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排序方式: 共有209条查询结果,搜索用时 15 毫秒
81.
Salman S. Alharthi Ahmed Noah Badr Karolina Gromadzka Kinga Stuper-Szablewska Adel Gabr Abdel-Razek Khaled Selim 《Molecules (Basel, Switzerland)》2021,26(23)
Mandarin is a favorite fruit of the citrus family. Mandarin seeds are considered a source of nontraditional oil obtained from byproduct materials. This investigation aimed to assess the biomolecules of mandarin seeds and evaluated their antimycotic and antimycotoxigenic impact on fungi. Moreover, it evaluated the protective role of mandarin oil against aflatoxin toxicity in cell lines. The two types of extracted oil (fixed and volatile) were ecofriendly. The fatty acid composition, tocopherol, sterols, and carotenoids were determined in the fixed oil, whereas volatiles and phenolics were estimated in the essential oil. A mixture of the two oils was prepared and evaluated for its antimicrobial impact. The reduction effect of this mixture was also investigated to reduce mycotoxin secretion using a simulated experiment. The protective effect of the oil was evaluated using healthy strains of cell lines. Fixed oil was distinguished by the omega fatty acid content (76.24%), lutein was the major carotenoid (504.3 mg/100 g) and it had a high β-sitosterol content (294.6 mg/100 g). Essential oil contained limonene (66.05%), α-pinene (6.82%), β-pinene (4.32%), and γ-terpinene (12.31%) in significant amounts, while gallic acid and catechol were recorded as the dominant phenolics. Evaluation of the oil mix for antimicrobial potency reflected a considerable impact against pathogenic bacteria and toxigenic fungi. By its application to the fungal media, this oil mix possessed a capacity for reducing mycotoxin secretion. The oil mix was also shown to have a low cytotoxic effect against healthy strains of cell lines and had potency in reducing the mortality impact of aflatoxin B1 applied to cell lines. These results recommend further study to involve this oil in food safety applications. 相似文献
82.
Copper(II) on a 4?Å molecular sieve support catalyses the chemoselective addition of alkyl- and arylmagnesium halides to chalcones. Only the 1,4-addition products were obtained in high yields. 相似文献
83.
84.
Zbigniew Grobelny Marek Matlengiewicz Sylwia Golba Justyna Jurek-Suliga Andrzej S. Swinarew Kinga Skrzeczyna 《International Journal of Polymer Analysis and Characterization》2015,20(3):206-222
Mono- and dipotassium salts of dipropylene glycol were applied for the polymerization of propylene oxide in mild conditions, i.e., tetrahydrofuran solution at ambient temperature. The structure of polymers was investigated by use of 13C NMR and MALDI-TOF techniques. The structure depends strongly on the kind of initiator and additives that are used such as coronand 18-crown-6 and dipropylene glycol. The lowest unsaturation, represented by allyloxy starting groups, has the polymer obtained by use of monopotassium salt without the ligand. The highest unsaturation degree is for the polymer synthesized in the presence of dipotassium salt–activated 18-crown-6. This polymer, obtained at high initial monomer concentration and low initial concentration of initiator, consists of two fractions, i.e., a low molar mass fraction (Mn = 9400) containing mainly macromolecules with alkoxide starting and end groups and a much higher molar mass fraction (Mn = 29500 g/mol) containing macromolecules with allyloxy starting groups and alkoxide or hydroxyl end groups. Addition of free glycol to this system decreases the molar mass of polymers. Similar results were obtained by use of dipotassium salts of other glycols. The mechanisms of the studied processes are discussed. 相似文献
85.
Three different modes of hydroformylation/aldol reaction sequences involving either acid-catalysed aldol reactions, Mukaiyama aldol addition of pre-formed enolsilanes or aldol addition of in situ generated boron enolates can be applied to unsaturated ketones and ketoesters to afford the corresponding carbocyclic aldol adducts in good yields proceeding through the intermediate activated ketoaldehydes. In selected cases, complimentary, synthetically useful diastereoselectivities were observed in the products. 相似文献
86.
J. Orbán Kinga Pozsonyi Krisztina Szarka Szilvia Barkó Emőke Bódis D. Lőrinczy 《Journal of Thermal Analysis and Calorimetry》2006,84(3):619-623
The thermodynamic properties of the ADP- and ATP-actin filaments were
compared by the method of differential scanning calorimetry. The lower melting
point for the ADP-F-actin filament (58.4 vs. 64.5°C for ATP-F-actin) indicated
that compared to the ATP-actin filaments its structure was less resistant
to heat denaturation. The detailed thermodynamic characterisation of the proteins
was carried out by the analysis of the calorimetric enthalpy, the entropy
and the free enthalpy changes. All of the determined parameters gave lower
values to the ADP-actin filaments than to the ATP-actin filaments. The calculated
values of the activation energy also demonstrated that compared to the ADP-F-actin
the ATP-F-actin was thermodynamically more resistant to the denaturing effect
of heat.
Based on all of this information we have concluded that the actin
filament prepared from ADP containing magnesium saturated actin monomers at
pH 8.0 is thermodynamically less stable than the ones obtained from ATP-actin
monomers. 相似文献
87.
Vyacheslav Boyko Roman Rodik Oksana Danylyuk Lyudmila Tsymbal Yaroslav Lampeka Kinga Suwinska Janusz Lipkowski Vitaly Kalchenko 《Tetrahedron》2005,61(52):12282-12287
The synthesis of new calix[4]arenes bearing two or four tetrazole liganting groups at the upper rim is decribed. The structures of tetrakis-tetrazolecalix[4]arene and its palladium dichloride (2:2) complex are examined by X-ray crystallography. 相似文献
88.
Brión M Sanchez JJ Balogh K Thacker C Blanco-Verea A Børsting C Stradmann-Bellinghausen B Bogus M Syndercombe-Court D Schneider PM Carracedo A Morling N 《Electrophoresis》2005,26(23):4411-4420
The European Consortium "High-throughput analysis of single nucleotide polymorphisms for the forensic identification of persons--SNPforID", has performed a selection of candidate Y-chromosome single nucleotide polymorphisms (SNPs) for making inferences on the geographic origin of an unknown sample. From more than 200 SNPs compiled in the phylogenetic tree published by the Y-Chromosome Consortium, and looking at the population studies previously published, a package of 29 SNPs has been selected for the identification of major population haplogroups. A "Major Y-chromosome haplogroup typing kit" has been developed, which allows the multiplex amplification of all 29 SNPs in a single reaction. Allele genotyping was performed with a single base extension reaction (minisequencing) detected by CE. The validation of the multiplex was performed in a total of 1126 unrelated males distributed among 12 worldwide populations. The approach takes advantage of the specific geographic distribution of the Y-chromosome haplogroups and demonstrates the utility of binary polymorphisms to infer the origin of a male lineage. 相似文献
89.
Florent Perret Stphanie Guret Kinga Suwinska Anthony W. Coleman 《Journal of Molecular Structure》2007,830(1-3):35-39
We report here, the first crystallographic structure of the new water soluble calixarene, para-sulfonatomethylcalix[4]arene. Anchoring a methylene group between the aromatic core of the calixarene and sulfonate groups extended the hydrophobic cavity but led to a more flexible macromolecule allowing formation of hydrogen bonds between vicinal sulfonate groups, causing the groups to point towards the cavity and effectively close it, with S S distances of 9.7 Å × 7.9 Å. The packing motif consists of bilayers of para-sulfonatomethylcalix[4]arene along both the a and b axis. 相似文献
90.
Both the consequences of 1,3-cyclization of calix[4]arenes by diamide formation, and the effect of 2- and 2,4-alkoxycarbonylmethylation of two 1,3-bridged calix[4]azacrowns on their metal ion-binding capacities have been studied by synthesis of the derivatives in their cone conformation and measurement of the stability constants for their complexation in a range of alkaline earth and transition metal cations. In these two cases, the conformation of the ligand in the solid state has been defined in detail by a crystal structure determination. In the first case, a tubular architecture performing methanol channels is displayed, however, in the second case a zigzag architecture generated by a chloroform network connecting calixarene molecules is present. Speciation in solution appears to be limited to the formation of 1:2 and/or 1:1 and/or 2:1 (M-L) complexes, depending on the system, with values of the stability constants determined by absorption spectroscopy in acetonitrile, lying in the ranges log β12 ca. 10, log β11 ca. 2-5, and log β21 ca. 7-9. There is evidence for selectivity toward Cu(II) and for some unexpected anion effects. None of these ligands appear to be an efficient extractant for the metals as their picrate. 相似文献