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211.
Journal of Solid State Electrochemistry - Carbon materials are used to improve the nickel hydroxide electrode capacity in rechargeable alkaline batteries. Herein, we present the preparation of... 相似文献
212.
213.
M I García-Moreno J M Benito C Ortiz Mellet J M García Fernández 《The Journal of organic chemistry》2001,66(23):7604-7614
A practical synthesis of polyhydroxylated 6-oxa-nor-tropanes incorporating the essential structural features of calystegine B(2) from 5-deoxy-5-thioureido and 5-ureido-L-idofuranose precursors is presented. The methodology relies on the ability of pseudoamide-type nitrogen atoms (thiourea, urea, and carbamate) to undergo nucleophilic addition to the masked aldehyde group of the monosaccharide. The generated hemiaminal functionality may further undergo in situ intramolecular glycosidation to give the bicyclic aminoacetal compounds, the whole process being favored by the anomeric effect. A series of derivatives bearing different substituents at nitrogen has been prepared and screened against several glycosidases in comparison with xylonojirimycin-type piperidine analogues. Interestingly, strong and highly specific inhibition of bovine liver beta-glucosidase was observed for 6-oxacalystegine B(2) analogues incorporating aromatic pseudoaglyconic groups. On the basis of these data, a 1-azasugar inhibition mode is proposed for this family of glycomimetics. 相似文献
214.
James V. Crivello Ricardo Acosta Ortiz 《Journal of polymer science. Part A, Polymer chemistry》2001,39(14):2385-2395
The synthesis of a series of novel cationically photopolymerizable epoxide monomers bearing benzyl, allyl, and propargyl acetal and ether groups that can stabilize free radicals was carried out. These monomers display enhanced reactivity in cationic photopolymerization in the presence of certain onium salt photoinitiators. Specifically, this article describes schemes for the synthesis of cycloaliphatic epoxy monomers bearing free‐radical stabilizing groups. During UV irradiation of an onium salt cationic photoinitiator, the aryl radicals that are generated abstract labile protons present in such monomers to generate the corresponding carbon‐centered radicals. Subsequently, these radicals can interact with the onium salt by a redox mechanism to induce the decomposition of these salts. The overall result is that additional cationic species are generated by this mechanism that increase the rate and extent of the cationic ring‐opening polymerization of the epoxide monomer. An investigation of the photopolymerizations of the monomers prepared during this work was carried out using Fourier transform real‐time infrared spectroscopy, and conclusions were drawn with respect to the relationship between their structures and reactivity. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2385–2395, 2001 相似文献
215.
Highly Enantioselective Copper(I)‐Catalyzed Conjugate Addition of Terminal Alkynes to 1,1‐Difluoro‐1‐(phenylsulfonyl)‐3‐en‐2‐ones: New Ester/Amide Surrogates in Asymmetric Catalysis 下载免费PDF全文
Amparo Sanz‐Marco Andrea García‐Ortiz Prof. Dr. Gonzalo Blay Isabel Fernández Prof. Dr. José R. Pedro 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(3):668-672
A highly enantioselective copper‐catalyzed conjugate alkynylation of monoactivated enones, namely 1,1‐difluoro‐1‐(phenylsulfonyl)‐3‐en‐2‐ones, is described. The reaction products are obtained with good yields and excellent enantioselectivities (from 92 to 99% ee). The β‐alkynylated difluoro(phenylsulfonyl) ketones can be converted into the corresponding β‐alkynylated difluoro‐ and trifluoromethyl ketones, esters and amides. This is the first example on the use of 1,1‐difluoro‐1‐(phenylsulfonyl)‐3‐en‐2‐ones as substrates in an enantioselective reaction, which have been shown to be new ester/amide surrogates. 相似文献
216.
Kinga Zr Roberto Ortiz Ebru Saatci Ronald Bardsley Tim Parr Elisabeth Csregi Mihaela Nistor 《Bioelectrochemistry (Amsterdam, Netherlands)》2009,76(1-2):93
An immunological capacitive biosensor for calpastatin was developed, optimized and applied for the analysis of meat extract samples. Anti-calpastatin antibody was immobilized on a gold electrode modified with a self-assembled monolayer of mercaptoundecanoic acid and Protein A from Staphylococcus aureus, and the obtained immunosensor was inserted as the working electrode in an electrochemical cell of a flow injection system. The dynamic range of the sensor was 20 to 160 ng/mL calpastatin. The electrode could be regenerated and re-used for more than 7 days with minimal reduction in sensitivity. For the analysis of real samples, the target analyte was extracted from the Longissimus dorsi muscle from beef carcasses directly after slaughtering. The extract was analyzed both with the developed immunosensor and microtiter plate ELISA, and a good correlation was obtained. However the immunosensor offers advantages of speed, simplicity, sensitivity and possibility for miniaturization over conventional assays for calpastatin quantification. 相似文献
217.
J. Belmar L. Ortiz J. Quezada M. Parra C. A. Jiménez 《Journal of heterocyclic chemistry》2014,51(Z1):E98-E103
Phenylene bis‐pyrazolone derivatives were obtained by condensation of two aromatic β‐diketo diesters with methyl‐, 2‐hydroxyethyl‐ and phenylhydrazines. The pyrazolone rings are connected to the central benzene ring by their C‐3 , leaving C‐4 free for further derivatization. Thus, and despite their low solubility, these compounds were successfully nitrosated in good yield providing new chelating dioximes. 相似文献
218.
Structure and Bonding in CE5− (E=Al–Tl) Clusters: Planar Tetracoordinate Carbon versus Pentacoordinate Carbon 下载免费PDF全文
Estefanía Ravell Said Jalife Jorge Barroso Mesías Orozco‐Ic Gerardo Hernández‐Juárez Dr. Filiberto Ortiz‐Chi Dr. Sudip Pan Dr. José Luis Cabellos Prof. Gabriel Merino 《化学:亚洲杂志》2018,13(11):1467-1473
The structure, bonding, and stability of clusters with the empirical formula CE5? (E=Al–Tl) have been analyzed by means of high‐level computations. The results indicate that, whereas aluminum and gallium clusters have C2v structures with a planar tetracoordinate carbon (ptC), their heavier homologues prefer three‐dimensional C4v forms with a pentacoordinate carbon center over the ptC one. The reason for such a preference is a delicate balance between the interaction energy of the fifth E atom with CE4 and the distortion energy. Moreover, bonding analysis shows that the ptC systems can be better described as CE4?, with 17‐valence electrons interacting with E. The ptC core in these systems exhibits double aromatic (both σ and π) behavior, but the σ contribution is dominating. 相似文献
219.
E. Ortiz A. Cuán C. Badillo C.M. Cortés‐Romero Q. Wang L. Noreña 《International journal of quantum chemistry》2010,110(13):2411-2417
A theoretical study of poly(vinylidene flouride‐trifluoroethylene) and poly(vinylidene fluoride‐chlorotrifluoroethylene, is presented. By density functional theory calculations, some of the properties of these materials have been obtained. Among such properties, the dipolar moment and the energies associated to the structural changes. The B3LYP functional and 6311+G(d,p) bases set were used with Gaussian program. Calculations associated to different conformations were carried out to get insight about the involved phase changes. The energetic, charges, and dipole moment were calculated. The conformations, namely, I = Tp, II = TGa, and III = TGp, where T means trans and G means gauche, for the two polymers aforementioned were compared with the poly(vinilydene fluoride) studies previously obtained. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem 110:2411–2417, 2010 相似文献
220.
Xin-Cindy Wang Thomas Blesgen Kaushik Bhattacharya Michael Ortiz 《Archive for Rational Mechanics and Analysis》2016,221(2):1035-1075
We reformulate the Kohn–Sham density functional theory (KSDFT) as a nested variational problem in the one-particle density operator, the electrostatic potential and a field dual to the electron density. The corresponding functional is linear in the density operator and thus amenable to spectral representation. Based on this reformulation, we introduce a new approximation scheme, termed spectral binning, which does not require smoothing of the occupancy function and thus applies at arbitrarily low temperatures. We prove convergence of the approximate solutions with respect to spectral binning and with respect to an additional spatial discretization of the domain. 相似文献