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81.
Hirota J Satomi Y Yoshikawa K Takao T 《Rapid communications in mass spectrometry : RCM》2003,17(5):371-376
Epsilon -N,N,N-trimethyllysine (K(me3)) is a component of a number of proteins and plays an important role in the expression of their biological functions. Trimethylation, which causes an incremental increase in mass of 42.0470 Da from that of the corresponding MH(+) ion, cannot be distinguished from the acetylation (+42.0106 Da), which also occurs on epsilon-amino groups of Lys or alpha-amino groups in many proteins, without high-accuracy mass measurement which is accurate to within the second decimal place. MALDI-MS and MS/MS have been applied for the analyses of post-translational modifications of histone H3, which is known to contain both multiple acetylation and methylation sites in its sequence. During the measurements of the modified peptides, a novel fragmentation which involves the loss of trimethylamine from K(me3) was found. This characteristic fragmentation, which was observed to produce ions separated by 59 Da from the conventional precursor ion or sequence ions, would be useful for probing K(me3) units in the sequence. 相似文献
82.
Mitsumasa Taguchi Grard Baldacchino Satoshi Kurashima Atsushi Kimura Yumi Sugo Yosuke Katsumura Koichi Hirota 《Radiation Physics and Chemistry》2009,78(12):1169-1174
This article reports a highly sensitive transient absorbance measurement system using pulsed energetic ions. The ions were pulsed by a beam chopper, which was synchronized with the cyclotron, and accelerated to the desired energy around 18 MeV/u. H, He, C and Ne ions can be used for the transient absorption measurement. The optical system can measure an absorbance smaller than 1.0×10−4 in the wavelength range of 400–740 nm. 相似文献
83.
Reflection spectra of silicate glasses were measured in the spectral region 2–13 eV. The bands due to bridging oxygen were found at 11.6 and 10.4–9.5 eV. The bands for non-bridging oxygens were found in the region 8.8–4.9 eV. They shift to lower energy with increasing ionic radius for the low valency cations while they shift to higher energy with increasing ionic radius for the high valency cations. The correlation between the measured bands and the absorption wavelength calculated from Drude-Voigt dispersion formula is discussed. 相似文献
84.
Oleg N. Ulenikov Eizi Hirota Mitsuru Akiyama S. Alanko M. Koivusaari R. Anttila G. Guelachvili R. N. Tolchenov 《Journal of Molecular Spectroscopy》1996,180(2):423-432
The infrared spectrum of doubly deuterated methane CH2D2has been recorded in the region from 1900 to 2400 cm−1at almost Doppler-limited resolution by using two high-resolution Fourier transform spectrometers. The vibrational bands observed include 2ν4, ν4+ ν7, 2ν7, ν2, ν8, ν4+ ν9, and ν7+ ν9, which were analyzed by taking into account Coriolis and Fermi interactions among them and also those with ν4+ ν5, ν3+ ν7, and ν5+ ν7. Most of the centrifugal distortion constants were constrained to appropriate values, while the vibrational term value and three rotational constants in each of the seven excited states were adjusted along with Coriolis and Fermi interaction parameters by the least-squares analysis of the observed spectrum. The vibration–rotation interaction constants αsthus determined for the ν2and ν8states were combined with those of other fundamental states already published to calculate the equilibrium C–H distance. 相似文献
85.
86.
POSSIBLE ROLE OF METALLOTHIONEIN IN THE CELLULAR DEFENSE MECHANISM AGAINST UVB IRRADIATION IN NEONATAL HUMAN SKIN FIBROBLASTS 总被引:1,自引:0,他引:1
Shizuko Kobayashi Yumiko Hirota Junko Sayato-Suzuki Makoto Takehana Hisao Nishimura Noriko Nishimura Chiharu Tohyama 《Photochemistry and photobiology》1994,59(6):650-656
Abstract: The role of metallothionein (MT) in protecting skin cells against UVB irradiation was investigated. Fibroblast strains from normal adult (HS-K) and neonatal (NB1RGB) human skins as well as keratinocyte strains from human skin (SV40-HSK) and newborn Balb/c mouse skin (Pam 212) were exposed to UVB irradiation.
The sensitivity of HS-K and NB1RGB cells to UVB irradiation was similar; those of SV40-HSK and Pam 212 cells were two- and six-fold as sensitive to UVB irradiation as HS-K cells, respectively. The HS-K cells contained the greatest cellular reduced form of glutathione (GSH) levels compared to the three other skin cells: the levels were 13-, 7- and 6-fold of those in NB1RGB, SV40-HSK and Pam 212 cells, respectively. These results indicated that the sensitivity of skin cells to UVB irradiation was not always associated with their endogenous GSH levels. In particular, despite the fact that NB1RGB cells contained a relatively small amount of GSH, they were less sensitive to UVB irradiation.
NB1RGB cells contained 4–30 times more MT than those in other skin cells examined. The sulfhydryl residues of MT molecules in the NB1RGB cells were estimated to be mostly unoccupied by metals, suggesting they act in a similar way to those of GSH. Moreover, NB1RGB cells in which the MT content was elevated by dexamethasone (1 μ M ) or Zn2+ (7 μg/mL) treatment were more resistant to UVB irradiation than nontreated ones.
These results suggest that, at least in neonatal human skin fibroblasts, MT may play a role in protection against UVB irradiation. 相似文献
The sensitivity of HS-K and NB1RGB cells to UVB irradiation was similar; those of SV40-HSK and Pam 212 cells were two- and six-fold as sensitive to UVB irradiation as HS-K cells, respectively. The HS-K cells contained the greatest cellular reduced form of glutathione (GSH) levels compared to the three other skin cells: the levels were 13-, 7- and 6-fold of those in NB1RGB, SV40-HSK and Pam 212 cells, respectively. These results indicated that the sensitivity of skin cells to UVB irradiation was not always associated with their endogenous GSH levels. In particular, despite the fact that NB1RGB cells contained a relatively small amount of GSH, they were less sensitive to UVB irradiation.
NB1RGB cells contained 4–30 times more MT than those in other skin cells examined. The sulfhydryl residues of MT molecules in the NB1RGB cells were estimated to be mostly unoccupied by metals, suggesting they act in a similar way to those of GSH. Moreover, NB1RGB cells in which the MT content was elevated by dexamethasone (1 μ M ) or Zn
These results suggest that, at least in neonatal human skin fibroblasts, MT may play a role in protection against UVB irradiation. 相似文献
87.
88.
The far-infrared laser magnetic resonance spectrum of AsH in the ground X3Σ? state has been observed using five optically pumped laser lines as sources. The AsH radical was produced by the reaction of metallic arsenic with microwave discharge products of a H2 and O2 mixture. From an analysis of the observed spectrum, the following rotational and fine structure constants were obtained: B0 = 215 877.54 (23), D0 = 9.834 (11), λ = 1 763 488 (56), and γ = ?8 114.5 (60), all in MHz with 3σ in parentheses. The hyperfine coupling constants were also determined for the two nuclei as follows: αAs = ?11.5 (14), βAs = ?159.4 (13), eQqAs = ?97.6 (72), αH=?49.80 (66), and βH=4.15 (60), again in MHz with 3σ in parentheses. 相似文献
89.
90.
The CCl radical was generated by a dc glow discharge in CCl4, and rotational transitions of C35Cl in both and were observed in the mm-wave region by using a source modulation microwave spectrometer. From an analysis of the observed spectra the magnetic and electric quadrupole hyperfine coupling constants of the 35Cl nucleus were determined precisely. The Λ-doubling constant p0 was determined to be positive, indicating that unknown 2Σ? excited electronic states are making dominant contributions to the Λ doubling in the ground state. The previous diode-laser result [J. Mol. Spectrosc.85, 416–426 (1981)] was reanalyzed by using improved wavelength standards and by fixing the ground-state parameters to the present microwave values including the B0 rotational constant 20 797.1725(38) MHz. The vibration-rotation constant αB and the equilibrium bond length re were thus determined to be 0.006 768 2(48) cm?1 and 1.645 218(16) Å, respectively, with 2.5 times standard deviations in parentheses. The spin density on the chlorine atom was estimated to be about 0.20 from the observed hyperfine coupling constants. 相似文献