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81.
Kohji Tashiro Kazuhiro Takeuchi Yasuaki Ohta Makoto Hanesaka Tomoko Hashida Yayoi Yoshioka Chellaswami Ramesh 《Macromolecular Symposia》2006,242(1):250-256
Structural changes occurring in the high temperature region of doubly-oriented nylon 10/10 sample have been investigated through the temperature-dependent simultaneous measurements of wide-angle and small-angle X-ray scatterings, and the results were compared with the infrared spectral data as well as the molecular dynamics simulation results. In the Brill transition region of 150–180 °C the methylene segments are conformationally disordered with keeping the intermolecular hydrogen bonds. During this phase transition the stacked lamellar structure did not change very much: the lamellae are tilted by ca. 34° from the draw axis and the long period is almost 160 Å. In the temperature region immediately below the melting point the molecular chains were found to be contracted by ca. 10% the original repeating period and the intermolecular hydrogen bonds were almost broken, causing the violent rotational and translational motions of the chains around the chain axis. At the same time the long period increased remarkably from 160 Å to 410 Å and the originally tilted lamellae stood up in parallel to the draw axis. 相似文献
82.
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84.
Danda Zhang 《Journal of Nonlinear Mathematical Physics》2018,25(1):34-53
The Adler-Bobenko-Suris (ABS) list contains scalar quadrilateral equations which are consistent around the cube, and have D4 symmetry and tetrahedron property. Each equation in the ABS list admits a beautiful decomposition. We revisit these decomposition formulas and by means of them we construct Bäcklund transformations (BTs). BTs are used to construct lattice equations, their new solutions and weak Lax pairs. 相似文献
85.
Dr. Hiroshi Hinou Risho Miyoshi Yasuaki Takasu Hirokazu Kai Dr. Masaki Kurogochi Dr. Shingo Arioka Dr. Xiao‐Dong Gao Dr. Nobuaki Miura Dr. Naoki Fujitani Dr. Shinya Omoto Dr. Tomokazu Yoshinaga Dr. Tamio Fujiwara Dr. Takeshi Noshi Dr. Hiroko Togame Prof. Hiroshi Takemoto Prof. Shin‐Ichiro Nishimura 《化学:亚洲杂志》2011,6(4):1048-1056
A potent inhibitor for Vibrio cholerae neuraminidase (VCNA) was developed by using a novel two‐step strategy, a target amino acid validation using mechanism‐based labeling information, and a potent inhibitor search using a focused library. The labeling information suggested the hidden dynamics of a loop structure of VCNA, which can be a potential target of the novel inhibitor. A focused library composed of 187 compounds was prepared from a 9‐azide derivative of 2,3‐dehydro‐N‐acetylneuraminic acid (DANA) to interrupt the function of the loop of the labeled residues. Inhibitor 3c showed potent inhibition properties and was the strongest inhibitor with FANA, a N‐trifluoroacetyl derivative of DANA. Validation studies of the inhibitor with a detergent and a Lineweaver–Burk plot suggested that the 9‐substitution group would interact hydrophobically with the target loop moiety, adding a noncompetitive inhibition property to the DANA skeleton. This information enabled us to design compound 4 having the combined structure of 3c and FANA. Compound 4 showed the most potent inhibition (Ki=73 nM , mixed inhibition) of VCNA with high selectivity among the tested viral, bacterial, and mammal neuraminidases. 相似文献
86.
The electrochemical oxidation reaction of nitrogen dioxide (NO2) using boron doped diamond (BDD) electrodes is presented. Cyclic voltammetry of NO2 in a 0.1 M KClO4 solution exhibits oxidation peaks at +1.1 V and +1.5 V (vs. Ag/AgCl) which are attributable to oxidation of HONO and NO2−, respectively. Moreover, the pH and scan rate dependences were investigated to study the oxidation mechanism. A linear calibration curve was observed in the concentration range of ∼1 to 5 mM (R2=0.99) with a detection limit of 11.1 ppb (S/B=3) for HONO and 58.6 ppb (S/B=3) for NO2−. In addition, the analytical performance was compared with those using glassy carbon, platinum and stainless steel as the working electrode. 相似文献
87.
A New Family of Anionic FeIII Spin Crossover Complexes Featuring a Weak‐Field N2O4 Coordination Octahedron 下载免费PDF全文
Prof. Dr. Kazuyuki Takahashi Kiko Kawamukai Mitsunobu Okai Prof. Dr. Tomoyuki Mochida Dr. Takahiro Sakurai Prof. Dr. Hitoshi Ohta Dr. Takashi Yamamoto Prof. Dr. Yasuaki Einaga Prof. Dr. Yoshihito Shiota Prof. Dr. Kazunari Yoshizawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(4):1253-1257
Unprecedented anionic FeIII spin crossover (SCO) complexes involving a weak‐field O,N,O‐tridentate ligand were discovered. The SCO transition was evidenced by the temperature variations in magnetic susceptibility, Mössbauer spectrum, and coordination structure. The DFT calculations suggested that larger coefficients on the azo group in the HOMO?1 of a ligand might contribute to the enhancement of a ligand‐field splitting energy. The present anionic SCO complex also exhibited the light‐ induced excited‐spin‐state trapping effect. 相似文献
88.
Yasuaki Nakayama Ruriko Sekiya Hiroki Oishi Naoto Hama Miki Yamazaki Dr. Takaaki Sato Prof. Dr. Noritaka Chida 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(36):12052-12058
This article describes the details of two new types of Overman rearrangement from allylic vicinal diols. Starting from identical diols, both bis(imidate)s and cyclic orthoamides were selectively synthesized by simply changing the reaction conditions. Whilst exposure of the bis(imidate)s to thermal conditions initiated the double Overman rearrangement to introduce two identical nitrogen groups in a single operation (the cascade‐type Overman rearrangement), the reaction of cyclic orthoamides resulted in a single rearrangement (the orthoamide‐type Overman rearrangement). The newly generated allylic alcohols from the orthoamide‐type reaction can potentially undergo a variety of further transformations. For instance, we demonstrated an Overman/Claisen sequence in one pot. The most conspicuous feature of this method is that it offers precise control over the number of Overman rearrangements from the same allylic vicinal diols. This method also excludes the tedious protecting‐group manipulations of the homoallylic alcohols, which are necessary in conventional Overman rearrangements. All of the performed rearrangements proceeded in a completely diastereoselective fashion through a chair‐like transition state. 相似文献
89.
Yasuaki Kawaguchi Shigeo Yasuda Akira Kaneko Yuki Oura Chisato Mukai 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(29):7738-7742
The efficient RhI‐catalyzed cycloisomerization of benzylallene‐alkynes produced the tricyclo[9.4.0.03,8]pentadecapentaene skeleton through a C H bond activation in good yields. A plausible reaction mechanism proceeds via oxidative addition of the acetylenic C H bond to RhI, an ene‐type cyclization to the vinylidenecarbene–RhI intermediate, and an electrophilic aromatic substitution with the vinylidenecarbene species. It was proposed based on deuteration and competition experiments. 相似文献
90.
Takahiro Kumamaru Yasuaki Okamoto Yuroku Yamamoto Fumio Nakata Yoko Nitta Hiroshi Matsuo 《Fresenius' Journal of Analytical Chemistry》1987,327(8):777-781
Summary The enhancement factors of various organic solvents in inductively coupled plasma atomic emission spectrometry (ICP-AES) were measured for diethyldithiocarbamate-cadmium(II) or mercury(II)-solvent systems by comparing the maximum emission intensity of an extract with that of the corresponding aqueous solution. The correlation between the enhancement factors obtained and physical parameters of the solvents were investigated. Among them, the best inverse linear relationship existed between log dielectric constant and log enhancement factor. The plot of log (boiling point x viscosity) vs. log enhancement factor also resulted in a line with a negative slope except water. Carbon tetrachloride, chlorofom and xylene, which gave much larger enhancement factors, were recommended for the use in ICP-AES.
Verstärkungseffekt durch organische Lösungsmittel in der ICP-AES相似文献