the activation energy was only 10 kcal mol(-1) for the free heptadiene, but on complexation with trehalose it drastically increased to ca. 40 kcal mol(-1). This indicates that trehalose has a significant depression effect on the oxidation of the diene compounds. These results strongly support the antioxidant mechanism deduced in the previous study and indicate that the formation of unique multiple hydrogen bonds between trehalose and cis-olefin bonds is rather a general event not confined to the case of UFA. 相似文献
138.
Wakahara T Kobayashi J Yamada M Maeda Y Tsuchiya T Okamura M Akasaka T Waelchli M Kobayashi K Nagase S Kato T Kako M Yamamoto K Kadish KM 《Journal of the American Chemical Society》2004,126(15):4883-4887
Ce@C(82) is isolated by high-performance liquid chromatography (HPLC) and the cage symmetry is determined as C(2)(v)() by measuring the (13)C NMR spectra of its anion. The (13)C NMR peaks of [Ce@C(82)](-) show temperature-dependent shifts ascribed to the f electron remaining on the Ce atom. Both Ce@C(82) and [Ce@C(82)](-) are silent in electron spin resonance spectroscopy (ESR) because of the highly anisotropic g matrix as well as of the fast relaxation process originating from the orbital angular momentum of the f electron. This is the complementary relationship to the observation of the paramagnetic shift in (13)C NMR. [Ce@C(82)](-) has lower stability in air than [La@C(82)](-). 相似文献
139.
Masanori Hirano Chiaki Nakahara Keisuke Ota Osamu Tanaike Michio Inagaki 《Journal of solid state chemistry》2003,170(1):39-47
Anatase-type TiO2 doped with 4.7 and 12.4 mol% ZrO2 that were directly precipitated as nanometer-sized particles from acidic precursor solutions of TiOSO4 and Zr(SO4)2 by simultaneous hydrolysis under hydrothermal conditions at 200°C, showed higher photocatalytic activity than pure anatase-type TiO2 for the decomposition of methylene blue. The crystallite growth and the phase transformation from anatase-type to rutile-type structure caused by heating at high temperature were retarded by doping ZrO2 into TiO2. The anatase-type TiO2 doped with ZrO2 showed high phase stability and maintained anatase-type structure even after heating at 1000°C for 1 h. 相似文献
140.
In the biological and physical investigation of a new class of deoxyribonucleic acid (DNA)-intercalating antitumor agents, novel 9-anilino-2,3-methylenedioxyacridines (twelve compounds) have been synthesized and evaluated for the activity against L1210 leukemia in vivo. A few of them possessed the same potency of the antitumor activity as 4′-(9-acridinylamino)methanesulfonyl-m-anisidine (amsacrine, m-AMSA), which is an important antitumor agent in clinical use. The molecular structure of a typical one, 9a in this series have been determined by the X-ray diffraction method using a single crystal. The results of this X-ray investigation have shown that the new class of acridine derivatives have the methylenedioxy group fused at the 2- and 3-positions of the acridine ring. 相似文献