全文获取类型
收费全文 | 132篇 |
免费 | 0篇 |
专业分类
化学 | 76篇 |
晶体学 | 5篇 |
力学 | 8篇 |
数学 | 12篇 |
物理学 | 31篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 3篇 |
2019年 | 1篇 |
2018年 | 10篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 8篇 |
2012年 | 11篇 |
2011年 | 6篇 |
2010年 | 7篇 |
2009年 | 8篇 |
2008年 | 7篇 |
2007年 | 6篇 |
2006年 | 4篇 |
2005年 | 8篇 |
2004年 | 2篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1997年 | 1篇 |
1995年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1974年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 2篇 |
排序方式: 共有132条查询结果,搜索用时 31 毫秒
1.
By alternating‐current electrochemical technique crystals of copper(I) π‐complex with 1‐allylpyridinium chloride of [C5H5N(C3H5)][Cu2Cl3] ( 1 ) composition have been obtained and structurally investigated. Compound 1 crystallizes in monoclinic system, space group C2/c a = 24.035(1) Å, b = 11.4870(9) Å, c = 7.8170(5) Å, β = 95.010(5)°, V = 2150.0(2) Å3 (at 100 K), Z = 8, R = 0.028, for 4836 independent reflections. In the structure 1 trigonal‐pyramidal environment of π‐coordinated copper(I) atom is formed by a lengthened to 1.376(2) Å C=C bond of allyl group and by three chlorine atoms. Other two copper atoms are tetrahedrally surrounded by chlorine atoms only. The coordination polyhedra are combined into an original infinite (Cu4Cl62—)n fragment. Structural comparison of 1 and the recently studied copper(I) chloride π‐complexes with 3‐amino‐, 2‐amino‐, 4‐amino‐1‐allylpyridinium chlorides of respective [LCu2Cl3] ( 2 ), [L2Cu2Cl4] ( 3 ), and [LCuCl2] ( 4 ) compositions allowed us to reveal the trend of the inorganic fragment complication which depends on pKa (base) value of the corresponding initial heterocycle. 相似文献
2.
Filinchuk Ya. E. Pavlyuk A. V. Ciunik L. Z. Mys'kiv M. G. 《Russian Journal of Coordination Chemistry》2004,30(11):818-824
The crystals of N-allylisoquinolinium chlorides of the compositions [C9H7N(C3H5)]2CuIICl4 (I), [C9H7N(C3H5)]CuICl2 · H2O (II), and [C9H7N(C3H5)]CuICl1.43Br0.57 · H2O (III) were prepared by alternating-current electrosynthesis. X-ray diffraction analysis (using diffractometer models DARCH1 for I, STOE for II, and KUMA/CCD for III, MoK
radiation) showed that the crystals of I are monoclinic, space group P21/n, a = 14.91(1) Å, b = 10.41(1) Å, c = 16.90(1) Å, = 109.73(8)°, V = 2470(8) Å3, Z = 4. The crystals of isostructural compounds II and III are triclinic, space group P, Z = 2; crystals II: a = 7.2446(6) Å, b = 7.4379(6) Å, c = 12.110(1) Å, = 80.95(1)°, = 85.55(1)°, = 86.60(1)°, V = 641.8(2) Å3; crystals III: a = 7.253(2) Å, b = 7.459(4) Å, c = 12.151(5) Å, = 80.82(4)°, = 83.73(3)°, = 86.81(4)°, V = 644.6(9) Å3. The structure of I is composed of CuIICl4
2– tetrahedra and N-allylisoquinolinium cations united by C–H···Cl hydrogen bonds in corrugated layers. The crystal structures of -complexesII and III are built of [C9H7(C3H5)]2Cu2
IX4 dimers, which form layers along the c axis due to the C–H···X hydrogen bonds. An important role in the structure formation is played by water molecules, which crosslink the organometallic layers to form a three-dimensional framework through the O–H···X contacts. 相似文献
3.
4.
Andrij Stetskiv Beata Rozdzynska‐Kielbik Volodymyr Pavlyuk 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(7):683-688
A new ternary dithulium hexacobalt icosastannide, Tm2.22Co6Sn20, and a new quaternary thulium dilithium hexacobalt icosastannide, TmLi2Co6Sn20, crystallize as disordered variants of the binary cubic Cr23C6 structure type (cF116). 48 Sn atoms occupy sites of m.m2 symmetry, 32 Sn atoms sites of .3m symmetry, 24 Co atoms sites of 4m.m symmetry, eight Li (or Tm in the case of the ternary phase) atoms sites of symmetry and four Tm atoms sites of symmetry. The environment of one Tm atom is an 18‐vertex polyhedron and that of the second Tm (or Li) atom is a 16‐vertex polyhedron. Tetragonal antiprismatic coordination is observed for the Co atoms. Two Sn atoms are enclosed in a heavily deformed bicapped hexagonal prism and a monocapped hexagonal prism, respectively, and the environment of the third Sn atom is a 12‐vertex polyhedron. The electronic structures of both title compounds were calculated using the tight‐binding linear muffin‐tin orbital method in the atomic spheres approximation (TB–LMTO–ASA). Metallic bonding is dominant in these compounds, but the presence of Sn—Sn covalent dumbbells is also observed. 相似文献
5.
A. A. Ryadun V. A. Nadolinny A. A. Pavlyuk S. F. Solodovnikov E. G. Boguslavskii 《Journal of Structural Chemistry》2013,54(1):59-64
An EPR study of Li2?2x Zn2+x (MoO4)3 crystals activated by copper ions shows that they occupy the M2 site, one of the three possible sites of both lithium and zinc. In the EPR spectra of Cu2+ copper a broadening of HFS lines and a nonequidistant splitting between them, which are unusual for the orientation H‖g zz , A zz , are observed. In this work possible reasons for such a broadening of HFS lines from copper ions are analyzed: a distortion of the oxygen octahedron due to the introduction of copper ions, second order perturbation theory corrections, superposition of HFS from 63Cu and 65Cu isotopes, and the effect of the charge redistribution in the oxygen octahedron because the cation vacancy providing charge compensation can be located at different distances from the copper ion. It is shown that the first three reasons do not explain the features observed in the EPR spectra. In the case of cation vacancies located in the M3 site and remote at different distances from the copper ion, the charge redistribution in the oxygen octahedron of copper should occur along with the dispersion of HFS parameters and the g-factor. The studies performed in X and Q bands confirm this assumption. The width of HFS lines from copper ions in the EPR spectra measured in the Q band is three times more compared to that measured in the X band. 相似文献
6.
D.?Yu.?VelikovskiiEmail author M.?M.?Mazur A.?A.?Pavlyuk V.?E.?Pozhar S.?F.?Solodovnikov L.?I.?Yudanova 《Physics of Wave Phenomena》2015,23(1):58-62
A KLuW laser crystal is investigated as an acousto-optic material. It is shown that the crystal can be used in devices for controlling high-power laser radiation. Obtainable characteristics of promising classical devices (modulator, deflector) are estimated. A possibility of developing a new type of device for both lasing and Q-switching is analyzed. 相似文献
7.
S. N. Borisenko A. V. Bicherov O. V. Pavlyuk M. I. Rudnev N. I. Borisenko E. V. Vetrova V. I. Minkin R. N. Borisenko A. V. Lekar 《Russian Journal of Physical Chemistry B, Focus on Physics》2009,3(8):1131-1133
The isomerization of a non-racemic mixture of glaucine isomers to des-glaucine (seco-glaucine) in a subcritical water medium
at 200–300°C was conducted with a yield of 53%. The structure of the product was confirmed by NMR spectroscopy and electrospray-ionization
mass spectrometry. 相似文献
8.
V. P. D’yakonov É. E. Zubov A. A. Pavlyuk M. T. Borowiec H. Szymczak 《Physics of the Solid State》1999,41(4):605-609
The results of measuring the temperature and field dependences of the magnetization of a RbDy(WO4)2 single crystal in the temperature range from 4.2 to 50 K and in magnetic fields up to 1.6 T are presented. The energies of
the exchange and dipole-dipole interactions are estimated. The magnetic structure of the ground state is determined.
Fiz. Tverd. Tela (St. Petersburg) 41, 672–676 (April 1999) 相似文献
9.
A series of five- to eight-membered nitrogen-containing heterocycles were prepared via a general and efficient one-pot, two-component sequence featuring rhodium-catalyzed insertion of a vinyl-substituted α-diazocarbonyls into the N-H bond of a series of tert-butoxycarbonyl-(Boc)-protected amines, followed by ring-closing metathesis catalyzed by ruthenium benzylidene complexes. This methodology allows easy and convenient access to highly functionalized azacycloalkenes in moderate yields and excellent chemoselectivity in a single transformation. 相似文献
10.
In this paper the spectra of Gd3+ ions studied by electron spin resonance (ESR) in four types of tungstate crystals KY(WO4)2, CdWO4, CsLa(WO4)2 and La2(WO4)3 are discussed. The tungstate crystals were grown by the low-temperature gradient Czochralski technique with Gd2O3 addition in melt. The estimation of spin Hamiltonian (SH) parameters was realized using an original simulation program developed.
The parameters of crystalline field in oxide crystals are comparable with Zeeman interaction so the solution of the Schr?dinger
equation was realized numerically. We have estimated 36 SH parameters from ESR angular diagrams of Gd3+, including g
x
, g
y
, g
z
, g
i
(where i = 1, …, 6), B
m
n
, C
m
n
(where m = 2, …, 6, n = 0 (or 1 for C
m
n
), …, m), and the Euler angles. The positions of Gd3+ ions in the crystal structures, the charge compensation and the influence of lattice parameters on the SH parameters B
2
0 and B
2
2 are discussed in this paper as well.
Authors' address: Nikolay V. Cherney, Institute of Inorganic Chemistry, Russian Academy of Sciences, Lavrentyev av. 3, Novosibirsk
630090, Russian Federation 相似文献