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61.
Zoltán Füredi Alexandr Kostochka Ruth Luo Jacques Verstraëte 《Discrete Mathematics》2018,341(5):1253-1263
The Erd?s–Gallai Theorem states that for , any -vertex graph with no cycle of length at least has at most edges. A stronger version of the Erd?s–Gallai Theorem was given by Kopylov: If is a 2-connected -vertex graph with no cycle of length at least , then , where . Furthermore, Kopylov presented the two possible extremal graphs, one with edges and one with edges.In this paper, we complete a stability theorem which strengthens Kopylov’s result. In particular, we show that for odd and all , every -vertex 2-connected graph with no cycle of length at least is a subgraph of one of the two extremal graphs or . The upper bound for here is tight. 相似文献
62.
63.
Raphaël Côte Carlos E. Kenig Frank Merle 《Communications in Mathematical Physics》2008,284(1):203-225
Given g and f = gg′, we consider solutions to the following non linear wave equation :
Under suitable assumptions on g, this equation admits non-constant stationary solutions : we denote Q one with least energy. We characterize completely the behavior as time goes to ±∞ of solutions (u, u
t
) corresponding to data with energy less than or equal to the energy of Q : either it is (Q, 0) up to scaling, or it scatters in the energy space.
Our results include the cases of the 2 dimensional corotational wave map system, with target , in the critical energy space, as well as the 4 dimensional, radially symmetric Yang-Mills fields on Minkowski space, in
the critical energy space.
Centre National de la Recherche Scientifique.
Institut des Hautes études Scientifiques.
The work of R.C. and F.M. has been supported in part by ANR grant ONDE NONLIN, and the work of C.E.K. has been supported in
part by NSF. 相似文献
64.
Stanislav Stříteský Martin Vala Jan David Eva Šafaříková Jan Víteček Martin Weiter 《Chemical Papers》2018,72(7):1635-1643
In this paper, the possibility to use diketopyrrolopyrrole (DPP) for the construction of electrical devices designed to interact with animal cells was studied. For this purpose, the biocompatibility and electrical properties of the selected DPP derivative (3,6-bis(5-(benzofuran-2-yl)thiophen-2-yl)-2,5-bis(2-ethyl-hexyl)pyrrolo[3,4-c]pyrrole-1,4-dione) [referred as DPP(TBFu)2] were researched. The electrical properties were studied using model organic field-effect transistors. Mainly investigated was under what conditions maximum charge carrier mobility can be achieved. Using the cumulative effect of self-assembled monolayers on dielectrics and electrodes and detailed thermal analysis of the DPP, a higher charge carrier mobility was achieved than has been previously reported (5.5?×?10?3 cm2 V?1 s?1). The biocompatibility was studied based on a culture of 3T3 fibroblasts. This research revealed that DPP(TBFu)2 can be used in applications involving direct contact with living animal cells. The conclusions found with these model devices can be applied to components suitable for biosensing applications, e.g., water- or electrolyte-gated organic field-effect transistors. 相似文献
65.
W. Muchlinsky E. Rother G. Jander O. Pfundt E. Göte W. Schramek L. W. Janssen J. A. C. Teegan A. Schleicher W. Lüdicke E. Denina J. M. Preston N. Rae J. K. Rummel K. Schierjott J. M. Kolthoff T. Kameda L. Blumen J. Pucherna Fr. Hein H. Pauling 《Analytical and bioanalytical chemistry》1932,89(3-4):128-135
66.
E. Wedekind W. E. Cohen W. Ender P. S. Billington F. A. Simmonds P. K. Baird W. M. Bray G. J. Ritter R. M. Seborg R. L. Mitchell H. A. Iddles P. J. Robbins W. J. Powell H. Whittacker N. C. Pervier R. A. Gortner A. Jolles A. Brüning M. Schnetka T. H. Whitehead R. C. Griffing C. G. Schwalbe Käte Berting Rütgerswerke A. -G. M. Dreifuß A. Staab W. Krieg H. Pflug H. Jacob R. Kaesbohrer H. Schmitz 《Analytical and bioanalytical chemistry》1935,100(1-2):64-75
67.
J. Wouters F. Moureau Ph. Perpète B. Norberg G. Evrard F. Durant 《Journal of chemical crystallography》1994,24(9):607-614
In order to examine the possibility of hydrogen bonding around the flavin ring, an X-ray diffraction study of the title compound was undertaken. Crystals of lumiflavin hydrochloride hydrate [2(C13H12N4O2) 4 HCl 7 H2O] are triclinic, space group
,Z=2,a=11.064(1),b=17.903(1),c=9.891(1)Å, =111.9(6), -96.4(8), =91.6(7)°. We present the crystal structure of this compound and compare it with other flavin derivatives and with the structure of the active site of some flavoproteins. 相似文献
68.
Julien Preat Denis Jacquemin Daniel P. Vercauteren Eric A. Perpète 《Theoretical chemistry accounts》2008,119(5-6):463-468
In this contribution, we set up a SAC-CI methodology to evaluate the n → π* and π → π* vertical transition energies of a series of thiocarbonyl derivatives. We show that Frozen-Core SAC-CI provides accurate
vertical excitations energies. Nevertheless, in order to obtain converged results, the R2S2 unliked integrals have to be taken
into account in L3-SAC-CI calculations. In addition, we present the comparative performances of three computational procedures,
INDO/S, TD-DFT, and SAC-CI, for the calculation of valence excited states energies and it turns out that: (1) no tuning of
the exact exchange (α) included in TD-DFT allows to consistently reproduce the SAC-CI results; (2) SAC-CI and TD-B3LYP both evaluate the n → π*, as well as the π → π* transition energies, with a similar accuracy.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
69.
Zampella A Sepe V Luciano P Bellotta F Monti MC D'Auria MV Jepsen T Petek S Adeline MT Laprévôte O Aubertin AM Debitus C Poupat C Ahond A 《The Journal of organic chemistry》2008,73(14):5319-5327
A new anti-HIV cyclodepsipeptide, homophymine A, was isolated from a New Caledonian collection of the marine sponge Homophymia sp. The structure of homophymine A was determined by interpretation of spectroscopic data, acid hydrolysis, and LC-MS analysis. Homophymine A contains 11 amino acid residues and an amide-linked 3-hydroxy-2,4,6-trimethyloctanoic acid moiety. Along with four D-, two L-, and one N-methyl amino acids, it also contains four unusual amino acid residues: (2S,3S,4R)-3,4-diMe-Gln, (2R,3R,4S)-4-amino-2,3-dihydroxy-1,7-heptandioic acid, L-ThrOMe, and (2R,3R,4R)-2-amino-3-hydroxy-4,5-dimethylhexanoic acid. In a cell-based XTT assay, homophymine A exhibited cytoprotective activity against HIV-1 infection with a IC50 of 75 nM. 相似文献
70.
In this Letter a fast and reliable computational protocol for the calculation of pKa* of photoacids is presented. The results obtained for several coumarins indicate that, beyond the obtained numerical accuracy, it is indeed possible to develop a reliable computational procedure for pKa* calculation by combining, in a judicious way, a reliable model for the excited states (TD-DFT) with a fast solvent model (PCM). The characteristics of the different components of the model will allow for routine applications to medium and large chemical systems, so that the proposed protocol could nicely integrate experimental analyses. 相似文献