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131.
A personal computer (PC)-based data acquisition and instrument control system has been developed for neutron spectrometers
in Dhruva reactor hall and Guide Tube laboratory. Efforts have been made to make the system versatile so that it can be used
for controlling various neutron spectrometers using single end-on detector in step scan mode. Commercially available PC add-on
cards have been used for input-output and timer-counter operations. An interface card and DC motor driver card have been developed
indigenously. Software for the system has been written in Visual C++ language using MS Windows operating system. This data
acquisition and instrument control system is successfully controlling four spectrometers at Dhruva reactor. 相似文献
132.
Gopalakrishna A. Suryanarayana S. V. Naik H. Nayak B. K. Patil B. J. Devraju S. Upreti R. R. Kinhikar R. Deshpande D. D. Maletha P. Kamaldeep Banerjee S. Saxena A. 《Journal of Radioanalytical and Nuclear Chemistry》2018,317(3):1409-1417
Journal of Radioanalytical and Nuclear Chemistry - The medical isotopes 99Mo and 64Cu were produced via the dual routes of 100Mo(γ,n)99Mo + 98Mo(n,γ)99Mo and 65Cu(γ,n)... 相似文献
133.
H. P. Sachin G. Achary S. Shiva Kumara Y. Arthoba Naik T. V. Venkatesha 《Russian Journal of Electrochemistry》2007,43(2):204-210
The electrochemical reduction of nitro group of orthonitroaniline (ONA) is carried out on Pb, Cu, and Sn electrodes. The effect
of current density, temperature, and acid concentration on product yield is studied. The polarization curve for ONA in acidic
condition is recorded. Under preparative electrolysis, ONA gives a mixture of hydroxylamine and phenylenediamine, the proportion
of phenylenediamine increasing with the electrolysis time. The product formation is confirmed by thin-layer chromatography,
melting-point test, UV-visible, IR, and NMR methods. The operating conditions are optimized for a good yield of orthophenylenediamine.
The catalytic activity of different metals for the reduction of nitro group is discussed. The percent yield of orthophenylenediamine
is found to be high on the lead electrode.
Published in Russian in Elektrokhimiya, 2007, Vol. 43, No. 2, pp. 215–221.
The text was submitted by the authors in English. 相似文献
134.
G. R. Dey D. B. Naik K. Kishore P. N. Moorthy 《Journal of Radioanalytical and Nuclear Chemistry》1992,163(2):391-400
Rate constants for the reaction of the primary species of water radiolysis, viz. e
aq'
–
, H and OH, with picolinic acid have been determined at various pHs. The semi-reduced species exhibits max at 305 and 350 nm. It is a strong reductant and has two pKa values of 1 and 5.7. The OH adduct of this compound also exhibits two pKa s at 2.1 and 5.2. H-atom reaction with picolinic acid gives rise to a mixture of species. 相似文献
135.
Summary The kinetics and mechanism of exchange of HPDTA in [Fe2HPDTA(OH)2] with cyanide ion (HPDTA=2-hydroxytrimethylenediaminetetraacetic acid) was investigated spectrophotometrically by monitoring the peak at 395 nm (
max of [Fe(CN)5OH]3– at pH=11.0±0.02,I=0.25m (NaClO4) at ±0.1°C).Three distinct observable stages were identified; the first is the formation of [Fe(CN)5OH]3–, the second the formation of [Fe(CN)6]3– from it and the third the reduction of [Fe(CN)6]3– to [Fe(CN)6]4– by HPDTA4– released in the first stage.The first stage follows first-order kinetics in [Fe2HPDTA(OH)2] and second-order in [CN–] over a wide range of [CN–], but becomes zero order at [CN–]<5×10–2
m. We suggest a cyanide-independent dissociation of [Fe2HPDTA)(OH)2] into [FeHPDTA(OH)] and [Fe(OH)]2+ at low cyanide concentrations and a cyanide-assisted rapid dissociation of [Fe2HPDTA(OH)2] to [FeHPDTA(OH)(CN)]3– and [Fe(OH)]2+ at higher cyanide concentrations. The excess of cyanide reacts further with [FeHPDTA(OH)(CN)]3– finally to form [Fe(CN)5OH]3–.The reverse reaction between [Fe(CN)5OH]3– and HPDTA4– is first-order in [Fe(CN)5OH]3– and HPDTA4–, and exhibits inverse first-order dependence on cyanide concentration.A six-step mechanism is proposed for the first stage of reaction, with the fifth step as rate determining. 相似文献
136.
Glawe DD Rodríguez F Stone MO Naik RR 《Langmuir : the ACS journal of surfaces and colloids》2005,21(2):717-720
Herein, we describe the formation of silica structures on indium tin oxide (ITO) surfaces using poly-L-lysine (PLL) to template the condensation of silicic acid. Precisely controlled electrostatic fields were used to preposition PLL onto ITO surfaces. Subsequent polypeptide-mediated silicification resulted in the formation of silica with concentration gradients that followed the pattern of the externally applied electrostatic field used in the deposition of the PLL. The resulting silica structures were securely attached to the ITO surface. The technique described here offers an inexpensive and rapid method for the deposition of polypeptides on surfaces. 相似文献
137.
Peter Rogl Subhash K. Naik Erwin Rudy 《Monatshefte für Chemie / Chemical Monthly》1977,108(6):1339-1352
The system VC0.88–HfC0.98–MoC was investigated by means of melting point, differential-thermoanalytical, X-ray diffraction and metallographic techniques on hot pressed and heat treated as well as melted alloy specimens and a constitutional diagram from 1500°C through the melting range established.The small miscibility gap within the HfC–MoC system (T
c=1630°C) interacts at lower temperatures with the solvus in a monotectoid-like reaction at 1575°C. Additions of VC to the HfC–MoC solid solution gradually increase its critical temperature.Solid state phase behaviour and melting behaviour was established within the isopleths VC0.88–MoC as well as within (V0.5Hf0.5)C–MoC and (V0.75Hf0.25)C–(Hf0.75Mo0.25)C.Phase equilibria within VC0.88–HfC–MoC are characterized by an extreme large miscibility gap at 1500°C connecting the VC–HfC and HfC–MoC systems.Originating at the VC–HfC binary an eutectic trough proceeds into the VC–HfC–MoC ternary with rising temperatures, connecting the maximum critical point of the disappearing miscibility gap [(V0.31Hf0.49Mo0.20)C] by a limiting tie line (2750±20°C). Isothermal sections have been calculated assuming regular solutions.With 5 Figures 相似文献
138.
Naik GH Priyadarsini KI Maity DK Mohan H 《The journal of physical chemistry. A》2005,109(10):2062-2068
Reaction of one-electron oxidant (Br(2)(*-)) with tryptophol (TP) and 5-hydroxytryptophol (HTP) have been studied in aqueous solution in the pH range from 3 to 10, employing nanosecond pulse radiolysis technique and the transients detected by kinetic spectrophotometry. One-electron oxidation of TP has produced an indolyl radical that absorbs in the 300-600 nm region with radical pK(a) = 4.9 +/- 0.2, while the reaction with HTP has produced an indoloxyl radical with lambda(max) at 420 nm and radical pK(a) < 3. Hydroxyl radicals ((*)OH) react with these two compounds producing (*)OH radical adducts that undergo water elimination to give one-electron-oxidized indolyl and indoloxyl radical species, respectively. The indoloxyl radicals react with the parent compound to form dimer radicals with an average association constant of (6.7 +/- 0.4) x 10(4) M(-1). No such dimerization is observed with indolyl radical, indicating that the presence of the 5-hydroxy group markedly alters its ability to form a dimer. A possible explanation behind such a difference in reactivity has been supported with ab initio quantum chemical calculations. 相似文献
139.
Prashant U. Naik 《Tetrahedron letters》2004,45(9):1933-1936
The ionic liquid, 1-butyl-3-methylimidazolium chloroaluminate, [bmim]Cl·AlCl3, N=0.67 mediated syntheses of aromatic sulfonamides via electrophilic substitution of arenes is reported. The protocol serves as a distinctly expeditious and ambient route towards the syntheses of these pharmaceutically useful compounds, yielding quantitative conversions at room temperature within 5-30 min in most of the cases. The Lewis acidity and molar stoichiometry of the ionic liquid influences the extent of conversion. The method has been used for the syntheses of a diverse range of sulfonamides by variation of arenes and sulfamoyl chlorides. With monosubstituted benzenes, the protocol offers an added advantage of exclusive selectivity towards the formation of para substituted sulfonamides over the ortho products. 相似文献
140.
Vommina V. Sureshbabu Rao Venkataramanarao Shankar A. Naik G. Chennakrishnareddy 《Tetrahedron letters》2007,48(39):7038-7041
An efficient synthesis of tetrazole analogues of amino acids starting from Nα-Fmoc amino acid in a three-step protocol is reported. The free amino tetrazoles were obtained in good yields and with excellent purity after removal of the Fmoc group. The synthesis of analogues of aspartic and glutamic acids in which the 5-tetrazolyl moiety is inserted at the β/γ carboxyl group starting from Fmoc-Asn and Fmoc-Gln and the incorporation of these tetrazoles into peptides are also described. 相似文献