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41.
Takumi Mizuno Noriaki Okamoto Takatoshi Ito Toshiyuki Miyata 《Heteroatom Chemistry》2000,11(6):428-433
Sulfur‐assisted carbonylation of 2‐aminobenzonitriles with carbon monoxide using K2CO3 as a base under ambient conditions (1 atm, 20°C) to afford 2‐hydroxy‐4‐mercaptoquinazolines in excellent yields was found. This carbonylation was applied to chemical fixation of carbon dioxide under mild conditions. Carbon dioxide (1 atm) easily reacted with 2‐aminobenzonitriles at 20°C assisted by 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) to give 2,4‐dihydroxyquinazolines in excellent yields. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:428–433, 2000 相似文献
42.
Katsufumi Tanaka Yuichiro Tanabe Takatoshi Morina Ryuichi Akiyama 《Liquid crystals》2008,35(3):253-264
Solid cast films with polydomain textures were prepared on a glass substrate with transparent interdigitated electrodes from an isotropic aqueous solution of hydroxypropyl cellulose via its liquid crystalline phase under the sinusoidal electric field with small amplitude and frequency of 0.05 V µm-1 and 105 Hz, respectively. The process was monitored using microdielectrometry as well as polarised optical microscopy. The apparent dielectric constant εr' and loss factor εr' sensitively changed with time depending on the process conditions. On the other hand, the logarithmic relation between εr' and εr' showed a single curve, when they were normalised by an effective portion of the electrostatic energy density estimated using each solid-film thickness. The conversion to the solid film was estimated during the process based on the concentration dependences of εr' and εr'. Characteristic times were reported for the onset of the biphasic phase, fully developed cholesteric phase and termination of the process. 相似文献
43.
Takatoshi Ichino Dr. Stephanie M. Villano Dr. Adam J. Gianola Dr. Daniel J. Goebbert Dr. Luis Velarde Dr. Andrei Sanov Prof. Stephen J. Blanksby Dr. Xin Zhou Dr. David A. Hrovat Dr. Weston Thatcher Borden Prof. W. Carl Lineberger Prof. 《Angewandte Chemie (International ed. in English)》2009,48(45):8509-8511
44.
The large-scale circulation, often called "wind," in the confined thermal turbulence of mercury is studied experimentally. The instantaneous velocity profile at 128 points is directly measured using ultrasonic velocimetry. The periodic velocity oscillation is observed in the case of the aspect-ratio Gamma = 1,2 but not in Gamma = 0.5. Its peak frequency is scaled by f(c) proportional Ra(gamma(c)), where Ra is the Rayleigh number and gamma(c) = 0.43,0.45 for Gamma = 1,2. f(c) is close to the wind circulation frequency f(p), and has the same order of transit time from the bottom to the top of the convection cell. A single roll circulation is expected in Gamma = 1; however, axisymmetric toroidal rings may exist near the upper and lower plate for Gamma = 0.5, which are stable up to Ra = 7 x 10 (10). 相似文献
45.
Kaya T Nagamine K Matsui N Yasukawa T Shiku H Matsue T 《Chemical communications (Cambridge, England)》2004,(2):248-249
[small beta]-Galactosidase expression in a small number of Escherichia coli cells has been measured in real time with an electrochemical sensor chip. E. coli cells were embedded using collagen gel within a micropore which was microfabricated onto a chip. The activity of the expressed [small beta]-galactosidase was determined using p-aminophenyl [small beta]-d-galactopyranoside (PAPG) as a substrate. 相似文献
46.
Higuchi M Koga T Taguchi K Kinishita T 《Chemical communications (Cambridge, England)》2002,(10):1126-1127
A polypeptide assembly prepared by stepwise polymerization on a self-assembled monolayer consisting of amino-alkanethiol and dialkyl disulfide oriented vertically and unidirectionally to the surface. 相似文献
47.
Nonradiative deactivation processes of excited aniline and its derivatives in aqueous solution were investigated by steady-state and time-resolved fluorescence measurements to reveal characteristic solvent effects of water on the relaxation processes of excited organic molecules. The magnitude of nonradiative rate (knr) of excited aniline derivatives increased significantly in water compared to that in organic solvents (cyclohexane, ethanol, and acetonitrile). The fluorescence lifetime measurements in organic solvent/H2O mixed solvents suggested that the fluorescence quenching in water was not due to exciplex formation but due to interactions with a water cluster. From temperature effect experiments on the fluorescence lifetime and quantum yield of aniline, N-methylaniline, and N,N-dimethylaniline, the apparent activation energies for the nonradiative deactivation rate in water were determined as 21, 30, and 41 kJ mol-1, respectively. Upon substitution of hydrogen atoms in the aromatic ring of aniline derivatives for deuterium atoms resulted in normal deuterium isotope effect in cyclohexane, i.e. knr decreased by deuterium substitution, while in water the same deuterium substitution led to an increase in knr (the inverse isotope effect). The inverse isotope effects implied that a direct internal conversion to vibrationally higher excited states in the electronically ground state is not a dominant mechanism but the transition to a close-lying energy level, e.g. the relaxation to charge transfer to solvent (ctts) state, would be associated with the quenching mechanism in water. 相似文献
48.
Katsufumi Tanaka Yuichiro Tanabe Takatoshi Morina Ryuichi Akiyama 《Liquid crystals》2013,40(3):253-264
Solid cast films with polydomain textures were prepared on a glass substrate with transparent interdigitated electrodes from an isotropic aqueous solution of hydroxypropyl cellulose via its liquid crystalline phase under the sinusoidal electric field with small amplitude and frequency of 0.05 V µm?1 and 105 Hz, respectively. The process was monitored using microdielectrometry as well as polarised optical microscopy. The apparent dielectric constant εr′ and loss factor εr″ sensitively changed with time depending on the process conditions. On the other hand, the logarithmic relation between εr″ and εr′ showed a single curve, when they were normalised by an effective portion of the electrostatic energy density estimated using each solid‐film thickness. The conversion to the solid film was estimated during the process based on the concentration dependences of εr′ and εr″. Characteristic times were reported for the onset of the biphasic phase, fully developed cholesteric phase and termination of the process. 相似文献
49.
Hideyuki Aoki Tomohiko Furuhata Shoji Tanno Takatoshi Miura Shigemori Ohtani 《Experimental Thermal and Fluid Science》1992,5(6):838-847
The effect of swirling flow on the unburned ratio and NO concentration in exhausted gas was studied for slurry [coal-water mixture (CWM)] spray combustion with variations of swirl numbers. A numerical analysis for CWM combustion was performed for axisymmetric flow in a cylindrical geometry. First, to check the performance of three previous k-ε turbulence models modified with swirling flow, velocity components of isothermal swirling jets were measured by laser-Doppler anemometry (LDA) and compared with predicted results. The two modified models gave more reliable results than the conventional one. Next, as the swirl number could not be estimated by the angular momentum derived from the vane angle of the circular swirler, the reduction rate of the tangential momentum flux through the tube of the circular swirler was measured and calculated. Both measured and predicted results showed that when the swirl number S′ given by the vane angle was 2.0, the effective swirl number Seff decreased by about 60% to S′. To take the results mentioned above into consideration, effects of swirl number on both the exhausted NO concentration and unburned ratio were investigated. The predicted unburned ratio showed good agreement with the experimental results. Both experimental and calculated results showed that the optimum operating conditions controlling the exhausted NO concentration and unburned ratio in this spray combustion system were obtained when the swirl number Seff was about 0.5. 相似文献
50.