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561.
Bryan MC Fazio F Lee HK Huang CY Chang A Best MD Calarese DA Blixt O Paulson JC Burton D Wilson IA Wong CH 《Journal of the American Chemical Society》2004,126(28):8640-8641
A covalent array for the display of complex oligosaccharides in microtiter plates has been developed. This strategy is conducive to the display of carbohydrates to proteins of interest such as lectins and antibodies, including the broadly neutralizing antibody 2G12 against HIV envelope oligomannose and can be cleaved from the surface for further characterization by mass spectrometry. The system was used to probe the multivalent interaction of 2G12 with an optimal epitope (Kd 0.1 muM). 相似文献
562.
Gary Tresadern Paul F. Faulder M. Paul Gleeson Zubeir Tai Grant MacKenzie Neil A. Burton Ian H. Hillier 《Theoretical chemistry accounts》2003,109(3):108-117
Hybrid quantum mechanical (QM)/molecular mechanical (MM) calculations are used to study two aspects of enzyme catalysis,
Kinetic isotope effects associated with the hydride ion transfer step in the reduction of benzyl alcohol by liver alcohol
dehydrogenase are studied by employing variational transition-state theory and optimised multidimensional tunnelling. With
the smaller QM region, described at the Hartree–Fock ab initio level, together with a parameterised zinc atom charge, good
agreement with experiment is obtained. A comparison is made with the proton transfer in methylamine dehydrogenase. The origin
of the large range in pharmacological activity shown by a series of α-ketoheterocycle inhibitors of the serine protease, elastase,
is investigated by both force field and QM/MM calculations. Both models point to two different inhibition mechanisms being
operative. Initial QM/MM calculations suggest that these are binding, and reaction to form a tetrahedral intermediate, the
latter process occurring for only the more potent set of inhibitors.
Recieved 3 October 2001 / Accepted: 6 September 2002 / Published online: 31 January 2003
Contribution to the Proceedings of the Symposium on Combined QM/MM Methods at the 222nd National Meeting of the American
Chemical Society, 2001
Correspondence to: I. H. Hillier
Acknowledgements. We thank EPSRC and BBSRC for support of the research and D.G. Truhlar for the use of the POLYRATE code. 相似文献
563.
Donald J. Burton 《Journal of fluorine chemistry》1984,25(1):21-25
Although fluorine chemistry is rapidly approaching its 100th anniversary, organofluorine chemistry, as most of us know it, is only 40–50 years old. Interest and enthusiasm in this area of chemistry essentially traces its origins to the discovery and industrial applications of the Freons and polytetrafluoroethylene (Teflon). The unique properties of these materials attracted attention to this neglected area of organic chemistry—particularly industrially—and stimulated work on methods for the introduction of fluorine into organic molecules. 相似文献
564.
C.I. Reactive Blue 2 analogues were bonded onto an agarose support matrix by a novel method which entailed immobilisation by the anthraquinone ring 1-amino group as opposed to the usual triazine ring coupling methods. Dyes with spacer arms attached to the anthraquinone ring 1-amino group were synthesised by reacting methoxytriazine analogues of C.I. Reactive Blue 2 with chloroacetyl chloride and ethylenediamine. Unlike the blue parent dyes, all C.I. Reactive Blue 2 analogues with derivatised anthraquinone ring 1-amino groups were of a characteristic red colour. This change of chromaticity was entirely expected since the anthraquinone ring 1-amino group is an important component of the C.I. Reactive Blue 2 chromophore. Chromatographic studies indicated that, in comparison to adsorbents comprising triazine ring-immobilised dyes, adsorbents formed from C.I. Reactive Blue 2 analogues immobilised by the anthraquinone ring were better suited to the isolation of horse liver alcohol dehydrogenase and other adenine nucleotide-requiring enzymes. Similarities between C.I. Reactive Blue 2 analogues immobilised by the anthraquinone ring and N6-(6-aminohexyl)adenine nucleotide derivatives could be identified which may account for these observations. These studies confirm that highly effective affinity ligands based on synthetic textile dyes can be designed in a rational manner. 相似文献
565.
The solvents acetonitrile, methanol, N, N-dimethylformamide, dimethyl sulfoxide, formamide, and deionized water were investigated for their ability to support current flow without added electrolyte. Using open tubular capillary electrophoresis, currents were measured to be in the nanoampere (10?9 A) range for all solvents but formamide (10?6 A). Comparisons with flow data showed no clear relationship between current and electroosmotic flow. Packed capillary columns (3-μm ODS) were used for separations using both pure solvent and hydrophobic dyes showed mild retention in pure ACN. A 16 polynuclear aromatic hydrocarbon (PAH) standard soluton was separated in 80/20 ACN/H2O with reduced plate heights (h) between 2.8 and 3.1 for retained species. A separation of nine androstenediones was achieved using a 70/30 MeOH/H2O mobile phase. 相似文献
566.
Radioactive 2,4-dichlorophenyl methanesulfonate labeled with 14C and 35S has been synthesized because it was needed to facilitate the study of the metabolic fate of this interesting nematicide. It was prepared from the reaction between methanesulfonyl chloride and 2,4-dichlorophenol in the presence of a base. Three hundred milligrams of each 14C- and 35S-2,4-dichlorophenyl methanesulfonate was obtained in a yield of 87% based on 14C-2,4-dichlorophenol or 35S-methanesulfonyl chloride, respectively. The specific activity was 3.8 mCi/mmol for the compound labeled with 35S and 2.5 mCi/mmol for the 14C material. Both tracers assayed over 99% after purification. 相似文献
567.
Pablo H Di ChennaPhilippe Dauban Alberto GhiniRicardo Baggio Maria Teresa GarlandGerardo Burton Robert H Dodd 《Tetrahedron》2003,59(7):1009-1014
Reaction of 11-pregnene-3,20-dione (6) or 3-α-acetoxy-11-pregnen-20-one (12) with trimethylsilylethanesulfonyl (‘Ses’) iminoiodinane 5 in the presence of copper (I) triflate gave the corresponding α,α-11,12-aziridino steroids 7 and 13 in 53 and 45% yields, respectively. The Ses group of each compound was removed using the TASF reagent and the resulting free aziridine NH was methylated to afford the 11α,12α-N-methyl aziridinosteroids 9 and 15, respectively. The latter is a conformationally constrained analogue of the endogenous neurosteroid pregnanolone (1). 相似文献
568.
Chen L Nourse JG Christie BD Leland BA Grier DL 《Journal of chemical information and computer sciences》2002,42(6):1296-1310
From REACCS, to MDL ISIS/Host Reaction Gateway, and most recently to MDL Relational Chemistry Server, a new product based on Oracle data cartridge technology, MDL's reaction database management and retrieval systems have undergone great changes. The evolution of the system architecture is briefly discussed. The evolution of MDL reaction substructure search (RSS) algorithms is detailed. This article mainly describes a novel RSS algorithm. This algorithm is based on a depth-first search approach and is able to fully and prospectively use reaction specific information, such as reacting center and atom-atom mapping (AAM) information. The new algorithm has been used in the recently released MDL Relational Chemistry Server and allows the user to precisely find reaction instances in databases while minimizing unrelated hits. Finally, the existing and new RSS algorithms are compared with several examples. 相似文献
569.
David E Portlock Dinabandhu NaskarLaura West William L SeibelTitan Gu Howard J KraussX.Sean Peng Paul M DybasEdward G Soyke Stephen B AshtonJonathan Burton 《Tetrahedron letters》2003,44(28):5365-5368
The synthesis of Δ3,10-isoquinine (5Z,5E) and Δ3,10-isoquinidine (6Z,6E) was achieved in one-step through positional isomerization of the terminal alkene in the parent cinchona alkaloids using catalytic amounts of 5% Rh/Al2O3 and excess hydrochloric acid in refluxing 50% aqueous EtOH. The products were obtained in good yields as a mixture of E and Z geometric isomers and fully characterized using spectroscopic methods. 相似文献
570.
I.M Chakravarti Catherine T Burton 《Journal of Mathematical Analysis and Applications》1982,89(2):515-529
Decomposition into a direct sum of irreducible representations of the representation of the full collineation group of a finite Desarguesian plane, as a group of matrices permuting the flags of the plane and the simple components of the corresponding commutant algebra, have been worked out here for the projective plane PG(2, 2) and the affine plane EG(2, 3). The dimension and the components of the covariance matrix of the observations from a design derived from such a plane, which commutes with such a permutation representation of the full collineation group of the plane, are thus determined. This paper is in the spirit of earlier works by, James (1957), Mann (1960), 6., 7., McLaren (1963), and Sysoev and Shaikan (1976). A. T. James, Ann. Math. Statist.28 (1957), 993–1002, H. B. Mann, Ann. Math. Statist.31 (1960), 1–15, E. J. Hannan, Research Report (Part. (I)), Summer Research Institute, Australian Math. Soc. and Methuen's Monographs on Applied Probability and Statistics, Supplementary Review Series in Applied Probability, Vol. 3, A. D. McLaren, Proc. Cambridge Philos. Soc.59 (1963), 431–450, and L. P. Sysoev and M. E. Shaikin, Avtomat. i Telemekh.5 (1976), 64–73. 相似文献