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51.
Lucas CL Lygo B Blake AJ Lewis W Moody CJ 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(6):1972-1978
A study of the regioselectivity of the Claisen rearrangement of meta-allyloxy aryl ketones showed that the electron-withdrawing carbonyl group has a major influence and strongly directs rearrangement to the more hindered ortho position. However, when the ketone is part of a ring structure, its electronic effect can be negated by conversion into its triisopropylsilyl enol ether, which dramatically reverses the regiochemistry of the Claisen rearrangement. DFT calculations suggest that the effect is electronic although there is also a steric effect of the bulky silyl group. This strategy for influencing the regiochemical outcome of the Claisen rearrangement was then employed in a short synthesis of the furo[2,3-g]chromene, (-)-pestalotheol D, that confirms the absolute stereochemistry of the natural product. 相似文献
52.
Linder J Garner TP Williams HE Searle MS Moody CJ 《Journal of the American Chemical Society》2011,133(4):1044-1051
The structurally unique natural product telomestatin incorporates seven oxazole rings and one sulfur-containing thiazoline in a macrocyclic arrangement. The compound is a potent inhibitor of the enzyme telomerase and therefore provides a structural framework for developing new potential therapeutic agents for cancer. An efficient formal total synthesis of telomestatin is reported in which the key steps are the use of dirhodium(II)-catalyzed reactions of diazocarbonyl compounds to generate six oxazole rings, demonstrating the power of rhodium carbene methodology in organic chemical synthesis. CD spectroscopy establishes that seco-derivatives of telomestatin are potent stabilizers of G-quadruplex structures derived from the human telomeric repeat sequence. Mass spectrometry studies, confirmed by molecular dynamics simulations, provide the first evidence that high affinity binding to terminal G-tetrads in both 1:1 and 2:1 ligand complexes is mediated through the macrocycle coordinating a monovalent cation, with selectivity for the antiparallel structure. 相似文献
53.
A new protocol for the synthesis of protected amino-1,4-benzoquinones by oxidation of the corresponding 2,5-dimethoxyaniline derivatives using PhI(OAc)(2) or PhI(OCOCF(3))(2) in water containing 2.5% methanol is reported. The process represents an improvement over previously reported methods, both in terms of yield and number of steps, and in the range of nitrogen protecting groups that it tolerates. A number of novel aminobenzoquinones were prepared and subsequently used as dienophiles in Diels-Alder reactions to form building blocks for the synthesis of the aminonaphthoquinone antibiotics such as salinisporamycin. 相似文献
54.
K. J. Moody W. Brüchle M. Brügger H. Gäggeler B. Haefner M. Schädel K. Sümmerer H. Tetzlaff G. Herrmann N. Kaffrell J. V. Kratz J. Rogowski N. Trautmann M. Skålberg G. Skarnemark J. Alstad M. M. Fowler 《Zeitschrift für Physik A Hadrons and Nuclei》1987,328(4):417-422
We have observedγ-rays following the β?-decay of243Np and244Np after chemical isolation of neptunium isotopes from the products of the reaction of 835 MeV136Xe with244Pu. The ground-state of 1.85-min243Np hasJ=5/2. The decay of 2.29-min244Np (probableJ π=7?) populates high-spin members of the ground state rotational band in244Pu. 相似文献
55.
Simon N. Davey Lee W. Tetler David A. Leigh Andrew E. Moody 《Journal of mass spectrometry : JMS》1993,28(5):559-563
The products of the reaction between fullerenes (C60/C70) and dimethylamine were investigated by fast atom bombardment (FAB) mass spectrometry and tandem mass spectrometry (MS/MS). The FAB mass spectrum shows peaks corresponding to the addition of up to eight dimethylamine species, exclusively to C70. MS/MS reveals an unusual fragmentation pattern. The mass spectrum of the reaction products, together with a number of tandem mass spectra, are shown. 相似文献
56.
P. A. Wilk J. H. Landrum D. A. Shaughnessy J. M. Kenneally N. J. Stoyer M. A. Stoyer K. J. Moody N. V. Aksenov G. A. Bozhikov E. E. Tereshatov G. K. Vostokin S. V. Shishkin S. N. Dmitriev 《Journal of Radioanalytical and Nuclear Chemistry》2008,275(3):651-657
A chemical separation method based on reversed-phase chromatography has been developed to separate the group five elements
from the reaction products produced in the bombardment of 243Am with 48Ca ions. Decontamination factors on the order of 106 were achieved for group-three elements such as americium, and 107 or more for selected reaction products as measured by gamma-ray spectrometry pre-and post-chemistry. Details of the chemical
separation scheme are discussed and compared to previously reported results. 相似文献
57.
The preparation of 3-(3,3-dimethyltriazen-l-yl)pyridine-4-carboxylic acid (5), a convenient shelf-stable precursor to 3,4-didehydropyridine, is described. 相似文献
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