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51.
Suguru Ohta Masayoshi Nakano Takashi Kubo Kenji Kamada Koji Ohta Ryohei Kishi Nozomi Nakagawa Benoît Champagne Edith Botek Shin-ya Umezaki Akihito Takebe Hideaki Takahashi Shin-ichi Furukawa Yasushi Morita Kazuhiro Nakasuji Kizashi Yamaguchi 《Chemical physics letters》2006,420(4-6):432-437
The static second hyperpolarizability (γ) of a singlet diradical system involving phenalenyl radicals linked with acetylene π-conjugated bridge, BPLE, is investigated as well as reference closed-shell systems, BPRY1 and BPRY2, by the hybrid density functional theory method. The γ value of BPLE with intermediate diradical character is shown to be about four times as large as that of BPRY1 with similar π-conjugation length and to be about twice as large as that of BPRY2 with longer π-conjugation length. This feature is in agreement with our prediction that the molecules with intermediate diradical characters enhance γ values compared to the closed-shell molecules. 相似文献
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Naumov P Sakurai K Ishikawa T Takahashi J Koshihara SY Ohashi Y 《The journal of physical chemistry. A》2005,109(32):7264-7275
The nitro-assisted proton transfer (NAPT), responsible for the photoactivity of ortho-nitrobenzylpyridines and a model for the nitro-based caged compounds, is studied along with the parent compound 2-(2',4'-dinitrobenzyl)pyridine (DNBP) with polarized optical spectroscopy and theoretical calculations. The transition dipole moments of a DNBP single-crystal identified oriented molecules of the long-lived enamine tautomer (NH), rather than of the aci-nitro tautomer (OH), as carriers of the photoinduced blue coloration. It is clarified that the blue second singlet transition owes to intramolecular charge transfer from the allyl-pyridinium part to the dinitrophenyl fragment of NH. The theoretical modeling of the ground-state potential energy surface showed that while NH and OH can interconvert by means of direct proton transfer, such a process between the initial form CH and either OH and NH would require significant rotation of the aromatic rings. In the ground state, OH is less stable but the kinetically preferred product over NH. Once created, regardless of whether via ground-state or excited-state routes, the aci-nitro group of OH undergoes energetically inexpensive rotation to deliver the proton to the nitrogen acceptor. The "softening" of the energy surface around OH due to its structural flexibility, that is, mediation of the proton transfer by the nitro group, is crucial to overcome the high barrier for a direct proton jump from CH to NH, even in cases of unfavorable donor-acceptor geometry. The very small structural change experienced by the surrounding of a molecule undergoing NAPT is promising for the design of photoactive systems which retain their crystallinity during a prolonged operation. 相似文献
54.
Kadota Shin-ya Okamoto Takuya Ono Masataka Tasaka Koji 《Lithuanian Mathematical Journal》2022,62(2):207-217
Lithuanian Mathematical Journal - We introduce a double zeta function of Mordell–Tornheim type and compute its values at nonpositive integer points. We then discuss a possible generalization... 相似文献
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Eietsu Hasegawa Minami Tateyama Tsuneaki Hoshi Taku Ohta Eiji Tayama Hajime Iwamoto Shin-ya Takizawa Shigeru Murata 《Tetrahedron》2014
A combination of 2-aryl substituted 1,3-dimethyl-benzimidazolines (DMBIHs) and tris(2,2′-bipyridine)ruthenium(II) chloride, Ru(bpy)3Cl2 was used to promote photoinduced electron-transfer (PET) reactions of α-halomethyl-substituted benzocyclic 1-alkanones. This photo-reagent system stimulates free radical forming, cleavage of both carbon–bromine and carbon–chlorine bonds that are not activated by carbonyl groups. The resulting free radicals undergo 5-exo hexenyl cyclization as well as sequential cyclization and ring-expansion (Dowd–Beckwith) reactions to form radicals that abstract hydrogen atoms from the radical cation of DMBIH to yield the observed products. The results of a study of the effects of substituents located on the 2-aryl ring of DMBIH suggest that steric and hydrogen-bonding interactions influence the nature of the reaction pathways followed by the radical intermediates. PET reactions using an iridium complex and DMBIH were also investigated. 相似文献
58.
K Shin-ya K Wierzba K Matsuo T Ohtani Y Yamada K Furihata Y Hayakawa H Seto 《Journal of the American Chemical Society》2001,123(6):1262-1263
59.
The purpose of this paper is to study the existence of zero points for set-valued pseudomonotone operators in a Banach space
by using a new condition which was recently proposed by the authors (Matsushita and Takahashi, Set-Valued Analysis 15:251–264,
2007).
相似文献
60.
Changes in reflection spectra were probed to study the dynamics of photoinduced transformation from ionic to neutral phases in tetrathiafulvalene- p -chloranil crystals. The results have revealed the formation of the precursor of metastable N -phase domains, dynamical lattice relaxation of and proliferation during phase transformation. 相似文献