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141.
Jun Hosoi Tetsuo Oikawa Masao Inoue Yoshio Matsui Tadashi Endo 《Journal of Electron Spectroscopy and Related Phenomena》1982,27(3):243-254
An interband π plasmon and π* edge have been observed in the spectrum of hexagonal boron nitride (h-BN). This result is in good agreement with that 相似文献
142.
143.
L-Threonine was transformed, stereospecifically, to a versatile β-lactam (5a) in 3 steps. This β-lactam was further converted to a key intermediate (25) for the synthesis of thienamycin and its biologically active analogues. Furthermore, the compound 5a was changed to iodides (18 and 23), cyanides (19 and 24), chloromethylketone (26) and aldehydes (30 and 31) which appear to have a latent potential as precursors for the syntheses of the carbapenems. 相似文献
144.
Masahito Ochiai Munetaka Kunishima Kenzo Sumi Yoshimitsu Nagao Eiichi Fujita Masao Arimoto Hideo Yamaguchi 《Tetrahedron letters》1985,26(37):4501-4504
New general methods for the synthesis of alkynyl(phenyl)iodonium tetrafluoroborate 2 from alkynyltrimethylsilanes 1 utilizing the combination of iodosylbenzene and triethyloxonium tetrafluoroborate or boron trifluoride etherate were developed. The medium effect observed in the reaction was also discussed. 相似文献
145.
Choji Kashima Masao Shimizu Kazuo Harada Yoshimori Omote 《Journal of heterocyclic chemistry》1988,25(6):1713-1717
N-Substituted 2-alkylthio-1,4-dihydro-4,4,6-trimethylpyrimidines easily reacted with methanol to give corresponding 2-methoxy-1,4-dihydropyrimidines, while the other nucleophiles did not react on the C-2 carbon of the pyrimidine rings. However, the substitution of alkylthio group easily proceeded intramolecularly even with weak nucleophilic groups, e.g., phenolic oxygen, thiophenolic sulfur, and anilino nitrogen atom, to yield bi- or tricyclic pyrimidine derivatives. 相似文献
146.
Toshio Motojima Shun-ichi Ikawa Masao Kimura 《Journal of Quantitative Spectroscopy & Radiative Transfer》1981,26(3):177-185
The i.r. absorption intensities have been measured of the fundamental vibrations of water molecules in metal halide aqueous solutions. Pseudo-isosbestic points were observed in the regions of both the stretching and bending vibrations and interpreted in terms of two states of water molecules in the solutions. The intensities of the stretching vibrations of water molecules coordinated to the dissolved ions have been estimated. The intensities become stronger in the order, Li+ > Na+ > K+ for the cations and F- > Cl- > Br- > I- for the anions. These orders are consistent with the strengths of the ion-water interactions, which are related to the dynamical behavior of the water molecules in the primary hydration shell. 相似文献
147.
Masao Doi 《Chemical physics》1975,11(1):115-121
A simplified version of the closure approximation, presented in the preceding paper, is applied to the reaction of rigid or flexible macromolecular systems. Two effects are found to be important for understanding the characteristic features of the reaction rates of these systems: (i) the orientation effect, which expresses the accessibility of the active sites, and (ii) the relaxation effect, which reflects the nature of the brownian motion of the active sites. 相似文献
148.
Shun-Ichi Ikawa Sachiko Takahasi Masao Kimura 《Journal of Quantitative Spectroscopy & Radiative Transfer》1975,15(12):1093-1099
The dielectric-field correction on i.r. band shape in the liquid has been studied by using the Lorentz internal field. The deformation of the band shape is inappreciable for a weak absorption band that becomes measurable only at a sample thickness larger than 10μ. The shapes of the strong singlet and doublet bands of hexafluorobenzene at 1530 cm?1 and near 1000 cm?1, respectively, and also of the doublet band of carbon tetrachloride near 790 cm?1 have been measured in dilute solutions and compared with those for the pure liquid. 相似文献
149.
The moment analyses were performed on the far-infrared absorption bands of CH3CN, CHCl3, CH2Cl2, and their deuterated compounds dissolved in nonpolar solvents. The values of torque acting on the solute molecules were estimated from the fourth moments. The band profiles were simulated by means of the continued-fraction representation of the time correlation function by Mori, using the moment values obtained. The third order long-time approximation of the correlation function yields essentially good simulations. The effective rotation angles of molecules between collisions were estimated from the first positive-to-negative turning points of the memory functions. The solvent effects on the torque and the rotation angle were consistent with each other. 相似文献
150.
Masao Doi 《Chemical physics letters》1974,26(2):269-272
The viscoelastic properties of concentrated polymer solutions are discussed on the basis of the fixed tube model proposed by de Gennes. It is shown that the steady flow viscosity is proportional to M3, where M is the molecular weight, and that the relaxation spectrum exhibits a hump in the relaxation time proportional to M3. 相似文献