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A series of 7‐(2‐oxoalkoxy)coumarins have been synthesized by conjugating substituted 7‐hydroxycoumarins with different chloroketones. The anti‐inflammatory properties of 7‐(2‐oxoalkoxy)coumarins were studied in LPS‐induced inflammatory response in J774 macrophages. Western blot was used to determine the expression of iNOS and COX‐2, NO was determined by measuring its metabolite nitrite by Griess reaction and IL‐6 was measured by ELISA. Seventeen of the studied compounds inhibited NO and IL‐6 production over 50% at 100 μM concentrations. IC50 values of the best inhibitors were 21 μM/24 μM (NO/IL‐6) for compound 12 and 30 μM/10 μM (NO/IL‐6) for compound 20 . The main result was that the substitution with 7‐(2‐oxoalkoxy) group improved the anti‐inflammatory properties of most of the investigated 7‐hydroxycoumarins.  相似文献   
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A new type of photoionization ion source was developed for the ionization of cold molecules in supersonic molecular beams (named Cold PI). The system was based on a GC–MS with supersonic molecular beams and its fly‐through EI of cold molecules ion source (Cold EI) plus quadrupole mass analyzer. A continuously operated deuterium VUV photoionization lamp was added and placed above and between the supersonic nozzle and skimmer whereas the Cold EI ion source served only as a portion of the ion transfer ion optics. The supersonic nozzle and skimmer were voltage biased and the VUV light crossed the supersonic expansion about 10 mm from the nozzle. We obtained over three orders of magnitude enhancement in the relative abundance of the molecular ion of squalane in Cold PI versus in photoionization of this compound as a thermal compound. Accordingly, we also proved that standard photoionization is not as soft ionization method as previously perceived for large compounds. We found that Cold PI is as soft as and possibly softer than field ionization; thus, it could be the softest known ionization method. The ionization yield was about 200–300 times weaker than with Cold EI yet our limit of detection was about 200 femtogram in SIM mode for cholesterol and pyrene which is reasonable. Practically, all hydrocarbons gave only molecular ions with rather uniform response whereas alcohols gave some molecular ions plus major fragment ions particularly with a loss of water (similarly to field ionization). We tested Cold PI in the GC–MS analysis of diesel fuels and analyzed the time averaged data for group type information. We also found that we can analyze the diesel fuels by fast under 20‐s flow injection analysis in which the generated averaged mass spectrum of molecular ions only could serve for the characterization of fuels.  相似文献   
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A new general method for the synthesis of enols of cyclic 3-alkynyl-substituted 1,2-diketones is developed. Sonogashira cross-coupling of silyl enolates of cyclic 3-bromo-cyclopentane- and 3-bromo-cyclohexane-1,2-diones with variety of substituted acetylenes afforded enols of cyclic 3-alkynyl-1,2-diones with good yields (up to 93%) in a short reaction time. The starting 3-bromo-1,2-diones are easily obtainable by direct bromination of 1,2-diones with NBS.  相似文献   
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A short and straightforward synthesis of the racemic tobacco alkaloids anatabine and anabasine in five and six steps, respectively, from 3-pyridinecarboxaldehyde utilizing Barbier-type Zn-mediated allylation and ring-closing olefin metathesis, as the key steps, is reported. Additionally, a complete NMR spectroscopic analysis of the final products is carried out and full assignment of the NMR spectra of anatabine and anabasine with accurate coupling constants is accomplished and reported here for the first time.  相似文献   
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The solvation effects observed in water‐organic solutions were studied by combining data for reaction kinetics and dissolution equilibria by means of a linear free‐energy (similarity) analysis. Kinetic data for the pH‐independent hydrolysis of (4‐methoxyphenyl)‐2,2‐dichloroacetate measured in this work and solubility data for naphthalene, and other substrates of low polarity, in aqueous binary mixtures of methanol, ethanol, acetonitrile, dimethyl sulfoxide (DMSO), and 1,4‐dioxane were used. Linear similarity relationships were discovered for these data over the full range of solvent compositions studied. To gain insight into the similarities observed between these different phenomena, molecular dynamics simulations were carried out for naphthalene and an ester in water–acetonitrile solutions. The results revealed considerable preferential solvation of these substrates by the co‐solvent. Linear relationships between the experimental data and the mole fractions of acetonitrile in the solvation shells of substrates were found. Surprisingly, a linear relationship was found between the mole fractions of acetonitrile in the solvation shells of the ester and naphthalene. This linearity indicated that a similar solvation mechanism governs even such different phenomena as dissolution and reaction kinetics. The relationships between the experimental data and the results of the molecular dynamics calculations found in this work explained the solvent effect observed in water‐organic solutions on the molecular level. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
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A LFE (Linear Free Energy) analysis of kinetic data for different organic reactions in various organic aqueous solutions was carried out. The rate constants of these reactions were compared with those for the solvolysis of tert-butyl chloride in the same solvents in terms of the LFE Relationships, and linear plots were observed in a wide range of the co-solvent content. This similarity points to a common nature of the solvent effect in these reactions in variety of water–organic mixtures, regardless of largely different reaction mechanisms. We explain these results by the prevalence of hydrophobic stabilization of the initial state of these reactions in water-rich solvent mixtures. Recently the same conclusion was also made on the basis of investigations into sonication effects in kinetics of organic reactions. A considerable contribution of hydrophobic effects to the Y scale by Grunwald and Winstein was deduced.  相似文献   
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Superhydrophobic polyolefin surfaces: controlled micro- and nanostructures   总被引:2,自引:0,他引:2  
Superhydrophobic polyolefin surfaces were prepared by simultaneous micro- and nanostructuring. Electropolished aluminum foil was microstructured with a micro working robot and then anodized in polyprotic acid. The surface microstructure can be tailored by adjusting the settings of the micro working robot and the nanostructure by adjusting the parameters of the anodization procedure. Surface structuring was done by injection molding where a microstructured anodized aluminum oxide mold insert was used to pattern the surfaces. Structuring had a marked effect on the contact angle between the injection-molded polyolefins and water. When the optimized microstructure was covered with nanostructure, the static contact angle between polypropylene and water obtained a value of about 165 degrees and the sliding angle decreased to about 2.5 degrees. The superhydrophobic state was achieved.  相似文献   
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