全文获取类型
收费全文 | 64篇 |
免费 | 2篇 |
专业分类
化学 | 17篇 |
力学 | 2篇 |
数学 | 2篇 |
物理学 | 45篇 |
出版年
2023年 | 1篇 |
2019年 | 1篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 4篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 3篇 |
2007年 | 2篇 |
2006年 | 1篇 |
2005年 | 5篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1981年 | 1篇 |
1977年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有66条查询结果,搜索用时 15 毫秒
51.
52.
Eric L. Finley James Dillon Rosalie K. Crouch Kevin L. Schey 《Photochemistry and photobiology》1998,68(1):9-15
Abstract— Radiolysis of water by ionizing radiation results in the production of pure hydroxyl radicals. This technique, combined with analysis by tandem mass spectrometry (MS/MS), has been used to study the effect of hydroxyl radicals on the intact bovine α-crystallin protein. After exposure to -γ-irradiation, the oxidized α-crystallin was digested with trypsin and the resulting peptides were fractionated by reverse-phase HPLC. The isolated fractions were analyzed by matrix-assisted laser desorption ionization and by MS/MS to determine the locations and identities of the modifications. Structural analysis revealed that methionine 1 of αA- and αB-crystallin and methionine 68 of αB-crystallin were oxidized to methionine sulfoxide. Hydroxytryptophan was formed from each tryptophan residue in α-crystallin, although only tryptophan 9 of αA-crystallin was converted into N-for-mylkynurenine. This study has, for the first time, identified the sites of modification and the structures produced in the intact α-crystallin protein by exposure to hydroxyl radicals. By determining the consequences of in vitro exposure of α-crystallin to pure hydroxyl radicals, the in vivo contribution of this reactive oxygen species to the overall oxidative stress of the lens will be achieved from the identification of the modifications to α-crystallin purified from intact human lenses. 相似文献
53.
A new procedure for the reduction of Preston tube data is introduced, based on the van Driest transformation. It appears to give results agreeing with the better calibration experiments, although a significant assumption in its derivation is violated.List of Symbols
M
s
Mach number sensed by Preston tube
-
M
Friction Mach number (=u/wall sound speed)
-
R
Gas constant
-
T
w
Wall temperature
-
d
Diameter of Preston tube
-
h
Height of effective centre of Preston tube
-
p
Preston tube pressure difference reading
-
p
i
Equivalent incompressible Preston tube reading
-
p
w
Wall pressure
-
r
Recovery factor (=0.896)
- u
Friction velocity (=[w/wall density]1/2)
-
Empirical constant allowing for departure from Crocco temperature-velocity correlation (=0.975)
-
Specific heat ratio
-
Fluid kinematic viscosity
-
w
Wall shear-stress 相似文献
54.
Various untabbed, thickness-tapered compression specimen geometries were studied experimentally. Both shear-loaded and end-loaded compression test methods were used to measure the strength and stiffness of carbon/epoxy and glass/epoxy unidirectional composite material systems. The compressive strength was found to be strongly dependent on specimen geometry, loading conditions, and the cracks that initiated in the taper regions and propagated to various lengths prior to catastrophic failure. A specific thickness-tapered specimen geometry that produced compressive strengths significantly higher than conventional specimen configurations resulted from the experimental optimization process. A method of determining compressive strains, and thus the compressive modulus, using this same specimen geometry and strain gages was also demonstrated. 相似文献
55.
R. Oulton A.I. Tartakovskii A. Ebbens J.J. Finley D.J. Mowbray M.S. Skolnick M. Hopkinson 《Physica E: Low-dimensional Systems and Nanostructures》2005,26(1-4):302
Vertically coupled Stranski Krastanow quantum dots (QDs) are predicted to exhibit strong tunnelling interactions that lead to the formation of hybridised states. We report the results of investigations into single pairs of coupled QDs in the presence of an electric field that is able to bring individual carrier levels into resonance and to investigate the Stark shift properties of the excitons present. Pronounced changes in the Stark shift behaviour of exciton features are identified and attributed to the significant redistribution of the carrier wavefunctions as resonance between two QDs is achieved. At low electric fields coherent tunnelling between the two QD ground states is identified from the change in sign of the permanent dipole moment and dramatic increase of the electron polarisability, and at higher electric fields a distortion of the Stark shift is attributed to a coherent tunnelling effect between the ground state of the upper QD and the excited state of the lower QD. 相似文献
56.
Jérôme JP. Leon 《Letters in Mathematical Physics》1981,5(1):75-80
We establish a transformation which connects the potentials of the one-dimensional Dirac and Klein-Gordon operators. This transformation links the solutions of the nonlinear evolution equations solvable by means of the two inverse spectral transforms which use the Dirac and Klein-Gordon direct and inverse spectral problems. 相似文献
57.
Allgeier DE Herbert SA Nee R Schlecht KD Finley KT 《The Journal of organic chemistry》2003,68(12):4988-4990
The addition of arylsulfinic acids to 2-methyl-1,4-benzoquinone provides high yields of sulfones in a wide variety of solvents. The distribution of isomeric products obtained is strongly influenced by either (1) the acidity of aqueous solvents or (2) the water content of alcohol solvents. The distribution of isomeric products does not change in the various anhydrous, aprotic solvents examined. 相似文献
58.
59.
A new perturbation approach is proposed that enhances the low‐order, perturbative convergence by modifying the zeroth‐order Hamiltonian in a manner that enlarges any small‐energy denominators that may otherwise appear in the perturbative expansion. This intruder state avoidance (ISA) method can be used in conjunction with any perturbative approach, but is most applicable to cases where small energy denominators arise from orthogonal‐space states—so‐called intruder states—that should, under normal circumstances, make a negligible contribution to the target state of interests. This ISA method is used with multireference Møller–Plesset (MRMP) perturbation theory on potential energy curves that are otherwise plagued by singularities when treated with (conventional) MRMP; calculation are performed on the 13Σ state of O2; and the 21Δ, 31Δ, 23Δ, and 33Δ states of AgH. This approach is also applied to other calculations where MRMP is influenced by intruder states; calculations are performed on the 3Πu state of N2, the 3Π state of CO, and the 21A′ state of formamide. A number of calculations are also performed to illustrate that this approach has little or no effect on MRMP when intruder states are not present in perturbative calculations; vertical excitation energies are computed for the low‐lying states of N2, C2, CO, formamide, and benzene; the adiabatic 1A1–3B1 energy separation in CH2, and the spectroscopic parameters of O2 are also calculated. Vertical excitation energies are also performed on the Q and B bands states of free‐base, chlorin, and zinc–chlorin porphyrin, where somewhat larger couplings exists, and—as anticipated—a larger deviation is found between MRMP and ISA‐MRMP. © 2002 Wiley Periodicals, Inc. J Comput Chem 10: 957–965, 2002 相似文献
60.