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751.
Florence Vacandio Marielle Eyraud Philippe Knauth Thierry Djenizian 《Electrochemistry communications》2011,13(10):1060-1062
Structural and electrical properties of self-organized zirconia nanotube layers can be tuned by a simple thermal treatment. The effect of F on the electrical conductivity of the MOx nanotubes grown by anodization in fluoride-containing electrolytes is demonstrated. 相似文献
752.
Jérôme Dedecker Florence Merlevède 《Stochastic Processes and their Applications》2011,121(5):1013-1043
In this paper, we give rates of convergence for minimal distances between linear statistics of martingale differences and the limiting Gaussian distribution. In particular the results apply to the partial sums of (possibly long range dependent) linear processes, and to the least squares estimator in some parametric regression models. 相似文献
753.
Dr. Gordon J. Florence Joanne C. Morris Dr. Ross G. Murray Dr. Raghava R. Vanga Jonathan D. Osler Dr. Terry K. Smith 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(25):8309-8320
A highly stereocontrolled synthesis of (+)‐chamuvarinin has been completed in 1.5 % overall yield over 20 steps. The key fragment coupling reactions were the addition of alkyne 8 to aldehyde 7 (under Felkin–Anh control), followed by the two step activation/cyclization to close the C20–C23 2,5‐cis‐substituted tetrahydrofuran ring and a Julia–Kocienski olefination at C8–C9 to introduce the terminal butenolide. The inherent flexibility of our coupling strategy led to a streamlined synthesis with 17 steps in the longest sequence (2.2 % overall yield), in which the key bond couplings are reversed. In addition, a series of structural analogues of chamuvarinin have been prepared and screened for activity against HeLa cancer cell lines and both the bloodstream and insect forms of Trypanosoma brucei, the parasitic agent responsible for African sleeping sickness. 相似文献
754.
Dr. Raghu Ram Kadiyala Dr. David Tilly Elisabeth Nagaradja Dr. Thierry Roisnel Dr. Vadim E. Matulis Prof. Oleg A. Ivashkevich Dr. Yury S. Halauko Dr. Floris Chevallier Dr. Philippe C. Gros Prof. Florence Mongin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(24):7944-7960
With the aim of synthesizing biaryl compounds, several aromatic iodides were prepared by the deprotonative metalation of methoxybenzenes, 3‐substituted naphthalenes, isoquinoline, and methoxypyridines by using a mixed lithium/zinc‐TMP (TMP=2,2,6,6‐tetramethylpiperidino) base and subsequent iodolysis. The halides thus obtained, as well as commercial compounds, were cross‐coupled under palladium catalysis (e.g., Suzuki coupling with 2,4‐dimethoxy‐5‐pyrimidylboronic acid) to afford various representative biaryl compounds. Deprotometalation of the latter compounds was performed by using the lithium/zinc‐TMP base and evaluated by subsequent iodolysis. The outcome of these reactions has been discussed in light of the CH acidities of these substrates, as determined in THF solution by using the DFT B3LYP method. Except for in the presence of decidedly lower pKa values, the regioselectivities of the deprotometalation reactions tend to be governed by nearby coordinating atoms rather than by site acidities. In particular, azine and diazine nitrogen atoms have been shown to be efficient in inducing the reactions with the lithium/zinc‐TMP base at adjacent sites (e.g., by using 1‐(2‐methoxyphenyl)isoquinoline, 4‐(2,5‐dimethoxyphenyl)‐3‐methoxypyridine, or 5‐(2,5‐dimethoxyphenyl)‐2,4‐dimethoxypyrimidine as the substrate), a behavior that has already been observed upon treatment with lithium amides under kinetic conditions. Finally, the iodinated biaryl derivatives were involved in palladium‐catalyzed reactions. 相似文献
755.
Nizam M. El-Ashgar Issa M. El-Nahhal Mohamed M. Chehimi Florence Babonneau Jacques Livage 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3):392-402
Abstract Polysiloxane-immobilized monoamine, diamine, and triamine ligand systems of the general formula P-(CH2)3-X [where P represents a polysiloxane three-dimension silica like network, and X represents monoamine(-NH2), diamine (-NH(CH2)2NH2), or triamine (-NH(CH2)2NH(CH2)2NH2) functional ligand groups] were prepared by hydrolytic polycondensation of the tetraethylorthosilicate (TEOS) and the appropriate amine silane coupling agent (RO)3Si-(CH2)3X in the presence of cetyltrimethylammonium bromide (CTAB) as surfactant using the sol-gel method. The polysiloxane-immobilized amine ligand systems exhibit a higher potential for divalent metal ions (Cu2+, Ni2+, Co2+) when CTAB was used as surfactant than those of the corresponding polysiloxane ligand systems prepared without CTAB. X-ray Photoelectron Spectroscopy (XPS) analyses show a significant change in the surface composition as resulting from the incorporation of CTAB, which can be related to the increase in the uptake of metal ions. 相似文献
756.
This paper features a market implied methodology to infer adequate starting values for the spot and long-run variances and for the mean reversion rate of a calibration exercise under the Heston model. More particularly, these initial parameters are obtained by matching the term structure of the future expected total variance, inferred from the volatility surface, with the model term structure. In the numerical study, we compare the goodness of fit and the parameter stability of the Heston model calibrated by using either plausible random or market implied starting values for a one-year sample period including the recent credit crunch. In particular, we show that the proposed methodology avoids getting stuck in one “bad” local minimum and stabilizes the calibrated parameters through time. 相似文献
757.
Dr. Xuewei Zhang Dr. Andrés F. Cardozo Si Chen Dr. Wenjing Zhang Dr. Carine Julcour Dr. Muriel Lansalot Dr. Jean‐François Blanco Dr. Florence Gayet Prof. Henri Delmas Prof. Bernadette Charleux Dr. Eric Manoury Dr. Franck D'Agosto Prof. Rinaldo Poli 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(47):15505-15517
Water‐borne phosphine‐functionalized core‐cross‐linked micelles ( CCM ) consisting of a hydrophobic core and a hydrophilic shell were obtained as stable latexes by reversible addition–fragmentation chain transfer (RAFT) in water in a one‐pot, three‐step process. Initial homogeneous aqueous‐phase copolymerization of methacrylic acid (MAA) and poly(ethylene oxide) methyl ether methacrylate (PEOMA) is followed by copolymerization of styrene (S) and 4‐diphenylphosphinostyrene (DPPS), yielding P(MAA‐co‐PEOMA)‐b‐P(S‐co‐DPPS) amphiphilic block copolymer micelles ( M ) by polymerization‐induced self‐assembly (PISA), and final micellar cross‐linking with a mixture of S and diethylene glycol dimethacrylate. The CCM were characterized by dynamic light scattering and NMR spectroscopy to evaluate size, dispersity, stability, and the swelling ability of various organic substrates. Coordination of [Rh(acac)(CO)2] (acac=acetylacetonate) to the core‐confined phosphine groups was rapid and quantitative. The CCM and M latexes were then used, in combination with [Rh(acac)(CO)2], to catalyze the aqueous biphasic hydroformylation of 1‐octene, in which they showed high activity, recyclability, protection of the activated Rh center by the polymer scaffold, and low Rh leaching. The CCM latex gave slightly lower catalytic activity but significantly less Rh leaching than the M latex. A control experiment conducted in the presence of the sulfoxantphos ligand pointed to the action of the CCM as catalytic nanoreactors with substrate and product transport into and out of the polymer core, rather than as a surfactant in interfacial catalysis. 相似文献
758.
Formation of High‐Valent Iron–Oxo Species in Superoxide Reductase: Characterization by Resonance Raman Spectroscopy
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Dr. Florence Bonnot Dr. Emilie Tremey Dr. David von Stetten Dr. Stéphanie Rat Dr. Simon Duval Dr. Philippe Carpentier Dr. Martin Clemancey Dr. Alain Desbois Dr. Vincent Nivière 《Angewandte Chemie (International ed. in English)》2014,53(23):5926-5930
Superoxide reductase (SOR), a non‐heme mononuclear iron protein that is involved in superoxide detoxification in microorganisms, can be used as an unprecedented model to study the mechanisms of O2 activation and of the formation of high‐valent iron–oxo species in metalloenzymes. By using resonance Raman spectroscopy, it was shown that the mutation of two residues in the second coordination sphere of the SOR iron active site, K48 and I118, led to the formation of a high‐valent iron–oxo species when the mutant proteins were reacted with H2O2. These data demonstrate that these residues in the second coordination sphere tightly control the evolution and the cleavage of the O? O bond of the ferric iron hydroperoxide intermediate that is formed in the SOR active site. 相似文献
759.
Svecova L Cremel S Sirguey C Simonnot MO Sardin M Dossot M Mercier-Bion F 《Journal of colloid and interface science》2008,325(2):363-370
This paper reports a comparative study of three methods for determining the surface charge and acid-base behavior of a TiO(2) rutile material. Electrophoretic mobility measurements were performed using two different batch protocols: (i) a "static" mode that consisted of immersing the rutile powder in aqueous solutions of given pH's and ionic strengths for 10 h, and (ii) a "dynamic" mode that consisted of using an automatic titrator to continuously adjust the solution pH with a contact time of 15 min. The same apparatus (a Nanosizer from Malvern) was used to measure the zeta potential of the particles in both methods. These batch experiments were next compared to the determination of the surface charge of rutile using nonlinear chromatography in column experiments. In that case, the rutile powder was compacted to enable the formation of a proper column bed. Therefore, Raman scattering and X-ray photoelectron spectra were used, as well as other physical information such as specific surface area and morphology of the particles, to verify that the rutile powder and compacted form were identical. The three approaches were then compared and discussed in relation to the acid-base behavior of the rutile material. 相似文献
760.
Brielles N Chantraine F Viana M Chulia D Branlard P Rubinstenn G Lequeux F Mondain-Monval O 《Journal of colloid and interface science》2008,328(2):344-352
We have studied the imbibition and dissolution of a porous material in two separate scenarios: (1) when the porous material contains a surfactant powder and (2) when the porous material is dissolved in a surfactant solution. We show that the dissolution kinetics in both scenarios is significantly affected by the presence of the surfactant and results in an increase in the characteristic imbibition time of the porous material, which can be well understood in the framework of the classical law of capillarity. Slowing of the imbibition kinetics was found to be affected by a modification of the liquid wetting properties, but is also affected by a variation in the solubility of the porous material in the presence of the surfactant. Furthermore, there is a depletion effect of the surfactant inside the rising liquid, which is in good agreement with previous work and theoretical predictions. 相似文献