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Gottfried Mrkl Andreas Pll Norbert G. Aschenbrenner Corinna Schmaus Theodor Troll Peter Kreitmeier Heinrich Nth Martin Schmidt 《Helvetica chimica acta》1996,79(5):1497-1517
Extremely Expanded Tetrathiafulvalenes with Polyene Spacers. Carotinoid Tetrathiafulvalenes. Polymethin-Tetracyanotetrathiafulvalene Radical Cations, a New Class of Violenes The synthesis of extended tetrathiafulvalenes 11 with di-, tetra-, hexa-, octa-, deca- and dodecamethine spacers is described by a PPh3-induced Wittig-reaction-like condensation of the corresponding polyenedials 10 with 2-thio-1,3-dithiole-4,5-dicarbonitrile ( 9 ). By the same procedure, the dimethyloctamethine- and the tetramethyl-hexadecamethine-tetrathiafulvalenes 14 and 15 , respectively, were obtained. The extended tetrathiafulvalenes represent multistep vinylogous redox systems of the ‘violene type’. They can be oxidized to give the cyanine-like radical cations, e.g. 11 sem, 14 sem, and 15 sem, and the dications, e.g. 11 ox, 14 ox, and 15 ox; their UV/VIS/NIR spectra are reported. The crystal and molecular structure of (all-E)-2,2′-(octa-2,4,6-trien-1,8-diylidene)bis[1,3-dithiole-4,5-dicarbonitrile] ( 11e ) was determined: it is a rod-like, planar molecule; in the crystal, it forms staples along the longest molecule axis. The CV measurements confirm that the redox potentials of 11, 14 , and 15 decrease asymptotically with the increasing length of the spacer. Because of the close relationship of the extended tetrathiafulvalenes (ETTF's) to the carotinoids, they are named ‘caroviologenes’; they formally belong to the class of molecular wires. 相似文献
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Florian Breitsameter Hans-Peter Schrdel Alfred Schmidpeter Heinrich Nth Susana Rojas-Lima 《无机化学与普通化学杂志》1999,625(8):1293-1300
Ylide Adducts of Pentele Trichlorides Ylides Ph3PCR2 form 1 : 1 adducts with PCl3, AsCl3 und SbCl3. The addition of HCl to dichlorophosphanyl- und dichloroarsanyl ylides also leads to such adducts. In solution the PCl3 adducts 2 are dissociated into ions. For the AsCl3 adducts 3 b and 3 e of triphenylphosphonium ethylide and isopropylide X-ray analyses show distinctly different degrees of transition from a zwitterionic ψ-tbp to a cationic ψ-tetrahedral structure. The SbCl3 adduct 4 b of the triphenylphosphonium ethylide on the other hand forms a rather asymmetric dimer and approaches a square-pyramidal geometry at the antimony atom. The 2 : 1 ylide adducts 11 with PCl3 form in solution the dications (Ph3PCR2)2PCl2+. The 2 : 3 adduct 15 of triphenylphosphonium methylide to AsCl3 also has an ionic structure in the crystal. There are cations (Ph3PCH2)2AsCl2+, which pairwise join with two AsCl3 molecules to form doubly charged supracations in the presence of As2Cl82– as counterions. 相似文献
67.
Mesomorphic properties and structures of two mix-substituted lipophilic phthalocyanine derivatives of the A3B type, with a different ratio of electron-donating (hexadecyloxy-) and electron-withdrawing (Cl-) substituents on the isoindol fragments ‘A’ and ‘B’, correspondingly, were studied by polarising optical microscopy, differential scanning calorimetry and small-angle X-ray scattering. Both compounds display columnar mesophases, and the type of organisation of the columns in the mesomorphic state was found to strongly depend on the number of peripheral chlorine substituents in the molecule. The di-chloro-substituted phthalocyanine forms a solid pasty lamellar phase at room temperature, which on heating undergoes successive transitions to two large-lattice columnar mesophases (2D-Colh and 3D-MCol) arising from the aggregation of several phthalocyanine-containing piles. On the contrary, aggregation of columns does not occur for the tetra-chloro-substituted phthalocyanine, which forms a nematic columnar mesophase of single phthalocyanine piles (1D-NCol). While the di-chloro-compound partly crystallises on cooling, the nematic phase of the tetra-chloro-compound freezes at room temperature. The reasons for this different self-organisation behaviour are not yet fully understood, but some hints may be deduced from the proposed supramolecular models. 相似文献
68.
Equilibrium Pressure Measurements in the System Se/O/Br The saturation pressure or saturation decomposition pressure of SeOBr2,l, Se2Br2,l and SeBr4,s were determined in a membran zero manometer. The decomposition behaviour follows from pressure measurements outside of saturation. From the equilibrium data are derived the Enthalpies of formation: Data see Inhaltsübersicht. Informations about the melting diagrams obtained via the barograms of the condensed compositions SeO2/SeBr4 and Se/Br. 相似文献
69.
Matthias Westerhausen Christin Birg Holger Piotrowski Tassilo Habereder Max Suter Heinrich Nth 《无机化学与普通化学杂志》2001,627(5):882-890
Formation of Alkaline Earth Metal‐Arsenic Cages via the Metalation of Triisopropylsilylarsane with Calcium, Strontium, and Barium Bis[bis(trimethylsilyl)amide] in Tetrahydrofuran The metalation of triisopropylsilylarsane with the alkaline earth metal bis[bis(trimethylsilyl)amides] in tetrahydrofuran yields the THF complexes of calcium ( 1 ), strontium ( 2 ), and barium‐bis(triisopropylsilylarsanide) ( 3 ). Dissolving of these compounds in toluene leads to the elimination of triisopropylsilylarsane and the formation of the THF complexes of tetraalkaline earth metal hexakis(triisopropylsilylarsanide)‐triisopropylsilylarsanediide of calcium ( 4 ), strontium ( 5 ), and barium ( 6 ), respectively. The central polyhedron of compound 4 can be described as two trigonal bipyramids with the metal atoms in apical positions, connected via the arsanediide substituent as a common corner. The central moieties of the compounds 5 and 6 consist of four trigonal bipyramids which are connected by common edges as well as common faces. 相似文献
70.
Dieter Leibfritz Erhard Haupt Norbert Dubischar Heinrich Lachmann Raymond Oekonomopulos Günther Jung 《Tetrahedron》1982,38(14):2165-2181
The uncommon amino-acid 2-methylalanine (α-aminoisobutyric acid, Aib) was investigated by 13C-NMR. The chemical shifts of amino- or carboxy-protected derivatives of Aib and of protected oligopeptides are discussed with respect to neighbouring groups and amino acids. The pH-dependence of the 13C-NMR spectra of Aib, Aib-Ala, Ala-Aib, Aib-Ala-Aib and Aib-Ala-Aib-Ala-Aib was studied. Using these examples, a new and advantageous method is demonstrated for the first time for the evalutions of NMR titration curves, which uses so-called chemical shift diagrams (CS diagrams). 相似文献