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811.
812.
813.
Phillip C. Wankat 《Separation & Purification Reviews》2013,42(2):199-200
Abstract E.F. Vansant and R. Dewolfs, Eds. Elsevier, Amsterdam, 1990; (Process Technology Proceedings, 8), hard bound, 700 pages, $233.00 相似文献
814.
Bernd E. Diebl Yang Li Mirza Cokoja Fritz E. Kühn Narayanan Radhakrishnan Stefan Zschoche Hartmut Komber Hui Yee Yeong Brigitte Voit Oskar Nuyken Phillip Hanefeld Hans‐Michael Walter 《Journal of polymer science. Part A, Polymer chemistry》2010,48(17):3775-3786
Acetonitrile ligated molybdenum (III) complexes of the structure [MoCl(NCCH3)5]2+ bearing different weakly coordinating anions [B(C6F5)4]? (WCA a), [B{C6H3(m‐CF3)2}4]? (WCA b) and [(C6F5)3B‐C3H3N2‐B(C6F5)3]? (WCA c) were applied as homogeneous catalysts of the polymerization of isobutylene. High monomer conversions were obtained in short reaction times (<30 min). The molecular weight of the resulting polyisobutylene is nearly independent of parameters such as temperature, solvent, monomer concentration, but is strongly influenced by the type of WCA and by chain transfer reactions which were observed in these systems. Highly reactive low molecular weight polyisobutylenes (Mn < 2000 g/mol) were obtained with a high content of exo double bond end groups as shown by 1H NMR analysis. Furthermore, experiments were performed to reduce the isomerization of these exo end groups into other internal double bonds by varying the polymerization parameters. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3775–3786, 2010 相似文献
815.
816.
Phillip S. Harrington 《Mathematische Zeitschrift》2009,262(1):199-217
Let be a bounded pseudoconvex domain with C
k
boundary, k ≥ 1. In this paper, we will prove that the Cauchy–Riemann operator has a bounded solution operator in the Sobolev space for all . 相似文献
817.
Iminium salts can provide high selectivity and high efficiency when used as organocatalysts for asymmetric epoxidation. For this purpose, they are normally used in conjunction with Oxone as the stoichiometric oxidant. Oxone, however, has limited stability, is insoluble in most organic solvents, is atom-inefficient, and produces considerable inorganic residue as the by-product of oxidation. In this paper we report for the first time the development of a reaction system driven by sodium hypochlorite as the stoichiometric oxidant. 相似文献
818.
Kraft SJ Williams UJ Daly SR Schelter EJ Kozimor SA Boland KS Kikkawa JM Forrest WP Christensen CN Schwarz DE Fanwick PE Clark DL Conradson SD Bart SC 《Inorganic chemistry》2011,50(20):9838-9848
Uranium compounds supported by redox-active α-diimine ligands, which have methyl groups on the ligand backbone and bulky mesityl substituents on the nitrogen atoms {(Mes)DAB(Me) = [ArN═C(Me)C(Me)═NAr], where Ar = 2,4,6-trimethylphenyl (Mes)}, are reported. The addition of 2 equiv of (Mes)DAB(Me), 3 equiv of KC(8), and 1 equiv of UI(3)(THF)(4) produced the bis(ligand) species ((Mes)DAB(Me))(2)U(THF) (1). The metallocene derivative, Cp(2)U((Mes)DAB(Me)) (2), was generated by the addition of an equimolar ratio of (Mes)DAB(Me) and KC(8) to Cp(3)U. The bond lengths in the molecular structure of both species confirm that the α-diimine ligands have been doubly reduced to form ene-diamide ligands. Characterization by electronic absorption spectroscopy shows weak, sharp transitions in the near-IR region of the spectrum and, in combination with the crystallographic data, is consistent with the formulation that tetravalent uranium ions are present and supported by ene-diamide ligands. This interpretation was verified by U L(III)-edge X-ray absorption near-edge structure (XANES) spectroscopy and by variable-temperature magnetic measurements. The magnetic data are consistent with singlet ground states at low temperature and variable-temperature dependencies that would be expected for uranium(IV) species. However, both complexes exhibit low magnetic moments at room temperature, with values of 1.91 and 1.79 μ(B) for 1 and 2, respectively. Iodomethane was used to test the reactivity of 1 and 2 for multielectron transfer. While 2 showed no reactivity with CH(3)I, the addition of 2 equiv of iodomethane to 1 resulted in the formation of a uranium(IV) monoiodide species, ((Mes)DAB(Me))((Mes)DAB(Me2))UI {3; (Mes)DAB(Me2) = [ArN═C(Me)C(Me(2))NAr]}, which was characterized by single-crystal X-ray diffraction and U M(4)- and M(5)-edge XANES. Confirmation of the structure was also attained by deuterium labeling studies, which showed that a methyl group was added to the ene-diamide ligand carbon backbone. 相似文献
819.
Maimone TJ Milner PJ Kinzel T Zhang Y Takase MK Buchwald SL 《Journal of the American Chemical Society》2011,133(45):18106-18109
A mechanistic investigation of the Pd-catalyzed conversion of aryl triflates to fluorides is presented. Studies reveal that C-F reductive elimination from a LPd(II)(aryl)F complex (L = t-BuBrettPhos or RockPhos) does not occur when the aryl group is electron rich. Evidence is presented that a modified phosphine, generated in situ, serves as the actual supporting ligand during catalysis with such substrates. A preliminary study of the reactivity of a LPd(II)(aryl)F complex based on this modified ligand is reported. 相似文献
820.
We report a universal method for the surface-initated polymerization (SIP) of an antifouling polymer brush on various classes of surfaces, including noble metals, metal oxides, and inert polymers. Inspired by the versatility of mussel adhesive proteins, we synthesized a novel bifunctional tripeptide bromide (BrYKY) that combines atom-transfer radical polymerization (ATRP) initiating alkyl bromide with l-3,4-dihydroxyphenylalanine (DOPA) and lysine. The simple dip-coating of substrates with variable wetting properties and compositions, including Teflon, in a BrYKY solution at pH 8.5 led to the formation of a thin film of cross-linked BrYKY. Subsequently, we showed that the BrYKY layer initiated the ATRP of a zwitterionic monomer, sulfobetaine methacrylate (SBMA), on all substrates, resulting in high-density antifouling pSBMA brushes. Both BrYKY deposition and pSBMA grafting were unambiguously confirmed by ellipsometry, X-ray photoelectron spectroscopy, and goniometry. All substrates that were coated with BrYKY/pSBMA dramatically reduced bacterial adhesion for 24 h and also resisted mammalian cell adhesion for at least 4 months, demonstrating the long-term stability of the BrYKY anchoring and antifouling properties of pSBMA. The use of BrYKY as a primer and polymerization initiator has the potential to be widely employed in surface-grafted polymer brush modifications for biomedical and other applications. 相似文献