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排序方式: 共有169条查询结果,搜索用时 15 毫秒
1.
Keiko Doi-Kawano Etsuko Nishimoto Yoshiaki Kouzuma Daisuke Takahashi Shoji Yamashita Makoto Kimura 《Journal of fluorescence》2009,19(4):631-639
The steady-state and time-resolved fluorescece spectroscopy is one of the most powerful method to detect and analyze subtle
conformation change and interaction between peptide elements in protein. Phytocystatin Scb isolated from sunflower seeds includes
a single Trp residue at position 85. In an attempt to investigate the interaction of the N-terminal region of Scb with the
first and second hairpin loops by fluorescence spectroscopy of Trp residue, two Scb mutants in which single Trp locates at
position 52 and 58, respectively, and their N-terminal removed mutants were generated. The N-terminal truncation changed the
fluorescence decay kinetics of Trp52 from the triple exponential to double. Furthermore, the time-resolved fluorescence anisotropy
residue indicated that the segmental motion of Trp52 was significantly enhanced by its N-terminal truncation. In contrast,
Trp58 and Trp85 had little influence. The N-terminal successive truncations of Scb and its mutants resulted in the weaken
inhibitors to papain. These results suggested that the N-terminal region of Scb interacts with the peptide segment preceding
the first hairpin loop, thereby stabilizing the conformation of the hairpin loop structure. 相似文献
2.
Tomohiro Sago Tomokatsu Tokami Hideyuki Itagaki Nobuhide Ishihara Christina Canter Jean-Michel Guenet 《Macromolecular Symposia》2011,303(1):48-55
Summary: Gelation of syndiotactic poly(p-tert-butylstyrene) (sPTBS), a syndiotactic polystyrene (sPS) derivative having a larger side-chain group, was first examined with several solvents. The temperature-concentration phase diagram of sPTBS/trans-decalin gel clearly exhibited that sPTBS formed a polymer-solvent molecular compound with a ratio of 2.7 trans-decalin per one monomer unit. Our polarized fluorescence technique demonstrated that there appeared to exist more spacious free volume among sPTBS chains than sPS in a gel state. A cause determining the morphology of sPTBS with organic solvents was discussed in the present paper. 相似文献
3.
Molecular mobility of the comb-shaped copolymer poly(4-[6-(acryloyloxy)hexyloxy]benzoic acid-co-butyl acrylate) and Li- and Rb-containing LC ionomers based on this polymer was studied at low temperatures by the methods of dielectric spectroscopy and thermally stimulated depolarization current. The above copolymers are shown to experience the γ2, γ1, and β-processes, which are related by the reorientation of the end СООН groups, by the mobility of a spacer, and by the reorientation of mesogenic fragments (dimers of oxybenzoic acids) with respect to a long axis, respectively. The formation of multiplet structures in ionomers leads to a suppression of the intensity of the β-process that relates with a partial breakdown of hydrogen-bonded dimmers and with a decrease of their molecular mobility. 相似文献
4.
B. Chowdhury 《Journal of Thermal Analysis and Calorimetry》2001,64(2):433-441
Pyrolysis of normally insulating aromatic polyimide is known to impart electrical conductivity to the polymer due to the formation
of carbonized regions in an insulating matrix with a concomitant change in the polymer’s structural arrangement. The wholly
pyrolyzed polyimide is potentially useful for specific applications in certain types of semiconductor devices because of the
polyimide’s insulator/conductor transition which creates a barrier type conduction. Pyrolysis, however, degrades the required
mechanical integrity of the polyimide for construction of such devices. In order to evaluate the fundamental aspects of barrier
conduction by high voltage electron transfer from metal contact that can still produce measurable current in thermally treated
non-pyrolyzed polyimide, the nature of depolarization in Kapton was assessed by the thermally stimulated depolarization current
(TSDC) technique. The results show that thermal treatment of polyimide without pyrolysis and therefore without loss of mechanical
integrity offers a viable means of steady electron conduction for semiconductor operation.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
V. V. Apanasovich E. G. Novikov N. N. Yatskov R. B. M. Koehorst T. J. Schaafsma A. van Hoek 《Journal of Applied Spectroscopy》1999,66(4):613-616
Results of investigation of the optical properties of zinc complexes of mesotetraphenylporphyrin and monopyridyltriphenylporphyrin
in impurity-free organic solvent are presented. Analyses of absorption and emission spectra and fluoresence decay kinetics
in terms of both a sum of exponentials and using simulation of energy-transformation processes in a tetramer-type Zn-porphyrin
complex compound are carried out.
Reported at the VIIIth International Conference on Spectroscopy of Porphyrins and Their Analogs, Minsk, September 22–26, 1998.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 4, pp. 549–552, July–August, 1999. 相似文献
6.
7.
Electrical field analysis of metal‐surface plasmon resonance using a biaxially strained Si substrate
Daisuke Kosemura Siti Norhidayah binti Che Mohd Yusoff Atsushi Ogura 《Journal of Raman spectroscopy : JRS》2014,45(6):414-417
Electrical field components of metal‐surface plasmon resonance were analyzed in detail. Both longitudinal optical (LO) and transverse optical (TO) phonon modes of a biaxially strained Si layer can be excited by surface‐enhanced Raman spectroscopy (SERS). The z to y polarization ratio in SERS measurements was calculated to be 0.78 using the intensity ratio of TO to LO phonon modes. The electrical field components of SERS were also calculated by the finite‐difference time‐domain method. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
8.
The chain segment motion and charge trapping and detrapping in nylon 1010 films were investigated by means of thermally stimulated depolarization current (TSDC). There were three current peaks (named α, ρ1, and ρ2 peaks, respectively) in the experimental TSDC spectra above room temperature. The α peak is attributed to a background dipole relaxation by the motion of chain segments and space charge contribution, the ρ1 peak is originated from a space charge trapped in the bulk amorphous regions and the interphase between crystalline and amorphous regions, the ρ2 peak is originated from space charge trapped in crystalline regions. By analyzing the characteristic parameters of these peaks, it was found that with in increase of the degree of crystallinity the activation energy of the a peak increased from 1.12 to 1.22 eV and the trap depth of the ρ2 peak increased from 2.70 to 2.82 eV, while the trap depth of the ρ1 peak decreased from 1.50 to 1.29 eV. Annealing induced a decrease of the chain segment mobility and promoted the creation of traps in nylon 1010. Annealing also decreased the stability of the trapped charges in the bulk amorphous and the interphase regions and increased the stability of the trapped charges in the crystalline regions. 相似文献
9.
10.
F. Namouchi H. Guermazi C. Zerrouki S. Agnel J.J. Bonnet 《European Polymer Journal》2007,43(11):4821-4829
Charges evolution in poly(methyl methacrylate) (PMMA) samples under thermal aging effect has been studied by means of two complementary techniques, thermal step method (TSM) and thermally stimulated depolarization current (TSDC). For the first method, measurements reveal that injected charges, whose quantity is found depending on the number of applied temperature cycles, remain close to the surface sample. TSDC measurements have been carried out for different temperatures ranging from 25 °C to 140 °C. Three distinguishable dipolar relaxations (β1, β2 and α) have been highlighted. In the same way, the presence of polarization and injected charges has been confirmed. In support of electric characterization, X-ray reflectometry has been used. The obtained results equally emphasized the thermal aging effect on the material. 相似文献