全文获取类型
收费全文 | 185篇 |
免费 | 4篇 |
国内免费 | 3篇 |
专业分类
化学 | 176篇 |
晶体学 | 1篇 |
数学 | 8篇 |
物理学 | 7篇 |
出版年
2023年 | 6篇 |
2022年 | 5篇 |
2021年 | 5篇 |
2020年 | 7篇 |
2019年 | 5篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2015年 | 2篇 |
2014年 | 4篇 |
2013年 | 9篇 |
2012年 | 9篇 |
2011年 | 13篇 |
2010年 | 13篇 |
2009年 | 6篇 |
2008年 | 8篇 |
2007年 | 8篇 |
2006年 | 13篇 |
2005年 | 10篇 |
2004年 | 16篇 |
2003年 | 9篇 |
2002年 | 6篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1990年 | 2篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有192条查询结果,搜索用时 15 毫秒
11.
Takuya Uto Takashi Hosoya Sachio Hayashi Toshifumi Yui 《Cellulose (London, England)》2013,20(2):605-612
In hot-water molecular dynamics simulation at 370 K, four cellulose IIII crystal models, with different lattice planes and dimensions, exhibited partial crystalline transformations of (1 ?1 0) chain sheets, in which hydroxymethyl groups were irreversibly rotated from gt into tg conformations, accompanied by hydrogen-bond exchange from the original O3–O6 to cellulose-I-like O2–O6 bonds. The final hydrogen-bond exchange ratio was about 95 % for some of the crystal models after 50 ns simulation. The corrugated (1 ?1 0) chain sheet was converted to a cellulose-I-like flat chain sheet with a slightly right-handed twist. The 3D structures of the three types of isolated chain sheet models were optimized using density functional theory calculations to compare their stabilities without crystal packing forces. The cellulose Iβ (1 0 0) models were more stable than the cellulose IIII (1 ?1 0) models. The optimized structure of cellulose IIII (1 0 0) models deviated largely from the initial sheet form. It was proposed to the crystalline transformation from cellulose IIII to Iβ that conversion of the chain sheet structure first take place, followed by sliding of the chain sheet along the fiber axis. 相似文献
12.
Cellulose - Cellulose I crystals swell on exposure to ethylenediamine (EDA) molecules to form a cellulose I–EDA complex, and successive extraction of EDA molecules converts the complex... 相似文献
13.
Tajima Kenji Imai Tomoya Yui Toshifumi Yao Min Saxena Inder 《Cellulose (London, England)》2022,29(5):2755-2777
Cellulose - Cellulose is produced by all plants and a number of other organisms, including bacteria. The most representative cellulose-producing bacterial species is Gluconacetobacter xylinus, an... 相似文献
14.
We report the generation of a nano-scale tubular structure of cellulose molecules (CelNT), through density functional theory (DFT) calculations. When a cellulose IIII (1 0 0) chain sheet model is optimized by DFT calculations, the sheet models spontaneously roll into tubes. The oligomers arrange in a right-handed, four-fold helix with one-quarter chain staggering, oriented with parallel polarity similar to the original crystal structure. Based on a one-quarter chain staggering relationship, six large CelNT models, consisting of 16 cellulose chains with DP = 80, are constructed by combinations of two types of chain polarities and three types of symmetry operations to generate a circular arrangement of molecular chains. All six CelNT models are examined by molecular dynamics (MD) calculations in chloroform. While four CelNT models retain a tubular form throughout MD calculations, the remaining two deform. 3D-RISM theory model is used to estimate the solvation free energies of the four CelNT models. The results suggest that the CelNT model with a chain arrangement of parallel polarity and right-handed helical symmetry forms the most stable tube structure. 相似文献
15.
Tooru Ooya Hideharu Mori Minoru Terano Nobuhiko Yui 《Macromolecular rapid communications》1995,16(4):259-263
A novel design of a biodegradable carrier for drug delivery was established by constructing a supramolecular assembly of drugs and polymer backbones without any covalent bonds. A biodegradable polyrotaxane was synthesized in which α-cyclodextrins (α-CDs) as drug carriers were threaded onto poly(ethylene glycol) chains which then were capped at each chain end by L -phenylalanine via peptide linkages. The release of α-CDs was observed only when the terminal peptide linkages were degraded. 相似文献
16.
Shinji Fukuhara Noriko Yui 《Transactions of the American Mathematical Society》2004,356(10):4237-4254
We introduce an elliptic analogue of the Apostol sums, which we call elliptic Apostol sums. These sums are defined by means of certain elliptic functions with a complex parameter having positive imaginary part. When , these elliptic Apostol sums represent the well-known Apostol generalized Dedekind sums. Also these elliptic Apostol sums are modular forms in the variable . We obtain a reciprocity law for these sums, which gives rise to new relations between certain modular forms (of one variable).
17.
The present investigation deals with the light-driven morphological changes in multilamella films of N-methyl-4-octadecyloxystilbazolium arylcarboxylates (C18OStz+X-) cast on glass slides. The results of XRD analysis show a photostimulated layer expansion and shrinkage of the stacked thin films along the c-axis under alternative illumination at >350 and 254 nm, respectively. It was revealed that such lamellar changes could be switched either way by a reversible transformation between the mono- and bilayer units in these stacked multilamella films. Moreover, such controlled structural adjustments in the alignment could be initiated by the photocyclodimerization of the stilbazolium moieties of the arylcarboxylate salts; i.e., a monolayer-to-bilayer transformation could be induced at a stage of only 10% cyclodimer formation. The photoinduced patterning on the surface of the films was also analyzed by SEM and fluorescence microscopic investigations. 相似文献
18.
Yui Hayashi Noriharu Takada Wahyudiono Hideki Kanda Motonobu Goto 《Plasma Chemistry and Plasma Processing》2017,37(1):125-135
Pulsed discharge plasma is typical oxidation technology for disposing organic compounds in aqueous solutions. When this electrical discharge plasma was applied in water, it may produce hydrogen peroxide (H2O2) without any catalyst or chemical agent. In order to increase H2O2 production by electrical discharge plasma in water, fine bubbles were introduced into the electrical discharge plasma in this experiment. Bipolar pulsed voltages were applied to cylindrical electrodes in the water while Ar or O2 bubbles were introduced, generating a pulsed discharge plasma. The introduction of the bubbles seemed to enhance the dissociation of water molecules and increased H2O2 formation, especially with O2 bubbling. Dissolved oxygen in the water contributed to H2O2 formation by pulsed discharge plasma with the bubbles, while dissociation of water molecules was the cause of H2O2 formation by pulsed discharge plasma without bubbles. More H2O2 was formed by pulsed discharge plasma with O2 bubbles, because the amount of dissolved oxygen in the water increased upon bubbling with O2. 相似文献
19.
Dhanpat Rai Mikazu Yui H. Todd Schaef Akira Kitamura 《Journal of solution chemistry》2010,39(7):999-1019
Prior to this study no data for the solubility product of BiPO4(cr) or the complexation constants of Bi with phosphate were available. The solubility of BiPO4(cr) was studied at 23±2?°C from both the over- and under-saturation directions as functions of a wide range in time (6–309 days), pH values (0–15), and phosphate concentrations (reaching as high as 1.0 mol?kg?1). HCl or NaOH were used to obtain a range in pH values. Steady state concentrations and equilibrium were reached in <6 days. The data were interpreted using the SIT model. These extensive data provided a solubility product value for BiPO4(cr) and an upper limit value for the formation of BiPO4(aq). Because the aqueous system in this study involved relatively high concentrations of chloride, reliable values for the complexation constants of Bi with chloride were required to accurately interpret the solubility data. Therefore as a part of this investigation, existing Bi–Cl data were critically reviewed and used to obtain values of equilibrium constants for various Bi–Cl complexes at zero ionic strength along with the values for various SIT ion interaction parameters. Predictions based on these thermodynamic quantities agreed closely with our experimental data, the chloride concentrations of which ranged as high as 0.7 mol?kg?1. The study showed that BiPO4(cr) is stable at pH values <9.0. At pH values >9.0, Bi(OH)3(am) is the solubility controlling phase. Reliable values for the Bi(OH)3(am) solubility reactions involving Bi(OH)3(aq) and $\mathrm{Bi}(\mathrm{OH})_{4}^{-}$ and the formation constants of these aqueous species are also reported. 相似文献
20.
Naohiro Kameta Dr. Hiroyuki Minamikawa Dr. Yuu Someya Dr. Hiroharu Yui Dr. Mitsutoshi Masuda Dr. Toshimi Shimizu Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(14):4217-4223
Transportation, release behavior, and stability of a green fluorescent protein (GFP, 3×4 nm) in self‐assembled organic nanotubes with three different inner diameters (10, 20, and 80 nm) have been studied in terms of novel nanocontainers. Selective immobilization of a fluorescent acceptor dye on the inner surface enabled us to not only visualize the transportation of GFP in the nanochannels but to also detect release of the encapsulated GFP to the bulk solution in real time, based on fluorescence resonance energy transfer (FRET). Obtained diffusion constants and release rates of GFP markedly decreased as the inner diameter of the nanotubes was decreased. An endo‐sensing procedure also clarified the dependence of the thermal and chemical stabilities of the GFP on the inner diameters. The GFP encapsulated in the 10 nm nanochannel showed strong resistance to heat and to a denaturant. On the other hand, the 20 nm nanochannel accelerated the denaturation of the encapsulated GFP compared with the rate of denaturation of the free GFP in bulk and the encapsulated GFP in the 80 nm nanochannels. The confinement effect based on rational fitting of the inner diameter to the size of GFP allowed us to store it stably and without denaturation under high temperatures and high denaturant concentrations. 相似文献