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641.
The structure of the title compound features mononuclear octahedral CoII cations, trans-[Co(H2O)2(MeCN)4]2+, and trinuclear anions, trans-[Co(H2O)2(MeCN)2(CoCl4)2]2–; the latter centrosymmetric units contain a central octahedral Co(H2O)2(MeCN)2 moiety with two tetrahedral [CoCl4]2– ligands. These two large ions are held in a network of intra- and inter-molecular hydrogen bonding. 相似文献
642.
Jan Janczak Ryszard Kubiak 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(6):m237-m240
Isomorphous triclinic forms of dichloro[phthalocyaninato(2−)]tin(IV), [Sn(C32H16N8)Cl2], and dichloro[phthalocyaninato(2−)]germanium(IV), [Sn(C32H16N8)Cl2], and a monoclinic form of the latter have been obtained from the reaction of pure tin and germanium powder, respectively, with phthalonitrile under a stream of ICl vapour. All three crystal structures consist of centrosymmetric [SnPcCl2] and [GePcCl2] [Pc is phthalocyaninate(2−)] molecules, which are separated but interacting. In the triclinic forms (Sn and Ge), the Pc macrocycles are not staggered but slipped, and in the monoclinic form (Ge), the molecules are additionally inclined. In both cases, the central Sn or Ge atom is six‐coordinated by the four isoindole N atoms of the Pc macrocyclic ligand and by two Cl atoms (located trans) into a tetragonal–bipyramidal structure. The arrangement of [SnPcCl2] and [GePcCl2] molecules in the crystal structure is determined mainly by intermolecular C—H⃛Cl, π–π and van der Waals interactions. 相似文献
643.
Rong-Ming Ho Adeyinka Adedeji David W. Giles Damian A. Hajduk Christopher W. Macosko Frank S. Bates 《Journal of Polymer Science.Polymer Physics》1997,35(17):2857-2877
A model asphalt has been separated into two parts, asphaltene and maltene, through solvent extraction by n-heptane. The interactions of asphaltene and maltene with the triblock copolymer poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) were investigated by transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), dynamic mechanical analysis (DMA), and differential scanning calorimetry (DSC). Asphaltene was found to be essentially immiscible with both blocks of SEBS, while maltene was miscible with SEBS. An unusual sequence of morphological transformations of SEBS microstructure with respect to the addition of maltene was observed. The morphology transformed from hexagonal cylinder, to perforated layers, to lamellae and then back to the original hexagonal cylinder. The observed transformation reflects a limited solubility for both S and EB domains: at lower concentration maltene is a preferential additive for S domains, while increasing concentration the swelling of EB-rich microdomains by maltene becomes significant. The basic understanding of the interactions of the components of asphalt with SEBS gives a simple path to characterize and predict the microstructure of triblock copolymers in asphalt oligomers. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2857–2877, 1997 相似文献
644.
Catriona H. E. Rooney Dr. Ayelet Gamliel David Shaul Prof. Damian J. Tyler Dr. James T. Grist Prof. Rachel Katz-Brull 《Chemphyschem》2023,24(18):e202300144
Deuterated 13C sites in sugars (D-glucose and 2-deoxy-D-glucose) showed 6.3-to-17.5-fold higher solid-state dynamic nuclear polarization (DNP) levels than their respective protonated sites at 3.35T. This effect was found to be unrelated to the protonation of the bath. Deuterated 15N in sites bound to exchangeable protons ([15N2]urea) showed a 1.3-fold higher polarization than their respective protonated sites at the same magnetic field. This relatively smaller effect was attributed to incomplete deuteration of the 15N sites due to the solvent mixture. For a 15N site that is not bound to protons or deuterons ([15N]nitrate), deuteration of the bath did not affect the polarization level. These findings suggest a phenomenon related to DNP of X-nuclei directly bound to deuteron(s) as opposed to proton(s). It appears that direct binding to deuterons increases the solid-state DNP polarization level of X-nuclei which are otherwise bound to protons. 相似文献
645.
646.
Nicolas Marx Laurence Croguennec Dany Carlier Lydie Bourgeois Pierre Kubiak Frederic Le Cras Claude Delmas 《ChemInform》2010,41(33):no-no
FePO4·H2O is prepared by Li+/H+ exchange from an aqueous HNO3 suspension of LiFePO4(OH) at about 60 °C. 相似文献