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71.
Gopee H Petersen BM Bond AD Jeppesen JO 《Chemical communications (Cambridge, England)》2007,(40):4110-4112
Dihalomonopyrrolo-TTF undergoes a bromine catalysed dimerisation reaction to yield a novel type of extended TTF derivative. 相似文献
72.
Mangesh A. Bangar Dhammanand J. Shirale Hemant J. Purohit Wilfred Chen Nosang V. Myung Ashok Mulchandani 《Electroanalysis》2011,23(2):371-379
We have fabricated a highly sensitive, simple and label‐free single polypyrrole (Ppy) nanowire based conductometric/chemiresistive DNA sensor. The fabrication was optimized in terms of probe DNA sequence immobilization using a linker molecule and using gold‐thiol interaction. Two resultant sensor designs working on two different sensing mechanisms (gating effect and work function based sensors) were tested to establish reliable sensor architecture with higher sensitivity and device‐to‐device reproducibility. The utility of the work function based configuration was demonstrated by detecting 19 base pair (bp) long breast cancer gene sequence with single nucleotide polymorphism (SNP) discrimination with high sensitivity, lower detection limit of ∼10−16 M and wide dynamic range (∼10−16 to 10−11 M) in a small sample volume (30 µL). To further demonstrate the utility of the DNA sensor for detection of target sequences with different number of bases, targets with 21 and 36 bases were detected. These sequences have implications in environmental sample analysis or metagenomics. Sensor response showed increase with the number of bases in the target sequence. For long sequence (with 36 bases), effect of DNA alignment on sensor performance was studied. 相似文献
73.
The molecular weight distributions were estimated for carbon fiber polymer precursors such as poly(acrylonitrile-co -itaconic acid) synthesized by semi batch solution polymerization in mixed solvents media with the azonitrile compounds as initiator under the different ratios of solvent and non solvent from 0.75 to 2.5 in weight.The copolymer was characterized by using Fourier transform infrared spectroscopy(FTIR) and nuclear magnetic resonance(1H-NMR) analyses.The molecular weight distributions were evaluated by Mv/Mn ratios estimated from viscosity and osmotic measurements,and Mw/Mn estimated from size exclusion chromatography.The molecular weight distributions of these polymers as determined from Mv/Mn and Mw/Mn are 2.9 to 3.2 and 2.0 to 2.5 respectively.The molecular distributions were close to a narrow distribution of 2.0 when the solvent/non-solvent ratio was varied between 1.4 and 2.0.Intrinsic viscosity[?]as a function of molecular weight of poly(acrylonitrile-co-itaconic acid) was evaluated by means of low angle laser light scattering with size exclusion chromatography(SEC-LALLS) and viscometry with SEC(SEC-VISCO).The relationship between[?]and Mw for poly(acrylonitrile-co-itaconic acid) in DMF at 50℃was[?]= 1.1×10-5Mw0.79,where[?]is obtained in dL/g. 相似文献
74.
Preeti Saluja Hemant Sharma Navneet Kaur Narinder Singh Doo Ok Jang 《Tetrahedron》2012,68(10):2289-2293
We synthesized an imine-linked, benzimidazole-based chemosensor that can be used for chromogenic recognition of Mg2+ and fluorescent recognition of Cr3+. The chemosensor shows sensitive, selective, and ratiometric recognition of Cr3+ through concurrent quenching at one wavelength and enhancement of fluorescence intensity at another wavelength. It can also be used to detect Mg2+ via UV–vis absorption spectroscopy. DFT calculations support these phenomena. The sensor can be used to strain microbe cells without breakage. 相似文献
75.
Hemant Bhate 《Linear and Multilinear Algebra》2013,61(3-4):395-402
We give a method for construction of finite, abelian hypergroups of matrices which, while including most previously known cases, also gives rise to a new family of hypergroups. 相似文献
76.
Let G be a finite non-abelian p-group, where p is a prime. Let Autc(G) and Autz(G) respectively denote the group of all class preserving and central automorphisms of G. We give a necessary and sufficient condition for G such that Autc(G) = Autz(G) and classify all finite non-abelian p-groups G with elementary abelian or cyclic center such that Autc(G) = Autz(G). We also characterize all finite p-groups G of order ≤ p 7 such that Autz(G) = Autz(G) and complete the classification of all finite p-groups of order ≤ p 5 for which there exist non-inner class preserving automorphisms. 相似文献
77.
Suthari Prashanthi P. Hemant Kumar Li Wang Arun Kumar Perepogu Prakriti Ranjan Bangal 《Journal of fluorescence》2010,20(2):571-580
Steady state and time resolved fluorescence quenching behaviors of meso-Tetrakis (pentafluorophenyl) porphyrin (H2F20TPP) in presence of different aliphatic and aromatic amines have been executed in homogeneous dichloromethane (DCM) solution.
At room temperature in DCM, free base (H2F20TPP) shows fluorescence with two distinct peaks at 640 and 711 nm and natural lifetime τ
f = 9.8 ns which are very similar to that of meso-tetraphenyl porphyrin (TPP). Unlike TPP, addition of both aliphatic and aromatic
amines to a solution containing H2F20TPP results in an efficient decrease in fluorescence intensity without altering the shape and peak position of fluorescence
emission. Upon addition of amines there was no change in optical absorption spectra of H2F20TPP. The fluorescence quenching rate constants ranged from 1 × 109 to 4 × 109 s−1, which are one order below to the diffusion control limit, and temperature dependent quenching rate constants yield the activation
energies which are found to be order of 0.1 eV. Femto second transient absorption studies reveal the existence of amine cation
radical and porphyrin anion radicals with very short decay time (15 ps). The fluorescence quenching reaction follows Stern–Volmer
kinetics. Steady state and time-resolved data are interpreted within general kinetic scheme of Marcus semi-classical model
which attributes bimolecular electron transfer process between amines and the lowest excited singlet state of H2F20TPP. Calculated internal reorganization energies are found to be in between 0.04 and 0.22 ev. Variation of electron transfer
rate as function of free energy change (∆G0) points the ET reactions in the present systems are in Marcus normal region. This is the first example of reductive fluorescence
quenching of free base neutral porphyrins in homogeneous organic solvent ever known. 相似文献
78.
Prashant Shukla Suhasini Mahata Hemant Kashyap Manorama Singh Vijai K. Rai Ankita Rai 《Tetrahedron letters》2019,60(30):1943-1948
Graphene oxide (GO)/GO-I2 co-catalyzed green synthesis of tosylaziridine bearing keto and nitrile/ester functional groups is reported. The strategy involves sequential GO-catalyzed oxidation of benzylic alcohol and GO-I2 catalyzed nitrene insertion into olefin of Morita-Baylis-Hillman adduct. Operational simplicity, use of water as solvent, ambient reaction conditions, excellent yield of products (88–96%) and recyclability of catalyst up to five times without any substantial change in morphology as well as catalytic efficiency are the salient features of the envisaged protocol. 相似文献
79.
Mir Mohammad Shahroz Hemant Kumar Sharma Abdulmalik S. A. Altamimi Mubarak A. Alamri Abuzer Ali Amena Ali Safar Alqahtani Ali Altharawi Alhumaidi B. Alabbas Manal A. Alossaimi Yassine Riadi Ahmad Firoz Obaid Afzal 《Molecules (Basel, Switzerland)》2022,27(4)
The dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) is a novel, promising and emerging biological target for therapeutic intervention in neurodegenerative diseases, especially in Alzheimer’s disease (AD). The molMall database, comprising rare, diverse and unique compounds, was explored for molecular docking-based virtual screening against the DYRK1A protein, in order to find out potential inhibitors. Ligands exhibiting hydrogen bond interactions with key amino acid residues such as Ile165, Lys188 (catalytic), Glu239 (gk+1), Leu241 (gk+3), Ser242, Asn244, and Asp307, of the target protein, were considered potential ligands. Hydrogen bond interactions with Leu241 (gk+3) were considered key determinants for the selection. High scoring structures were also docked by Glide XP docking in the active sites of twelve DYRK1A related protein kinases, viz. DYRK1B, DYRK2, CDK5/p25, CK1, CLK1, CLK3, GSK3β, MAPK2, MAPK10, PIM1, PKA, and PKCα, in order to find selective DYRK1A inhibitors. MM/GBSA binding free energies of selected ligand–protein complexes were also calculated in order to remove false positive hits. Physicochemical and pharmacokinetic properties of the selected six hit ligands were also computed and related with the proposed limits for orally active CNS drugs. The computational toxicity webserver ProTox-II was used to predict the toxicity profile of selected six hits (molmall IDs 9539, 11352, 15938, 19037, 21830 and 21878). The selected six docked ligand–protein systems were exposed to 100 ns molecular dynamics (MD) simulations to validate their mechanism of interactions and stability in the ATP pocket of human DYRK1A kinase. All six ligands were found to be stable in the ATP binding pocket of DYRK1A kinase. 相似文献
80.
Piero Zanello Giuliana OpromollaLuca PardiKeith H. Pannell Hemant K. Sharma 《Journal of organometallic chemistry》1993,450(1-2):193-196
The electrochemical behaviour of the ferrocenylacyl derivatives [FcCOER3] (E = C, Si or Ge; R = Me or Ph) is examined. One-electron oxidations to the substantially stable monocations [FcCOER3]+ occur at potentials significantly higher than that observed with ferrocene, but only minor differences hold within the series, independent of the nature of both E and R. In contrast the EPR spectra of the monocations for E = C show that the unpaired electron resides mainly on the iron, whereas for E = Si or Ge the electron density is essentially localized on the C5H4COER3 fragment. 相似文献