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141.
Yoshiro Kobayashi Toshinori Yamashita Katsuhiro Takahashi Hisashi Kuroda Itsumaro Kumadaki 《Tetrahedron letters》1982,23(3):343-344
Aryltrifluoromethylacetylenes were synthesized by an intramolecular Wittig reaction of trifluoroacetylarylidenephosphoranes, which were synthesized from arylmethyl halides. 相似文献
142.
The crystal structure of [(CH3)4N]4Na2H[alpha-PW11O39].8H2O has been determined by using the Weissenberg camera at the BL04B2 beamline of SPring-8, revealing that it contains a disorder-free lacunary [alpha-PW11O39]7- anion with one sodium cation embedded into its lacuna that links the oxometalate building blocks into a one-dimensional chain, which is then woven into a three dimensional latticework by another Na+. 相似文献
143.
Katsuhiro Sumi Mutsumi Kimura Isei Nakamura 《Journal of polymer science. Part A, Polymer chemistry》1994,32(7):1243-1254
A vinyl monomer containing the pendant tetraphenylporphyrin (TPP) group, 4-vinyltetraphenylporphyrin (VTPP), was synthesized. A homopolymer (PVTPP) which is insoluble in water, and three water-soluble polymers were obtained by radical polymerization. The water-soluble polymers are two anionic polymers (PVPTSPP and PVTPP-StSO3) and a cationic polymer (PVTPP-VPyM). PVPTSPP has sulfonic acid groups in a TPP group and very high charge density. PVTPP-StSO3 was obtained by copolymerization of VTPP and sodium 4-styrenesulfonate. PVTPP-VPyM was obtained by quarternarization of a copolymer of VTPP and 4-vinylpyridine. Polymeric manganese(III) complexes (PMn-VTPP, PMnVPTSPP, PMnVTPP-StSO3, and PMnVTPP-VPyM) were prepared from the polymers and manganese acetate. The acetate ligand in PMnVTPP can be easily substituted by another ligand such as Cl?, AcO?, OH?, and SCN?. The substitution reaction occurs in the interface between water and chloroform. The sulfonated homopolymer, PMnVPTSPP, cannot incorporate with anionic ligands because of the strong electrostatic repulsion. In the anionic copolymer, PMnVTPP-StSO3, the ligand substitution reaction with SCN ligand needs activation energy of 53 kJ/mol. In the cationic polymer complex, PMnVTPP-VPyM, the OH ligand can be easily substituted with the SCN ligand and the equilibrium constant of the reaction was estimated at 1.38 × 10?3. © 1994 John Wiley & Sons, Inc. 相似文献
144.
Mayu Fukuda Mai Morikawa Dr. Daisuke Hirose Dr. Tsuyoshi Taniguchi Dr. Tatsuya Nishimura Prof. Eiji Yashima Prof. Katsuhiro Maeda 《Angewandte Chemie (International ed. in English)》2023,62(15):e202217020
We report an ultra-fast helix induction and subsequent static helicity memory in poly(biphenylylacetylene) (PBPA- A ) assisted by a catalytic amount of nonracemic ammonium salts comprised of non-coordinating tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BArF−) as a counter anion. The remarkable acceleration of the helix-induction rate in PBPA- A accompanied by the significant amplification of the asymmetry relies on the two methoxymethoxy groups of the biphenyl pendants, which can gain access to enfold the chiral ammoniums in a crown-ether manner in specific aromatic solvents, leading to ultra-fast helicity induction, which is completed within 30 s. In aromatic solvents, helicity memory is lost rapidly, but is quite stable in long-chain hydrocarbons. The best use of specific solvents for helicity induction and static helicity memory, respectively, provides a highly sensitive chirality sensing system toward a small amount of chiral amines and amino acids when complexed with BArF−. 相似文献
145.
In order to use the linear temperature programmed retention index (LTRI) for the negative ion chemical ionization (NCI) mode in which n-alkanes cannot be detected, LTRIs were newly defined using homologous series of pentafluorobenzyl and hexafluoroisopropyl esters. The method for converting LTRI based on n-alkanes to the new LTRIs was also developed and applied to PCB and chlorinated pesticide analysis. The results demonstrated that the LTRI databases, which were developed based on n-alkanes, could be utilized for NCI analysis. 相似文献
146.
A novel tripodal ligand, tris[(4'-methyl-2,2'-bipyridyl-4-yl)methyl]carbinol (L), has been synthesized. The spectroscopic, electrochemical, and photocatalytic properties of the new trinuclear complexes (Ru(2)Re and RuRe(2)) linked by the tripodal bridging ligand L are then investigated. In addition, 2-fold-improved photocatalytic activities were obtained in the case of these trinuclear complexes compared to the mixtures of the appropriate monometallic model complexes in the reduction of CO(2) under visible irradiation. 相似文献
147.
Single-scattering spectroscopy for extremely dense colloidal suspensions by use of a low-coherence interferometer 总被引:1,自引:0,他引:1
Single-scattering spectroscopy by use of a low-coherence interferometer is introduced to measure the power spectra of light scattered from extremely dense colloidal suspensions. The power spectrum of a heterodyne component can be obtained by subtraction of the power spectrum of a homodyne component from the measured power spectrum. The heterodyne power spectrum for light scattered from the medium is shown to coincide with the single-scattering spectrum to a depth of up to a few times the mean-free path length. Therefore single-scattering spectroscopy is newly proposed as a means by which to analyze the characteristics of extremely dense colloidal suspensions. 相似文献
148.
149.
We investigate a semiclassical conductance for ballistic open three-dimensional (3-d) billiards. For partially or completely broken-ergodic 3-d billiards such as SO(2) symmetric billiards, the dependence of the conductance on the Fermi wavenumber is dramatically changed by the lead orientation. Application of a symmetry-breaking weak magnetic field brings about mixed phase-space structures of 3-d billiards which ensures a novel Arnold diffusion that cannot be seen in 2-d billiards. In contrast to the 2-d case, the anomalous increment of the conductance should inevitably include a contribution arising from Arnold diffusion as well as a weak localization correction. Discussions are devoted to the physical condition for observing this phenomenon. 相似文献
150.
Abstract— Quenching of excited state of Ru(bpy)2 (poly-4-methyl-4'-vinyl-2,2'-bipyridine)Cl2 by sodium anthraquinone-2-sulfonate was found to be a static process. The quenching was interpreted by application of a modified Perrin model. Radius of the quenching sphere was estimated to correspond to 6.65 monomer units and was unchanged on varying the Ru2 + content of the polymer. Energy migration along the polymer chain was denied. 相似文献