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51.
Tiberiu Frentiu Michaela Ponta Sorin D. Anghel Alpar Simon Ana-Maria Incze Emil A. Cordos 《Mikrochimica acta》2004,147(1-2):93-103
A medium power radiofrequency capacitively coupled plasma (275W, 27.12MHz) with low argon consumption (0.5Lmin–1) was investigated to be used for the determination of aluminium in water samples pneumatically nebulised by atomic emission spectrometry. The plasma torch was operated in two geometric configurations, coaxial and coaxial-annular with single (SRTr.f.CCP) or double ring electrodes (DRTr.f.CCP), respectively. The optimum experimental parameters (observation height, Ar flow rate, distance between ring electrodes, matrix interference of Na+ and Ca2+ and anion nature) for Al 396.152nm emission were established. Under optimum operating conditions of the DRTr.f.CCP torch (6cm distance between annular electrodes), a detection limit of 70ngmL–1 aluminium was found. Both operating parameters and several figures of merit of the investigated plasmas were compared to those of microwave plasmas and inductively coupled plasma used in atomic emission spectrometry. The method was used to control the quality of drinking and industrial water. Samples were mineralised with 2mL of 1+1 HNO3 and 10mL of 1+1 HCl. In the range of 0.15–3.5mgL–1 Al3+ the relative standard deviation varied between 3.7 and 8.6% (n=3). For two certified drinking water samples containing 0.206 and 0.218mgL–1 Al3+ the recovery (n=5) was 97.6±6.8% and 98.6±7.3%, respectively. 相似文献
52.
Ertuğrul Gazi Sağlam Nurcan Acar Berline Mougang-Soumé Hakan Dal Tuncer Hökelek 《Phosphorus, sulfur, and silicon and the related elements》2016,191(1):22-29
Benzyl(4-methoxyphenyl)dithiophosphinic acid (HL) was obtained as solid and was treated with the NiCl26H2O, CoCl26H2O, ZnCl2, and CdCl2 to prepare its Ni(II), Co(II), Zn(II), and Cd(II) complexes. The nickel complex was further treated with pyridine which led to the formation of octahedral dipyridine derivative. HL was obtained through the addition reaction of the perthiophosphonic acid anhydride Lawesson reagent, (LR), [2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide], with the corresponding Grignard compound (benzylmagnesium bromide) in diethyl ether medium.The complexes were all of the stoichiometry of [M(L)2]x, with x = 1 for M = Ni2+ and x = 2 for M = Co2+, Cd2+ and Zn2+. The coordination geometry was square planar in the nickel(II) complex and tetrahedral in the others. Similar to many other nickel(II) complexes, the Ni(L)2 reacts reversibly with pyridine to yield the octahedral complex ({(Py)2Ni(L)2}).The compounds were characterized by elemental analysis; MS, FTIR, and Raman spectroscopies. The magnetic susceptibilities of the complexes were measured to confirm the hybridization patterns and the geometries. Single-crystal X-ray analyses of Ni(L)2 and [Co(L)2]2 complexes were also carried out to prove the molecular topologies. 相似文献
53.
54.
Nurcan Baser‐Kirazli Roger A. Lalancette Frieder Jkle 《Angewandte Chemie (International ed. in English)》2020,59(22):8689-8697
We introduce a new boron‐doped cyclophane, the hexabora[16]cyclophane B6‐FMes , in which six tricoordinate borane moieties alternate with short conjugated p‐phenylene linkers. Exocyclic 2,4,6‐tris(trifluoromethyl)phenyl (FMes) groups serve not only to further withdraw electron density but at the same time sterically shield the boron atoms, resulting in a macrocycle that is both highly electron‐deficient and stable. The optical and electronic properties are compared with those of related linear oligomers and the electronic structure is further evaluated by computational methods. The studies uncover unique properties of B6‐FMes , including a low‐lying and extensively delocalized LUMO and a wide HOMO–LUMO gap, which arise from the combination of a cyclic π‐system, strong electronic communication between the closely spaced borons, and the attachment of electron‐deficient pendent groups. The binding of small anions to the electron‐deficient macrocycle and molecular model compounds is investigated and emissive exciplexes are detected in aromatic solvents. 相似文献
55.
Nurcan Ekici Ziya Kantarci Sevim Akyüz 《Journal of inclusion phenomena and macrocyclic chemistry》1991,10(1):9-18
Two new benzene clathrates of the form Cd(Pyrazine)M(CN)4C6H6, where M = Cd or Hg, have been prepared and their infrared and Raman spectra are reported. 相似文献
56.
Tiberiu?FrentiuEmail author Michaela?Ponta Sorin D.?Anghel Alpar?Simon Ioan?Marginean Emil A.?Cordos 《Mikrochimica acta》2003,143(4):245-254
This paper presents a statistical comparison of Cu, Mn and Zn determinations in biological samples by low power radiofrequency capacitively coupled Ar plasma (275W; 27.12MHz; 0.4Lmin–1 flow rate) atomic emission spectrometry and flame atomic absorption spectrometry using statistical analysis according to the Bland and Altman test and linear regression. For a content (µgg–1 dry mass) of 5-43 Cu, 10-15800 Mn and 8-1100 Zn in fish fillet and freshwater molluscs, there was no significant bias in r.f.CCP-AES for a 95% confidence level. Certified reference materials were analysed by r.f.CCP-AES, and a good agreement between analysis results and certified values was obtained. Matrix effects of Ca and Na and their influence on the detection limits of Cu, Mn and Zn are presented for both methods. As compared to FAAS, r.f.CCP-AES is more prone to interferences and, consequently, the detection limits for Cu, Mn and Zn in biological samples (2; 2 and 3µgg–1 dry mass) are higher than those in FAAS. In spite of these problems, r.f.CCP-AES is capable of accurate and precise analyses of biological samples. 相似文献
57.
Anghel SD Frentiu T Darvasi E Rusu AM Simon A Cordos EA 《Analytical and bioanalytical chemistry》1996,355(3-4):250-251
The excitation temperatures of Ar and Fe, the ionization temperatures of Ar and Ca and the electron number densities have been determined for a radiofrequency capacitively coupled plasma in the tip-ring electrode geometry. The temperatures and the electron number densities possess their maximum value close to the electrodes. 相似文献
58.
59.
Tuncer Hkelek Nurcan Akduran Saliha Bege Adem Kl Zeynel Kl 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(11):1404-1406
The title compound, C45H55NO6P2, consists of an acyclic P=N—P(O) monophosphazene chain and five bulky 2,4,6‐trimethylphenoxy side groups which predominantly determine the molecular shape. Although the P—N single [1.586 (3) Å] and P=N double [1.517 (3) Å] bonds are significantly different from each other, both are substantially shorter than the ideal P—N single bond. The P—N—P angle [146.0 (2)°] corresponds to the upper limit reported for acyclic phosphazene derivatives in the literature. 相似文献
60.
Oztürk C Topal K Aviyente V Tüzün NS Sánchez Fernández E Arseniyadis S 《The Journal of organic chemistry》2005,70(18):7080-7086
[reaction: see text] We comment on the effects of angular substitution on the outcome of a Pb(OAc)4 (LTA) mediated heterodomino reaction, with selected bicyclic unsaturated 1,2-diols, which is considered to proceed through a series of transformations in a single vessel. The first two, oxidative and pericyclic, are followed by the key step, an electrophilic addition of LTA to the olefin, responsible for the course of the domino process. In this study, the electrophilic addition of LTA to the double bond has been modeled with B3LYP, where the 6-31G* basis set is used for C, O, and H atoms and the LANL2DZ method is used for Pb. The modeling in the gaseous phase and in solution has revealed the concerted nature of the addition of LTA to the double bond of the intermediate. The fact that LTA adds from the same side as the substituent R, for R=H and from the opposite side when R=CH3 has been attributed to steric hindrance, which causes deformation of the olefinic intermediate. 相似文献