首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   101篇
  免费   3篇
化学   45篇
晶体学   1篇
力学   9篇
数学   33篇
物理学   16篇
  2022年   5篇
  2021年   2篇
  2020年   3篇
  2019年   7篇
  2018年   6篇
  2017年   7篇
  2016年   11篇
  2015年   4篇
  2014年   3篇
  2013年   4篇
  2012年   2篇
  2011年   5篇
  2010年   5篇
  2009年   2篇
  2007年   1篇
  2006年   1篇
  2003年   2篇
  2002年   1篇
  2001年   2篇
  1999年   1篇
  1997年   2篇
  1996年   1篇
  1995年   3篇
  1994年   1篇
  1993年   4篇
  1992年   1篇
  1991年   2篇
  1990年   4篇
  1987年   1篇
  1986年   1篇
  1985年   3篇
  1984年   2篇
  1983年   2篇
  1974年   1篇
  1971年   1篇
  1968年   1篇
排序方式: 共有104条查询结果,搜索用时 265 毫秒
71.
There are obtained conditions for the convergence and estimates of the rate of convergence in terms of norms of Orlicz spaces of random series of the form where fk(¯t) is an orthonormal system of eigenfunctions of a certain integral equation, k are random variables in an Orlicz space, ¯t Rn.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 43, No. 6, pp. 841–848, June, 1991.  相似文献   
72.
73.
In the course of self-assembly in the systems MX2–nicotinic hydrazide (HN)–pyruvic acid, where М = Co, Ni; X = Сl, CH3COO, complexes of composition: [CoCl(HNРv)(H2O)2], [Co(HNРv)2], [Ni(HIРv)2] have been synthesized. Local atomic structure of the coordination centers was established by the method of X-ray absorption spectroscopy. Thermal stability, electric conductivity, and magnetic susceptibility of the complexes have been determined.  相似文献   
74.
The composition and structure of the Cu2+ coordination cores in the previously synthesized [CuCl(HNPv)] · H2O, [CuCl(HIPv)] · H2O, [Cu(AOc)(HNPv)], [Cu(AOc)(HIPv)], [Cu(NO3)(HNPv)], and [Cu(NO3)(HIPv)] complexes, where HNPv and HIPv pyruvic acid nicotinoyl and isonicotinoyl hydrazones, respectively, have been determined. The binuclear complex [Cu2(HNPv)2(H2O)2(μ-Cl)] has been synthesized for the first time and characterized by elemental analysis and IR, EPR, and EXAFS spectroscopy. Its dimeric structure has been proved by magnetic susceptibility measurement and EPR.  相似文献   
75.
Mono-and mixed-ligand complexes with the composition [Ni(Cyt)2(H2O)2]Cl2, [Ni(Thr)2(H2O)2] and [Ni(Thr)(Cyt)(H2O)2]Cl are synthesized and studied. Using IR spectroscopy it is determined that in the complex compounds, cytosine is bidentate (C=O group oxygen and heterocycle N3), threonine interacts with the Ni(II) ion due to amino and carboxyl groups. The models of the atomic structure of the studied compounds are proposed based on the EXAFS and XANES spectroscopy results.  相似文献   
76.
Copper(II) complexes isolated from the Cu(CH3COO)2–2-(7-bromo-2-oxo-5-phenyl-3H-1,4-benzodiazepin-1-yl)acetohydrazide (Hydr)–salicylaldehyde (HSal)–isopropanol system [Cu2(HydrSal)2(μ-CH3COO)] (I), [Cu(HydrSal)2] (II) (HydrSal (hydrazone)is the condensation product of hydrazide and salicylaldehide) are synthesized and investigated. The complexes are characterized by elemental analysis, electrical conductivity measurements, and IR spectroscopy. The composition and structure of the Cu2+ coordination core are determined by ESR spectroscopy (I), magnetic susceptibility measurements and extended X-ray absorption fine structure (EXAFS) spectroscopy (II).  相似文献   
77.
4-Methyl-N-{2-([1-alkyl-2-[2-(p-tolylsulfonylamino)phenyl]benzimidazol-5-yl]iminomethyl)phenyl}-benzenesulfamides (H2L) and zinc complexes on their basis Zn2L2 have been synthesized. The structure of the ligands and complexes has been studied by IR, UV, 1Н NMR spectroscopy, X-ray absorption spectroscopy, and X-ray diffraction analysis.  相似文献   
78.
The Cu, Ni, and Со complexes based on the following new azomethine compounds containing azobenzene groups in the ortho- or para-positions of the amine fragment are synthesized: 2-allyl-6-[(E)-[4-(E)-phenylazophenyl]iminomethyl]phenol (HL1), 2-allyl-6-[(E)-[4-methyl-2-[(E)-phenylazo]-p-tolylazo] iminomethyl]phenol (HL2), 5-methoxy-2-[(E)-[4-[(E)-phenylazo]phenyl]iminoethyl]phenol (HL3), and 5-methoxy-2-[(E)-[4-methyl-2-[(E)-p-tolylazo]phenyl]iminomethyl]phenol (HL4). The structures of the complexes are determined by the data of IR and 1Н NMR spectroscopy (for the azomethine compounds), X-ray absorption spectroscopy, and magnetochemistry. The coordination centers of all Cu complexes have a distorted square structure. A direct dependence of the geometry of the coordination polyhedron on the position of azobenzene groups in the amine fragments of the ligands is found for the Ni and Co complexes. The octahedral environment of the nickel and cobalt ions takes place in the case of the ortho-position of the amine fragment, whereas the square environment for the Ni complexes or the tetrahedral environment for the Co complexes is observed at the para-position. The molecular structures of two azomethines HL1 and HL4 are determined by X-ray diffraction analysis (CIF files CCDC nos. 1552836 (HL1) and 1552837 (HL4)).  相似文献   
79.
By self-assembling in the systems MX2–2-(7-bromo-2-oxo-5-phenyl-2,3-dehydro-1Н-1,4-benzdiazepin-1-yl)acetohydrazide (Hydr)–salicyl aldehyde (HSal) (М = Co, Ni, Zn; X = Cl, CH3COO) the complexes of composition [Co(HydrSal)2], [Ni(HydrSal)2], [Zn(HydrHSal)Cl2], [Zn(HydrSal)(CH3COO)(H2O)] have been synthesized. The local atomic structure of the coordination unit was determined by the method of X-ray absorption spectroscopy. Thermal stability, electroconductivity, and magnetic susceptibility of the complexes have been studied.  相似文献   
80.
Highly luminescent, photostable, and soluble lanthanide pentafluorobenzoates have been synthesized and thoroughly characterized, with a focus on EuIII and TbIII complexes as visible emitters and NdIII, ErIII, and YbIII complexes as infrared emitters. Investigation of the crystal structures of the complexes in powder form and as single crystals by using X‐ray diffraction revealed five different structural types, including monomeric, dimeric, and polymeric. The local structure in different solutions was studied by using X‐ray absorption spectroscopy. The photoluminescence quantum yields (PLQYs) of terbium and europium complexes were 39 and 15 %, respectively; the latter value was increased almost twice by using the heterometallic complex [Tb0.5Eu0.5(pfb)3(H2O)] (Hpfb=pentafluorobenzoic acid). Due to the effectively utilized sensitization strategy (pfb)?→Tb→Eu, a pure europium luminescence with a PLQY of 29 % was achieved.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号