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排序方式: 共有147条查询结果,搜索用时 15 毫秒
1.
Prof. Dr. Tomoaki Tanase Dr. Kanako Nakamae Yume Okawa Mami Hamada Dr. Arimasa Matsumoto Prof. Dr. Takayuki Nakajima Prof. Dr. Takuya Nakashima Prof. Dr. Tsuyoshi Kawai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(8):e202104060
A P-stereogenic linear tetraphosphine tetraoxide, (R,R)- or (S,S)-dpmppm(=O)4, was synthesized to prepare C2 dinuclear M(hfa)3 complexes (M=Eu, Tb, Y) as the first example of lanthanide(III) complexes with P-chiral multidentate phosphine oxides. The mononuclear M(hfa)3 complexes (M=Eu, Y) with a P-chiral diphosphine dioxide, tpdpb(=O)2, were also prepared, and comparison of their photophysical properties for the EuIII complexes revealed that significant chiral induction from the P-chiral centers arises on the achiral M(hfa)3 units through intramolecular π-π stacking constraint in the dinuclear system. 相似文献
2.
The normal impact of single water drops onto a plane water surface was studied experimentally to reveal the amount of secondary drops produced from the rim of crown-like interfacial structure. Within the experimental ranges tested, the ratio of the total mass of secondary drops to the mass of primary drop was approximately within 0–1 and correlated well as the function of dimensionless parameter K that consisted of the impact Weber number We and the Ohnesorge number Oh (K = We Oh
−0.4). The dependences of the number and the mean diameter of secondary drops on K and dimensionless film thickness were also investigated. 相似文献
3.
Dr. Masanori Shigeno Takuya Okawa Masaya Imamatsu Kanako Nozawa-Kumada Yoshinori Kondo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(44):10294-10297
We herein demonstrate that the amide base generated in situ from CsF and N(TMS)3 catalyzes the deprotonative coupling reactions of terminal alkynes with polyfluoroarenes, wherein mono- and dialkynylations occur efficiently for penta- and hexafluorobenzenes, respectively. Tetraalkynylated products could also be synthesized from dialkynylated compounds. 相似文献
4.
Shinpei Okawa Takeshi Hirasawa Ryota Sato Toshihiro Kushibiki Miya Ishihara Toshiharu Teranishi 《Optical Review》2018,25(3):365-374
Gold nanoparticles (AuNPs) are used as a contrast agent of the photoacoustic (PA) imaging. The efficiency of AuNPs has been discussed with the absorption cross section. However, the effects of the scattering of the light by AuNPs and surrounding medium on the PA signal from AuNPs have not been discussed. The PA signals from the aqueous solution of AuNPs were examined in the numerical simulation and the experiment. In the numerical simulation, the absorption and scattering cross sections of spherical and polyhedral AuNPs were calculated by Mie theory and discrete dipole approximation. Monte Carlo simulation calculated the absorbed light energy in the aqueous solution of AuNPs. Based on the PA wave equation, the PA signals were simulated. In the experiment, the PA signal from the aqueous solution of AuNP was measured by use of a piezoelectric film and a Q-switched Nd:YAG laser operated at 532 nm. The results of the numerical simulation and the experiment agreed well. In the numerical simulation and the experiment, a single Au nanocube with 50-nm edge generated the peak value of the PA signal significantly. It was approximately 350 times and twice as large as the peak values of the spherical AuNPs with 10- and 50-nm diameters, respectively. The peak value of the PA signal depended on both the absorption and scattering coefficients of the AuNPs and the surrounding medium. The peak value increased with the scattering coefficient in a quadratic manner. The character of the temporal profile of the PA signal such as full width at half maximum depended on the scattering coefficient of the AuNPs. 相似文献
5.
6.
Shinnosuke Okawa 《Advances in Mathematics》2011,(5):2869
We show that the bounded derived category of coherent sheaves on a smooth projective curve except the projective line admits no non-trivial semi-orthogonal decompositions. 相似文献
7.
Tetsu Hanmura Masahiko Ichihashi Ryuji Okawa Tamotsu Kondow 《International journal of mass spectrometry》2009,280(1-3):184
Reactions of NO molecules on cobalt cluster ions were studied in a beam-gas geometry by using a tandem mass spectrometer. Single-particle collision reactions of ComNO+ (m = 3–10) with NO were found to proceed in such a manner that NO decomposition dominates at m = 4–6 with the maximum reaction cross section at m = 5 and chemisorption dominates in m ≥ 7. On the other hand, in two-particle collision reactions of Con+ (n = 2–10) with NO, NO decomposition at n ≥ 5 and chemisorption of two NO molecules with Co atoms loss at n ≥ 8 were found to proceed. These results indicate that the size-dependency of the multiple collision reactions originates from secondary attacking of an NO molecule to primary products of the initial single collision reactions. The DFT calculation supports the scheme that both the decomposition and chemisorption of two-particle collision reactions proceed via a common intermediate, ComN2O2+, in which the two NO molecules are dissociatively chemisorbed on the cobalt cluster ion, and the size-dependency of the two-particle collision reactions is explained in terms of the structure of this reaction intermediate. 相似文献
8.
The sensing characteristics of an amperometric NOx sensor with yttria-stabilized zirconia and a La-based perovskite-type oxide
sensing electrode were examined. La1-xSrxMO3 (M = Co, Mn, x = 0, 0.2, 0.4, 0.6) were synthesized using the spray pyrolysis method. The NO2 response of a sensor fabricated with La1-xSrxMnO3 increased with increasing amount of Sr, and the trend was in contrast to that of the sensors fabricated with La1-xSrxCoO3. LaSr0.2MnO3 was determined to be the most appropriate material for the sensor in terms of a high NO2 response and low O2 current. In order to discuss the effects of Sr addition to La-based perovskite oxides for the sensor, NO adsorption and desorption
properties of oxides and the relationship between the oxidation number of the B-site cation and Sr substitution were examined
using temperature-programmed desorption and X-ray photoelectron spectroscopy, respectively. 相似文献
9.
Shojiro MakiMakiko Okawa Toshimichi MakiiTakashi Hirano Haruki Niwa 《Tetrahedron letters》2003,44(18):3717-3721
A catalyst deposited on a polypropylene sheet having an activity of almost the same level as commercially available Pd black and capable of promoting hydrogenolysis-free hydrogenation was developed. 相似文献
10.
Fluorescence resonance energy transfer by quencher adsorption into hydrogels containing fluorophores
Kaori Okawa Takashi Miyata Tadashi Uragami 《Journal of Polymer Science.Polymer Physics》2006,44(22):3245-3252
We synthesized anionic hydrogels containing fluorophores and investigated the adsorption of a cationic quencher having an amino group into hydrogels by fluorescence resonance energy transfer (FRET). FRET from the fluorophore to the quencher in hydrogels was examined by fluorescence intensity and fluorescence decay using a fluorescence spectrophotometer and femtosecond laser spectroscopy. The fluorescence intensity of the fluorophore‐containing hydrogels decreased rapidly with increasing amounts of adsorbed cationic quencher. The fluorescence emission of the fluorophore in the quencher‐adsorbed hydrogels containing fluorophores decayed more rapidly than that of the original hydrogels. The aforementioned result indicates that the fluorescence of the fluorophore‐containing hydrogels is quenched due to FRET from the fluorophore to the quencher as the cationic quenchers can approach the fluorophores in hydrogels by electrostatic interactions. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3245–3252, 2006 相似文献