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排序方式: 共有123条查询结果,搜索用时 46 毫秒
101.
Dr. Yukihiro Yoshida Kazuhide Isomura Prof. Hideo Kishida Yoshihide Kumagai Prof. Motohiro Mizuno Dr. Masafumi Sakata Dr. Takashi Koretsune Dr. Yoshiaki Nakano Prof. Hideki Yamochi Dr. Mitsuhiko Maesato Prof. Gunzi Saito 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(17):6023-6030
Coronene, which is the smallest D6h‐symmetric polycyclic aromatic hydrocarbon, attracts particular attention as a basic component of electronic materials because it is the smallest fragment of graphene. However, carrier generation by physical methods, such as photo‐ or electric field‐effect, has barely been studied, primarily because of the poor π‐conduction pathway in pristine coronene solid. In this work we have developed unprecedented π‐stacking columns of cationic coronene molecules by electrochemical hole‐doping with polyoxometallate dianions. The face‐to‐face π–π interactions as well as the partially charged state lead to electrical conductivity at room temperature of up to 3 S cm?1, which is more than 10 orders of magnitude higher than that of pristine coronene solid. Additionally, the robust π–π interactions strongly suppress the in‐plane rotation of the coronene molecules, which has allowed the first direct observation of the static Jahn–Teller distortion of cationic coronene molecules. 相似文献
102.
Dr. Shunpei Hitosugi Dr. Sota Sato Dr. Taisuke Matsuno Dr. Takashi Koretsune Dr. Ryotaro Arita Prof. Dr. Hiroyuki Isobe 《Angewandte Chemie (International ed. in English)》2017,56(31):9106-9110
Cylinder-shaped graphitic networks in carbon nanotubes have attracted interest from scientists in various disciplines. The chemical synthesis of segments thereof is considered as a challenging and appealing subject in chemistry, and deepens our understanding of curved and conjugated arrays of hexagons. We herein report the synthesis of cylinder-shaped molecules containing non-hexagon bridges in their conjugated systems. Multiple pentagon units were embedded in the cylinder-shaped discrete molecules, and the stereoisomerism originating from their helical carbon arrangements was studied. Structural analysis by NMR, UV/Vis absorption spectroscopy, and single-crystal X-ray diffraction provided fundamental experimental information on the curved systems with conjugation across the pentagons. This study provides the first experimental guide for further explorations of anomalous non-hexagon arrays of graphitic carbon materials with cylindrical shapes. 相似文献
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105.
Ryoko Shimada Yuri Komori Takao Koda Toru Fujimura Tadashi Itoh Kazuo Ohtaka 《Molecular Crystals and Liquid Crystals》2013,570(1):5-8
Abstract Quasi two-dimensional (2D) photonic band structures have been investigated on ordered polystyrene particle layers by means of polarized transmission spectra for oblique incidence of light. The results are discussed in terms of quasi-2D photonic band effect. 相似文献
106.
Shinsuke Inagaki Masahiko Numata Yuko Kitamaki Nobuyasu Hanari Ryoko Iwasawa 《Accreditation and quality assurance》2016,21(5):361-366
The National Metrology Institute of Japan has issued a certified reference material of biodiesel fuel derived from palm oil (NMIJ CRM 8302-a) for the measurement and quality control of water, methanol, six elements (sulfur, phosphorus, sodium, potassium, magnesium, and calcium), density, and kinematic viscosity. This paper presents the technical details for the characterization of the water content in NMIJ CRM 8302-a. Because the water content in biodiesel is easily affected by ambient humidity, sample handling is extremely difficult. Thus, a sample handling technique that overcomes this limitation was established, and optimized coulometric and volumetric Karl Fischer titrations were performed in order to accurately determine the water content with traceability to the International System of Units. The certified water content and its expanded uncertainty with a coverage factor k = 2 were 393 mg kg?1 and 25 mg kg?1, respectively. 相似文献
107.
Sun K Suzuki N Li Z Araki R Ueno K Juodkazis S Abe M Noji S Misawa H 《Electrophoresis》2008,29(19):3959-3963
A microchannel chip has been used to fractionate selected segments from an electrophoretic flow of separated fragments. A sample, which covers the size from 35 to 670 bp, was initially separated using an 8.8-cm-long channel at the electric field strength of 100 V/cm. The target fragment of 318 bp was selected and extracted from the separation channel. High-resolution fractionation was achieved by introducing new procedures for blocking, extraction, and segment transfer. Fractionation quality with and without blocking were compared using a 310 Genetic Analyzer (Applied Biosystems). The results show that no contamination was found in the sample, which was fractionated with blocking; however, a contamination by short segments was found in the sample, which was fractionated without blocking. Furthermore, fractionation by the chip was found to be of higher fidelity than that by the polyacrylamide slab gel, which displayed a small overlapped peak after the target peak. Compared with the traditional method, our chips enable faster and high-fidelity fractionation, thus providing a new tool for bioanalysis and other applications. 相似文献
108.
Mugitani R Fais L Kajikawa S Werker JF Amano S 《The Journal of the Acoustical Society of America》2007,122(3):1332
Japanese infants at the ages of 6, 12, and 18 months were tested on their ability to discriminate three nonsense words with different phonotactic status: canonical keetsu, noncanonical but possible keets, and noncanonical and impossible keet. The results showed that 12 and 18 months olds discriminate the keets/keetsu pair, but infants in all age groups fail to discriminate the keets/keet pair. Taken together with the findings in our previous study [Kajikawa et al., J. Acoust. Soc. Am. 120(4), 2278-2284 (2006)], these results suggest that Japanese infants develop the perceptual sensitivity for native phonotactics after 6 months of age, and that this sensitivity is limited to canonical patterns at this early developmental stage. 相似文献
109.
Nobuyasu Hanari Nobuyasu Itoh Taichi Yamazaki Naomi Fujiki Ryoko Iwasawa Masahiko Numata 《Accreditation and quality assurance》2013,18(2):137-142
The composition of impurities in perfluorooctanoic acid (PFOA) was measured and determined to be notably different between lots. Since the purity of PFOA varied, the accuracy of prepared calibration solution concentrations was reduced. In this study, factors influencing the purity were investigated using a Karl Fischer titrator and a LC/MS to support the development of reference materials. The results showed variances of water and isomer/homologue contents under different ambient conditions during sample handling. Moreover, these variances, especially for water, greatly affected the purity of PFOA (0.95–0.99 kg kg?1). Therefore, PFOA of reliable purity should be used for the preparation of calibration solutions. 相似文献
110.
Nobuyasu Hanari Ryoko Iwasawa Satoko Otsuka Naomi Fujiki Ayako Matsumoto Toshihide Ihara Keiichiro Ishikawa Takashi Yarita 《Accreditation and quality assurance》2010,15(12):673-679
Water content variation of candidate p-n-heptylphenol (HP) reference material (ampoule form) for preparation of a primary standard solution based on the Japan Calibration
Service System, a national standards dissemination system, under the Measurement Law of Japan, was examined by a Karl-Fischer
water content meter. As prepared samples, liquid-phase HP and upper, middle, and lower layers of solid-phase HP were measured
since characteristic phase transition occurs near room temperature (melting point: 28.98 °C). As a result of water content
in liquid- and solid-phase HP, water content variation among three layers of solid-phase is found in within ampoules, though
water content variation of liquid-phase is not found. Between-ampoule variation of water content is also found using total
ampoules of liquid-phase HP used to eliminate within-ampoule variation. Moreover, water content variation is secondarily confirmed
by the results of the amount-of-substance fraction of HP based on a differential scanning calorimeter. From these results
in this study, it is concluded that within- and between-ampoule variations of water content may depend on phase transition
and water loss during ampouling of candidate reference material, respectively. 相似文献