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31.
Irena Akhrem Dzhul’etta Avetisyan Lyudmila Afanas’eva Nikolai Kagramanov Pavel Petrovskii Alexander Orlinkov 《Tetrahedron letters》2010,51(6):907-911
A novel ‘alkane-like’ methodology for the direct and very simple one-pot functionalization of amides and an ester of 1-adamantanecarboxylic acid provides access to new and synthetically challenging 1,3-dicarbonyl-containing adamantanoid compounds with the same or different functional groups. 相似文献
32.
Daria V. Chernysheva Victor A. Klushin Alexander F. Zubenko Lyudmila S. Pudova Oleg A. Kravchenko Victor M. Chernyshev Nina V. Smirnova 《Mendeleev Communications》2018,28(4):431-433
The Pt/C catalysts with various Pt content (5-30 wt%) synthesized via electrochemical pulse alternating current technique have been evaluated for the base-free aerobic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid. The higher Pt content in the catalyst (30 wt%) provides the product yield up to 65% upon performing the process in concentrated (~0.1 M) aqueous solutions of the substrate. 相似文献
33.
Georgi E. Chernev Borislava V. Borisova Lyudmila V. Kabaivanova Isabel M. Salvado 《Central European Journal of Chemistry》2010,8(4):870-876
This work reports the sol-gel synthesis of silica hybrids. We determined the effect of the type and quantity of silica precursors
and organic compounds on the resulting structure, surface area, nanostructure design and size, and potential applications.
The structure of the synthesized hybrids was analyzed using FT-IR, XRD, BET-Analysis, SEM, and AFM. We demonstrate the immovilization
of whole living thermophilic bacterial cells with cyanocompound degradation activity in the synthesized silica hybrid biomaterials
by entrapment, chemical binding, and adsorption. 相似文献
34.
Lyudmila I. Larina Vladimir G. Rozinov Mikhail Yu. Dmitrichenko Lyudmila A. Es'kova 《Magnetic resonance in chemistry : MRC》2009,47(2):149-157
The structure of novel phosphorus‐containing N‐vinylazoles prepared by action of phosphorus pentachloride has been studied by multinuclear 1H, 13C, 15N, 31P and two‐dimensional (2D) NMR spectroscopy. N‐vinyl‐substituted 1,2‐diazoles and 1,2,3‐triazoles have undergone phosphorylation, exclusively, on double bond. N‐vinylazoles‐based hexa‐coordinated phosphorus compounds have been synthesized for the first time. 31P NMR spectroscopy provides the most convenient and unambiguous method for the investigation of E—Z‐isomeric structures of phosphorylated enamines. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
35.
Nadiia V. Roik Lyudmila A. Belyakova 《Journal of inclusion phenomena and macrocyclic chemistry》2011,69(3-4):315-319
The inclusion complex with stoichiometric composition 1:1 was formed as a result of intermolecular interactions between para-aminobenzoic acid and ??-cyclodextrin. The stability constant of ????-cyclodextrin-para-aminobenzoic acid?? inclusion complex at 289, 292 and 313 K was calculated by the Ketelar equation. The influence of temperature on the stability of ????-cyclodextrin-para-aminobenzoic acid?? inclusion complex was also examined, and thermodynamic parameters involved in the complex formation (??G, ??H, ??S) were calculated. Supramolecular complex formation between para-aminobenzoic acid and ??-cyclodextrin was confirmed by X-ray diffraction and IR spectroscopy studies. 相似文献
36.
Georgi Chernev Nadezhda Rangelova Petar Djambazki Sanchi Nenkova Isabel Salvado Maria Fernandes Aiying Wu Lyudmila Kabaivanova 《Journal of Sol-Gel Science and Technology》2011,58(3):619-624
The purpose of the present work is the sol–gel synthesis, structure characterization and potential application of hybrid biomaterials
based on silica precursor (MTES) and natural polymers such as gelatin or pectin. The structure formation in the biomaterials
was investigated by XRD, FTIR, BET and AFM. The results showed that all studied hybrid biomaterials have an amorphous structure.
The FT-IR spectra of the obtained materials with MTES showed chemical bonds at 2,975, 1,255, 880 and 690 cm−1 due to the presence of Si–O–R (CH3 and C2H5) and Si–C bonds. In the samples synthesized with TEOS the inorganic and organic components interact by hydrogen bonding,
Van der Waals or electrostatic forces. Surface area of investigated samples decreases with increasing of the natural polymers
content. The structure evolution was studied by AFM and roughness analysis. Depending on the chemical composition a different
design and size of particles and their aggregates on the surface structure were established. The hybrid biomaterials were
used for immobilization of bacterial cells and applied in the biodegradation of the toxic compound 4-chlorobutyronitrile,
possible constituent of waste water effluents in a laboratory glass bioreactor. Optimization of the process at different temperatures
was carried out. 相似文献
37.
Dolashka P Moshtanska V Dolashki A Velkova L Rao GS Angelova M Betzel C Voelter W Atanasov B 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,83(1):67-73
The native form of Cu/Zn-superoxide dismutase, isolated from fungal strain Humicola lutea 103 is a homodimer that coordinates one Cu(2+) and one Zn(2+) per monomer. Cu(2+) and Zn(2+) ions play crucial roles in enzyme activity and structural stability, respectively. It was established that HLSOD shows high pH and temperature stability. Thermostability of the glycosylated enzyme Cu/Zn-SOD, isolated from fungal strain H. lutea 103, was determined by CD spectroscopy. Determination of reversibility toward thermal denaturation for HLSOD allowed several thermodynamic parameters to be calculated. In this communication we report the conditions under which reversible denaturation of HLSOD exists. The narrow range over which the system is reversible has been determined using the strongest test of two important thermodynamic independent variables (T and pH). Combining both these variables, the "phase diagram" was determined, as a result of which the real thermodynamic parameters (ΔC(p), ΔH(exp)°, and ΔG(exp)°) was established. Because very narrow pH-interval of transitions we assume they are as result of overlapping of two simple transitions. It was found that ΔH(o) is independent from pH with a value of 1.3 kcal/mol and 2.8 kcal/mol for the first and the second transition, respectively. ΔG(o) was pH-dependent in all studied pH-interval. This means that the transitions are entropically driven, these. Based on this, these processes can be described as hydrophobic rearrangement of the quaternary structure. It was also found that glycosylation does not influence the stability of the enzyme because the carbohydrate chain is exposed on the surface of the molecule. 相似文献
38.
Kazakova LI Shabarchina LI Sukhorukov GB 《Physical chemistry chemical physics : PCCP》2011,13(23):11110-11117
Enzyme based micron sized sensing system with optical readout was fabricated by co-encapsulation of urease and dextran couple with pH sensitive dye SNARF-1 into polyelectrolyte multilayer capsules. Co-precipitation of calcium carbonate, urease and dextran followed up by multilayer film coating and Ca-extracting by EDTA resulted in the formation of 3.5-4 micron capsules, what enable the calibrated fluorescence response to urea in concentration range from 10(-6) to 10(-1) M. The presence of urea can be monitored on a single capsule level as illustrated by confocal fluorescent microscopy. Variations in urease:dye ratio in capsules, applicability and limits of use of that type multi-component microencapsulated sensors are discussed. 相似文献
39.
Nikolai A. Ustynyuk Oleg V. Gusev Lyudmila N. Novikova Mikhail G. Peterleitner Larisa I. Denisovich Tat’yana A. Peganova Oleg V. Semeikin Dmitry A. Valyaev 《Journal of Solid State Electrochemistry》2007,11(12):1621-1634
In this review, redox-induced reactions of π- and σ,π-complexes leading to the selective formation (or cleavage) of C–H, C–C,
and C–O bonds have been summarized. To illustrate the synthetic potential of such methodology, the following representative
reactions studied in our group are discussed: (1) oxidatively induced hydrogen elimination from “open” cyclic diene and dienyl
complexes resulting in formation of “closed” dienyl and arene complexes, respectively; (2) reductive activation of C–H bonds
in diene, vinylidene, and carbyne complexes forming new multiple C–C bonds; (3) oxidative dehydrodimerization of vinylidene
complexes into binuclear μ-divinylidene species; and (4) oxidatively induced addition of oxygen nucleophiles to μ-divinylidene
complexes affording cyclic μ-dicarbene derivatives.
Oleg V. Gusev, deceased on October 31. 相似文献
40.
Lyudmila F. Lourie Galina V. Shevchenko Alexander N. Chernega Eduard B. Rusanov Judith A.K. Howard 《Journal of fluorine chemistry》2006,127(3):377-385
The selective fluorolactonization was achieved by treatment of cis-5-norbornene-2,3-endo-dicarboxylic acid or its monomethyl and dimethyl esters with F-TEDA-BF4 or XeF2. The reactions of 5-norbornene-endo-2-carboxylic acid and its monomethyl ester with F-TEDA-BF4 or XeF2 proceed in a non-selective manner to give fluorolactonization, addition and rearrangement products. The basic factor responsible for selectivity of the fluorolactonization is the presence of two endo-oriented carboxyl groups in the substrate molecule. The electrophilicity and type of the fluorinating agent is of secondary importance in this regard. It is postulated that the fluorolactonization of norbornenecarboxylic acids and their methyl esters with F-TEDA-BF4 or XeF2 is realized mainly via “open” fluoronorbornyl carbocation intermediates which in the reaction with XeF2 are postulated as the tight ion pairs. 相似文献