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41.
Spatial structures as a result of a modulational instability are obtained in the integrable discrete nonlinear Schrödinger equation (Ablowitz-Ladik equation). Discrete slow space variables are used in a general setting and the related finite differences are constructed. Analyzing the ensuing equation, we derive the modulational instability criterion from the discrete multiple scales approach. Numerical simulations in agreement with analytical studies lead to the disintegrations of the initial modulated waves into a train of pulses. 相似文献
42.
Ferdinand Tantangmo Bruno Ndjakou Lenta Silvre Ngouela Louis Marie Kamdem Bernard Weniger Etienne Tsamo Annelise Lobstein Catherine Vonthron‐Sncheau 《Helvetica chimica acta》2010,93(11):2210-2217
Phytochemical investigation of the bark and leaves of Pancovia laurentii (Sapindaceae) resulted in the isolation of a new ceramide and a new cerebroside, named pancoviamide ( 1 ), and pancovioside ( 2 ) respectively, together with six known compounds: uracil, (R)‐N‐[(1S,2S,3R)‐2,3‐dihydroxy‐1‐(hydroxymethyl)heptadec‐5‐en‐1‐yl]‐2‐hydroxytetracosanamide, stigmasta‐7,22‐dien‐3‐ol, β‐stitosterol, β‐sitosterol 3‐O‐β‐D ‐glucopyranoside, and 2,3‐dihydroxypropyl pentadecanoate. The structures of 1 and 2 were determined by means of spectroscopic methods. Compounds 1 and 2 were tested in vitro for their antiprotozoal properties against several protozoa and for their cytotoxicity. 相似文献
43.
Milo? Luká? Ivan Lacko Marián Bukovsky Zuzana Kyselová Janka Karlovská Branislav Horváth Ferdinand Devínsky 《Central European Journal of Chemistry》2010,8(1):194-201
We synthesized nine quaternary ammonium compounds (QUATs) starting from phenylalanine, N-alkyl-N,N-dimethyl-(1-hydroxy-3-phenylpropyl)-2-ammonium bromides, which were prepared as optically pure substances. Five compounds
were prepared as S-enantiomers and four compounds as R-enantiomers. These compounds were evaluated by their activities against bacteria and fungi. Three microbial strains were
used in the study: the gram-negative bacteria Escherichia coli, the gram-positive bacteria Staphylococcus aureus and the fungi Candida albicans. The activities were expressed as minimum bactericidal or fungicidal concentrations (MBC). The most active compounds were
(2S)-N-tetradecyl-N,N-dimethyl-(1-hydroxy-3-phenylpropyl)-2-ammonium bromide and (2R)-N-tetradecyl-N,N-dimethyl-(1-hydroxy-3-phenylpropyl)-2-ammonium bromide, with MBC values exceeding those of commercial benzalkoniumbromide
(BAB) used as standard. The relationships between structure and biological activity of the tested QUATs were quantified by
the bilinear model (QSAR) and are discussed. 相似文献
44.
45.
Paul Barbic Leo Binder Susanne Voß Ferdinand Hofer Werner Grogger 《Monatshefte für Chemie / Chemical Monthly》2001,132(4):465-472
Summary. Thin-film electrodes allow the manufacturing of flat batteries of variable design. Their electric performance is better than
that of customary cells because of a larger contact area between anode and cathode and better utilization of the electrochemically
active materials. Bipolar thin-film electrodes for the rechargeable alkaline zinc/manganese dioxide system were assembled
using graphite-filled plastics (high-density polyethylene and polyisobutylene). In a different approach, extremely thin electrodes
were obtained using 25 μm thick foils made of non-conductive micro-porous polypropylene. The electroactive materials were
electrolytically deposited into the pores of the previously metallized foil, providing the required conductive connection
through the plastic matrix by themselves. Cycle behavior, cumulated capacities, and energies of batteries with up to two bipolar
units were measured. At this early stage of development, batteries based on graphite-filled polymer foils showed better results
with regard to storage capacity per unit area and to cycle life. Prototypes based on micro-porous polypropylene suffered from
the relatively small fraction of pore volume available for the deposition of active material (about 38%) and from current
collector corrosion.
Received May 30, 2000. Accepted December 18, 2000 相似文献
46.
47.
Ideals and filters in D-posets are defined. Therole of idempotent elements and atoms in the theory ofideals and filters is studied. 相似文献
48.
Dr. Ferdinand v. Arlt 《Monatshefte für Chemie / Chemical Monthly》1901,22(2):144-150
Ohne Zusammenfassung 相似文献
49.
Ferdinand Ihringer 《Journal of Algebraic Combinatorics》2017,46(2):263-274
We describe a general construction of strongly regular graphs from the collinearity graph of a finite classical polar spaces of rank at least 3 over a finite field of order q. We show that these graphs are non-isomorphic to the collinearity graphs and have the same parameters. For most of these parameters, the collinearity graphs were the only known examples, and so many of our examples are new. 相似文献
50.
Nuss G Saischek G Harum BN Volpe M Belaj F Mösch-Zanetti NC 《Inorganic chemistry》2011,50(24):12632-12640
Reaction of potassium tris(mercapto-tert-butylpyridazinyl)borate K[Tn(tBu)] with copper(II) chloride in dichloromethane at room temperature led to the diamagnetic copper boratrane compound [Cu{B(Pn(tBu))(3)}Cl] (Pn = pyridazine-3-thionyl) (1) under activation of the B-H bond and formation of a Cu-B dative bond. In contrast to this, stirring of the same ligand with copper(I) chloride in tetrahydrofuran (THF) gave the dimeric compound [Cu{Tn(tBu)}](2) (2) where one copper atom is coordinated by two sulfur atoms and one hydrogen atom of one ligand and one sulfur of the other ligand. Hereby, no activation of the B-H bond occurred but a 3-center-2-electron B-H···Cu bond is formed. The reaction of copper(II) chloride with K[Tn(tBu)] in water gave the same product 2, but a formal reduction of the metal center from Cu(II) to Cu(I) occurred. When adding tricyclohexyl phosphine to the reaction mixture of K[Tn(R)] (R = tBu, Me) and copper(I) chloride in MeOH, the distorted tetrahedral Cu complexes [Cu{Tn(R)}(PCy(3))] (R = tBu 3, Me 4) were formed. Compound 4 is exhibiting an "inverted" κ(3)-H,S,S, coordination mode. The copper boratrane 1 was further investigated by density functional theory (DFT) calculations for a better understanding of the M→B interaction involving the d(8) electron configuration of Cu. 相似文献