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241.
The protein sequence of the hyoscyamine 6β-hydroxylase gene from Hyoscyamusniger was analysed in silico for its potential of heterologous expression. Therefore different parameters determining the proteins properties and structure in prokaryotic or eukaryotic protein expression systems were taken into account. In silico prediction of co- and post-translational modifications revealed 25 putative glycosylation sites, one of which reported to be a co-factor stabilizing residue in 2-oxoglutarate dependent dioxygenases. Potential protein solubility and degradation (PEST) motifs were also evaluated. Together with the calculated physico-chemical properties the results indicated reasonable solubility but potential instability of the protein in Escherichia coli and Saccharomyces cerevisiae. Further a synthetic h6h-gene was introduced into the prokaryotic or eukaryotic hostsEscherichia coli and Saccharomyces cerevisiae to determine protein expression. The protein could be expressed in both organisms, though stability was confirmed to be an issue. 相似文献
242.
In this work, we present an extension of the forward–reverse representation introduced by Bayer and Schoenmakers (Annals of Applied Probability, 24(5):1994–2032, 2014) to the context of stochastic reaction networks (SRNs). We apply this stochastic representation to the computation of efficient approximations of expected values of functionals of SRN bridges, that is, SRNs conditional on their values in the extremes of given time intervals. We then employ this SRN bridge-generation technique to the statistical inference problem of approximating reaction propensities based on discretely observed data. To this end, we introduce a two-phase iterative inference method in which, during phase I, we solve a set of deterministic optimization problems where the SRNs are replaced by their reaction-rate ordinary differential equations approximation; then, during phase II, we apply the Monte Carlo version of the expectation-maximization algorithm to the phase I output. By selecting a set of overdispersed seeds as initial points in phase I, the output of parallel runs from our two-phase method is a cluster of approximate maximum likelihood estimates. Our results are supported by numerical examples. 相似文献
243.
Dinuclear Cobalt Complexes with a Decadentate Ligand Scaffold: Hydrogen Evolution and Oxygen Reduction Catalysis
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Dr. Carlo Di Giovanni Dr. Carolina Gimbert‐Suriñach Dr. Michael Nippe Dr. Jordi Benet‐Buchholz Prof. Jeffrey R. Long Dr. Xavier Sala Prof. Antoni Llobet 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(1):361-369
A new decadentate dinucleating ligand containing a pyridazine bridging group and pyridylic arms has been synthesized and characterized by analytical and spectroscopic techniques. Four new dinuclear cobalt complexes featuring this ligand have been prepared and thoroughly characterized both in the solid state (X‐ray diffraction) and in solution (1D and 2D NMR spectroscopy, ESI‐MS, and electrochemical techniques). The flexible but stable coordination environment provided by the ligand scaffold when coordinating Co in different oxidation states is shown to play a crucial role in the performance of the set of complexes when tested as catalysts for the photochemical hydrogen evolution reaction (HER) and chemical oxygen reduction reaction (ORR). 相似文献
244.
A. Nawrocka M. Szymaska‐Chargot A. Mi A. A. Ptaszyska R. Kowalski P. Wako W. I. Gruszecki 《Journal of Raman spectroscopy : JRS》2015,46(3):309-316
Dietary fibres are regarded as the source of polysaccharides and antioxidants such as polyphenols. However, addition of dietary fibre to bread causes significant reduction in its quality. The bread quality is connected with the structure of gluten proteins. For this reason, Fourier transform Raman spectroscopy was applied to determine changes in structure of gluten proteins modified by seven dietary fibres. The fibres were added to model flour reconstituted with wheat gluten and wheat starch. The model flour was used to provide gluten proteins of definite structure. The obtained results showed that six out of seven fibres caused similar changes in β‐turn structures. The appearance of the band at 1642 cm−1 and the shift toward lower wavenumbers of the band at 1670 cm−1 in the difference spectra indicated hydrogen bonding of carbonyl groups in β‐turns leading to protein folding/aggregation. Addition of fibre preparations caused also changes in conformation of disulfide bridges (S–S), corresponding to transformation to trans‐gauche‐gauche and trans‐gauche‐trans conformations at the expense of the stable gauche‐gauche‐gauche conformation. The S–S bonds in less stable conformations were formed inside the protein complex as well as between protein complexes in the form of β‐structures. Generally, the observed changes in gluten proteins after addition of dietary fibres were results of interactions between fibre polysaccharides and gluten proteins rather than between polyphenols and gluten proteins. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Basically the aim of this work is to define the accurate configuration of 4-substituted (sulfo- and sulfonamidoalkyl)piperidine-2-carboxylic acids which have been conceived as potential NMDA antagonists. H NMR and 2D NMR (COSY) followed by qualitative Homonuclear NOE have led to the assignement of the (±) cis and (±) trans configuration of the whole family's compounds. 相似文献
247.
《光谱学快报》2013,46(5):469-492
Abstract N‐Phenylmaleimide, 2, and N‐(2‐trifluoromethylphenyl)maleimide, 3, were separately added to phencyclone, 1, to yield the corresponding phencyclone Diels–Alder adducts, 4 and 5. The resulting adducts (and some precursors) have been characterized by one‐ and two‐dimensional 1H and 13C NMR at 300 and 75 MHz, and by 19F NMR at 282 MHz, at ambient temperatures. The NMR data are consistent, for both adducts, with: (a) hindered rotation of the bridgehead unsubstituted phenyl groups about the C(sp2)–C(sp3) bonds, based on slow exchange limit (SEL) spectra and (b) endo adduct configuration based on magnetic anisotropic effects in the 1H NMR. The NMR spectra of the phencyclone adduct, 4, of N‐phenylmaleimide, indicate free rotation on the NMR timescales (fast exchange limit, FEL spectra) about the N‐phenyl bond. The spectra for the adduct, 5, of N‐(2‐trifluoromethylphenyl)maleimide are interpreted as consistent with SEL regimes, for the N‐aryl rotations, with a single rotamer present in which the trifluoromethyl group is directed “out of” the adduct cavity, and away from the phenanthrenoid moiety. This conclusion is based, in part, on NMR data suggesting the apparent slow N‐aryl bond rotation in a pair of atropisomers corresponding to the acetic acid addition products from the N‐(2‐trifluoromethylphenyl)maleimide. Evidence of magnetic anisotropic effects due to the phenanthrenoid moiety and proximal carbonyls is discussed. 1H, 13C, and 19F assignments are presented and interpreted. Molecular modeling calculations at the Hartree–Fock level, 6‐31G* basis set, were performed to provide geometry optimizations for energy‐minimized structures of selected compounds. 相似文献
248.
We consider a generalized version of Knuth's parking problem, in which caravans consisting of a random number of cars arrive at random on the unit circle. Then each car turns clockwise until it finds a free space to park. Extending a recent work by Chassaing and Louchard 8 , we relate the asymptotics for the sizes of blocks formed by occupied spots with the dynamics of the additive coalescent. According to the behavior of the caravans' size tail distribution, several qualitatively different versions of the eternal additive coalescent are involved. © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2006 相似文献
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