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61.
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63.
Quantification of lipid modified estrogenic derivative (ESC8) in rat plasma by LC‐MS: application to a pharmacokinetic study
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Ajaz Ahmad Sujan Kumar Mondal Basit Latief Jan Debabrata Mukhopadhyay Rajkumar Banerjee Khalid M. Alkharfy 《Biomedical chromatography : BMC》2016,30(12):2024-2030
A lipid‐conjugated, estrogenic derivative molecule, ESC8, compared with other estrogenic molecules, encourages cell death in both ER‐positive and ER‐negative breast cancer cells. A rapid and highly sensitive assay method has been developed and validated for the estimation of a ESC8 in rat plasma using liquid chromatography coupled with mass spectrometry under positive‐ion mode with electrospray ionization. The sample process includes using methanol for precipitation of ESC8 and dextromethorphan (internal standard, IS) from plasma. Chromatographic separation was achieved with methanol–water–formic acid (70:30:0.1% v/v/v) pumped at a flow rate of 0.3mL/min and a C18 column (50 × 2.1 mm i.d., 1.7 μm particle size) with a total run time of 5 min. The m/z ions monitored were 568.5 and 272.1 for ESC8 and IS, respectively. The lower limit of quantitation achieved was 1.08 ng/mL and linearity was observed from 5 to 500 ng/mL. The intra‐ and inter‐day precisions were <4%. The proposed method was successfully applied to a preliminary pharmacokinetic study of ESC8 liposomal formulation following an intraperitoneal administration of 3.67 mg/kg in rats. The concentrations of ESC8 in plasma were quantifiable up to 36 h. The peak concentration of ESC8 was found to be 110.72 ng/mL, the area under the concentration–time curve was 1625.23ng/mL h and the half‐life was 11.72 h. 相似文献
64.
K. A. Dubey Y. K. Bhardwaj C. V. Chaudhari N. K. Goel S. Sabharwal K. Rajkumar S. K. Chakraborty 《先进技术聚合物》2011,22(12):1888-1897
Varying compositions of styrene–butadiene rubber (SBR) and ethylene–propylene diene monomer (EPDM) 50:50 blend containing multiple walled carbon nanotube (MWNT) as nanoparticulate filler (0.5–5%) were prepared and their efficacy for radiation vulcanization was analyzed by gel‐content, Charlesby‐Pinner parameter, and crosslinking density measurements. Radiation sensitivity of the nanocomposites increased with increase in the MWNT fraction and radiation dose in the dose range studied. The elastic modulus, tensile strength increased with the radiation dose, while elongation at break exhibited downward trend. The extent of reinforcement as assessed using Kraus equation suggested high reinforcement of blend on MWNT addition. The reinforcing mechanism of nanocomposites was studied by various micromechanics models which predicted higher modulus than the experimentally observed results, indicating agglomeration in the nanocomposites. The thermal stability of the composites increased with increase in MWNT loading has been attributed to the antioxidancy induced by nanotubes and higher crosslinking extent of the nanocomposites. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
65.
Rajkumar Eswaran Swarnalatha Kalayar Muthu Mareeswaran Paulpandian Rajagopal Seenivasan 《Journal of fluorescence》2014,24(3):875-884
With the aim of mimicking, at basic level the photoinduced electron transfer process in the reaction center of photosystem II, ruthenium(II)-polypyridyl complexes, carrying amino acids were synthesized and studied their photoinduced electron transfer reactions with quinones by steady state and time resolved measurements. The reaction of quinones with excited state of ruthenium(II)-complexes, I–V in acetonitrile has been studied by luminescence quenching technique and the rate constant, kq, values are close to the diffusion controlled rate. The detection of the semiquinone anion radical in this system using time-resolved transient absorption spectroscopy confirms the electron transfer nature of the reaction. The semiclassical theory of electron transfer has been successfully applied to the photoluminescence quenching of Ru(II)-complexes with quinones. Figure
Transient absorption spectra of complex IV in the presence of Chloranil 相似文献
66.
Rajkumar M Bhuvaneswari J Velayudham M Rajkumar E Rajagopal S 《Journal of fluorescence》2011,21(4):1729-1737
Electron-transfer(ET) from organic sulfides to excited state rhenium(I)-based heteroleptic tricarbonyl complexes [Re(bpy)(CO)3(py)]+ (I) and [Re(bpy)(CO)3(ind))]+ (II) in acetonitrile solution is facile and luminescence quenching constants, kq, are in the range 105–108 M−1s−1. The detection of the sulfide radical cation in this system using time-resolved absorption spectroscopy is a direct evidence
for the ET nature of the reaction. The kq values for the quenching of Re(I)-complexes with organic sulfides are analyzed with a scheme involving rate controlling electron
transfer process. The measured rate constants for the electron transfer (ET) reaction are close to the values calculated from
Marcus theory. 相似文献
67.
Foldamers to Nanotubes: Influence of Amino Acid Side Chains in the Hierarchical Assembly of α,γ4‐Hybrid Peptide Helices
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Dr. Sandip V. Jadhav Rajkumar Misra Dr. Hosahudya N. Gopi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(50):16523-16528
Supramolecular assembly of various artificially folded 12‐helical architectures composed of γ4‐Val, γ4‐Leu and γ4‐Phe residues is investigated. In contrast to the 12‐helices composed of γ4‐Val and γ4‐Leu residues, the helices with γ4‐Phe residues displayed unique elongated nanotubular architectures. The elongated nanotube assembly was further explored as a template for biomineralization of silver ions to silver nanowires. A comparative study using an analogous α‐peptide helix reveals the importance of the spatial arrangement of aromatic side chains along the helical cylinder in a 12‐helix. These results suggested that the proteolytically and structurally stable α,γ4‐hybrid peptide 12‐helices may serve as a new generation of potential templates in the design of functional biomaterials. 相似文献
68.
Anjana Sinha Rajkumar Roychoudhury 《International Journal of Theoretical Physics》1994,33(7):1511-1522
The Dirac equation in (1+1)-dimensional curved space-time is solved explicitly for the spatially flat Robertson-Walker space-time and the cigar metric considered by Witten. 相似文献
69.
70.
Rajkumar Jana 《Journal of organometallic chemistry》2008,693(25):3780-3786
(η5-methylcyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt (1) and its derivatives, [(1-acetyl-2-methyl)η5-cyclopentadienyl](η4-tetraphenylcyclobutadiene)cobalt (2) [(1-acetyl-3-methyl)η5-cyclopentadienyl](η4-tetraphenylcyclobutadiene)cobalt (3) [(1-carbomethoxy-2-methyl)η5-cyclopentadienyl](η4-tetraphenylcyclobutadiene)cobalt (4) and [(1-carbomethoxy-3-methyl)η5-cyclopentadienyl](η4-tetraphenylcyclobutadiene) cobalt (5) have been prepared in yields varying from 11% to 28% by introducing the substituents on the cyclopentadienyl ring of methylcyclopentadienyl sodium and then reacting with diphenylacetylene and CoCl(PPh3)3. The carboxylic acids [(1-carboxy-2-methyl)η5-cyclopentadienyl](η4-tetraphenylcyclobutadiene)cobalt (6), [(1-carboxy-3-methyl)η5-cyclopentadienyl](η4-tetraphenylcyclobutadiene)cobalt (7) have been prepared after ester hydrolysis of compounds 4 and 5 using KOH/ethanol. [(1-dimethylaminomethyl-3-methyl)η5-cyclopentadienyl](η4-tetraphenylcyclobutadiene) cobalt (8), was prepared selectively by direct substitution on the cyclopentadienyl ring of (η5-methylcyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt in 65% yield. The 1,2-isomer was formed only in traces in this reaction. Reactivity of (η5-methylcyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt and its carbomethoxy derivative have been compared with (η5-cyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt. All new compounds were characterized by 1H and 13C NMR, FT-IR, mass spectra and CHN analysis. Compounds 2, 4, 6 and 8 have also been structurally characterized by single crystal X-ray structural analysis. 相似文献