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111.
Interface-selective, Raman-based observation of molecular vibrations is demonstrated at a liquid-liquid interface. An aqueous solution of oxazine 170 dye interfaced with hexadecane is irradiated with pump and probe light pulses of 630-nm wavelengths in 17-fs width. The ultrashort pulses are broadened due to group velocity dispersion when traveling through the hexadecane layer. The dispersion is optically corrected to give an optimized instrumental response. The pump pulse induces a vibrational coherence of the dye via impulsive stimulated Raman scattering. The probe pulse generates second-harmonic light at the interface. The efficiency of the generation is modulated as a function of the pump-probe delay by the coherently excited molecules. Fourier transformation of the modulated efficiency presents the frequency spectrum of the vibrations. Five bands are recognized at 534, 557, 593, 619, and 683 cm(-1). The pump-and-probe process induces a fourth-order optical response that is forbidden in a centrosymmetric media. The contribution of an undesired, cascaded optical process is quantitatively considered and excluded. 相似文献
112.
1-Siloxy-1-alkenylcopper species were generated by 1,2-Csp2-to-O silyl migration of the copper enolates of acyltriphenylsilanes. The alkenylcopper species reacted with methyl, benzyl, allylic, and tributylstannyl halides to give geometrically pure (Z)-enol silyl ethers. In the presence of Pd(0) catalyst, the cross-coupling of the alkenyl copper species with aryl and alkenyl iodides also proceeded to give the (Z)-enol silyl ethers with high stereoselectivity. 相似文献
113.
Titanium dioxide (TiO2) (110) surfaces with Pt adatoms were examined using a noncontact atomic force microscope (NC-AFM) and a Kelvin probe force microscope (KPFM). Topographic images with NC-AFM identify Pt atoms adsorbed at three different sites. These sites are on the Ti atom rows, on the O atom rows, and in O atom vacancies. Most Pt adatoms were observed on Ti atom rows. Successively recorded images show that the Pt adatoms on Ti atom rows (adatoms A) and O atom rows (adatoms C) are mobile while the adatoms in the O atom vacancies (adatoms B) are not. Adatoms A and adatoms B were identified in KPFM images. However, adatoms C were not visualized in KPFM images because they moved quickly or were swept out by the tip. The KPFM measurements reveal that the work function on adatoms A are lower than that on the surrounding (1 x 1) surface by 0.24 eV whereas adatoms B reduced the work function by 0.26 eV. The work function decrease is interpreted with an electric dipole moment directed toward the vacuum, as a result of electron transfer from the adatoms to the TiO2 substrate. In an O atom vacancy, the adatom B is in contact with two Ti atoms and therefore the electron transfer can be enhanced. 相似文献
114.
Tsutomu Mizuta Makoto Onishi Tohru Nakazono Hiroshi Nakazawa Katsuhiko Miyoshi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8-9):2157-2158
A reaction of CpMn(CO) 2 (fcpp) (fcpp = 1,1'-ferrocenediylphenylphosphine) with Pt(PPh 3 ) 4 gave an Mn-Pt dinuclear complex, which reacted with HC L CPh to give CpMn(CO) 2 {PPh(ferroccene)(C L CPh)}. 相似文献
115.
Masashi Onishi Tomonori Kashiwada Yoichi Ishiguro Yasushi Koyano Masayuki Nishimura Hiroo Kanamori 《Fiber and Integrated Optics》1997,16(3):277-285
An optimum fiber structure for a practical dispersion-compensating fiber (DCF) has been explored theoretically and experimentally, taking dispersion, attenuation, bending loss characteristics, polarization mode dispersion, and nonlinear effects into account. A high figure of merit (FOM) of 280 ps/nm/dB has been successfully achieved with a simple matched cladding design. Furthermore, it was confirmed that the optimized structure with enhanced FOM also benefits self-phase modulation (SPM) suppression. 相似文献
116.
Kecheng Jie Nicole Onishi Jennifer A. Schott Ilja Popovs De‐en Jiang Shannon Mahurin Sheng Dai 《Angewandte Chemie (International ed. in English)》2020,59(6):2268-2272
Porous liquids are a type of porous materials that engineer permanent porosity into unique flowing liquids, exhibiting promising functionalities for a variety of applications. Here a Type I porous liquid is synthesized by transforming porous organic cages into porous ionic liquids via a supramolecular complexation strategy. Simple physical mixing of 18‐crown‐6 with task‐specific anionic porous organic cages affords a porous ionic liquid with anionic porous organic cages as the anionic parts and 18‐crown‐6/potassium ion complexes as the cationic parts. In contrast, mixing of 15‐crown‐5 and anionic porous organic cages in a 2:1 ratio gives only solids, while the addition of excess 15‐crown‐5 affords a Type II porous liquid. The permanent porosity in the cage‐based porous liquids has been also confirmed by molecular simulation, positron (e+) annihilation lifetime spectroscopy, and enhanced gas sorption capacity compared with pure crown ethers. 相似文献
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119.
Tomoaki Masuzawa Masanori Onishi Ichitaro Saito Takatoshi Yamada Angel T. T. Koh Daniel H. C. Chua Shuichi Ogawa Yuji Takakuwa Yusuke Mori Tatsuo Shimosawa Ken Okano 《固体物理学:研究快报》2013,7(7):473-476
High‐sensitivity ultraviolet (UV) photodetection has been attempted by utilizing the carrier multiplication effect in amorphous selenium. The prototype photodetector presented in this Letter showed an extremely high sensitivity to UV light, so that up to 1000 carriers are generated per incident photon. This result should lead to the development of an ultrahigh‐sensitivity photodetector that can be used for spectrometric applications covering the visible to UV region. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
120.
Kazuaki Ninomiya Hiromi Takamatsu Ayaka Onishi Kenji Takahashi Nobuaki Shimizu 《Ultrasonics sonochemistry》2013,20(4):1092-1097
The present study demonstrated that the combined use of the sonocatalytic reaction (using ultrasound and titanium dioxide) and the Fenton reaction exhibited synergistically enhanced hydroxyl (OH) radical generation. Dihydroxybenzoic acid (DHBA) concentration as index of OH radical generation was 13 and 115 μM at 10 min in the sonocatalytic reaction and Fenton reaction, respectively. On the other hand, the DHBA concentration was 378 μM at 10 min in the sonocatalytic–Fenton reaction. The sonocatalytic–Fenton reaction was used for degradation of lignin. The lignin degradation ratio was 1.8%, 49.9%, and 60.0% at 180 min in the sonocatalytic reaction, Fenton reaction, and sonocatalytic–Fenton reaction, respectively. Moreover, the sonocatalytic–Fenton reaction was applied to pretreatment of lignocellulosic biomass to enhance subsequent enzymatic saccharification. The cellulose saccharification ratio was 11%, 14%, 16% and 25% at 360 min of pretreatment by control reaction, the sonocatalytic reaction, Fenton reaction, and sonocatalytic–Fenton reaction, respectively. 相似文献