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1.
Yuta Kitamura Noriyuki Miyazaki Toshiro Mabuchi Teruhiko Nawata 《Journal of Crystal Growth》2009,311(15):3954-3962
We developed a method for simulating birefringence of an annealed ingot of MgF2 single crystal for lithography optics. This method provides the optical path difference caused by crystal symmetry and residual stress existing in the crystal. The method consists of the heat conduction analysis, the residual stress analysis and the birefringence analysis. Because there exists no experimental data on the inelastic behavior of MgF2 single crystal, the residual stress was estimated with the elastic thermal stress analysis using the finite element method by assuming a stress-free temperature. In this analysis, the temperature dependence of material properties and crystal anisotropy were taken into account. In the birefringence analysis, the distributions of optical path difference were calculated by an approximate method using the result of the residual stress analysis. This approximate method uses the average stress along the wave normal and is equivalent to the exact method in case of low stress dealt with the present study. In this analysis, it is possible to consider both the intrinsic birefringence and the stress birefringence in any crystal orientation. The distribution of the optical path difference in the annealed ingot obtained from the present calculation agrees qualitatively with that of the experiment. Its calculated value also agrees reasonably well with that of the experiment, when a stress-free temperature is adequately selected. 相似文献
2.
Dr. Yoshiyuki Kageyama Tomonori Ikegami Yuta Kurokome Prof. Dr. Sadamu Takeda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(25):8669-8675
Macroscopic and spatially ordered motions of self‐assemblies composed of oleic acid and a small amount of an azobenzene derivative, induced by azobenzene photoisomerization, was previously reported. However, the mechanism of the generation of submillimeter‐scale motions by the nanosized structural transition of azobenzene was not clarified. Herein, an underlying mechanism of the motions is proposed in which deprotonation of carboxyl groups in cooperation with azobenzene photoisomerization causes a morphological transition of the self‐assembly, which in turn results in macroscopic forceful dynamics. The photoinduced deprotonation was investigated by potentiometric pH titration and FTIR spectroscopy. The concept of hierarchical molecular interaction generating macroscale function is expected to promote the next stage of supramolecular chemistry. 相似文献
3.
Yuta Takaki Ryota Ozawa Dr. Takashi Kajitani Prof. Takanori Fukushima Prof. Masaaki Mitsui Prof. Kenji Kobayashi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(47):16760-16764
Cyclic arylene ethynylene hexamer 1 , composed of alternating 2,7‐anthrylene ethynylene units and meta‐phenylene ethynylene units, was synthesized. It shows C3 symmetry and possesses a flat and rigid conformation with a large equilateral triangle‐like cavity. Macrocycle 1 self‐associates through π–π stacking interactions between the anthracene‐containing macrocyclic aromatic cores with indefinite‐association constant KE=6980 m ?1 in CDCl3 at 303 K. Macrocycle 1 also self‐assembles into π‐stacked nanofibers in the drop‐cast film. 相似文献
4.
The conductance through single 7,7,8,8‐tetracyanoquinodimethane (TCNQ) connected to gold electrodes is studied with the nonequilibrium Green’s function method combined with density functional theory. The aim of the study is to derive the effect of a dicyano anchor group, ?C(CN)2, on energy level alignment between the electrode Fermi level and a molecular energy level. The strong electron‐withdrawing nature of the dicyano anchor group lowers the LUMO level of TCNQ, resulting in an extremely small energy barrier for electron injection. At zero bias, electron transfer from electrodes easily occurs and, as a consequence, the anion radical state of TCNQ with a magnetic moment is formed. The unpaired electron in the TCNQ anion radical causes an exchange splitting between the spin‐α and spin‐β transmission spectra, allowing the single TCNQ junction to act as a spin‐filtering device. 相似文献
5.
6.
Mark Kristan Espejo Cabello Dr. Yuta Uetake Dr. Yu Yao Prof. Dr. Susumu Kuwabata Prof. Dr. Hidehiro Sakurai 《化学:亚洲杂志》2021,16(16):2280-2285
An aqueous colloidal dispersion of Pt nanoparticles (NPs) stabilized by fullerenol C60(OH)12 (Pt:C60(OH)12) was successfully synthesized via liquid-phase chemical reduction. The subsequent pyrolysis of Pt:C60(OH)12 at different temperatures was conducted to afford Pt-doped carbon with different chemical compositions (Pt:C60n). X-ray absorption spectroscopy (XAS) and Infrared (IR) absorption spectroscopy and thermogravimetric measurements revealed that the thus-prepared nanocomposite consists of Pt NPs and high valent Pt-C60(OH)12 complex. One distinct feature of C60(OH)12 matrix as catalyst support is the suppression of size growth of Pt NPs during the pyrolysis up to 300 °C. Electrochemical experiments using cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were performed to find that Pt:C60300 (pyrolyzed at 300 °C) exhibited higher activity than others, that was attributed to the π-extended feature of the as-obtained carbon. 相似文献
7.
Saito S Nakano Y Hikichi A Suzuki R Yoshimoto K Maeda M Aoyama M Shibukawa M 《The Analyst》2011,136(13):2697-2705
Novel fluorescent probes have been developed for the ultratrace detection of heavy metal ions by capillary electrophoresis using laser-induced fluorescence detection. Based on a molecular design, the probes are composed of an octadentate chelating moiety, a macrocyclic DOTA (tetraazacyclododecanetetraacetic acid) and an acyclic DTPA (diethylenetriaminepentaacetic acid) frame, a spacer and a fluorophore (fluorescein). These were chosen on the basis of their ability to form kinetically inert and highly emissive complexes, and to prevent a quenching effect even with heavy and paramagnetic metal ions. Addition of a cationic polymer, polybrene, in the separation buffer provided high resolution and simultaneous detection of Ca(2+), Mg(2+), Cu(2+), Zn(2+), Ni(2+), Co(2+), Mn(2+), Cd(2+) and Pb(2+). The direct fluorescence detection of these metal ions with high sensitivity at lower ppt levels, typically 2-7 × 10(-11) M (potentially sub-ppt), was successfully achieved. While separation of anionic compounds using a counter cation ("Ion Association (IA)" mode) is typically controlled by the ion association equilibrium constants, K(ass), it was found that differences in the mobilities, μ(ep(IAC)), of the ion association complexes formed between the probe complexes and counter cations are the driving forces for separation in this new method. This suggests that each of the polybrene-probe complexes has different chemical structures among metal ions, which were able to be determined by CD spectra in this investigation. This novel separation mode was termed the "Ion Association Complex (IAC)" mode, distinct from the IA mode. 相似文献
8.
Dr. Masayuki Iwasaki Miki Iyanaga Yuta Tsuchiya Yugo Nishimura Wenjuan Li Prof. Dr. Zhiping Li Prof. Dr. Yasushi Nishihara 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(9):2459-2462
A catalytic variant of the direct thiolation of arenes, bearing directing groups, with disulfides or thiols has been developed under palladium and copper co‐catalysis. Both sulfenyl moieties of the disulfide could be incorporated into the thiolated products, therefore, the reactions reached completion with only half an equivalent of disulfide, with respect to the starting arene. Experimental evidence suggested that the reaction proceeds through a PdII/PdIV mechanism. 相似文献
9.
Adsorption and photochemical behaviors of the novel cationic xanthene derivative on the clay surface
Yuta Ohtani Yohei Ishida Yuka Ando Hiroshi Tachibana Tetsuya Shimada Shinsuke Takagi 《Tetrahedron letters》2014
Novel tetra-cationic xanthene derivative (Flu) was synthesized. Its adsorption and photochemical behaviors on the clay surface were investigated. Fluorescence quantum yield (?f) and fluorescence lifetime were 0.50 and 2.9 ns for Flu/clay complex. ?f of Flu was enough high (>0.1) even at high density conditions (0.080 molecules nm−2). It is supposed that the strong interaction between clay and Flu by the ‘Size-Matching Effect’ realizes the highly emissive clay complexes at high density adsorption condition by a suppression of a molecular aggregation, which tends to decrease the photochemical activity. 相似文献