全文获取类型
收费全文 | 265篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
化学 | 188篇 |
晶体学 | 7篇 |
力学 | 1篇 |
数学 | 4篇 |
物理学 | 70篇 |
出版年
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2016年 | 5篇 |
2015年 | 1篇 |
2013年 | 7篇 |
2012年 | 9篇 |
2011年 | 11篇 |
2010年 | 10篇 |
2009年 | 9篇 |
2008年 | 11篇 |
2007年 | 14篇 |
2006年 | 23篇 |
2005年 | 16篇 |
2004年 | 14篇 |
2003年 | 21篇 |
2002年 | 8篇 |
2001年 | 7篇 |
2000年 | 8篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 11篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1968年 | 1篇 |
1932年 | 1篇 |
1931年 | 2篇 |
1923年 | 2篇 |
排序方式: 共有270条查询结果,搜索用时 31 毫秒
71.
Itoh K Nishizawa T Yamagata J Fujii M Osaka N Kudryashov I 《The journal of physical chemistry. B》2005,109(1):264-270
Raman microspectroscopy was applied to study the polymerization kinetics of the Langmuir-Blodgett (LB) films of 10,12-pentacosadiynoic acid (DA) adsorbed on surface enhanced Raman scattering (SERS) active Ag island films. A two-dimensional (2D) Raman microscopic image measured at 1520 cm(-1) exhibits bright and dim spots with the diameter of several hundred nanometers. Raman microscopic spectra, measured by defocusing the excitation laser light (532 nm, diameter of ca. 10 mum) on the samples at room temperature, proved the occurrence of the surface processes consisting of the formation of polydiacetylene (PDA) in the blue phase, its conversion to the red phase, and subsequent bleaching. These reactions were negligible under the same condition for the DA-LB films prepared on a smooth (i.e., SERS-inactive) Ag film, indicating that the 532-nm-induced polymerization and the bleaching process are enhanced by the SERS-active substrates. At low temperatures below -50 degrees C, the Raman microscopic measurements proved the formation of the blue phase and its conversion to the red phase with much lower reaction rates compared to the corresponding rates at room temperature. The bleaching, however, was much suppressed at the low temperatures. The kinetic analyses of the formation of the blue phase and its conversion to the red phase were performed by using the intensity changes of the Raman bands due to the blue (1477 cm(-1)) and red (1517 cm(-1)) phases as a function of the irradiation time. The results strongly suggested the existence of at least two processes taking place simultaneously on the SERS-active substrates; that is, one of the processes is a sequential reaction, DA-monomers --> PDA in the blue phase --> PDA in the red phase, and the other is another sequential reaction, DA-monomers --> PDA in the red phase --> degradation species (probably amorphous carbon). Thus, even at the low temperatures, there occurs the surface reaction consisting of the formation of PDA and its degradation. The reaction can be ascribed to a process taking place at the highly SERS-active site, which gives the bright spot (so-called "hot spot") on the 2D Raman image, as proved by the confocal Raman microscopic measurement in the following paper. 相似文献
72.
Kaoru Dokko Soichi Horikoshi Takashi Itoh Matsuhiko Nishizawa Takayuki Abe Minoru Umeda Isamu Uchida 《Journal of Solid State Electrochemistry》2002,6(3):188-193
A microelectrode technique was applied to investigate the electrochemical properties of LiMn2O4 particles at elevated temperatures. Cyclic voltammograms of LiMn2O4 were measured after the particles were exposed to the electrolytes. This technique results in rapid and precise evaluation
of the redox behavior of the materials. A significant capacity fading was observed in 1 M LiPF6/EC+PC electrolytic solution, which indicates that both LiMn2O4 and LiPF6 participate in the reaction to produce an inert material on the particle surface. Next, the capacity fading for two different
BET surface area particles were compared using 1 M LiPF6/EC+PC at 50 °C. The reaction was found not to be controlled by the surface area. Finally, a Li1.1Mn1.9O4 particle was employed. The fading in discharge was ca. 10% for 50 cycles even at 50 °C, which means that the partial substitution
of Mn in LiMn2O4 by Li substantially enhanced the capacity stability.
Electronic Publication 相似文献
73.
Course of cyclization of dienols, polyenes, and dienyne mediated by mercuric salts were controlled by stability of cationic intermediates and source of mercuric salts. Reaction of (E)-5,9-dimethyl-4,8-decadiene-1-ol with mercuric acetate gave the intramolecular oxymercuration product, whereas one with mercuric triflate produced the olefin cyclization products. 相似文献
74.
Tomoaki Nishizawa Nobuo Sugimoto Atsushi Shimizu 《Journal of Quantitative Spectroscopy & Radiative Transfer》2011,112(2):254-267
We developed backward and forward types of algorithms for estimating the vertical profiles of extinction coefficients at 532 nm for three component aerosols (water-soluble, dust, and sea salt) using three-channel Mie-scattering lidar data of the backscatter (β) at 532 and 1064 nm and the depolarization ratio (δ) at 532 nm. While the water-soluble and sea-salt particles were reasonably assumed to be spherical, the dust particles were treated as randomly oriented spheroids to account for their nonsphericity. The introduction of spheroid models enabled us to more effectively use the three-channel data (i.e., 2β+1δ data) and to reduce the uncertainties caused by the assumption of spherical dust particles in our previously developed algorithms. We also performed an extensive sensitivity study to estimate retrieval errors, which showed that the errors in the extinction coefficient for each aerosol component were smaller than 30% (60%) for the backward (forward) algorithm when the measurement errors were ±5%. We demonstrated the ability of the algorithms to partition aerosol layers consisting of three aerosol components by applying them to shipborne lidar data. Comparisons with sky radiometer measurements revealed that the retrieved optical thickness and angstrom exponent of aerosols using the algorithms developed in this paper agreed well with the sky radiometer measurements (within 6%). 相似文献
75.
76.
77.
78.
Ryuhei Harada Ryunosuke Yoshino Hiroaki Nishizawa Yasuteru Shigeta 《Journal of computational chemistry》2019,40(15):1530-1537
Outlier flooding method (OFLOOD) is an efficient conformational sampling method developed by the authors. In the present study, to further enhance the conformational sampling efficiency, a set of parameters (temperatures and pressures) specified as inputs in the original OFLOOD were shuffled before restarting the short-time molecular dynamics (MD) simulations. Because of the diversity of these parameters, it was confirmed that the extended OFLOOD becomes superior to the original one in finding the folding pathways of Trp-cage. © 2019 Wiley Periodicals, Inc. 相似文献
79.
Nishizawa S Sankaran NB Seino T Cui YY Dai Q Xu CY Yoshimoto K Teramae N 《Analytica chimica acta》2006,556(1):133-139
In combination with abasic site (AP site)-containing DNAs, potential use of a biotic fluorescence compound, Vitamin B2 (riboflavin), is demonstrated for the fluorescence detection of the thymine (T)-related single-nucleotide polymorphisms. Our method is based on construction of the AP site in DNA duplexes, which allows small ligands to bind to target nucleotides accompanied by fluorescence signaling: an AP site-containing probe DNA is hybridized with a target DNA so as to place the AP site toward a target nucleobase, by which hydrophobic microenvironments are provided for ligands to recognize target nucleotides through stacking and hydrogen-bonding interactions. In 10 mM sodium cacodylate buffer solutions (pH 7.0) containing 100 mM NaCl and 1.0 mM EDTA, Vitamin B2 is found to selectively bind to T (K11 = 1.8 × 106 M−1 at 5 °C) over other nucleobases, and this is accompanied by significant quenching of its fluorescence. While the sensing functions depend on the flanking sequences to the AP site, Vitamin B2 is applicable to the detection of T/C (cytosine), T/G (guanine) and T/A (adenine) mutation sequences of the CYP2A6 gene, where the flanking nucleobases are guanines in both positions (-GXG-, X = AP site). 相似文献
80.
Nishizawa T Grüschow S Jayamaha DH Nishizawa-Harada C Sherman DH 《Journal of the American Chemical Society》2006,128(3):724-725
Rebeccamycin is a member of the family of indolocarbazole antibiotics with broad spectrum antitumor activity. The indolocarbazole framework is derived from two molecules of tryptophan, but very little is known about the enzymes involved in rebeccamycin biosynthesis. Here, we show that RebD is responsible for all catalytic steps forming the central pyrrole ring of chlorochromopyrrolic acid from two molecules of chloroindolepyruvic acid. This transformation does not require any additional cofactors and constitutes the first step of bis-indole formation in the biosynthesis of rebeccamycin. 相似文献