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211.
Motomasa Kobayashi Nam Kyung Lee Byeng Wha Son Kazunori Yanag Yoshimasa Kyogoku Isao Kitagawa 《Tetrahedron letters》1984,25(51):5925-5928
Four new cytotoxic steroids named stoloniferone-a (7a), -b (7b), -c (7c), and -d (7d) were isolated from the stoloniferan Okinawan soft coral Clavularia viridis and their absolute stereostructures were elucidated. 相似文献
212.
Susuki Y Hojo K Okazaki I Kamata H Sasaki M Maeda M Nomizu M Yamamoto Y Nakagawa S Mayumi T Kawasaki K 《Chemical & pharmaceutical bulletin》2002,50(9):1229-1232
A bivalent poly(ethylene glycol) or PEG hybrid of fibronectin-related peptides was prepared. An active site peptide (RGD) and its synergistic site peptide (PHSRN) of fibronectin were conjugated with an amino acid-type PEG (aaPEG) to form PHSRN-aaPEG-RGD. A moderate spatial array between RGD and PHSRN in fibronectin may be required for synergic activity. The bivalent hybrid exhibited potent cell spreading activity and exhibited potent anti-metastatic activity in a model of experimental metastasis with B16-BL6 cells in mice. PEG may serve as a spacer for maintaining the desired spatial array. 相似文献
213.
Mayumi Oyama Shin-ichi Sasaki Mototsugu Yoshida 《Journal of mathematical chemistry》1991,8(1):217-227
The reduction of drawing time is desirable in writing a complex molecular structure by use of a plotter. The stepwise clustering method is applied to find efficient drawing paths for six structures of protein and DNA molecules. All the optimization ratios of path lengths exceed 50%, while the necessary CPU times are of the order of 0.1 second. These results show the effectiveness of the method for molecular graphics. A summary of the algorithm and other possible applications are also discussed. 相似文献
214.
Masaru MouriShigeyasu Kuroda Mitsunori OdaRyuta Miyatake Mayumi Kyogoku 《Tetrahedron》2003,59(6):801-811
The azuleno[1,2-a]acenaphthylene (1a) was prepared from 1-pyrrolidinylacenaphthylene (5) and 2H-cyclohepta[b]furan-2-one (6) by the method of the Takase-Yasunami azulene synthesis. Its 1H and 13C NMR spectra indicate that 1a comprises azulene and naphthalene rather than acenaphtylene and heptafulvene in accordance with speculation drawn from a previous study of the DEPE calculations. The solid-state structure of 1a was elucidated by X-ray crystallographical analysis, indicating that 1a is nearly planar and exhibits little bond alternation as seen in the optimized structure at the MB3LYP/6-311G∗ level of theory. All bond lengths observed by the X-ray analysis are in good agreement within 0.024 Å with those calculated. Under pyrolytic conditions 1a underwent azulene-naphthalene rearrangement to give 9 and 10. The electrophilic substitution of 1a was observed at the 7-position and the second reaction at the 3-position. The cycloaddition reaction of 1a with dimethyl acetylenedicarboxylate (DMAD) yielded the 1:1 cycloadduct with a heptalene skeleton 16a and the 1:2 cycloadduct 19, along with the substitution product 17. The X-ray structural analysis of the cycloadducts 16a and 19 is also described. 相似文献
215.
We have previously reported a highly sensitive method for the measurement of catechol-O-methyltransferase (COMT) activities in rat erythrocytes with norepinephrine (NE), an endogenous native substrate, using high-performance liquid chromatography (HPLC)-fluorescence or peroxyoxalate chemiluminescence reaction detection. Applying this method to COMT activities in rat liver and kidney, known to have the highest activities of all organs, the optimum reaction conditions were investigated. Under the optimum conditions, soluble (S)-COMT and membrane-bound (MB)-COMT activities in rat liver, with NE as a substrate, were 2.17 +/- 0.33 and 0.16 +/- 0.02 nmol/min/mg protein (n = 5), respectively. In rat kidney, S-COMT and MB-COMT activities were 1.81 +/- 0.20 and 0.079 +/- 0.009 nmol/min/mg protein (n = 5), respectively. Since liver and kidney play important roles in inactivating catecholamines, using the proposed method would yield critical information to delineate the role of metabolism of catecholamines in rat tissues. 相似文献
216.
Yasuyoshi Miki Osamu Tomii Hayami Nakao Mayumi Kubo Hiroko Hachiken Shoji Takemura Masazumi Ikeda 《Journal of heterocyclic chemistry》1988,25(1):327-331
Treatment of 3-(or-hydroxybenzyl)pyrazolo[1,5-a]pyridines with trifluoroacetic acid in dichloromethane resulted in the formation of pyrazolo[1,5-a]pyridines, bis[α-(pyrazolo[1,5-a]pyrid-3-yl)benzyl] ethers, and phenylbis(pyrazolo[1,5-a]pyrid-3-yl)methanes, depending upon the presence or absence of the substituents at the 2- and/or 4-positions and the reaction conditions employed. 相似文献
217.
Mayumi Kaneko Masanobu Nakayama Masataka Wakihara 《Journal of Solid State Electrochemistry》2007,11(8):1071-1076
This paper describes two kinds of elastomeric binders which are styrene–butadiene (ST–BD) copolymer and 2-ethylhexyl acrylate–acrylonitrile
(2EHA–AN) copolymer for electrode materials of rechargeable Li-ion batteries. These elastomeric binders were swollen by electrolyte
solution (EC/DEC=1/2, 1 M LiPF6), and 2EHA–AN copolymer retained larger amount of electrolyte solution than ST–BD copolymer. The Li-ionic conduction behavior
was investigated for both copolymer films swollen by electrolyte solution. The Li-ion conductivity of ST–BD copolymer was
9.45 × 10−8 S·cm−1 and that of 2EHA–AN copolymer was 1.25 × 10−5 S·cm−1 at room temperature, and the corresponding amounts of activation energy were 0.31 and 0.26 eV, respectively. Because the
observed activation energy in elastomeric binder was different from that in the bulk of electrolyte solution (0.09 eV), Li-ion
conduction of the bulk of elastomeric binder swollen by electrolyte was affected by the polymer structure of binders. Electrochemical
performance of cathode material, LiCoO2, was investigated with three kinds of binders: ST–BD copolymer, 2EHA–AN copolymer, and poly(vinylidene fluoride). The initial
charge–discharge capacity of the LiCoO2 electrode with 2EHA–AN copolymer showed highest capacity, suggesting that Li+-ion conduction inside of the elastomeric binder contributes to the enhancement of charging and discharging capacity. This
result indicates that elastomeric binder with sufficient Li-ionic conductivity can be an attractive candidate for improving
cathode of lithium-ion battery. 相似文献
218.
Kashimoto K Shibata K Matsuda T Hoshide M Jimura Y Watanabe I Tanida H Matsubara H Takiue T Aratono M 《Langmuir : the ACS journal of surfaces and colloids》2008,24(13):6693-6697
The total-reflection XAFS measurement possessing bromide ion selectivity at the interfacial region was applied to the adsorbed film of hexadecyltrimethylammonium chloride (HTAC) and dodecyltrimethylammonium bromide (DTAB) mixture. The surface compositions XjH of individual ions j ( j = HTA+, Cl(-), DTA+, and Br (-)) were evaluated by combining the surface excess concentration of Br(-) estimated from the XAFS with the surface composition of the respective surfactants from the surface tension results. It is clearly shown that HTA+ and Br(-) are preferentially adsorbed to DTA+ and Cl(-) at the air/water interface. The preferential adsorption was estimated numerically in terms of activity coefficient fi+/-(H,p) of component i and excess Gibbs energy of adsorption ?prH,E. Then, the magnitude of ?prH,E was compared with that of ?prH,E attributable to intrinsic interaction between ions. 相似文献
219.
Aqueous chromatographic system for separation of biomolecules using thermoresponsive polymer modified stationary phase 总被引:2,自引:0,他引:2
Kanazawa H Nishikawa M Mizutani A Sakamoto C Morita-Murase Y Nagata Y Kikuchi A Okano T 《Journal of chromatography. A》2008,1191(1-2):157-161
We have investigated a new method for HPLC using packing materials modified with a functional polymer, such as thermoresponsive poly(N-isopropylacrylamide) (PNIPAAm). PNIPAAm-modified silica exhibits temperature-controlled hydrophilic-hydrophobic surface property changes in aqueous systems. Temperature-responsive chromatography is performed with an aqueous mobile phase without using an organic solvent. We designed ternary copolymers of NIPAAm introduced 2-(dimethyl-amino) ethyl methacrylate (DMAEMA) as a cationic monomer and butyl methacrylate (BMA) as a hydrophobic monomer. A cationic thermoresponsive hydrogel grafted surface would produce an alterable stationary phase with both thermally regulated hydrophobicity and charge density for separation of bioactive compounds. In this study, we achieved successful separation of lysozyme without the loss of bioactivity by temperature-responsive chromatography. The electrostatic and hydrophobic interactions could be modulated simultaneously with the temperature in an aqueous mobile phase, thus the separation system would have potential applications in the separation of biomolecules. 相似文献
220.