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291.
Subbiah RP Lee H Veerapandian M Sadhasivam S Seo SW Yun K 《Analytical and bioanalytical chemistry》2011,400(2):547-560
A bio-nanofilm consisting of a tetrad nanomaterial (nanotubes, nanoparticles, DNA, polymer) was fabricated utilizing in situ
reduction and noncovalent interactions and it displayed effective antibacterial activity and biocompatibility. This bio-nanofilm
was composed of homogenous silver nanoparticles (AgNPs) coated on single-walled carbon nanotubes (SWCNTs), which were later
hybridized with DNA and stabilized in poly(vinyl alcohol) (PVA) in the presence of a surfactant with the aid of ultrasonication.
Electron microscopy and bio-AFM (atomic force microscopy) images were used to assess the morphology of the nanocomposite (NC)
structure. Functionalization and fabrication were examined using FT–Raman spectroscopy by analyzing the functional changes
in the bio-nanofilm before and after fabrication. UV–visible spectroscopy and X-ray powder diffraction (XRD) confirmed that
AgNPs were present in the final NC on the basis of its surface plasmon resonance (370 nm) and crystal planes. Thermal gravimetric
analysis was used to measure the percentage weight loss of SWCNT (17.5%) and final SWCNT-AgNPs-DNA/PVA (47.7%). The antimicrobial
efficiency of the bio-nanofilm was evaluated against major pathogenic organisms. Bactericidal ratios, zone of inhibition,
and minimum inhibitory concentration were examined against gram positive and gram negative bacteria. A preliminary cytotoxicity
analysis was conducted using A549 lung cancer cells and IMR-90 fibroblast cells. Confocal laser microscopy, bio-AFM, and field
emission scanning electron microscopy (FE-SEM) images demonstrated that the NCs were successfully taken up by the cells. These
combined results indicate that this bio-nanofilm was biocompatible and displayed antimicrobial activity. Thus, this novel
bio-nanofilm holds great promise for use as a multifunctional tool in burn therapy, tissue engineering, and other biomedical
applications. 相似文献
292.
Yeh-Siang L Subramaniam G Hadi AH Murugan D Mustafa MR 《Molecules (Basel, Switzerland)》2011,16(4):2990-3000
Generation of reactive oxygen species plays a pivotal role in the development of cardiovascular diseases. The present study describes the effects of the methanolic extract of Phoebe grandis (MPG) stem bark on reactive oxygen species-induced endothelial dysfunction in vitro. Endothelium-dependent (acetylcholine, ACh) and -independent relaxation (sodium nitroprusside, SNP) was investigated from isolated rat aorta of Sprague-Dawley (SD) in the presence of the β-NADH (enzymatic superoxide inducer) and MPG extract. Superoxide anion production in aortic vessels was measured by lucigen chemiluminesence. Thirty minutes incubation of the rat aorta in vitro with β-NADH increased superoxide radical production and significantly inhibited ACh-induced relaxations. Pretreatment with MPG (0.5, 5 and 50 μg/mL) restored the ACh-induced relaxations (R(max): 92.29% ± 2.93, 91.02% ± 4.54 and 88.31 ± 2.36, respectively) in the presence of β-NADH. MPG was ineffective in reversing the impaired ACh-induced relaxations caused by pyrogallol, a non-enzymatic superoxide generator. Superoxide dismutase (a superoxide scavenger), however, reversed the impaired ACh relaxations induced by both β-NADH and pyrogallol. MPG also markedly inhibited the β-NADH-induced generation of the superoxide radicals. Furthermore, MPG scavenging peroxyl radicals generated by tBuOOH (10?? M).These results indicate that MPG may improve the endothelium dependent relaxations to ACh through its scavenging activity as well as by inhibiting the NADH/NADPH oxidase induced generation of superoxide anions. 相似文献
293.
294.
Sreedevi Mannam 《合成通讯》2013,43(19):2822-2829
A new procedure for the selective and direct oxidation of aliphatic primary alcohols having substitution at β- and γ-positions to corresponding carboxylic acids was developed using a catalytic amount of ligand and additive-free CuCl with anhydrous t BuOOH in acetonitrile solvent under very mild reaction conditions. This procedure is very simple and mild and works efficiently without any additives at room temperature. 相似文献
295.
Shahul Hameed P. Gajanan Shanbhag Vikas Shinde Murugan Chinnapattu Praveena Manjrekar Jayashree Puttur 《合成通讯》2013,43(24):3315-3321
Short and efficient route for the synthesis of oxazinone- and thiazinone-containing bicyclic heteroaromatic aldehydes, which involves the key step of palladium-catalyzed reductive carbonylation, is described. Overall routes for the synthesis of these aldehydes are short, versatile, and scalable with good yields of the product. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] 相似文献
296.
Kadarkarai Murugan C. P. Sanoopa Pari Madhiyazhagan Devakumar Dinesh Jayapal Subramaniam Chellasamy Panneerselvam 《Natural product research》2016,30(7):826-833
Aedes aegypti is a primary vector of dengue, a mosquito-borne viral disease infecting 50–100 million people every year. Here, we biosynthesised mosquitocidal silver nanoparticles (AgNP) using the aqueous leaf extract of Crotalaria verrucosa. The green synthesis of AgNP was studied by UV–vis spectroscopy, SEM, EDX and FTIR. C. verrucosa-synthesised AgNPs were toxic against A. aegypti larvae and pupae. LC50 of AgNP ranged from 3.496 ppm (I instar larvae) to 17.700 ppm (pupae). Furthermore, we evaluated the predatory efficiency of dragonfly nymphs, Brachydiplax sobrina, against II and III instar larvae of A. aegypti in an aquatic environment contaminated with ultra-low doses of AgNP. Under standard laboratory conditions, predation after 24 h was 87.5% (II) and 54.7% (III). In an AgNP-contaminated environment, predation was 91 and 75.5%, respectively. Overall, C. verrucosa-synthesised AgNP could be employed at ultra-low doses to reduce larval population of dengue vectors enhancing predation rates of dragonfly nymphs. 相似文献
297.
298.
The 1,3-dipolar cycloaddition reaction of tryarylideneacetyacetone derivatives with N-metalated azomethine ylides in the presence of titanocene dichloride and triethylamine has been investigated. This two-step synthetic sequence is very efficient and yielded the highly substituted pyrrolidines in good yields. The structure and stereochemistry of one of the products has been established by single-crystal x-ray structure and spectroscopic techniques. 相似文献
299.
Murugan Indrani Ramasamy Ramasubramanian Sudalaiandi Kumaresan Mao‐Lin Hu Manuel Soriano‐García 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(1):m23-m25
In the title complex, {[Cu(C8H8NO3S)2(H2O)]·2H2O}n, the CuII cation has a distorted square‐pyramidal coordination environment consisting of five O atoms, one from a water molecule, one from an N—O group and the other three from the carboxylate groups of two 3‐(2‐pyridylsulfanyl)propionate N‐oxide anions. The aqua[3‐(2‐pyridylsulfanyl)propionato N‐oxide]copper(II) moieties are bridged by 3‐(2‐pyridylsulfanyl)propionate N‐oxide anions to form an infinite three‐dimensional coordination polymer with a zigzag chain structure. The crystal structure is stabilized by hydrogen bonds. 相似文献
300.
Characteristics of high Mach number compressible vortex ring generated at the open end of a short driver section shock tube
is studied experimentally using high-speed laser sheet-based flow visualization. The formation mechanism and the evolution
of counter rotating vortex ring (CRVR) formed ahead of the primary vortex ring are studied in details for shock Mach number
(M) 1.7, with different driver section lengths. It has been observed that the strength of the embedded shock, which appears
at high M, increases with time due to the flow expansion in the generating jet. Strength of the embedded shock also varies with radius;
it is strong at smaller radii and weak at larger radii; hence, it creates a velocity gradient ahead of the embedded shock.
At critical Mach number (M
c ≥ 1.6), this shear layer rolls up and forms a counter rotating vortex ring due to Biot-Savart induction of the vortex sheet.
For larger driver section lengths, the embedded shock and the resultant shear layer persists for a longer time, resulting
in the formation of multiple CRVRs due to Kelvin–Helmholtz type instability of the vortex sheet. CRVRs roll over the periphery
of the primary vortex ring; they move upstream due to their self-induced velocity and induced velocity imparted by primary
ring, and interact with the trailing jet. Formation of these vortices depends strongly upon the embedded shock strength and
the length of the generating jet. Primary ring diameter increases rapidly during the formation and the evolution of CRVR due
to induced velocity imparted on the primary ring by CRVR. Induced velocity of CRVR also affects the translational velocity
of the primary ring considerably. 相似文献