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51.
K. Randle R. Wellum J. E. Whitley 《Journal of Radioanalytical and Nuclear Chemistry》1973,16(1):205-214
Radiochemical separations are essential for the determination of trace elements in silver artefacts by neutron activation
analysis due to the high levels of both short and long-lived activities produced by the matrix, but the sensitivity of the
technique permits the examination of small samples. The noble metals are considered most significant from a diagnostic standpoint,
and radiochemical techniques have been developed for their determination in samples of a few milligrams. Methods have been
investigated for the determination of Pd, Rh, Ir and Pt in samples removed from museum specimens of known provenance. 相似文献
52.
A unified analysis for a class of long-step primal-dual path-following interior-point algorithms for semidefinite programming 总被引:1,自引:0,他引:1
We present a unified analysis for a class of long-step primal-dual path-following algorithms for semidefinite programming whose search directions are obtained through linearization of the symmetrized equation of the central pathH
P
(XS) [PXSP
–1 + (PXSP
–1)
T
]/2 = I, introduced by Zhang. At an iterate (X,S), we choose a scaling matrixP from the class of nonsingular matricesP such thatPXSP
–1 is symmetric. This class of matrices includes the three well-known choices, namely:P = S
1/2 andP = X
–1/2 proposed by Monteiro, and the matrixP corresponding to the Nesterov—Todd direction. We show that within the class of algorithms studied in this paper, the one based on the Nesterov—Todd direction has the lowest possible iteration-complexity bound that can provably be derived from our analysis. More specifically, its iteration-complexity bound is of the same order as that of the corresponding long-step primal-dual path-following algorithm for linear programming introduced by Kojima, Mizuno and Yoshise. © 1998 The Mathematical Programming Society, Inc. Published by Elsevier Science B.V.Corresponding author.This author's research is supported in part by the National Science Foundation under grants INT-9600343 and CCR-9700448 and the Office of Naval Research under grant N00014-94-1-0340.This author's research was supported in part by DOE DE-FG02-93ER25171-A001. 相似文献
53.
W. J. Dibdin Otto Hehner Aug Houzeau J. W. Mallet Ch. Smart Reuben Haines J. Stapleton A. Percy Smith Philip Holland Ira Remsen Charles W. Marsh Leroy W. Mc. Cay Jorissen A. Athenstädt Brucker Edmund J. Mills J. C. Thresh Whitley Williams Robert Brewer Lee J. Skalweit William Henry Watson C. R. Tichborne C. Schneider H. de Varigny Felix Plateau Rauber Paul Bert J. F. Wolfbauer Albert R. Leeds K. Kraut H. Precht L. Spiegelberg B. Wittjen 《Analytical and bioanalytical chemistry》1885,24(1):119-128
54.
Free energy, energy, and entropy of swelling in Cs-, Na-, and Sr-montmorillonite clays 总被引:1,自引:0,他引:1
A Monte Carlo method for grand canonical and grand isoshear ensemble simulations has been used to characterize the free energy, energy, and entropy of clay mineral swelling. The Monte Carlo approach was found to be more efficient at simulating water content fluctuations in the highly constrained clay environment than a previously developed molecular dynamics method. Swelling thermodynamics calculated for Cs-, Na-, and Sr-montmorillonite clays indicate a strong dependence of swelling on the interlayer ion identity, in agreement with various experimental measurements. The Sr clay swells most readily, and both the Na and Sr clays prefer expanded states (two-layer hydrate or greater) when in contact with bulk water. In contrast, swelling is inhibited in the Cs clay. Differences in swelling behavior are traced directly to the tendency of the different ions to hydrate. The swelling free energies are decomposed into their energetic and entropic components, revealing an overall energetic driving force for the swelling phenomena. Entropic effects provide a smaller, mediating role in the swelling processes. The results provide a unique molecular perspective on experimentally well-characterized swelling phenomena. 相似文献
55.
David C. Whitley 《Journal of mathematical chemistry》1998,23(3-4):377-397
A van der Waals surface graph is the graph defined on a van der Waals surface by the intersections of the atomic van der Waals
spheres. A van der Waals shape graph has a vertex for each atom with a visible face on the van der Waals surface, and edges
between vertices representing atoms with adjacent faces on the van der Waals surface. These are discrete invariants of three‐dimensional
molecular shape. Some basic properties of van der Waals surface graphs are studied, including their relationship with the
Voronoi diagram of the atom centres, and a class of molecular embeddings is identified for which the dual of the van der Waals
surface graph coincides with the van der Waals shape graph.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
56.
A hybrid quantum dot-antibody fragment fluorescence resonance energy transfer-based TNT sensor 总被引:7,自引:0,他引:7
Goldman ER Medintz IL Whitley JL Hayhurst A Clapp AR Uyeda HT Deschamps JR Lassman ME Mattoussi H 《Journal of the American Chemical Society》2005,127(18):6744-6751
We demonstrate the use of luminescent QDs conjugated to antibody fragments to develop solution-phase nanoscale sensing assemblies, based on fluorescence resonance energy transfer (FRET) for the specific detection of the explosive 2,4,6-trinitrotoluene (TNT) in aqueous environments. The hybrid sensor consists of anti-TNT specific antibody fragments attached to a hydrophilic QD via metal-affinity coordination. A dye-labeled TNT analogue prebound in the antibody binding site quenches the QD photoluminescence via proximity-induced FRET. Analysis of the data collected at increasing dye-labeled analogue to QD ratios provided an insight into understanding how the antibody fragments self-assemble on the QD. Addition of soluble TNT displaces the dye-labeled analogue, eliminating FRET and resulting in a concentration-dependent recovery of QD photoluminescence. Sensor performance and specificity were evaluated. 相似文献
57.
T. A. Carlson M. O. Krause W. A. Svensson P. Gerard F. A. Grimm T. A. Whitley B. P. Pullen 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1986,2(4):309-318
The general properties of the Cooper minimum in molecules are reviewed. Experimental results from synchrotron radiation together with theoretical calculations are presented on both the partial cross sections and angular distribution parameters, β. A detailed examination of HCl is used as an example. Previously unpublished results on CCl n H4?n , CCl n F4?n , ethylene dichloride, I2 and ICl are included. The Cooper minimum is largely discussed as a perturbation from atomic behavior, and is examined as a function of atomic number. The Cooper minimum is also examined as a function of chemical environment. Finally, needs for future research are briefly described. 相似文献
58.
The RF values of some metallic ions have been determined by partition chromatography on filter paper, employing as solvents, diethyl ether saturated with normal hydrochloric, hydrobromic, sulphuric and nitric acids respectively. 相似文献
59.
60.
Photopolymerization of coordinated ionic liquid monomers: Realizing the benefits of structured media using only common reagents 下载免费PDF全文
John W. Whitley Ian A. Adams Kelsey L. Terrill Spenser S. Hayward Michael T. Burnette Jason E. Bara 《Journal of polymer science. Part A, Polymer chemistry》2016,54(13):2004-2014
Here, we provide a detailed report on a new type of structured media for improving photopolymerizations: coordinated ionic liquids (ILs). Coordinated ILs are readily formed from the bistriflimide ([Tf2N]?) anion and coordination complexes composed of Li+ cations with polar organic monomers without an additional cosolvent. Photopolymerization kinetics and monomer conversion were monitored in real time using attenuated total reflectance Fourier transform infrared spectroscopy and the material properties of the products were examined using gel permeation chromatography and differential scanning calorimetry. Generally, coordinated IL monomers displayed improved reaction kinetics at both high and low salt concentrations as well as distinct product properties. The noncovalent (and reversible) interactions between monomer and salt in coordinated ILs hold promise as an efficient and versatile form of structured media for photopolymerizations. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2004–2014 相似文献