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81.
Hikaru Morimoto Marie Minato Tomohiko Nakagawa Masahide Sato Yoshio Kobayashi Kohsuke Gonda Motohiro Takeda Noriaki Ohuchi Noboru Suzuki 《Journal of Sol-Gel Science and Technology》2011,59(3):650-657
A preparation method for gadolinium compound (Gd) nanoparticles coated with silica (Gd/SiO2) is proposed. Gd nanoparticles were prepared with a homogeneous precipitation method at 80 °C using 1.0 × 10−3 M Gd(NO3)3 and 0.5 M urea in the presence of 1.0 g/L stabilizer. Among stabilizers examined. Sodium n-dodecyl sulfate (SDS) was suitable
as the stabilizer for preparing small Gd nanoparticles, and consequently Gd nanoparticles with a size of 46.2 ± 12.4 nm were
prepared using the SDS. Silica-coating of the Gd nanoparticles was performed by a St?ber method at room temperature using
0.013 M TEOS and 2.0 × 10−3 M NaOH in water/1-propanol solution in the presence of 1.0 × 10−3 M Gd nanoparticles, which resulted in production of Gd/SiO2 particles with an average size of 64.2 ± 14.4 nm. The Gd/SiO2 particles were surface-modified with 3-aminopropyltrimethoxysilane and succinic anhydride. It was confirmed by measurement
of electrophretic light scattering that amino group or carboxyl group was introduced onto the Gd/SiO2 particles. The gadolinium concentration of 1.0 × 10−3 M in the as-prepared colloid solution was increased up to a gadolinium concentration of 0.4 M by centrifugation. The core–shell
structure of Gd/SiO2 particles was undamaged, and the colloid solution was still colloidally stable, even after the concentrating process. The
concentrated Gd/SiO2 colloid solution showed an X-ray image with contrast as high as a commercial Gd complex contrast agent. Internal organs in
a mouse could be imaged injecting the concentrated colloid solution into it. 相似文献
82.
Funai T Miyazaki Y Aotani M Yamaguchi E Nakagawa O Wada S Torigoe H Ono A Urata H 《Angewandte Chemie (International ed. in English)》2012,51(26):6464-6466
Silver turns up the A-C: In the presence of Ag(I) ions, a DNA polymerase incorporated deoxyadenosine (from dATP) at the site opposite cytosine in the template strand to afford the full-length product (see scheme), meaning that DNA polymerases prefer a C-Ag(I)-A base pair to the more thermodynamically stable C-Ag(I)-C base pair. 相似文献
83.
An acidic polysaccharide having activity on the reticuloendothelial system from the root of Astragalus mongholicus. 总被引:3,自引:0,他引:3
An acidic polysaccharide, designated as AMon-S, was isolated from the roots of Astragalus mongholicus BUNGE. It was homogeneous on electrophoresis and gel chromatography, and its molecular mass was estimated to be 7.6 x 10(4). It showed significant reticuloendothelial system-potentiating activity in a carbon clearance test. It is composed of L-arabinose: D-galactose: D-galacturonic acid: D-glucuronic acid in the molar ratio of 18:18:1:1, in addition to small amounts of O-acetyl groups and peptide moiety. A part of the hexuronic acid residues exist as the methyl esters. Methylation analysis, carbon-13 nuclear magnetic resonance and periodate oxidation studies enabled elucidation of its structural features and revealed mainly alpha-arabino-beta-3,6-galactan type structural units. 相似文献
84.
Shun-ichi Tanaka Sanshiro Hattori Joon-Sung Chang Masana Minami 《Optics Communications》1973,9(1):54-57
A multiple object-beam holography is proposed, where a two-dimensional rectangular amplitude grating and a phase plate of matrix form placed at the frequency plane of the grating constitute the main parts of a speckle-free periodic illumination system of continuous tone transparencies. Demonstration experiments are made, where the number of diffracted orders of the grating, the ratio of the widths of transparent and opaque zones of the grating, the retardation of each matrix zone of the phase plate and the distance between planes of the image of the grating and a transparency are taken as variables. 相似文献
85.
86.
Ishiuchi S Asakawa T Mitsuda H Miyazaki M Chakraborty S Fujii M 《The journal of physical chemistry. A》2011,115(37):10363-10369
In our previous work, we found that synephrine has six conformers in the gas phase, while adrenaline, which is a catecholamine and has the same side chain as synephrine, has been reported to have only two conformers. To determine the conformational geometries of synephrine, we measured resonance enhanced multiphoton ionization, ultraviolet-ultraviolet hole burning, and infrared dip spectra by utilizing the laser desorption supersonic jet technique. By comparing the observed infrared spectra with theoretical ones, we assigned geometries except for the orientations of the phenolic OH group. Comparison between the determined structures of synephrine and those of 2-methylaminno-1-phenylethanol, which has the same side chain as synephrine but no phenol OH group, leads to the conclusion that the phenolic OH group in synephrine does not affect the conformational flexibility of the side chain. In the case of adrenaline, which is expected to have 12 conformers if there are no interactions between the catecholic OH groups and the side chain, some interactions possibly exist between them because only two conformations are observed. By estimation of the dipole-dipole interaction energy between partial dipole moments of the catecholic OH groups and the side chain, it was concluded that the dipole-dipole interaction stabilizes specific conformers which are actually observed. 相似文献
87.
Koki Yoshizawa Dr. Keisuke Hirata Prof. Shun-ichi Ishiuchi Prof. Masaaki Fujii Dr. Anne Zehnacker 《Chemphyschem》2023,24(18):e202300172
Alkali metal complexes of cyclic dipeptide cyclo Tyr-Tyr have been studied under cryogenic ion trap conditions. Their structure was obtained by combining Infra-Red Photo-Dissociation (IRPD) and quantum chemical calculations. The structural motif strongly depends on the relative chirality of the tyrosine residues. For residues of identical chirality, the cation interacts with one amide oxygen and one of the aromatic rings only; the distance between the aromatic rings does not change with the nature of the metal. In contrast, for residues of opposite chirality, the metal cation is located in between the two aromatic rings and interacts with both of them. The distance between the two aromatic rings strongly depends on the metal. Electronic spectra obtained by Ultra Violet Photodissociation (UVPD) spectroscopy and analysis of the UV photo-fragments shed light on the excited state deactivation processes, which depend on both the chirality of the residue and that of the metal ion core. Na+ stands out by the presence of low-lying charge transfer states resulting in the broadening of the electronic spectrum. 相似文献
88.
The major pectic arabinogalactan having activity on the reticuloendothelial system from the roots and rhizomes of Saposhnikovia divaricata 总被引:3,自引:0,他引:3
N Shimizu M Tomoda R Gonda M Kanari N Takanashi N Takahashi 《Chemical & pharmaceutical bulletin》1989,37(5):1329-1332
The major acidic polysaccharide, named saposhnikovan A, was isolated from the roots and rhizomes of Saposhnikovia divaricata. It showed remarkable reticuloendothelial system-potentiating activity in a carbon clearance test. It is composed of L-arabinose: D-galactose: D-galacturonic acid in the molar ratio of 6:15:10, and its molecular weight was estimated to be 54000. About 35% of the D-galacturonic acid residues exist as the methyl esters. Methylation analysis, 13C-nuclear magnetic resonance, and controlled Smith degradation studies indicated that the polysaccharide has the alpha-1----4-linked D-galacturonan backbone bearing alpha-1----5-linked L-arabino-beta-3,6-branched D-galactan side chains. 相似文献
89.
90.
The controlled Smith degradation of MVS-VI, the major acidic polysaccharide having remarkable anti-complementary activity isolated from the seeds of Malva verticillata L., was performed. Methylation analysis of both the primary and the secondary Smith degradation products indicated that the core structural features of MVS-VI include a backbone chain composed of beta-1,3-linked D-galactose residues. The majority of galactose units in the backbone carry side chains composed of beta-1,3- and beta-1,6-linked D-galactosyl residues at position 6. The controlled Smith degradation products showed considerable anti-complementary activity. 相似文献