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71.
Ramasamy Karvembu Rathinasabapathi Prabhakaran Kuppusamy Senthilkumar Periasamy Viswanathamurthi Karuppannan Natarajan 《Reaction Kinetics and Catalysis Letters》2005,86(1):211-216
Summary Primary and secondary alcohols were oxidized to their corresponding aldehydes or ketones in good yields using Ru/Al2O3 as catalyst in the presence of acetone. The catalyst can be recovered by simple filtration and reused after washing with acetone. 相似文献
72.
Viswanathamurthi Periasamy Dharmaraj Nallasamy Anuradha Sankaran Natarajan Karuppannan 《Transition Metal Chemistry》1998,23(4):337-341
Ruthenium(III) complexes of Schiff bases derived from the condensation of salicylaldehyde or o-vanillin with diamines have been prepared and characterised. The complexes are of the type [RuX(EPh3)(L)] [X=Cl or Br; E=P or As; L=bis(salicylaldehyde)tetramethylenediimine, bis(salicylaldehyde)o-phenylenediimine, bis(o-vanillin)ethylenediimine, bis(o-vanillin)propylenediimine, bis(o-vanillin)tetramethylenediimine or bis(o-vanillin)o-phenylenediimine]. The Schiff bases behave as dibasic tetradentate ligands. 相似文献
73.
Kai Linke Nagarajan Periasamy Emiley A. Eloe Matthias Ehrmann Roland Winter Douglas H. Bartlett 《高压研究》2013,33(3):431-442
High hydrostatic pressure (HHP) is suggested to influence bacterial physiology by changing the structure and function of membranes and/or integral membrane proteins. In this work, the HHP-modulated dimerization behavior of the transmembrane regulatory protein ToxR from Photobacterium profundum SS9 was investigated, in response to changes in membrane organization induced by temperature and addition of phenethyl alcohol, in a background of different organisms (Escherichia coli and P. profundum) and mutants deficient in unsaturated fatty acid synthesis. Reporter strains were constructed by chromosomal integration of an ompL-promoter lacZ fusion cassette. Arabinose-controlled ToxR expression was achieved by plasmid pBADK-ToxR-his. The results demonstrate that changes in the lipid environment have a marginal effect on the function of ToxR; instead, ToxR activity appears to be largely determined by the properties of the protein itself. 相似文献
74.
Time-resolved area normalized emission spectroscopy (TRANES) is a new method for the analysis of fluorescence of dyes in complex
chemical and biological systems (A S R Koti, M M G Krishna and N Periasamy, 2001,J. Phys. Chem.
105, 1767). The model-free method extends the power of time-resolved emission spectroscopy (TRES) analysis and removes the ambiguity
in the interpretation when the emission spectrum is time-dependent. Observation of an isoemissive point in TRANES analysis
of fluorescence is an unambiguous indication for the presence of two emissive species in the sample. The isoemissive point
occurs at a wavelength where the ratio of the radiative rates of the two species is equal to the ratio of their total radiative
rates. The polarity-sensitive nile red dye shows time-dependent emission spectra in the organized bilayer assemblies of TX
micelle and bilayer egg-phosphotidylcholine (egg-PC) membrane. Time-dependent spectra in complex systems support many important
models (solvation model and heterogeneity in the ground and/or excited state). TRANES analysis shows that the fluorescence
emission of nile red in TX micelle and egg-PC membrane is due to two emissive species solubilized in different sites. 相似文献
75.
A series of divalent non-transition metal, especially Mg doped LiCoO2 solid solutions with the general formula LiMgxCo1−xO2 (x=0.00–0.20) was synthesized by the solid state fusion method trying to reduce the cost and toxicity, and to improve the
overall electrochemical cell performance. All synthesized cathodes were characterized by XRD, TG/DTA, FTIR, SEM, particle
size analysis and charge-discharge performances at constant current of 0.05 mA. All compounds were found to possess phase
purity, have better crystallinity, preferred surface morphology and size-reduced particles of uniform distribution. The incorporation
of the larger Mg2+ ion compared to the Li+ ion up to 0.20 mol-% leads to an increase in the unit cell volume, which restricts the concentration of the Co-O bond upon
delithiation. Mg2+, commonly known for its structure stabilizing effect, has been found to have only a small effect on the crystal lattice of
LiCoO2, especially at higher substituent levels, mainly due to the migration of Mg2+ ions from slab to inter-slab structure. The effect of Mg2+ on the modification of the capacity and structural stability compared to the unmodified LiCoO2 cathode is discussed in detail. 相似文献
76.
Rajendiran V Karthik R Palaniandavar M Stoeckli-Evans H Periasamy VS Akbarsha MA Srinag BS Krishnamurthy H 《Inorganic chemistry》2007,46(20):8208-8221
The copper(II) complex [Cu(tdp)(ClO4)].0.5H2O (1), where H(tdp) is the tetradentate ligand 2-[(2-(2-hydroxyethylamino)ethylimino)methyl]phenol, and the mixed ligand complexes [Cu(tdp)(diimine)]+ (2-5), where diimine is 2,2'-bipyridine (bpy) (2), 1,10-phenanthroline (phen) (3), 3,4,7,8-tetramethyl-1,10-phenanthroline (tmp) (4), and dipyrido-[3,2-d:2',3'-f]-quinoxaline (dpq) (5), have been isolated and characterized by analytical and spectral methods. Complexes 1 and [Cu(tdp)(phen)]ClO4 (3) have been structurally characterized, and their coordination geometries around copper(II) are described as distorted octahedral. The equatorially coordinated ethanolic oxygen in 1 is displaced to an axial position upon incorporating the strongly chelating phen, as in 3. The solution structures of all the complexes have been assessed to be square-based using electronic absorption and electron paramagnetic resonance (EPR) spectroscopy. The interaction of the complexes with calf thymus DNA (CT DNA) has been explored by using absorption, emission, and circular dichroic spectral and viscometric studies, and modes of DNA binding for the complexes have been proposed. Absorption spectral (Kb = 0.071 +/- 0.005 (2), 0.90 +/- 0.03 (3), 7.0 +/- 0.2 (4), 9.0 +/- 0.1 x 10(5) M(-1) (5)), emission spectral (Kapp = 4.6 (1), 7.8 (2), 10.0 (3), 12.5 (4), 25.0 x 10(5) M(-1) (5)), and viscosity measurements reveal that 5 interacts with DNA more strongly than the other complexes through partial intercalation of the extended planar ring of the coordinated dpq with the DNA base stack. Interestingly, only complex 4 causes a B to A conformational change upon binding DNA. All the complexes hydrolytically cleave pBR322 supercoiled DNA in 10% DMF/5 mM Tris-HCl/50 mM NaCl buffer at pH 7.1 in the absence of an activating agent, and the cleavage efficiency varies in the order 5 > 3 > 2 > 4 > 1 with 5 displaying the highest Kcat value (5.47 +/- 0.10 h(-1)). The same order of cleavage is observed for the oxidative cleavage of DNA in the presence of ascorbic acid as a reducing agent. Interestingly, of all the complexes, only 5 displays efficient photonuclease activity through double-strand DNA breaks upon irradiation with 365 nm light through a mechanistic pathway involving hydroxyl radicals. The protein binding ability of 1-5 has been also monitored by using the plasma protein bovine serum albumin (BSA), and 4 exhibits a protein binding higher than that of the other complexes. Further, the anticancer activity of the complexes on human cervical epidermoid carcinoma cell line (ME180) has been examined. Interestingly, the observed IC50 values reveal that complex 4, which effects conformational change on DNA and binds to BSA more strongly, exhibits a cytotoxicity higher than the other complexes. It also exhibits approximately 100 and 6 times more potency than cisplatin and mitomycin C for 24 and 48 h incubation times, respectively, suggesting that 4 can be explored further as a potential anticancer drug. Complexes 4 and 5 mediate the arrest of S and G2/M phases in the cell cycle progression at 24 h harvesting time, which progress into apoptosis. 相似文献
77.
Conversion of propargyl alcohols to chloroallenes and arylalkynes using the TiCl4/R3N reagent system
Whereas the reaction of certain propargyl alcohols with TiCl4 in the presence of tertiary alkylamines gives the corresponding chloroallenes in 37-58% yields, reaction with the tertiary arylamines gives the corresponding arylalkynes in 68-77% yields. 相似文献
78.
Arun Prakash Periasamy Yu-Jung Chang Shen-Ming Chen 《Bioelectrochemistry (Amsterdam, Netherlands)》2011,80(2):114-120
We investigated the direct electrochemistry of glucose oxidase (GOx) at gelatin-multiwalled carbon nanotube (GCNT) modified glassy carbon electrode (GCE). GOx was covalently immobilized onto GCNT modified GCE through the well known glutaraldehyde (GAD) chemistry. The immobilized GOx showed a pair of well-defined reversible redox peaks with a formal potential (E0′) of ? 0.40 V and a peak to peak separation (ΔEp) of 47 mV. The surface coverage concentration (Г) of GOx in GCNT/GOx/GAD composite film modified GCE was 3.88 × 10? 9 mol cm? 2 which indicates the high enzyme loading. The electron transfer rate constant (ks) of GOx immobilized onto GCNT was 1.08 s? 1 which validates a rapid electron transfer processes. The composite film shows linear response towards 6.30 to 20.09 mM glucose. We observed a good sensitivity of 2.47 μA mM?1 cm? 2 for glucose at the composite film. The fabricated biosensor displayed two weeks stability. Moreover, it shows no response to 0.5 mM of ascorbic acid (AA), uric acid (UA), acetaminophen (AP), pyruvate (PA) and lactate (LA) which shows its potential application in the determination of glucose from human serum samples. The composite film exhibits excellent recovery for glucose in human serum at physiological pH with good practical applicability. 相似文献
79.
Periasamy Meenakshi Rajendran Bhuvaneshwari Muthaiyan Ahalliya Rathi Lakshmanan Thirumoorthi Dugganaboyana Chinna Guravaiah Muthedath Janardhanan Jiji Velliyur Kanniappan Gopalakrishnan 《Applied biochemistry and biotechnology》2010,162(4):1153-1159
Diabetes mellitus is a complex disorder that disturbs the metabolism of carbohydrates, fats, and proteins. Medicinal plants play an important role in the management of diabetes mellitus. The present study was aimed to evaluate the antidiabetic potential of Zaleya decandra roots on alloxan-induced diabetes in rats. Oral administration of ethanolic extract of the root (200 mg/kg body weight/day) for 15 days restored the levels of glucose, cholesterol, triglycerides, total proteins, urea, creatinine, lipid peroxidation level, and antioxidant enzymes significantly in diabetic rats. Histopathological studies showed significant changes like necrosis and degeneration in the liver and pancreas of alloxan-induced diabetic rats. Also these histopathological abnormalities were found to be normalized after treatment with Z. decandra extract. The efficacy of the root extract was found to be equivalent when compared to the standard hypoglycemic drug glibenclamide (1.25 mg/kg body weight/day, orally) in diabetic rats. 相似文献
80.
Manisekar Muthukumar Periasamy Viswanathamurthi 《Central European Journal of Chemistry》2010,8(1):229-240
A series of new hexa-coordinated ruthenium(II) complexes of the type [Ru(CO)(EPh3)(B)(L)] (E = P or As; B = PPh3, AsPh3 or Py; L = chalcone thiosemicarbazone) have been prepared by reacting [RuHCl(CO)(EPh3)2(B)] (E = P or As; B = PPh3, AsPh3 or Py) with chalcone thiosemicarbazones in benzene under reflux. The new complexes have been characterized by analytical
and spectroscopic (IR, UV-vis, 1H, 31P and 13C NMR) methods. On the basis of data obtained, an octahedral structure was assigned for all of the complexes. The chalcone
thiosemicarbazones behave as dianionic tridentate O, N, S donors and coordinate to ruthenium via the phenolic oxygen of chalcone, the imine nitrogen of thiosemicarbazone and thienol sulfur. The new complexes exhibit catalytic
activity for the oxidation of primary and secondary alcohols to their corresponding aldehydes and ketones and they were also
found to be efficient catalysts for the transfer hydrogenation of carbonyl compounds. 相似文献