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排序方式: 共有546条查询结果,搜索用时 140 毫秒
1.
Mark P. Stockham Alice Griffiths Dr. Bo Dong Prof. Peter R. Slater 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(6):e202103442
Lithium garnets are promising solid-state electrolytes for next-generation lithium-ion batteries. These materials have high ionic conductivity, a wide electrochemical window and stability with Li metal. However, lithium garnets have a maximum limit of seven lithium atoms per formula unit (e.g., La3Zr2Li7O12), before the system transitions from a cubic to a tetragonal phase with poor ionic mobility. This arises from full occupation of the Li sites. Hence, the most conductive lithium garnets have Li between 6–6.55 Li per formula unit, which maintains the cubic symmetry and the disordered Li sub-lattice. The tetragonal phase, however, forms the highly conducting cubic phase at higher temperatures, thought to arise from increased cell volume and entropic stabilisation permitting Li disorder. However, little work has been undertaken in understanding the controlling factors of this phase transition, which could enable enhanced dopant strategies to maintain room temperature cubic garnet at higher Li contents. Here, a series of nine tetragonal garnets were synthesised and analysed by variable temperature XRD to understand the dependence of site substitution on the phase transition temperature. Interestingly the octahedral site cation radius was identified as the key parameter for the transition temperature with larger or smaller dopants altering the transition temperature noticeably. A site substitution was, however, found to make little difference irrespective of significant changes to cell volume. 相似文献
2.
Bob Boyd Gareth Brenton Eddie Clayton Jonathan Curtis R. M. Elliott G. A. Errock B. N. Green R. H. Bateman Simon J. Gaskell Iwan Griffiths Zdenek Herman Philip Jonathan Rich Kondrat Mila Laušević Chris Lock Deepak Mathur John F. J. Todd Károly Vékey 《Rapid communications in mass spectrometry : RCM》2016,30(11):1253-1264
3.
4.
Swirl-stabilised combustion is one of the most widely used techniques for flame stabilisation, uses ranging from gas turbine
combustors to pulverised coal-fired power stations. In gas turbines, lean premixed systems are of especial importance, giving
the ability to produce low NOx systems coupled with wide stability limits. The common element is the swirl burner, which depends
on the generation of an aerodynamically formed central recirculation zone (CRZ) and which serves to recycle heat and active
chemical species to the root of the flame as well as providing low-velocity regions where the flame speed can match the local
flow velocity. Enhanced mixing in and around the CRZ is another beneficial feature. The structure of the CRZ and hence that
of the associated flames, stabilisation and mixing processes have shown to be extremely complex, three-dimensional and time
dependent. The characteristics of the CRZ depend very strongly on the level of swirl (swirl number), burner configuration,
type of flow expansion, Reynolds number (i.e. flowrate) and equivalence ratio. Although numerical methods have had some success
when compared to experimental results, the models still have difficulties at medium to high swirl levels, with complex geometries
and varied equivalence ratios. This study thus focuses on experimental results obtained to characterise the CRZ formed under
varied combustion conditions with different geometries and some variation of swirl number in a generic swirl burner. CRZ behaviour
has similarities to the equivalent isothermal state, but is strongly dependent on equivalence ratio, with interesting effects
occurring with a high-velocity fuel injector. Partial premixing and combustion cause more substantive changes to the CRZ than
pure diffusive combustion. 相似文献
5.
Zhen-Dan Shi Omid Motabar Ehud Goldin Ke Liu Noel Southall Ellen Sidransky Christopher P. Austin Gary L. Griffiths Wei Zheng 《Analytical and bioanalytical chemistry》2009,394(7):1903-1909
Alpha-galactosidase A hydrolyzes the terminal alpha-galactosyl moieties from glycolipids and glycoproteins in lysosomes. Mutations
in α-galactosidase cause lysosomal accumulation of the glycosphingolipid, globotriaosylceramide, which leads to Fabry disease.
Small-molecule chaperones that bind to mutant enzyme proteins and correct their misfolding and mistrafficking have emerged
as a potential therapy for Fabry disease. We have synthesized a red fluorogenic substrate, resorufinyl α-d-galactopyranoside, for a new α-galactosidase enzyme assay. This assay can be measured continuously at lower pH values, without
the addition of a stop solution, due to the relatively low pK
a of resorufin (~6). In addition, the assay emits red fluorescence, which can significantly reduce interferences due to compound
fluorescence and dust/lint as compared to blue fluorescence. Therefore, this new red fluorogenic substrate and the resulting
enzyme assay can be used in high-throughput screening to identify small-molecule chaperones for Fabry disease.
Zhen-Dan Shi and Omid Motabar contributed equally to this work 相似文献
6.
Jennifer E. Mihalick William P. Griffiths III James E. Muten Travis A. Olson John B. Hein 《Journal of solution chemistry》1999,28(8):1019-1030
Solution calorimetry was used to determine enthalpies and stability constants for binding of lead(II) or cadmium(II) by galacturonic acid and several monosaccharides in aqueous solution. New values for enthalpies of solution in water are reported for galacturonic acid and maltose monohydrate. The interaction of water solvent with the reactants is the largest factor in the binding process. 相似文献
7.
8.
Resolution and uniqueness of estimated parameters of a model of thin filament regulation in solution
Srboljub M. Mijailovich Xiaochuan Li Juan C. del Álamo R. Hugh Griffiths Vojislav Kecman Michael A. Geeves 《Computational Biology and Chemistry》2010,34(1):19-33
The estimation of chemical kinetic rate constants for any non-trivial model is complex due to the nonlinear effects of second order chemical reactions. We developed an algorithm to accomplish this goal based on the Damped Least Squares (DLS) inversion method and then tested the effectiveness of this method on the McKillop–Geeves (MG) model of thin filament regulation. The kinetics of MG model is defined by a set of nonlinear ordinary differential equations (ODEs) that predict the evolution of troponin–tropomyosin–actin and actin–myosin states. The values of the rate constants are estimated by integrating these ODEs numerically and fitting them to a series of stopped-flow pyrene fluorescence transients of myosin-S1 fragment binding to regulated actin in solution. The accuracy and robustness of the estimated rate constants are evaluated for DLS and two other methods, namely quasi-Newton (QN) and simulated annealing (SA). The comparison of these methods revealed that SA provides the best estimates of the model parameters because of its global optimization scheme. However it converges slowly and does quantify the uniqueness of the estimated parameters. On the other hand the QN method converges rapidly but only if the initial guess of the parameters is close to the optimum values, otherwise it diverges. Overall, the DLS method proves to be the most convenient method. It converges fast and was able to provide excellent estimates of kinetic parameters. Furthermore, DLS provides the model resolution matrix, which quantifies the interdependence of model parameters thereby evaluating the uniqueness of their estimated values. This property is essential for estimating of the dependence of the model parameters on experimental conditions (e.g. Ca2+ concentration) when it is assessed from noisy experimental data such as pyrene fluorescence from stopped-flow transients. The advantages of the DLS method observed in this study should be further examined in other physicochemical systems to firmly establish the observed effectiveness of DSL vs. the other parameter estimation methods. 相似文献
9.
Gonzalo Fiz Pontiveros Simon Griffiths Robert Morris David Saxton Jozef Skokan 《Combinatorica》2016,36(1):71-89
The Ramsey number r(K 3,Q n ) is the smallest integer N such that every red-blue colouring of the edges of the complete graph K N contains either a red n-dimensional hypercube, or a blue triangle. Almost thirty years ago, Burr and Erd?s conjectured that r(K 3,Q n )=2 n+1?1 for every n∈?, but the first non-trivial upper bound was obtained only recently, by Conlon, Fox, Lee and Sudakov, who proved that r(K 3,Q n )?7000·2 n . Here we show that r(K 3,Q n )=(1+o(1))2 n+1 as n→∞. 相似文献
10.
Martin Griffiths Jonny Griffiths 《International Journal of Mathematical Education in Science & Technology》2016,47(2):291-298
We study here a pair of sequences of polynomials that arise from a particular iterated mapping on the plane. We show how these sequences come about, and give some of their interesting mathematical properties. 相似文献