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171.
Dr. Kazuto Takaishi Yusuke Nakatsuka Hitomi Asano Yuya Yamada Prof. Dr. Tadashi Ema 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(6):e202104212
RutheniumII complexes bearing three axially chiral bipyridyl ligands were synthesized as a new family of chiral complex dyes, and Δ-(S)- and Λ-(S)-diastereomers were obtained. The X-ray crystal structure analyses, spectroscopy, and DFT calculations suggested that all the bipyridyls maintained chirality in both the ground and excited states, and the Δ-(S)- and Λ-(S)-isomers are the matched (more relaxed) and mismatched (more constrained) pairs, respectively. The mismatched Λ-(S)-isomer exhibited red circularly polarized phosphorescence (CPP) both in solution and in the solid state. The solution state CPP is the most intense of ruthenium complexes, while the solid state CPP is the first example of them. It is supposed that, for the Λ-(S)-isomer, the six cumulative CH/π interactions suppress further distortion in the T1 state. 相似文献
172.
Kosuke Sato Dr. Yuya Oaki Dr. Daisuke Takahashi Prof. Kazunobu Toshima Prof. Hiroaki Imai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(13):5034-5040
In biomineralization, acidic macromolecules play important roles for the growth control of crystals through a specific interaction. Inspired by this interaction, we report on an application of the hierarchical structures in CaCO3 biominerals to a stationary phase of chromatography. The separation and purification of acidic small organic molecules are achieved by thin‐layer chromatography and flash chromatography using the powder of biominerals as the stationary phase. The unit nanocrystals and their oriented assembly, the hierarchical structure, are suitable for the adsorption site of the target organic molecules and the flow path of the elution solvents, respectively. The separation mode is ascribed to the specific adsorption of the acidic molecules on the crystal face and the coordination of the functional groups to the calcium ions. The results imply that a new family of stationary phase of chromatography can be developed by the fine tuning of hierarchical structures in CaCO3 materials. 相似文献
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174.
Tomohiro Hirano Takahiro Kamikubo Yuya Okumura Yoichi Bando Ryosuke Yamaoka Takeshi Mori Koichi Ute 《Journal of polymer science. Part A, Polymer chemistry》2009,47(10):2539-2550
Radical polymerization of N‐isopropylacrylamide (NIPAAm) in toluene at low temperatures, in the presence of fluorinated‐alcohols, produced heterotactic polymer comprising an alternating sequence of meso and racemo dyads. The heterotacticity reached 70% in triads when polymerization was carried out at ?40 °C using nonafluoro‐tert‐butanol as the added alcohol. NMR analysis revealed that formation of a 1:1 complex of NIPAAm and fluorinated‐alcohol through C?O···H? O hydrogen bonding induces the heterotactic specificity. A mechanism for the heterotactic‐specific polymerization is proposed. Examination of the phase transition behavior of aqueous solutions of heterotactic poly(NIPAAm) revealed that the hysteresis of the phase transition between the heating and cooling cycles depended on the average length of meso dyads in poly(NIPAAm). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2539–2550, 2009 相似文献
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177.
Yuya Koda 《Mathematische Zeitschrift》2008,260(1):203-228
Branched spines of three-manifolds can be used to represent the homotopy class of vector fields on the ambient manifolds.
In this paper, we introduce a way to present branched spines as Heegaard-type diagrams, punctured Heegaard diagrams, and explain a way to compute the Reidemeister–Turaev torsion using these diagrams. 相似文献
178.
Photoinduced electron-transfer reactions and magnetic field effects (MFEs) on the decay rates of the photogenerated biradical in a phenothiazine (Ph)–C60 linked compound with a biphenyl group (Ph(BP)C60) were examined in benzonitrile and benzene. Fluorescence and transient absorption spectra indicate that the intramolecular electron-transfer for Ph(BP)C60 from the Ph to the singlet or triplet excited state of C60 was suppressed by the biphenyl group. The decay rates of the photogenerated biradical decreased in the 0–0.2 T magnetic field range and increased in the 0.2–1 T magnetic field range. The reverse phenomena of the MFEs in Ph(BP)C60 were strongly enhanced with increasing temperature and similar to those in Ph(n)C60 (n = 6?12). The MFEs in Ph(BP)C60 can be governed by spin-lattice relaxation and/or spin-spin relaxation mechanisms as observed in Ph(n)C60 (n = 6?12). Time-resolved EPR spectra of Ph(BP)C60 showed absorption, emission, absorption and emission patterns, and are quite different from those in Ph(n)C60 (n = 4?12). The result indicates that the magnitude and distribution of the exchange interaction |2J| in Ph(BP)C60 are smaller than those in Ph(n)C60 (n = 4?12) and charge recombination occurs in the inverted region because the sign of the J is positive. 相似文献
179.
Acetylation of substituted α,α′‐benzylidenedimethanols with 10 equivalents of vinyl acetate in the presence of 50 w/w% of porcine pancreas lipase (PPL) type II regiospecifically proceeded to afford only the corresponding E‐monoacetates in excellent yields without Z‐monoacetates, diacetate, or the starting materials. 相似文献
180.
Dr. Yuya Bando Dr. Tsuneaki Sakurai Prof. Dr. Shu Seki Prof. Dr. Hiromitsu Maeda 《化学:亚洲杂志》2013,8(9):2088-2095
The fusion of bowl‐shaped π‐conjugated corannulene units to anion‐responsive π‐conjugated dipyrrolyldiketone‐boron complexes resulted in new molecular materials with a unique self‐assembly capability. The bowl‐fused receptor with aliphatic tails could form both supramolecular gels and mesophases through π‐stacking interactions and also exhibited anion‐responsive characteristics. The presence of the π‐bowl unit not only afforded enhanced self‐assembly capability both in solution and in the mesophases, as evidenced by gelation experiments and phase‐transition profiles, but also enhanced intrinsic charge‐carrier mobility. 相似文献