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排序方式: 共有248条查询结果,搜索用时 62 毫秒
61.
Jeffrey A Campbell Viola Bordunov Chris A Broka John Dankwardt Robert T Hendricks James M Kress Keith A.M Walker Jin-Hai Wang 《Tetrahedron letters》2004,45(19):3793-3796
The 3-arylmethylation of indoles using TMSOTf/Et3SiH with a wide variety of substituted benzaldehydes has been accomplished. Under these mild Lewis acid mediated reductive conditions, it was demonstrated that indoles bearing both 6-MeSO2 and 2-methyl substituents could be 3-arylmethylated in good to excellent yields to afford the corresponding 3-arylmethyl indoles, effective as selective COX-2 inhibitors. In addition, the viability of this method for the reductive alkylation of indoles by ketones was demonstrated and shown to be C-3 regioselective. For indoles bearing both a 6-MeSO2 and 2-cyano substituent where this indole reductive alkylation methodology was unsuccessful, an unprecedented Pd(0) mediated arylorganozinc coupling with the requisite substituted 3-methylcarbonatomethylindole proved successful in affording the desired 2-cyano-6-MeSO2-3-arylmethylindoles effective as selective COX-2 inhibitors. 相似文献
62.
George Horvai Andrea Hrabéczy-Páll Viola Horváth Imre Klebovich 《Mikrochimica acta》1994,113(3-6):171-178
A highly sensitive reversed-phase HPLC method has been developed for the determination of nifedipine in human plasma with electrochemical detection. A liquid-liquid extraction procedure is used in sample preparation with an average extraction recovery of 75%. Removing the highly lipophilic plasma components using a special column switching technique reduced the duration of the HPLC measurement from 30 to 9 min. The method is applicable for the pharmacokinetic characterization and bioavailability study of a sustained-release (retard) formulation of nifedipine and for human drug monitoring as it is indicated by the validation of the analysis method. The assay gave a linear response over the concentration range 2.5–50 ng/ml. All the validation parameters are within the internationally required limits. 相似文献
63.
Viola Groehn Lothar Frhlich HaraldH.H.W. Schmidt Wolfgang Pfleiderer 《Helvetica chimica acta》2000,83(10):2738-2750
Various 6‐substituted pteridines and 5,6,7,8‐tetrahydropterins carrying photolabile functions at the side chain (see 7 , 20 – 22 , 34 – 36 , 38 , and 39 ) as well as at the 5‐position (see 27 – 29 ) were synthesized from pterin and from 6‐phenylpterin ( 1 ) and 6‐(hydroxymethyl)pterin ( 10 ). Attachment of the photoaffinity labels via ester bonds required a special protecting‐group strategy based upon acid‐labile (see 30 – 33 ) and β‐eliminating blocking groups (see 17 – 19 ). The 6‐(4‐azidophenyl)pterin ( 7 ) was obtained from 6‐phenylpterin ( 1 ) via intermediates 2 and 4 – 6 , due to the low solubility of simple pterins in general. The pteridine derivatives 21 , 22 , 25 , 26 , 28 , 29 , 32 , 33 , 35 , 36 , 38 , and 39 were screened as inhibitors of neuronal (type I) NO synthase (see Table) from porcine cerebellum, of which 22 , 35 , 36 , and 38 showed interesting inhibitory activity with similar potency and effectiveness. 相似文献
64.
Ignazio Blanco Alberta Latteri Gianluca Cicala Antonio DAngelo Veronica Viola Vincenzo Arconati Michelina Catauro 《Molecules (Basel, Switzerland)》2022,27(3)
This paper aims to synthesize, via the sol–gel method, a biomaterial usable in the medical field. Here, the silica-PEG-quercetin system was evaluated in relation to the different concentrations of PEG (0, 6, 12, 24, 50 wt%) and quercetin (0, 5, 10, 15 wt%), respectively. In addition, Fourier Transform-Infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), and Kirby–Bauer analyses were performed. FT-IR was used to evaluate the hybrid formation and the influence of both PEG and Quercetin in the hybrid synthesized materials, SEM was used to evaluate the morphological properties, while the Kirby–Bauer test was used to understand the ability of the materials to inhibit the growth of the assayed bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, and Staphylococcus aureus). 相似文献
65.
Oliver Oeckler Viola Duppel Josef Bauer Hansjürgen Mattausch Arndt Simon 《无机化学与普通化学杂志》2002,628(7):1607-1614
Tetragonal rare earth boride carbides with structure types derived from La5B2C6 and Sc3C4, respectively, can intergrow coherently. Slabs of both types with various thicknesses from one unit‐cell parameter up to macroscopic domains may grow together, sharing a common square net of metal atoms. There is a tendency towards phase separation in order to achieve long‐range order. However, phasoid‐like crystallites have also been observed. Long‐range order is also achieved by the formation of ordered intergrowth compounds. They are characterised by a regular periodic sequence of lamellar slabs (each of one or a few unit cells thickness) of both basic structure types. 相似文献
66.
67.
A method for determining the elastic constants of an isotropic material, based on crack edge displacement data, is extended to an orthotropic material. Complex potentials are used to obtain the stresses and displacements for plane strain. Mode I crack problems in three mutually orthogonal planes are considered and solved. In particular, the expressions of crack edge displacements are obtained in an explicit form. An iterative statistical identification method, based on a Bayesan approach, is used to identify the elastic constants of an orthotropic medium from the Mode I crack displacements measured from the mid-point of the crack. Some graphics are displayed to illustrate the convergence of the pertinent parameters and the approach of the analytical displacements to their experimental values. 相似文献
68.
69.
70.
A. R. Kalyuskii Yu. E. Shapiro A. V. Bordunov V. N. Pastushok N. G. Luk'yanenko 《Chemistry of Heterocyclic Compounds》1993,29(3):343-348
Two-dimensional NMR spectroscopy (NOESY, COSY-DQF) has been used in a study of nitrogen-containing cryptahemispherands and their complexes with alkali metals. On the basis of experimentally established interproton distances, the preferred conformations of these molecules have been established. It has been shown that the important features of structure determining the molecular conformation are (a) the orientation of the N-CH2(Ar) bond relative to the plane of the crown ether and (b) the length of the methylene bridge (spacer). The spatial and torsional angles have been determined. It has been established that as the length of the bridge is increased, the structure of these molecules approaches a betaine structure, with mutually parallel positions of the phenyl rings. Upon complexation, their orientation changes to mutually perpendicular, and this leads to enlargement of the inner cavity of the molecule and a corresponding rearrangement of its dimensions toward the ionic radius of the alkali metal.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 406–411, March, 1993. 相似文献