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1.
Hybrid materials in which reduced graphene oxide (rGO) is decorated with Au nanoparticles (rGO–Au NPs) were obtained by the in situ reduction of GO and AuCl4?(aq) by ascorbic acid. On laser excitation, rGO could be oxidized as a result of the surface plasmon resonance (SPR) excitation in the Au NPs, which generates activated O2 through the transfer of SPR‐excited hot electrons to O2 molecules adsorbed from air. The SPR‐mediated catalytic oxidation of p‐aminothiophenol (PATP) to p,p′‐dimercaptoazobenzene (DMAB) was then employed as a model reaction to probe the effect of rGO as a support for Au NPs on their SPR‐mediated catalytic activities. The increased conversion of PATP to DMAB relative to individual Au NPs indicated that charge‐transfer processes from rGO to Au took place and contributed to improved SPR‐mediated activity. Since the transfer of electrons from Au to adsorbed O2 molecules is the crucial step for PATP oxidation, in addition to the SPR‐excited hot electrons of Au NPs, the transfer of electrons from rGO to Au contributed to increasing the electron density of Au above the Fermi level and thus the Au‐to‐O2 charge‐transfer process.  相似文献   
2.
New synthesised porphyrin dimers, with an amide or ester linkage between the two porphyrin units, were studied using liquid secondary ion mass spectrometry (LSIMS). The formation of reduced species was observed for all the compounds and it was found that the extent of reduction is dependent on the matrix used and on the structure of the porphyrin dimer. The main fragmentation pathways lead to monomer fragments resulting from cleavage of the amide or ester linkage between the two porphyrin units. The consistency of the fragmentations for all the dimers studied leads to the proposal of a common designation for the fragment ions. LSIMS, in addition to molecular weight determination, can provide important structural information for this type of compound.  相似文献   
3.
Fast atom bombardment mass spectrometry in the positive mode was used for the characterization of sodiated glycerol phosphatidylcholines. The relative abundance (RA) of the protonated species is similar to the RA of the sodiated molecular species. The sodiated fragment ion, [M + Na - 59](+), corresponding to the loss of trimethylamine, and other sodiated fragment ions, were also observed. The decomposition of the sodiated molecule is very similar for all the studied glycerol phosphatidylcholines, in which the most abundant ion corresponds to a neutral loss of 59 Da. Upon collision-induced dissociation (CID) of the [M + Na](+) ion informative ions are formed by the losses of the fatty acids in the sn-1 and sn-2 positions. Other major fragment ions of the sodiated molecule result from loss of non-sodiated and sodiated choline phosphate, [M + Na - 183](+), [M + Na - 184](+.) and [M + Na - 205](+), respectively. The main CID fragmentation pathway of the [M + Na - 59](+) ion yields the [M + Na - 183](+) ion, also observed in the CID spectra of the [M + Na](+) molecular ion. Other major fragment ions are [M + Na - 205](+) and the fragment ion at m/z 147. Collisional activation of [M + Na - 205](+) results in charge site remote fragmentation of both fatty acid alkyl chains. The terminal ions of these series of charge remote fragmentations result from loss of part of the R(1) or R(2) alkyl chain. Other major informative ions correspond to acylium ions.  相似文献   
4.
The product-ion spectra of the sodiated molecules of glycerol phosphatidylcholine phospholipids (GPC) were obtained, using fast-atom bombardment (FAB) as the ionization method, in a tandem mass spectrometer. The product-ion spectra of these sodiated molecules of GPCs were found to differ significantly from those of the protonated GPC molecules. This difference is due to the absence of the ion of m/z 184 (protonated-phosphocholine moiety) and to the presence of an ion resulting from the loss of trimethylamine (m=59 Da) from the polar head group, which is the dominant fragmentation. This characteristic neutral loss provides a means of identification of this class of phospholipids and of differentiation from other phospholipid classes in complex mixtures by performing a constant-neutral-loss scan of 59.  相似文献   
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Frutalin, a galactose-specific lectin used to detect specific tumour markers, is a protein with low expression level in breadfruit. In the present study, fed-batch fermentation in a stirred tank bioreactor was used as a strategy to enhance protein production by a recombinant Pichia pastoris KM71H. By using this process, the production of recombinant frutalin was 4-fold higher than the value obtained in shaker flasks batch assays. Supplementation of the fermentation medium with trace elements (Pichia trace minerals, PTM) was also evaluated in order to stimulate production of the recombinant protein. The addition of PTM to the minimum medium afforded a recombinant protein production of 13.4 mg L?1, which was 2.5-fold higher than that achieved from the culture medium without PTM supplementation. These results are significant as the development of strategies to improve the production of recombinant frutalin may broaden its application in cancer diagnosis.  相似文献   
7.
Hybrid materials have seized attention from scientific community mainly as heterogenic catalysts in organic reactions on a large scale succeeding in some organic compounds with high yields. One of the most important classes of hybrid materials used for this purpose involves the complexation of Zn and aminoacids. Herein, we introduced Zn[Pro]2 and Zn[Gly]2 in the synthesis of several β-enaminones via solvent free protocol and using an ultrasound device.  相似文献   
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Scientific evidence has shown an association between organochlorine compounds (OCC) exposure and human health hazards. Concerning this, OCC detection in human adipose samples has to be considered a public health priority. This study evaluated the efficacy of various solid‐phase extraction (SPE) and cleanup methods for OCC determination in human adipose tissue. Octadecylsilyl endcapped (C18‐E), benzenesulfonic acid modified silica cation exchanger (SA), poly(styrene‐divinylbenzene (EN) and EN/RP18 SPE sorbents were evaluated. The relative sample cleanup provided by these SPE columns was evaluated using gas chromatography with electron capture detection (GC–ECD). The C18‐E columns with strong homogenization were found to provide the most effective cleanup, removing the greatest amount of interfering substance, and simultaneously ensuring good analyte recoveries higher than 70%. Recoveries > 70% with standard deviations (SD) < 15% were obtained for all compounds under the selected conditions. Method detection limits were in the 0.003–0.009 mg/kg range. The positive samples were confirmed by gas chromatography coupled with tandem mass spectrometry (GC‐MS/MS). The highest percentage found of the OCC in real samples corresponded to HCB, o,p′‐DDT and methoxychlor, which were detected in 80 and 95% of samples analyzed respectively. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
10.
The molecular hybridization approach has been used to develop compounds with improved efficacy by combining two or more pharmacophores of bioactive scaffolds. In this context, hybridization of various relevant pharmacophores with phenothiazine derivatives has resulted in pertinent compounds with diverse biological activities, interacting with specific or multiple targets. In fact, the development of new drugs or drug candidates based on phenothiazine system has been a promising approach due to the diverse activities associated with this tricyclic system, traditionally present in compounds with antipsychotic, antihistaminic and antimuscarinic effects. Actually, the pharmacological actions of phenothiazine hybrids include promising antibacterial, antifungal, anticancer, anti-inflammatory, antimalarial, analgesic and multi-drug resistance reversal properties. The present review summarizes the progress in the development of phenothiazine hybrids and their biological activity.  相似文献   
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