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121.
Shin-ya K Sugeta H Shin S Hamada Y Katsumoto Y Ohno K 《The journal of physical chemistry. A》2007,111(35):8598-8605
The absolute configuration and conformation of 1-phenylethanol (1-PhEtOH) have been determined by matrix-isolation infrared (IR) and vibrational circular dichroism (VCD) spectroscopy combined with quantum chemical calculations. Quantum chemical calculations have identified that there are three conformers, namely, I, II, and III, in which characteristic intramolecular interactions are found. The IR spectrum-conformation correlation for 1-PhEtOH has been developed by the Ar matrix-isolation IR measurement and used for the assignments of the observed IR bands. In a dilute CCl(4) solution, 1-PhEtOH exists predominantly as conformer I along with a trace amount of conformer II. By considering conformations and intermolecular hydrogen-bonding in the spectral simulation for (S)-1-PhEtOH, we have successfully reproduced the VCD spectrum of (-)-1-PhEtOH observed in a dilute CS(2) solution. Thus, (-)-1-PhEtOH is of S-configuration and conformer I in the dilute solution. The same method has been applied to analyze the VCD spectra measured in the liquid state of (-)-1-PhEtOH. The absolute configuration of 1-PhEtOH in the condensed phase is enabled by identifying VCD bands that are insensitive to conformational changes and intermolecular interactions. The present work provides a combinatorial procedure for determination of both the absolute configuration and the conformation of chiral molecules in a dilute solution and condensed phase. 相似文献
122.
Molecular aggregates of partially fluorinated quaternary ammonium salt gemini surfactants 总被引:1,自引:0,他引:1
Matsuoka K Yoshimura T Shikimoto T Hamada J Yamawaki M Honda C Endo K 《Langmuir : the ACS journal of surfaces and colloids》2007,23(22):10990-10994
The size and shape of novel partially fluorinated gemini surfactant 1,2-bis[dimethyl-(3-perfluoroalkyl-2-hydroxypropyl)ammonium]ethane bromide (CnFC3-2-C3CnF, where n=4, 6, and 8) were investigated in aqueous solution by means of light scattering and transmission electron microscopy (TEM). The sizes of these molecular aggregates changed with increasing carbon number of the alkyl chain and concentration. For example, the apparent hydrodynamic radius by dynamic light scattering was 18 nm at a concentration of cmcx5 for n=4, 115 nm at the cmcx15 for n=6, and 62 nm at the cmcx30 for n=8, at 298.2 K. The shapes of CnFC3-2-C3CnF aggregates drastically changed with the alkyl chain length; the aggregates were mainly in the form of large or irregular small aggregates (n=4), string-like aggregates (n=6), and vesicles (n=8). The bromide-ion activity was measured using a bromide-ion-selective electrode to determine the degree of counterion binding to the aggregates. The degree of counterion binding to aggregate was very small compared with that in the typical hydrogenated gemini surfactants. These results indicated that the small curvature of large aggregates was not influenced by an electrostatic repulsion between the cationic head groups in the case of the bulky molecular volume of fluorinated gemini surfactants. 相似文献
123.
Hamada T Miura Y Ishii K Araki S Yoshikawa K Vestergaard M Takagi M 《The journal of physical chemistry. B》2007,111(37):10853-10857
The dynamic response of a raft-exhibiting giant liposome to external stimuli, such as the addition of Triton X-100 or osmotic stress, was studied. We observed that daughter vesicles are generated inside of the liposome through endocytic budding. It was found that the budding to generate daughter vesicles is classified into two different routes, simple budding through the invagination of a whole raft and budding from the boundary of a raft accompanied by waving motion. Smaller rafts show a preference for simple budding, whereas large rafts mainly adopt the other process. We discuss the mechanism of this difference in terms of the kinetic pathway of internalization by considering the line energy and bending energy of the membrane. 相似文献
124.
125.
Coupled Reaction Channels and Cluster Folding Analysis for 3He+20Ne Elastic and Inelastic Scattering
Physics of Particles and Nuclei Letters - The previously measured angular distributions for 3He elastically and inelastically scattered from 20Ne target at energies 33.4 and 68 MeV are reanalyzed... 相似文献
126.
Phase behaviors of argon in several types of cylindrical and slit pores are examined by grand-canonical Monte Carlo simulations. Condensation processes in single- and multi-walled carbon nanotubes along with those in hard-wall tubes are compared. Effects of the pore size on pressure-tensor components, the fluid-wall surface tension, and the adsorption are also compared for the different fluid-pore interactions. The chemical potential at which the fluid begins to condense in the single-walled nanotube is greater than that in the multi-walled nanotube by an amount nearly equal to the difference in the potential-well depth of the fluid-pore interaction, and the adsorption isotherms overlap each other almost completely for narrow pores and partially for wider pores. Similar analyses are performed for slit pores of two different hydrocarbon models. 相似文献
127.
Yamada H Kumauchi M Hamada N Zheng XG Park IH Masuda K Yoshihara K Tokunaga F 《Photochemistry and photobiology》2006,82(6):1422-1425
We report a unique lambdamax shift of the absorption maximum of a photoactive yellow protein (PYP) analogue reconstituted with a fluorinated chromophore (F-PYP). The difference in lambdamax between the free chromophore and the protein was significantly larger than that with the native chromophore. We concluded that the unusual lambdamax shift is caused by the electronegative character of the fluorine atom and not by steric hindrance. This result suggests that formation of a hydrogen bond between the fluorine atom and one or more amino acid residues could neutralize its electron-withdrawing character. The properties of analogues of PYP with brominated and methylated chromophore could be explained as an effect of steric hindrance. 相似文献
128.
Ramadan M. Abdel‐Motaleb Abdel‐Moneim A. Makhloof Hamada M. Ibrahim Mohamed H. Elnagdi 《Journal of heterocyclic chemistry》2006,43(4):931-934
3‐Amino‐3‐phenyl‐2‐phenylazoacrylonitrile 6 is obtained in good yield via reaction of 5 with phenyl magnesium bromide. The compound 6 is readily converted into 4a . The so formed alkanenitrile reacted with phenylmagnesium bromide to yield 8 . Compound 8 could be also obtained from reaction of 9 with phenylmagnesium bromide. The arylhydrazononitriles 8 and 4a reacted with chloroacetonitrile to yield the 4‐aminopyrazoles 12a,b . Compound 12a reacted with acetic anhydride to yield the 15a and with benzoyl chloride to yield the pyrazole 16 which was converted into 15b . Refluxing 10 in acetic acid gave a mixture of the azadiene 21 and the cinnoline 22 is obtained. The azadiene 21 is converted into 22 either thermally or photochemically. 相似文献
129.
The near infrared (NIR) absorption was investigated on the glucose aqueous solutions with various optical pathlengths (PLs) and processed by ultrasonic cavitation. In water, the strong absorption peak at a wavelength of 1430 nm, appeared in the case of short PL, was separated into several peaks in the case of wide PL due to increasing the number of H(2)O clusters. In a d(+) glucose solution, it was seen that NIR absorption was reduced at peculiar wavelengths of 970 nm and 1130 nm and its profile changed in a capricious manner in the region from 1300 nm to 1600 nm. The cavitation generated lots of OH(-) ion in water and made the capricious absorption profile regularly graded with the cavitation time toward less-absorptive direction. These effects are supposed to be caused by the dipole moments of H(2)O clusters arranged by the interaction between them and generated basic OH ions. The statistical principal component regression (PCR) and partial least-squares (PLS) regression demonstrated that the treatment of UC was helpful to enhance the glucose sensitivity. 相似文献