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排序方式: 共有195条查询结果,搜索用时 42 毫秒
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The yellow compounds pyoverdins were isolated from Pseudomonas chlororaphis, which was isolated from mud in Japan. Degradation of tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) by pyoverdin (20 mg) was carried in sea water (30 ml) containing a 6 µg l?1 concentration of TBT, DBT, and MBT at 24 °C for 24 h in aerobic conditions. TBT, DBT, and MBT in sea water were analyzed by gas chromatography–mass spectrometry in selected ion monitoring mode. DBT in sea water was degraded to MBT by pyoverdins isolated from P. chlororaphis. However, TBT and MBT in sea water was not degraded by pyoverdins. The optimum degradation of DBT in sea water was at pH 4.8–8.2, at a temperature 25–30 °C. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
104.
Catalytic Cracking of Naphtha to Light Olefins 总被引:6,自引:0,他引:6
Y. Yoshimura N. Kijima T. Hayakawa K. Murata K. Suzuki F. Mizukami K. Matano T. Konishi T. Oikawa M. Saito T. Shiojima K. Shiozawa K. Wakui G. Sawada K. Sato S. Matsuo N. Yamaoka 《Catalysis Surveys from Japan》2001,4(2):157-167
A catalytic process that produces light olefins from naphtha was developed to improve the yield of the conventional steam cracker. In laboratory-scale tests, a newly developed zeolite-based catalyst at a reaction temperature of 650°C produced an ethylene-plus-propylene yield of about 60%, which is about 10% higher than the conventional process operated at around 820°C. A feasibility study carried out for a catalytic cracking process using the developed catalyst, that cracks 3000 tons-naphtha/day, indicated an energy saving of about 20% compared with the conventional process. 相似文献
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Ueda K Kitajima M De Fanis A Tamenori Y Yamaoka H Shindo H Furuta T Tanaka T Tanaka H Yoshida H Sankari R Aksela S Fritzsche S Kabachnik NM 《Physical review letters》2003,90(15):153005
Using very high resolution achieved by the Doppler-free resonant Raman Auger technique, we have resolved the lowest terms of the series of inner-valence excitations 2s2p(5)((1,3)P)np 2S, 2P, and 2D in Ne+. The measured Auger anisotropic parameters and branching ratios help to establish the assignments of these levels. The measured lifetime widths are in reasonable agreements with ab initio calculations available in the literature. 相似文献
107.
Organocatalytic Activation of the Leaving Group in the Intramolecular Asymmetric SN2′ Reaction
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Yusuke Kuroda Dr. Shingo Harada Akinori Oonishi Dr. Yousuke Yamaoka Prof. Dr. Ken‐ichi Yamada Prof. Dr. Kiyosei Takasu 《Angewandte Chemie (International ed. in English)》2015,54(28):8263-8266
A Brønsted‐acid‐catalyzed intramolecular enantioselective SN2′ reaction was developed utilizing trichloroacetimidate as a leaving group. The findings indicated that dual activation of the substrates is operative. This metal‐free allylic alkylation allows highly enantioselective access to 2‐vinylpyrrolidines bearing various substituents. 相似文献
108.
Naoto Yamaoka 《Journal of Mathematical Analysis and Applications》2007,325(2):932-948
This paper is concerned with the oscillation problem for the nonlinear differential equation with a damping term,
109.
The sensitization mechanisms of a pyrromethene dye with a radical‐generating reagent, 3,5,3′,5′‐tetramethylpyrromethene‐BF2 (BH) with 3,3′,4,4′‐tetrakis(t‐butyldioxycarbonyl)benzophenone (BP), in a poly‐ (methylmethacrylate) (PMMA) film were investigated by laser flash phoptolysis using a total reflection cell and single photon counting. From the laser flash photolysis, strong fluorescence was detected though no transient absorption was detected. The fluorescence intensity was significantly decreased with increasing concentration of BP, apparently exhibiting Perrin‐type static quenching at a quenching radius, Rf = 26 Å. From the examination of decay profile using single photon counting, logarithmic plots of fluorescence decay in a PMMA film afforded a nonlinear, convex reduction, corresponding to a streched exponential decay, while the logarithmic plots in acetonitrile showed a linear relationship. With increasing concentration of BH, the fluorescence maximum was shifted to red, and the intensity of fluorescence was significantly reduced. The red shift of fluorescence, the nonlinear fluorescence logarithmic decay and the large reduction in fluorescence indicate a dispersive photoexcited state and a relaxation of excitation energy hopping across an array of sites with Gaussian energy distribution. Moreover, after incorporating BP, the convex logarithmic plots became more steep, and the fluorescence maximum was also shifted to red, exhibiting a nonstatic quenching process competitive to the excitation energy hopping. Thus the sensitization of photoinitiator system containing BH and BP, whose contents were almost same as that in the commercial products, was due to a static quenching process from dispersive singlet excited BH to BP ground state, and the nonstatic quenching process competitive to the excitation energy hopping was minimal. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
110.
Takanori Takahashi Kazuhiro Ikegaya Hirohmi Watanabe Nobukazu Miyagawa Shigeru Takahara Tsuguo Yamaoka 《先进技术聚合物》2000,11(6):307-315
A novel water‐dispersible reactive microgel, which had a diameter of 40–90 nm, was synthesized for photopolymer materials. The microgels have segments with substituted ammonium groups, to provide water solubility, in their polymer networked structure. It has unsaturated groups connected to the quaternary nitrogens by ionic bonding (I‐type microgel). The I‐type microgel was compared with one that has methacryloyl groups connected with the quaternary nitrogens of the microgel by covalent bonding (C‐type microgel). The I‐type microgels were able to separately control the modified amount of quaternary nitrogen and methacryloyl group. In the presence of 2,4‐diethylthioxantone as a photoinitiator and pentaerthritol triacrylate as a crosslinker, the photopolymer containing the C‐type or I‐type microgels had sensitivity high enough for practical use. Not only the amount of the methacryloyl group of the microgel but the amount of the quaternary nitrogen affected the sensitivity and the rate of polymerization of the water‐dispersible photopolymer containing the I‐type microgels. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献