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131.
Kobayashi T Takenaka M Saijo K Hashimoto T 《Journal of colloid and interface science》2003,262(2):456-465
We investigated the self-assembling structure of the 1,3:2,4-bis-O-(p-methylbenzylidene)-D-sorbitol (PDTS)/n-dibutylphthalate (DBP) system in the parameter space of temperature T and solute concentration Phi(PDTS). Optical microscopic studies revealed that the phase diagram can be divided into four regions. In region I at high T the system is a homogeneous solution. In region II at lower T and low Phi(PDTS), the system still has fluidity but has microgels having spherulitic texture of PDTS crystallites. Regions III and IV at even lower T but higher Phi(PDTS) are in a gel state. In region III, the PDTS forms volume-filling spherulites due to the solid-liquid phase transition of the saturated PDTS solutions. In region IV at the lowest T, both the liquid-liquid phase-separation process and the solid-liquid transition of the PDTS are involved in the self-assembling processes. In this region a bicontinuous phase-separated structure is first formed by liquid-liquid phase separation via spinodal decomposition (SD). The subsequent solid-liquid transition of the PDTS in the PDTS-rich region forms percolating crystalline fibrils rather than spherulites. The formation of the crystalline fibrils pins further growth of the bicontinuous structure via SD. 相似文献
132.
Kenji Okitsu Hiroshi Nakamura Norimichi Takenaka Hiroshi Bandow Yasuaki Maeda Yoshio Nagata 《Research on Chemical Intermediates》2004,30(7-8):763-774
The reaction of 1,1-diphenyl-2-picrylhydrazyl (DPPH) with a radical intermediate was investigated in the sonolysis of several organic solvents. The rate of the DPPH consumption in the sonolysis of methanol obeyed first-order kinetics at low concentrations of DPPH, while the rate became zero-order as the concentration of DPPH further increased. The radical trapping reactions of DPPH were found to be considerably slow compared with the formation of hydrogen molecules in the sonolysis of alcohols and hydrocarbons. These results indicate that H atoms formed in the solvent sonolysis quickly react to form stable molecules such as hydrogen in the cavitation bubble and/or at the interface region. The rates of the DPPH consumption were strongly dependent on the vapor pressure and relative evaporation rate of the solvents. It was proposed that the optimum vapor pressure exists for an effective formation of radical species. 相似文献
133.
Vladimir F. Petrov Sofia I. Torgova Ludmila A. Karamysheva Shunsuke Takenaka 《Liquid crystals》2013,40(8):1141-1162
In this review the effect on physico-chemical and electro-optical properties of the introduction of the trans-1,4-cyclohexylene fragment into the molecular core of liquid crystals is discussed, rationalized in terms of existent theories, and compared with the effect of other well-known molecular fragments. 相似文献
134.
Ben Nanzai Kenji Okitsu Norimichi Takenaka Hiroshi Bandow 《Research on Chemical Intermediates》2009,35(8-9):841-849
The effect of initial concentration of linear alkylbenzene sulfonate (LAS: p-octylbenzene sulfonate (LAS C8), p-nonylbenzene sulfonate (LAS C9), p-dodecylbenzene sulfonate (LAS C12)) on the rate of sonochemical degradation was investigated over a wide concentration range under Ar atmosphere by 200 kHz ultrasonic irradiation. The degradation rate of each LAS increased with increasing initial concentration of LAS and then started to decrease with the different behavior depending on the types of LASs. This result indicated that the cavitation efficiency was gradually changed by their concentrations and the optimum LAS concentrations for their effective degradation existed. The maximum degradation rates were observed at 250 μM of LAS C12, 1250 μM of LAS C9, and 2500 μM of LAS C8, respectively. These optimum concentrations were found to be about four to six times smaller than these critical micelle concentrations (CMCs). It was also found that the maximum degradation rates at the optimum concentrations were observed to be almost linearly correlated with their CMCs. Based on the obtained results, it could be suggested that the micelle formation occurs in the interfacial region of cavitation bubbles during rectified diffusion and this phenomenon reduces the cavitation efficiency. In addition, from the results of the rate of the sonochemical degradation of LASs and the yield of hydrogen peroxide, the existence of thermal gradient in the interfacial region of cavitation bubbles was also confirmed. 相似文献
135.
Mikihito Takenaka Shusuke Aburaya Satoshi Akasaka Hirokazu Hasegawa Nikos Hadjichristidis George Sakellariou Yasuhiko Tada Hiroshi Yoshida 《Journal of Polymer Science.Polymer Physics》2010,48(22):2297-2301
We have demonstrated directed self‐assembly of poly(styrene‐b‐dimethylsiloxiane) (PS‐b‐PDMS) down to sub‐10‐nm half‐pitch by using grating Si substrate coated with PDMS. The strong segregation between PS and PDMS enables us to direct the self‐assembly in wide grooves of the grating substrate up to 500 nm in width. This process can be applied to form various type of sub‐10‐nm stripe pattern along variety of grating shape. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010 相似文献
136.
Hiroki Takeshita Keiichi Saito Masamitsu Miya Katsuhiko Takenaka Tomoo Shiomi 《Journal of Polymer Science.Polymer Physics》2010,48(2):168-174
Structure formation by coupling between formation of crosslinking points and liquid–liquid phase separation was investigated for aqueous methyl cellulose solution by small‐angle X‐ray scattering (SAXS) and light scattering (LS) techniques. The sol–gel phase diagram and the SAXS results suggested that the liquid–liquid phase separation occurred before gelation. By LS measurements, the structure due to the liquid–liquid phase separation was directly observed. By applying speckle analysis on the LS profiles, it was suggested that the gelation and the phase separation strongly coupled each other: the increase in the apparent molecular weight by crosslinking induced the liquid–liquid phase separation. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 168–174, 2010 相似文献
137.
Shunsuke Takenaka Shiro Miyake Shigekazu Kusabayashi 《Molecular Crystals and Liquid Crystals》2013,570(2-4):211-223
The thermal properties for a homologous series of 4-(4-alkoxyphenoxycarbonyl)phenyl 5-cyano-2-furancarboxylates have been examined. The smectic A phase commences from the hexyloxy homolog, and the octyloxy, nonyloxy and decyloxy homologs show two kinds of smectic A phases and experience the SA-SA transition. The lower phase which shows a typical fan shaped texture is assigned to a smectic A with a bilayer arrangement of the molecules (SA2). The higher phase which shows a typical fan shaped texture on the cooling stage and a broken fan one on the heating stage, is assigned to a smectic A with a partially bilayer arrangement of the molecules (SAd). The SA-SA transitions could be easily detected by both differential scanning calorimeter and optical microscopic method. 相似文献
138.
Takeyasu Tasaka Hiroaki Okamoto Vladimir F. Petrov Shunsuke Takenaka 《Liquid crystals》2013,40(7):1025-1034
The effect of alkyl and alkoxy chain lengths on the layer structures of smectic A and C phases has been examined by X-ray diffraction measurements on three isomeric systems: 4-alkoxyphenyl and 4-n-alkylphenyl 4-[(4-octyloxyphenyl)carbonyloxy]benzoates (1); 4-octyloxyphenyl 4-[4-(octyloxyphenyl)carbonyloxy]benzoates (2); 4-octyloxyphenyl, 4-alkoxyphenyl and 4-n-alkylphenyl terephthalates (3); and p-phenylene 4-octyloxybenzoates, 4-alkoxybenzoate and 4-n-alkylbenzoate (4). Although all the derivatives exhibit smectic A and/or C phases having a monolayer arrangement of the molecules, the layer spacings are considerably affected by alternation of the ester linkages. The layer spacings for the homologues of 1 are a little shorter than the calculated molecular lengths, while those for 2 agree with the calculated molecular lengths. The layer spacings for 3 show a notable even-odd alternation in the higher homologues. The results are discussed in terms of a subtle change in the molecular structures due to replacement of the ester groups. 相似文献
139.
Kazuhiro Takenaka Toyohiro Nagano Shinobu Takizawa Hiroaki Sasai 《Tetrahedron: Asymmetry》2010,21(4):379-381
Asymmetric synthesis of novel chiral ligands, bis(isoxazoline) on a spiro[4.4]nonane scaffold and isoxazole–isoxazoline on a spiro[4.5]decane scaffold, has been achieved by utilizing an enantiomerically pure alcohol as the starting material. 相似文献
140.
Hisanori Sugiura Yoshiaki Saklrai Yoshihide Masuda Hitoshi Takeda Shigekazu Kusabayashi Shunsuke Takenaka 《Liquid crystals》2013,40(3):441-450
Abstract The thermal properties of 4-octyloxyphenyl 4-(4-R-3-nitrobenzoyloxy) benzo-ates (1) and 4-(4-octyloxybenzoyloxy)phenyl 4-R-3-nitrobenzoates (2) have been examined, where R = hydrogen, halogens, alkyl and alkoxy groups. The derivatives of compound 1 incorporating hydrogen, halogens, methoxy and nitro groups show a smectic A phase having a bilayer arrangement, and the others with a long alkoxy group show the SA phase with the monolayer arrangement. The derivatives of compound 2 incorporating halogens, and the nitro group show the SA phase with the monolayer arrangement. The alkoxy derivatives show a smectic C phase as well as the nematic phase. The nitro group at the lateral position tends to increase the ratio of the SA-N transition temperature to the N-I. The effect of the nitro group on the smectic properties has been discussed in terms of the structural and electrostatic nature of the nitro group. 相似文献