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161.
Mohammed Mohsin Meena Nagar Alka Choudhary 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):1331-1338
Abstract Dialkyl (alkylene) dithiophosphate adducts of stannous chloride were synthesized by the reaction of anhydrous tin(II) chloride (SnCl2) and dialkyl (alkylene) dithiophosphoric acid in a 1:1 molar ratio, under anhydrous reaction conditions, below 5 °C in a closed vessel. The newly synthesized adducts were characterized by physicochemical and spectroscopic techniques [FT-IR, NMR (1H, 31P, and 119Sn), and mass spectrometry]. Coordination modalities have indicated a donor–acceptor interaction between sulfur and tin(II) moieties, where tin(II) acts as a Lewis acid. The adducts were found to have significant antibacterial activity against Escherichia coli and Pseudomonas aeruginosa, and antifungal activity against Aspergillus niger and Candida albicans. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. 相似文献
162.
Abdulbaset A. Zaid Mohammad Mohsin Mazahar Farooqui D.M. Janrao 《Journal of Saudi Chemical Society》2013,17(1):43-45
Proton–ligand dissociation constant of 1-cyclopropyl-1,4-dihydro-4-oxo-7-(1-piperazinyl) quinolone-3-carboxylic acid is ciprofloxacin and metal–ligand stability constants of its complexes with some metal ions have been determined potentiometrically in the presence of (0.01, 0.02 and 0.03 mol/dm3) NaClO4. The order of the stability constants of the formed complexes increases in the sequence Cu2+, Fe3+, Ni2+ and Zn2+ and decreases with increase in the concentration of ionic strength. 相似文献
163.
Fozia T. Minhas Shahabuddin Memon Imdadullah Qureshi M. Mujahid M.I. Bhanger 《Comptes Rendus Chimie》2013,16(8):742-751
In the present investigation, p-morpholinomethylcalix[4]arene (1) has been examined as a carrier in supported liquid membrane (SLM) for Cu(II) transport. The influence of different parameters, such as solvent, membrane dipping time, support membrane, co-anions, donor and acceptor pH, and carrier concentration on Cu(II) transport, was checked. The permeability values were calculated by using Danesi mass transfer model. Higher Cu(II) permeability was observed in diphenyl ether, with 1 h dipping time, Celgard 2500 and Cl? as co-anion. The optimum pH for donor phase was 2 and that for acceptor phase was neutral at 10?3 M carrier concentration. Diffusion coefficients were calculated using Reinhoudt's model, lag time measurements as well as by Wilke–Chang relation and compared. The transport was found to be diffusion-controlled in the membrane phase and the diffusion coefficient was calculated to be 1.54 × 10?10 m/s whereas the extraction constant was calculated to be 1.19 × 10?5 m/s. 相似文献
164.
M. Mohsin Khan N. Ahmad A. Kamal A. A. Masoodi M. Irfan 《Indian Journal of Physics》2011,85(1):189-193
Correlation and fluctuations are now well accepted analysis techniques in heavy-ion collisions at relativistic energies. At
the current stage of RHIC exploration, matter in bulk and many of the physics questions about the final stage of collisions
are addressed with the help of correlation techniques. In the present work after a general introduction to the underlying
formalism to the exotic phenomena of correlation and fluctuations, discussion on various parameters disentangling dynamical
fluctuations is presented. Analysis to investigate dynamical fluctuations and correlation is carried out in terms of F
q
- and G
q
-moments. A study of various other parameters involving multiplicity and pseudorapidity of relativistic charged particles
produced in high energy nuclear interactions reveals the presence of correlation and fluctuations in particle production in
these collisions. The experimental data on 14.5A GeV/c 28Si-nucleus interactions has been analyzed. A parallel analysis of correlation free data generated using MC-RAND Monte Carlo
code, UrQMD data and for the HIJING generated events has also been carried out. 相似文献
165.
The monolithic integration of four 1.5?μm range AlGaInAs/InP distributed feedback lasers with a 4×1 multimode-interference optical combiner, a curved semiconductor optical amplifier, and an electro-absorption modulator using relatively simple technologies--sidewall grating and quantum well intermixing--has been demonstrated. The four channels span the wavelength range of 1530 to 1566?nm with a channel spacing of 12?nm. The epitaxial structure was designed to produce a far-field pattern as small as 21.2°×25.1°, producing a coupling efficiency with an angled-end single-mode fiber at twice that of a conventional device design. 相似文献
166.
Redox Mechanism and Evaluation of Kinetic and Thermodynamic Parameters of 1,3‐Dioxolo[4,5‐g]pyrido[2,3‐b]quinoxaline Using Electrochemical Techniques
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Aamir Hassan Shah Afzal Shah Usman Ali Rana Salah Ud‐Din Khan Hidayat Hussain Sher Bahadar Khan Rumana Qureshi Amin Badshah 《Electroanalysis》2014,26(10):2292-2300
The electrochemical behavior of a biologically important heterocyclic compound, 1,3‐dioxolo[4,5‐g]pyrido[2,3‐b]quinoxaline was investigated by cyclic, square wave and differential pulse voltammetry in solutions of different pH. Kinetic and thermodynamic parameters like standard rate constant, diffusion coefficient, apparent energy of activation, standard Gibbs free energy and enthalpy and entropy changes were evaluated. Limits of detection and quantification were determined by square wave voltammetry. The redox mechanism of the compound was proposed on the basis of experimental results. Computational chemistry was used as a tool for the verification of experimental outcomes and assessment of different theoretical parameters 相似文献
167.
I.E. Qureshi M.I. Shahzad M.T. Javed S. Manzoor G. Sher F. Aleem H.A. Khan 《Radiation measurements》2005,40(2-6):437-441
The fragmentation of Pb ions at 158 A GeV energy produced in the interaction with Pb target has been studied using a CR-39 track detector. A stack comprising of 64 detectors was prepared such that a target of 1 cm thickness was sandwiched between the sheets of CR-39. The purpose of this exposure geometry was to calibrate CR-39 with respect to relativistic heavy ions as well as to study the fragmentation of Pb ions at 158 A GeV energy. The exposure was carried out at the SPS beam facility of CERN at normal incidence with a fluence of . Two detectors from the exposed stack have been selected for this study: one before and the other after the target material. After etching, the detectors were scanned using an optical microscope and the etched track lengths and the diameters of the track openings were measured manually. Considering that the lengths of tracks provide the best charge resolution for Z>65, we have measured track lengths for a sufficiently large number of fragments to identify individual charge states for 65<Z<83. The total charge-changing cross section has also been determined. 相似文献
168.
The dynamic properties of a biased two-level system in contact with a dissipative bath are studied in the weak coupling limit
using a resolvent expansion method. The theory yields consistent results at low temperatures, a regime in which the widely
used dilute bounce gas approximation (DBGA) to an underlying functional integral expression breaks down. The present results
are however equivalent to a recently adapted functional integral technique that goes beyond the DBGA. The calculated expressions
are relevant for analyzing the neutron scattering data on tunneling of light interstitials, e.g., hydrogen, in metals, at
very low temperatures. 相似文献
169.
A. H. Qureshi M. Arshad K. Masud A. Saeed 《Journal of Thermal Analysis and Calorimetry》2005,81(2):363-367
Summary This paper deals with the first investigation concerning the thermal behaviour of Ni(II) complexes with ligands having biguanide moieties. The new complex [NiL(1)](ClO4)2·2.5H2O (1) with the Schiff base resulted in [2+1] condensation of N,N-dimethylbiguanide with pentane-2,4-dione (L(1)) and the complex [Ni2L(2)](ClO4)4 (2), with the Schiff base, L(2), resulted through the oxidative condensation of L(1) have been synthesized and characterised. The bonding and stereochemistry of the complexes have been characterized by IR and electronic spectra. The cyclic voltammograms show the characteristic waves for mononuclear and respectively binuclear Ni(II) complexes and indicate that both complexes exhibit catalytic effects on the CO2 electrochemical reduction. The thermal behaviour provided confirmation of the complexes composition as well as the number and the nature of water molecules and the intervals of thermal stability. The different nature of the ligands generates a different thermal behaviour for complexes. 相似文献
170.
The microgram detection of phenols and determination of nitro- and nitroso-phenols is based on their treatment in alkaline solution with a chlorinated hypochlorite solution, resulting in characteristic colours. Ion-exchange resin beads are used to make the test sensitive and selective. A few nitro and nitroso compounds have been determined spectrophotometrically. 相似文献