全文获取类型
收费全文 | 168篇 |
免费 | 22篇 |
国内免费 | 1篇 |
专业分类
化学 | 169篇 |
晶体学 | 1篇 |
数学 | 1篇 |
物理学 | 20篇 |
出版年
2024年 | 1篇 |
2022年 | 1篇 |
2021年 | 6篇 |
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 1篇 |
2016年 | 10篇 |
2015年 | 9篇 |
2014年 | 7篇 |
2013年 | 6篇 |
2012年 | 16篇 |
2011年 | 11篇 |
2010年 | 6篇 |
2009年 | 9篇 |
2008年 | 8篇 |
2007年 | 18篇 |
2006年 | 12篇 |
2005年 | 8篇 |
2004年 | 12篇 |
2003年 | 2篇 |
2002年 | 6篇 |
2001年 | 3篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1991年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 1篇 |
排序方式: 共有191条查询结果,搜索用时 31 毫秒
91.
Dr. Zhiou Li Dr. Yoshihisa Sei Prof. Munetaka Akita Dr. Michito Yoshizawa 《化学:亚洲杂志》2014,9(4):1016-1019
A fluorescent macrocycle containing four anthracene panels linked by meta‐phenylene spacers and amino hinges was synthesized. The macrocycle adopts a twisted, compressed conformation that places embedded anthracene fluorophores in close contact. Emission from the convoluted macrocycle is highly solvatochromic and significantly enhanced as compared with that of the partial structures. 相似文献
92.
We recently found that [Eu(pda)2]? (pda: 1,10‐phenanthroline‐2,9‐dicarboxylic acid), which has an achiral structure in crystals, exhibits circularly polarized luminescence (CPL) in aqueous solutions containing chiral amino acids such as arginine and histidine. CPL measurements were performed for agar gel, which includes an aqueous solution of [Eu(pda)2]? and chiral arginine or histidine. The spectral shape, concentration, and pH dependences on CPL intensity in the agar gels were very close to those in aqueous solutions, indicating that the CPL of the EuIII complex in the agar gels was induced by mechanism similar to that in aqueous solutions. We performed spatially resolved CPL measurements using a laboratory‐built microscopic CPL spectroscopic system for agar‐gel samples, where d ‐ and l ‐ amino acids were separately dispersed. We successfully recorded CPL imaging maps showing spatial dispersions of d ‐ and l ‐amino acid in the agar gels. 相似文献
93.
Masafumi Yano Shohei Tsuda Masakazu Tatsumi Munetaka Oyama Kazunobu Sato Takeji Takui 《Polyhedron》2009,28(9-10):1883-1887
A triamine, 2,2′,4,4′-tetrabromo-3″,4″-dimethyl-5,5′-bis(di(4-methylphenyl)amino)triphenylamine, was designed and synthesized as a model precursor for purely organic cationic high-spin systems. Cyclic voltammetry measurements revealed that the triamine gives stable mono-, di-, and tricationic states at ambient temperature. Novel electron transfer stopped-flow (ETSF) methods were invoked for characterizing the absorption spectra of the corresponding mono- and oligo-cationic states. The triamine-based trication was generated by chemical oxidation at room temperature, and the triamine was quantitatively recovered upon reduction. The electronic ground state of the trication is discussed. 相似文献
94.
Raman spectroscopy and control charts based on the net analyte signal (NAS) were applied to polymorphic characterization of carbamazepine. Carbamazepine presents four polymorphic forms: I-IV (dihydrate). X-ray powder diffraction was used as a reference technique. The control charts were built generating three charts: the NAS chart that corresponds to the analyte of interest (form III in this case), the interference chart that corresponds to the contribution of other compounds in the sample and the residual chart that corresponds to nonsystematic variations. For each chart, statistical limits were developed using samples within the quality specifications. It was possible to identify the different polymorphic forms of carbamazepine present in pharmaceutical formulations. Thus, an alternative method for the quality monitoring of the carbamazepine polymorphic forms after the crystallization process is presented. 相似文献
95.
The effect of surface modification of indium tin oxide (ITO) by multi wall carbon nanotube (MWNT) and gold nanoparticles attached multi wall carbon nanotube (AuNP-MWNT) has been studied to determine tryptophan, an important and essential amino acid for humans and herbivores. A detailed comparison has been made among the voltammetric response of bare ITO, MWNT/ITO and AuNP-MWNT/ITO in respects of several essential analytical parameters viz. sensitivity, detection limit, peak current and peak potential of tryptophan. The AuNP-MWNT/ITO exhibited a well defined anodic peak at pH 7.2 at a potential of ∼669 mV for the oxidation of tryptophan as compared to 760 mV at MWNT/ITO electrode. Under optimum conditions linear calibration curve was obtained over tryptophan concentration range 0.5-90.0 μM in phosphate buffer solution of pH 7.2 with detection limit and sensitivity of 0.025 μM and 0.12 μA μM−1, respectively. The oxidation of tryptophan occurred in a pH dependent, 2e− and 2H+ process and the electrode reaction followed adsorption controlled pathway. The method has been found selective and successfully implemented for the determination of tryptophan in human urine and plasma samples using standard addition method. The electrode exhibited an efficient catalytic response with good reproducibility and stability. 相似文献
96.
Yusuke Hashimoto Munetaka Taguchi Shun Fukami Hiroki Momono Tomohiro Matsushita Hiroyuki Matsuda Fumihiko Matsui Hiroshi Daimon 《Surface and interface analysis : SIA》2019,51(1):115-119
Fe 2p core-level photoelectron spectra of magnetite were measured using soft X-ray and hard X-ray, and its emission angle dependence was investigated. The photoelectron diffraction pattern from different atomic sites differs because the atomic arrangement surrounding each site is different. By selecting the forward-focusing-peak (FFP) directions characteristic to each atomic site and measuring the kinetic energy dependence of the FFP intensities at the Fe 2p core-level range, we succeed in detecting the variation of the peak intensity of Fe 2p core-level spectra at different emission directions. This result, consistent with recent results, suggests that the lower-binding-energy peak of the Fe 2p core-level spectrum may be assigned as the B site component. 相似文献
97.
Kazuki Miyazawa Dr. Takashi Koike Prof. Dr. Munetaka Akita 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(33):11677-11680
A simple and regiospecific aminohydroxylation of olefins by photoredox catalysis has been developed. N‐protected 1‐aminopyridinium salts are the key compounds and serve as amidyl radical precursors by the action of Ir photocatalysts, fac‐[Ir(ppy)3] and [Ir(ppy)2(dtbbpy)](PF6) (ppy=2‐pyridylphenyl, dtbbpy=4,4′‐di‐tert‐butyl‐2,2′‐bipyridine). The present photocatalytic system allows for synthesis of vicinal aminoalcohol derivatives from olefins with various functional groups under mild reaction conditions with easy handling. 相似文献
98.
Masafumi Yano Mitsuru Manabe Masakazu Tatsumi Munetaka Oyama Kazunobu Sato Takeji Takui 《Polyhedron》2009,28(9-10):1935-1939
A starburst-shaped ligand, 4,4′4″-tris[N,N-bis(2-pyridylmethyl) aminomethyl] triphenylamine, and its palladium and copper trinuclear complexes were designed and prepared. NMR techniques, COSY and ROESY, were applied to the palladium complex to examine its conformation in solution. The palladium complex was found to prefer a folded conformation even at 75 °C, indicating the occurrence of strong intramolecular stacking interaction. CV measurements of the palladium complex showed reversible TTA/TTA+ redox couples. ETSF measurements showed that the corresponding radical pendant complex is very unstable. Molecular design rules for triarylamine-based spin bearing ligands are discussed. 相似文献
99.
Kiyonori Kuroda Kohei Yazaki Yuya Tanaka Munetaka Akita Hayato Sakai Taku Hasobe Nikolai V. Tkachenko Michito Yoshizawa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(4):1127-1131
Unlike previously well‐studied, acyclic pentacene oligomers, the first synthesis of a cyclic pentacene trimer with a fixed tubular conformation is reported. A short‐step synthesis starting from common pentacenequinone yielded the target molecule with a 1.5 nanometer length and a subnanometer pore. Steady‐state spectroscopic analyses revealed that the close proximity of the non‐conjugated, three pentacene chromophores allows the nanotube to display stepwise electrochemical/chemical oxidation characteristics. Furthermore, time‐resolved transient absorption measurements elucidated the generation of an excited triplet state of the nanotube, with high quantum yield reaching about 180 % through intramolecular singlet fission and a very long triplet lifetime. 相似文献
100.
Gang Chang Yasuhiko Shimotsuma Masaaki Sakakura Toshirou Yuasa Hidekazu Homma Munetaka Oyama Kiyotaka Miura Jiarong Qiu Peter G. Kazansky Kazuyuki Hirao 《Applied Surface Science》2008,254(16):4992-4998
Metal nanowires with electric conductive properties can be useful for optical polarization control medium and electro-conductive nanomaterial. We report on metallic Cu nanowires with a length of 1.0 μm and a diameter of 85 nm which were successfully photo-converted from commercial scale-like Cu particles, dispersed in a methanol solution, by using femtosecond laser irradiation. The growth mechanism of Cu nanowires under laser irradiation was suggested to be a nucleation growth process. 相似文献