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71.
Abstract

Cuminum cyminum is famous for its spicy fruits used for culinary and therapeutic properties worldwide. Brine shrimp test was performed for detecting cytotoxic fractions and subfractions. Ethyl acetate (EA) and hexane (HE) fractions demonstrated LC50 of 52.40 and 60.77 µg/ml against Artemia salina while other fractions showed no toxicity (LC50> 500 µg/ml). Bioguided elucidation of EA and HE fractions were carried out and cytotoxicity of pure compounds were investigated against breast cancer cell lines (MCF-7 and MDA-MB-231) and normal cell line (NIH/3T3) by MTT assay. Four flavone structures as luteolin, apigenin, luteolin-7-O-glucoside and apigenin-7-O-glucoside from EA and cuminoid A from HE were purified and identified. Luteolin-7-O-glucoside demonstrated potent anticancer activities against MCF-7 cell line (IC50 of 3.98 µg/ml) with selectivity index of 8.0. In conclusion, flavonoids especially luteolin-7-O-glucoside play a significant role in cytotoxic effect of C. cyminum fruits and can be introduced as candidate for chemopreventive and chemotherapeutic drugs.  相似文献   
72.
A new version of magnetic solid‐phase extraction performed in a narrow‐bore tube has been proposed for the extraction and preconcentration of different pesticides from various vegetable and fruit juices followed by gas chromatography. A few milligrams of C8@SiO2@Fe3O4 nanoparticles are added into an aqueous sample solution placed in a narrow‐bore tube. The sorbent particles move down through the tube under gravity and are collected at the end of the tube by applying an external magnetic field. The end of the tube is narrower and it is connected to a stopcock. After a predetermined time, the stopcock is opened and the solution is passed through the bed of the sorbent maintained by the magnet. Then the adsorbed analytes are desorbed using an elution solvent. To achieve high enrichment factors, a dispersive liquid–liquid microextraction method is carried out. The nanoparticles were characterized by scanning electron microscopy, X‐ray diffraction, and FTIR spectroscopy. Under the optimum extraction conditions, limits of detection and quantification were in the ranges of 0.1–0.3 and 0.3–0.9 μg/L, respectively. High enrichment factors (1166–1605) and good extraction recoveries (58–80%) were obtained.  相似文献   
73.
The synthesis and glucosidase inhibitory activities of two C-3'- and C-5'-β-maltose-extended analogues of the naturally occurring sulfonium-ion inhibitor, de-O-sulfonated ponkoranol, are described. The compounds are designed to test the specificity towards four intestinal glycoside hydrolase family 31 (GH31) enzyme activities, responsible for the hydrolysis of terminal starch products and sugars into glucose, in humans. The target sulfonium-ion compounds were synthesized by means of nucleophilic attack of benzyl protected 1,4-anhydro-4-thio-D-arabinitol at the C-6 position of 6-O-trifluoromethanesulfonyl trisaccharides as alkylating agents. The alkylating agents were synthesized from D-glucose by glycosylation at C-4 or C-2 with maltosyl trichloroacetimidate. Deprotection of the coupled products by using a two-step sequence, followed by reduction afforded the final compounds. Evaluation of the target compounds for inhibition of the four glucosidase activities indicated that selective inhibition of one enzyme over the others is possible.  相似文献   
74.

Abstract  

The crystal growth of (C6H14N2)[Cr2O7], consists of a diazabicyclo[2.2.2]octane-1,4-diium cation and a discrete dichromate anion, in solution has been determined under the influence of various factors. Four factors, which influence the crystal size, crystal growth and nucleation, were chosen. These factors are concentration, temperature, type of solvent and method of crystallization. Taguchi design of experiments (DOE) method has been used for to plan a minimum number of experiments and optimization of crystallization processes. Crystallization of diazabicyclo[2.2.2]octane-1,4-diium dichromate with desirable particle size, shape and minimum time of crystal growth as performance characteristics were studied. The changes in the crystal growth habit were observed and could be explained by the differences in the morphology on the various photograph of this compound.  相似文献   
75.
Zinc oxide (ZnO) is a semiconductor compound with a potential for wide use in various applications, including biomaterials and biosensors, particularly as nanoparticles (the size range of ZnO nanoparticles is from 2 to 100?nm, with an average of about 35?nm). Here, we report isolation of novel ZnO-binding peptides, by screening of a phage display library. Interestingly, amino acid sequences of the ZnO-binding peptides reported in this paper and those described previously are significantly different. This suggests that there is a high variability in sequences of peptides which can bind particular inorganic molecules, indicating that different approaches may lead to discovery of different peptides of generally the same activity (e.g., binding of ZnO) but having various detailed properties, perhaps crucial under specific conditions of different applications.  相似文献   
76.
In the present study, the modification of a mesoporous organosilica nanocomposite SBA-15 (Santa Barbara Amorphous 15) was carried out in two steps, first through the surface functionalization of SBA-Pr-NH2 with 2-chloroquinoline-3-carbaldehyde to form SBA-Pr-NCQ, and then through a post-modification process with palladium ions. The target nanocompound structure of SBA-Pr-NCQ-Pd was characterized by different techniques (thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, Energy-dispersive X-ray spectroscopy (EDX), and Fourier transform infrared spectroscopy). The catalytic performance of the porous inorganic–organic hybrid nanocomposite (SBA-Pr-NCQ-Pd) in one of the most important carbon–carbon bond-forming processes, the Mizoroki–Heck coupling reaction of aryl halides and methacrylate in water/ethanol media, was examined. Compared to previous reports, this protocol afforded some advantages, such as high yields of products, short reaction times, catalyst stability without leaching, simple methodology, easy workup, and greener conditions. Also, the nanocatalyst can be easily separated from the reaction mixture and reused several times without a significant decrease in activity and promises economic as well as environmental benefits.  相似文献   
77.
Molecular Diversity - 4-Hydroxycoumarins are some of the most versatile heterocyclic scaffolds and are frequently applied in the synthesis of various organic compounds. 4-Hydroxycoumarin-based...  相似文献   
78.
Rapid and efficient condensation reactions of o‐phenylenediamine and o‐aminothiophenol with various aldehydes were carried out using tungstophosphoric acid impregnated zirconium phosphate in solvent‐free conditions to afford the corresponding 2‐substituted arylbenzimidazole and arylbenzothiazole derivatives in good to excellent yields. This procedure constitutes a simple and practical green synthetic method for 2‐arylbenzimidazoles and 2‐arylbenzothiazoles and their structural analogs. Furthermore, the catalyst can be reused for several times but it will be less active. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:202–207, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20534  相似文献   
79.

Background

Experiencing emotions engages high-order orbitofrontal and medial prefrontal areas, and expressing emotions involves low-level autonomic structures and peripheral organs. How is information from the cortex transmitted to the periphery? We used two parallel approaches to map simultaneously multiple pathways to determine if hypothalamic autonomic centres are a key link for orbitofrontal areas and medial prefrontal areas, which have been associated with emotional processes, as well as low-level spinal and brainstem autonomic structures. The latter innervate peripheral autonomic organs, whose activity is markedly increased during emotional arousal.

Results

We first determined if pathways linking the orbitofrontal cortex with the hypothalamus overlapped with projection neurons directed to the intermediolateral column of the spinal cord, with the aid of neural tracers injected in these disparate structures. We found that axons from orbitofrontal and medial prefrontal cortices converged in the hypothalamus with neurons projecting to brainstem and spinal autonomic centers, linking the highest with the lowest levels of the neuraxis. Using a parallel approach, we injected bidirectional tracers in the lateral hypothalamic area, an autonomic center, to label simultaneously cortical pathways leading to the hypothalamus, as well as hypothalamic axons projecting to low-level brainstem and spinal autonomic centers. We found densely distributed projection neurons in medial prefrontal and orbitofrontal cortices leading to the hypothalamus, as well as hypothalamic axonal terminations in several brainstem structures and the intermediolateral column of the spinal cord, which innervate peripheral autonomic organs. We then provided direct evidence that axons from medial prefrontal cortex synapse with hypothalamic neurons, terminating as large boutons, comparable in size to the highly efficient thalamocortical system. The interlinked orbitofrontal, medial prefrontal areas and hypothalamic autonomic centers were also connected with the amygdala.

Conclusions

Descending pathways from orbitofrontal and medial prefrontal cortices, which are also linked with the amygdala, provide the means for speedy influence of the prefrontal cortex on the autonomic system, in processes underlying appreciation and expression of emotions.
  相似文献   
80.
Caffeine was applied as a green and natural catalyst for the one-pot, four-component sequential condensation between 2-hydroxy-1,4-naphthoquinone, aromatic 1,2-diamines, ammonium thiocyanate and acid chlorides in the presence of a basic ionic liquid (1-butyl-3-methylimidazolium hydroxide) to afford the corresponding benzo[a] [1,3]oxazino[6,5-c]phenazine derivatives. In this one-pot transformation, five bonds and two new rings are efficiently formed. This protocol has the advantages of operational simplicity, high yields, easy workup, avoidance of hazardous or toxic catalysts and organic solvents and high chemo- and regioselectivities.  相似文献   
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