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671.
Takanori Shibata Shiho Yoshida Yoshikazu Arai Maiko Otsuka Kohei Endo 《Tetrahedron》2008,64(5):821-830
A chiral iridium complex catalyzed a consecutive and enantioselective [2+2+2] cycloaddition of polyynes to give axially chiral compounds. Intermolecular reaction of tetraynes, possessing aryl groups on their termini, with protected but-2-yne-1,4-diols gave C2-symmetrical quateraryl compounds. Intramolecular reaction of hexaynes, possessing aryl or alkyl groups on their termini gave C2-symmetrical biaryl compounds. The catalytic synthesis of a pentacene derivative with axial chiralities is also discussed. 相似文献
672.
Takashi Kajiwara Kohei Takahashi Tomonari Hiraizumi Shinya Takaishi Masahiro Yamashita 《Polyhedron》2009,28(9-10):1860-1863
Tb(III)–Cu(II) based single-molecule magnets (SMMs) were synthesized to investigate the relationship between magnetic anisotropy and the symmetry of the ligand field, by the reaction of [TbCu(o-vanilate)2(NO3)3] with 2,2-dimethyl-1,3-propanediamine (3), followed by the reaction of one another equivalent of o-vaniline (4). Both complexes behave as SMM in the temperature range of 2.8–4.0 K (3) and 2.8–5.2 K (4), showing semi-circle shapes of Cole–Cole plots with α parameters in the ranges of 0.27–0.41 and 0.11–0.32. The energy barriers Δ/kB for the spin flippings were estimated from the Arrhenius plots to be 29(2) K for 3 and 32.2(6) K for 4, respectively. 相似文献
673.
Lumin Zhang Xiaojia Si Yangyang Yang Marc Zimmer Sina Witzel Kohei Sekine Matthias Rudolph A. Stephen K. Hashmi 《Angewandte Chemie (International ed. in English)》2019,58(6):1823-1827
Herein we report a highly selective photoredox C(sp3)?H alkylation/arylation of ethers through the combination of a photo‐organocatalyst (benzaldehyde) and a transition‐metal catalyst (nickel). This method provides a simple and general strategy for the C(sp3)?H alkylation/arylation of ethers. A selective late‐stage modification of (?)‐ambroxide has also been conducted to demonstrate the applicability of the method. 相似文献
674.
We developed an insulator‐based dielectrophoretic (iDEP) creek‐gap device that enables the isomotive movement of cells and that is suitable for determining their DEP properties. In the iDEP creek‐gap device, a pair of planar insulators forming a single fan‐shaped channel allows the induction of the isomotive iDEP force on cells. Hence, the cells’ behavior is characterized by straight motion at constant velocity in the longitudinal direction of the channel. Operation of the device was demonstrated using human breast epithelial cells (MCF10A) by applying an AC voltage of Vpp = 34 V peak‐to‐peak and frequencies of 200 kHz and 50 MHz to the device. Subsequently, the magnitude of DEP forces and the real part of the ClausiusMossotti (CM) factor, Re(β), were deduced from the measured cell velocity. The values of Re(β) were 0.14 ± 0.01 for the frequency of 200 kHz and ?0.12 ± 0.01 for 50 MHz. These results demonstrated that the DEP properties of the cells could be extracted over a wide field frequency range. Therefore, the proposed iDEP creek‐gap device was found to be applicable to cell analysis. 相似文献
675.
Kohei Tamao Masahiro Asahara Tomoyuki Saeki Akio Toshimitsu 《Journal of organometallic chemistry》2000,600(1-2):118-123
Some new aspects of intramolecularly amine-coordinated silylenes, ammonium silaylide, and amine-coordinated magnesium (chloro)silylenoids are summarized. The divalent silicon species bearing the 8-(dimethylamino)-1-naphthyl group, generated by the thermal degradation of a pseudo-pentacoordinated ethoxy- or fluoro-disilane, behaves as a nucleophilic ammonium silaylide as well as the amine-coordinated silylene, whose electrophilic character is weakened in comparison with that of free silylenes in some reactions in the presence of trapping agents such as 1,3-diene, diphenyl acetylene (in the absence or presence of water), and phenylacetylene, and in the absence of any trapping agent. The amine-coordinated silylenoid also behaves as an ambiphile, but the reaction courses are different from those observed with the amine-coordinated silylene and silaylide. A novel amino-group migration from naphthyl carbon to silicon has been observed in both species. 相似文献
676.
By the treatment of 0.3 molar amount of NbCl5 and LiAlH4, o-arylated alpha,alpha,alpha-trifluorotoluenes afforded fluorene derivatives in good yields. C-F bonds of the CF3 group and the neighboring ortho C-H bond were doubly activated to give the coupling products. 相似文献
677.
A new microdermabrasion system is used for peeling the stratum corneum in a controlled manner. The system uses inert corundum powders under various degrees of vacuum. The fine corundum powders ejected by suction power, being quickly in contact with the skin surface, abrade and remove a tiny fragment of stratum corneum. The fraction of the stratum corneum removed by microdermabrasion can be controlled by the operating conditions; the duration of application (L) and the degree of vacuum setting (V). The stratum corneum barrier function with respect to the rate of skin penetration is well correlated by the product of the square of the degree of the vacuum and the duration of the probe setting. 相似文献
678.
Kamiya K Tanaka Y Endang H Umar M Satake T 《Chemical & pharmaceutical bulletin》2005,53(12):1597-1599
From the fruits of Morinda citrifolia L., one new anthraquinone, 5,15-O-dimethylmorindol, together with five known anthraquinones and one new iridoid, morindacin, together with two known iridoids, were isolated. Their structures were elucidated by analysis of spectroscopic data. 相似文献
679.
The electrochemical characteristics of various kinds of multilayers of gold nanoclusters (GNCs) were investigated. Two types of gold nanoclusters, one covered by self-assembled monolayers (SAMs) of mercaptoundecanoic acid (MUA), hexanethiol (C6SH), and ferrocenylhexanethiol (FcC6SH), MHF-GNC, and the other with MUA and C6SH, MH-GNC, were used. The multilayers were constructed on a Au(111) surface based on a carboxylate/metal cation (Cu++)/carboxylate or carboxylate/cationic polymer (poly(allylamine hydrochloride):PAH)/carboxylate electrostatic interaction. While the multilayers constructed by the former method were stable only in nonaqueous solutions, those constructed by the latter method were stable even in aqueous solutions. Electrochemical measurements of the multilayers of MHF-GNCs showed a pair of waves corresponding to the redox of the ferrocene group around 350-480 mV and the charge of these peaks, i.e., the amount of adsorbed GNC, increased linearly with the construction cycle up to 6 cycles in the former and to 18 cycles in the latter. A rather reversible redox response of the ferrocene moiety was observed even at the gold electrodes with five GNC layers of two different sequences in which MHF-GNC exists as the layer closest to the gold electrode, ie., the first layer, or as the outermost layer with MH-GNC in the other layers. These results show the facile transfer of electrons and ions through the multilayers of the SAM-covered GNCs and electron transfer between the ferrocene moiety and the Au(111) electrode takes place through the GNC cores by hopping. 相似文献
680.