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61.
The folding space for all the protein sequences is limited. Therefore it was observed that many proteins, whose sequences are not related, have similar fold characteristics. The fold databases like SCOP and CATH have classified various protein folds. However, in-depth analysis of the functional features of these folds was not done. We analyzed about twenty unique SH3-like folded proteins in their structural environment and functional characteristics. From our analysis it is apparent that the SH3-like folds could carry out various functions by modulation of loops and the functional region is restricted to one side of a particular sheet helped by two or three loops. The functions vary from oligonucleotide-binding to peptide-binding and other ligand binding. Although certain degree of sequence similarity was observed among the SH3-fold proteins, the similarity was restricted to the beta-strand regions of the proteins. 相似文献
62.
Summary Fast gradient HIC has been interfaced with low angle laser light scattering photometry (LALLS) to separate and characterize proteins. Molecular weights (MWs) have been determined on-line for a set of four proteins. A fast HIC column has been used to elute proteins under fast (5 min) and conventional (10 min) gradients. Certain variables used in the calculation of MW, such as refractive index of the mobile phase (RI) and differential refractive index (dn/dc) have been calculated offline.The MWs for three of the four proteins studied matched literature values at any given gradient time. One of the proteins, -lactoglobulin-A (-LACT), was a dimer when injected. Our results have indicated that fast gradient HIC can be easily interfaced with LALLS in spite of a significant change in RI across the gradient.Dedicated to Professor Leslie S. Ettre on the occasion of his 70th birthday. 相似文献
63.
C. Agarwal A. Goswami P. C. Kalsi S. Singh A. Mhatre A. Ramaswami 《Journal of Radioanalytical and Nuclear Chemistry》2008,275(2):445-451
Cumulative yields of 27 fission products have been determined in 229Th(n,f) by recoil catcher technique followed by gamma-ray spectrometry. Absolute fission yields were arrived at from the fission
rate measured by track etch counting method. Mass yields were obtained from the cumulative yields using the charge distribution
parameters reported in the literature. The values agree well with the reported values obtained both by physical and radiochemical
methods. The resulting asymmetric mass distribution shows strong fluctuation in the yields in the light and heavy wings with
a periodicity of five mass units. 相似文献
64.
The Ramanujan Journal - In recent work, Miezaki introduced the notion of a spherical T-design in $$\mathbb {R}^2$$ , where T is a potentially infinite set. As an example, he offered the $$\mathbb... 相似文献
65.
66.
Vishal Kandathil Manjunatha Kempasiddaiah Sanna Kotrappanavar Nataraj Sasidhar Balappa Somappa Siddappa A. Patil 《应用有机金属化学》2020,34(3):e5357
The utilization of deoxyribonucleic acid (DNA) in nanotechnology is a promising area of research wherein the distinct properties of DNA are exploited for the design and development of new materials and applications. The biodegradability and natural profusion of DNA makes it highly suitable for use in various fields. In this report, we have treated DNA as a bioligand, supported on functionalized magnetite for the grafting of palladium (Pd) nanoparticles to make Pd-DNA bio-nanocatalyst. The Pd-DNA was subjected to Fourier-transform infrared spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Brunauer–Emmett–Teller, energy dispersive X-ray spectroscopy, vibrating sample magnetometry, X-ray photoelectron spectroscopy, and inductively coupled plasma optical emission spectrometry analysis. The prepared Pd-DNA was found to be highly efficient in catalyzing Suzuki–Miyaura cross-coupling reaction with excellent yields when compared with commercially available palladium-based catalysts. Also, the Pd-DNA could be easily recovered from the reaction mass using an external magnet and recycled up to six times without substantial loss of activity. Furthermore, Felbinac, a non-inflammatory drug, was synthesized in quantitative yields using the Pd-DNA bio-nanocatalyst. 相似文献
67.
68.
Stephen P. Thomas Rosalind M. French Vishal Jheengut Varinder K. Aggarwal 《Chemical record (New York, N.Y.)》2009,9(1):24-39
Organoboranes and boronic esters readily undergo nucleophilic addition, and if the nucleophile also bears an α‐leaving group, 1,2‐metallate rearrangement of the ate complex results. Through such a process a carbon chain can be extended, usually with high stereocontrol and this is the focus of this review. A chiral boronic ester (substrate control) can be used for stereocontrolled homologations with (dichloromethyl)lithium in the presence of ZnCl2. Subsequent alkylation by an organometallic reagent also occurs with high levels of stereocontrol. Chiral lithiated carbanions (reagent control) can also be used for the reaction sequence with achiral boronic esters and boranes. Aryl‐stabilized sulfur ylide derived chiral carbanions can be homologated with a range of boranes including vinyl boranes in good yield and high diastereo‐ and enantioselectivity. Lithiated alkyl chlorides react with boronic esters, again with high stereocontrol, but both sets of reactions are limited in scope. Chiral lithiated carbamates show the greatest substrate scope and react with both boronic esters and boranes with excellent enantioselectivity. Furthermore, iterative homologation with chiral lithiated carbamates allows carbon chains to be “grown” with control over relative and absolute stereochemistry. The factors responsible for stereocontrol are discussed. © 2009 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 9: 24–39; 2009: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.20168 相似文献
69.
We report on the use of large-scale distributed computing simulation and novel analysis techniques for examining the dynamics of a small protein. Matters addressed include folding rate, very long time scale kinetics, ensemble properties, and interaction with water. The target system for the study, the villin headpiece, has been of great interest to experimentalists and theorists both. Sampling totaled nearly 500 mus-the most extensive published to date for a system of villin's size in explicit solvent with all atom detail-and was in the form of tens of thousands of independent molecular dynamics trajectories, each several tens of nanoseconds in length. We report on kinetics sensitivity analyses that, using a set of short simulations, probed the role of water in villin's folding and sensitivity to the simulation's electrostatics treatment. By constructing Markovian state models (MSMs) from the collected data, we were able to propagate dynamics to times far beyond those directly simulated and to rapidly compute mean first passage times, long time kinetics (tens of microseconds), and evolution of ensemble property distributions over long times, otherwise currently impossible. We also tested our MSM by using it to predict the structure of villin de novo. 相似文献
70.
[Structure: see text] The total synthesis and preliminary biological evaluation of the first bryostatin analogs (bryologs) to incorporate B-ring substitution are reported. Asymmetric syntheses of two new polyketide "spacer" domains are described, one exploiting the pseudosymmetry of the C1-C13 region. These fragments are convergently joined to the "recognition" domain through a remarkably versatile macrotransacetalization process. The resulting new analogs exhibit potent nanomolar or picomolar affinity to protein kinase C (PKC), comparable to or better than that found for bryostatin. 相似文献