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21.
Yang Liu Dr. Yong Yu Jacky W. Y. Lam Dr. Yuning Hong Mahtab Faisal Wang Zhang Yuan Dr. Ben Zhong Tang Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(28):8433-8438
A handy, specific, sensitive bioprobe has been developed. Tetraphenylethene (TPE) was functionalized by a maleimide (MI) group, giving a TPE‐MI adduct that was nonemissive in both solution and the solid state. It was readily transformed into a fluorogen showing an aggregation‐induced emission (AIE) property by the click addition of thiol to its MI pendant. The click reaction and the AIE effect enabled TPE‐MI to function as a thiol‐specific bioprobe in the solid state. Thus, the spot of TPE‐MI on a TLC plate became emissive when it had been exposed to L ‐cysteine, an amino acid containing a thiol group, but remained nonemissive when exposed to other amino acids that lack free thiol units. The thiol‐activated emission was rapid and strong, readily detected by the naked eye at an analyte concentration as low as approximately 1 ppb, thanks to the “lighting up” nature of the bioprobing process. Similarly, the emission of TPE‐MI was turned on only by the proteins containing free thiol units, such as glutathione. Clear fluorescence images were taken when living cells were stained by using TPE‐MI as a visualization agent, affording a facile fluorescent maker for mapping the distribution of thiol species in cellular systems. 相似文献
22.
Maysa Faisal Suyagh Godwill Iheagwaram Prashant Laxman Kole Jeff Millership Paul Collier Henry Halliday James C. McElnay 《Analytical and bioanalytical chemistry》2010,397(2):687-693
A selective and sensitive high-performance liquid chromatography method with UV detection for the determination of metronidazole in dried blood spots (DBS) has been developed and validated. DBS samples [spiked or patient samples] were prepared by applying blood (30 µL) to Guthrie cards. Discs (6 mm diameter) were punched from the cards and extracted using water containing the internal standard, tinidazole. The extracted sample was chromatographed without further treatment using a reversed phase system involving a Symmetry® C18 (5 µm, 3.9?×?150 mm) preceded by a Symmetry® guard column of matching chemistry and a detection wavelength of 317 nm. The mobile phase comprised acetonitrile/0.01?M phosphate solution (KH2PO4), pH 4.7, 15:85, v/v, with a flow rate of 1 mL/min. The calibration was linear over the range 2.5–50 mg/mL. The limits of detection and quantification were 0.6 and 1.8 µg/mL, respectively. The method has been applied to the determination of 203 DBS samples from neonatal patients for a phamacokinetic/pharmacodynamic study. 相似文献
23.
We present a Floquet analysis of photoemission of electrons from a solid surface due to its interaction with a laser beam. The method we use is based on a three-dimensional quasifree electron model. The model takes account of the changes in the effective mass of the electron inside and outside the solid and in the reflected and refracted beams due to the presence of the surface. It is shown that the photoemission of electrons from the solid surface may take place not only with no absorption of photons but also along with the emission of extra photons. 相似文献
24.
Synthesis of Novel and Thermally Stable Water Insoluble Coumarin‐based Azo Dyes via a Mild and Green Procedure 下载免费PDF全文
A series of novel azo coumarin dyes were synthesized by the diazotization of 7‐amino coumarins in the presence of catalytic amounts of tungstate sulfuric acid (TSA) followed by coupling with phenol derivatives. Tungstate sulfuric acid catalyzes this reaction at room temperature and short reaction time with high yields. 相似文献
25.
26.
Mahtab HejazifarSaeid Azizian Hassan SarikhaniQiang Li Dongyuan Zhao 《Journal of Analytical and Applied Pyrolysis》2011,92(1):258-266
Grapevine rhytidome (the outer layer of bark on trunk), as an abundant and low-cost precursor, was used to prepare granular activated carbon with high surface area for the removal of methyl violet from aqueous solution. Microwave heating source was used to reduce the treatment time and energy consumption. To optimize the preparation, the effects of the different parameters, such as phosphoric acid concentration, acid/precursor weight ratio, impregnation time, microwave power, radiation time, and oven heating time on the ability of the samples for removal of methyl violet were studied. The obtained activated carbon was characterized by N2 adsorption/desorption, SAXS, TEM and SEM methods. The adsorption of methyl violet onto the activated carbon was studied from both equilibrium and kinetic point of view and the results were compared with the commercial granular activated carbon. The rate of adsorption onto the prepared activated carbon was faster than commercial activated carbon. Different kinetic models were used to analyze the experimental kinetic data. The obtained activated carbon showed higher adsorption capacity (more than twice) for the adsorption of methyl violet in comparison with the commercial one. The equilibrium data were analyzed using different isotherm models. Adsorption was found to be maximum in the pH range 7-9. 相似文献
27.
Reza Ranjbar-Karimi Mahtab Mashak-Shoshtari Reza Kia 《Journal of fluorine chemistry》2011,132(4):285-290
Bis-perfluoropyridyl bridged by 1,4 and 1,2 dihydropyridine compounds was synthesized by reaction of 2 and 4 aminopridine derivatives with pentafluoropyridine. The structures were determined by X-ray crystallography. Compound 3a comprises two crystallographically independent molecules in the asymmetric unit in which one of them shows 1-D infinite chains along [0 1 0] direction due to the intermolecular C-H?N hydrogen bonds. In compound 5 intermolecular C-H?F and C-H?N hydrogen bonds link neighbouring molecules to each other. In addition, in both structures a series of C-F?π interactions stabilize the crystal packing. 相似文献
28.
Abduljelil Iliyas Kelly Hawboldt Faisal Khan 《Journal of Thermal Analysis and Calorimetry》2011,106(1):53-61
Thermal methods of analysis such as DSC and TGA provide a powerful methodology for the study of solid reactions. This paper
proposes an improved thermal analysis methodology for thermal stability and safety investigation of complex solid-state reactions.
The proposed methodology is based on differential iso-conversional approach and involves peak separation and individual peak
analysis for kinetic analysis and safety prediction. The proposed thermal analysis method was coupled with Mineral Libration
Analysis (MLA) to investigate self-heating of sulfide mineral ores. The influence of sample’s mineralogy on thermal degradation
was examined and discussed. The information gained from the advanced kinetic analysis of DSC/TGA measurements were up-scaled
for TMR and SADT determination. The described thermal analysis method provides not only an understanding of sulfide mineral
self-heating, but also aids the design of effective mitigation measures for their adverse environmental and safety effects. 相似文献
29.
Faisal A. Almalki Ashraf N. Abdalla Ahmed M. Shawky Mahmoud A. El Hassab Ahmed M. Gouda 《Molecules (Basel, Switzerland)》2021,26(13)
In the current study, a simple in silico approach using free software was used with the experimental studies to optimize the antiproliferative activity and predict the potential mechanism of action of pyrrolizine-based Schiff bases. A compound library of 288 Schiff bases was designed based on compound 10, and a pharmacophore search was performed. Structural analysis of the top scoring hits and a docking study were used to select the best derivatives for the synthesis. Chemical synthesis and structural elucidation of compounds 16a–h were discussed. The antiproliferative activity of 16a–h was evaluated against three cancer (MCF7, A2780 and HT29, IC50 = 0.01–40.50 μM) and one normal MRC5 (IC50 = 1.27–24.06 μM) cell lines using the MTT assay. The results revealed the highest antiproliferative activity against MCF7 cells for 16g (IC50 = 0.01 μM) with an exceptionally high selectivity index of (SI = 578). Cell cycle analysis of MCF7 cells treated with compound 16g revealed a cell cycle arrest at the G2/M phase. In addition, compound 16g induced a dose-dependent increase in apoptotic events in MCF7 cells compared to the control. In silico target prediction of compound 16g showed six potential targets that could mediate these activities. Molecular docking analysis of compound 16g revealed high binding affinities toward COX-2, MAP P38α, EGFR, and CDK2. The results of the MD simulation revealed low RMSD values and high negative binding free energies for the two complexes formed between compound 16g with EGFR, and CDK2, while COX-2 was in the third order. These results highlighted a great potentiality for 16g to inhibit both CDK2 and EGFR. Taken together, the results mentioned above highlighted compound 16g as a potential anticancer agent. 相似文献
30.
Numerical values for axion decay channel branching ratio in positronium decays are presented. From the 3S1 state the maximum is of the order of 10?6. If the axion mass were to be in the vicinity of the positronium mass, the best way of observing the signal would be the decay from the 21P1 state. The feasibility of attaining this by optical pumping is indicated. 相似文献