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1.
Ricaurte Rodríguez Manuel Nogueras Justo Cobo John N. Low Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(7):o376-o378
Molecules of the title compound, C12H13ClN4, are linked by two independent N—H...N hydrogen bonds into a chain of edge‐fused R22(8) rings. The significance of this study lies in its attempt to rationalize the patterns of supramolecular aggregation in the title compound and in a range of analogous 4,6‐disubstituted 2‐aminopyrimidines. 相似文献
2.
A series of nitrosyl complexes of empirical formula Kn[M(CN)5NO], where M = V, Cr, Mn and Co and n = 3, or M = Mo and n = 4, have been prepared which are notional analogues of the widely used vasodilator sodium nitroprusside. Their reactivity towards common nucleophiles (OH?, NH2R, NHR2, HS? and RS?), acid and photolysis has been investigated to elucidate the desired properties required of new metal nitrosyls which may have some potential as new non-cyanide-based vasodilators. 相似文献
3.
Jaime Portilla Jairo Quiroga Justo Cobo John N. Low Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(6):o332-o333
In the title compound, C13H10O4, prepared by the condensation reaction between phthalic anhydride and pentane‐2,4‐dione, one of the acetyl groups in the pentane‐2,4‐dione fragment is almost coplanar with the isobenzofuran ring system, while the other group is twisted out of this plane by almost 80°. The corresponding C—C and C—O distances in the two acetyl units are consistent with dipolar delocalization into the coplanar unit only. There is no supramolecular aggregation of the molecules, but a number of rather short intermolecular contacts of C—H...O, O...O and O...C types occur. 相似文献
4.
Crystals of the title compound H2C(SiPh3)2 are triclinic, space group P, with a = 9.290(2), b = 12.128(4), c = 16.882(4) Å, α = 62.08(1), β = 106.88(1), γ = 117.28(2)° and Z = 2. The central skeletal angle SiCSi is 128.8(7)°. The structures of the molecules H2C(SiR3)2 (R = H, CH3, and Ph) are compared and discussed: a simple model for the skeletal geometry of species H2C(MR3)2 is proposed, and tested against experimental data and theoretical calculations. 相似文献
5.
The MINDO/3 technique gives geometries for (CH4)+, (CCl4)+ and the intermediate ions (CHnCl4 ? n)+ (n = 1, 2, 3) which have symmetries in precise accord with the predictions of the Jahn—Teller effect. The ground state of (CH4)+ has D2d symmetry, with a C3v structure ca. 45.6 kJ mol?1 higher. (CCl4)+ has a C2v ground state, with a D2d structure ca. 144 kJ mol?1 higher: no bound state of C3v symmetry could be found. (CH3Cl)+ and (CHCl3)+ both have Cs symmetry, and (CH2Cl2)+ has C2v symmetry. The analogous fluoro ions are discussed briefly. 相似文献
6.
MNDO calculations have been carried out on the reactions of the electron-rich germylene L2Ge [L=(H3Si)2N] with diazo compounds, as models for the experimentally observed reactions of L2Ge [L=(Me3Si)2N]. The most stable form of the 11 adduct of L2Ge with N2C(COOMe)2 is found to have a cyclic configuration resulting from a strong intramolecular interaction between the oxygen of one of the carbonyl groups and the germanium atom. Protonation of this cyclic adduct occurs at nitrogen, giving an intermediate, addition to which of nucleophiles X– provides acyclic L2Ge(X)NHN(COOMe)2, as observed experimentally. Two similar cyclic adducts are formed between L2Ge and N2C(COCH3)(COOCH3), the most stable of which provides, after a proton shift, the observed 1,3,4,2-oxadiazagermine system
. Adduct formation between Me2Si=NSiMe3 and simple Lewis bases (H2O, NH3, THF, H2CO) is calculated to be strong, but the corresponding adducts of Me2Ge=NSiMe3 are very weak: much stronger adducts are predicted for L2GeNNC(COOMe)2. 相似文献
7.
8.
Crystals of thio-bis[triphenyltin(IV)], S(Ph3Sn)2, are orthorhombic, space-group P212121, with a = 18.469(5), b = 17.648(5), c = 9.848(6) Å and Z = 4. The SnS distances are 2.405(9) and 2.417(7) Å and SnSSn angle is 107.3(2)°: there are no anomalous features in the structure analogous to those in O(Ph3Sn)2-MNDO calculations for a series of organometallic sulphides (Me3M)2S+n (M = Be, B, C, N, Si, P) indicate that the inversion barrier to linearity increases monotonically, and the skeletal bending force constant at linearity decreases correspondingly as the group Me3M becomes more electro-negative. 相似文献
9.
Crystals of oxo-bis[tribenzylgermanium(IV)], O[(PhCH2)3Ge]2, are rhombohedral, space group R, having a = 9.621(2) Å, α = 85.48(3)°. The structure was solved by Patterson methods using diffractometer data and refined by full-matrix least squares to R = 0.0876. The structure consists of molecules lying along the 3-fold axis of the unit cell, in which the GeOGe fragments are strictly linear and centrosymmetric. The GeO distance is 1.730(1) Å and the GeC distance is 1.980(5) Å. 相似文献
10.
Vaduganathan Yasodha Subbaiah Govindarajan John N. Low Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(5):m207-m215
The structures of five metal complexes containing the 4‐oxo‐4H‐pyran‐2,6‐dicarboxylate dianion illustrate the remarkable coordinating versatility of this ligand and the great structural diversity of its complexes. In tetraaquaberyllium 4‐oxo‐4H‐pyran‐2,6‐dicarboxylate, [Be(H2O)4](C7H2O6), (I), the ions are linked by eight independent O—H...O hydrogen bonds to form a three‐dimensional hydrogen‐bonded framework structure. Each of the ions in hydrazinium(2+) diaqua(4‐oxo‐4H‐pyran‐2,6‐dicarboxylato)calcate, (N2H6)[Ca(C7H2O6)2(H2O)2], (II), lies on a twofold rotation axis in the space group P2/c; the anions form hydrogen‐bonded sheets which are linked into a three‐dimensional framework by the cations. In bis(μ‐4‐oxo‐4H‐pyran‐2,6‐dicarboxylato)bis[tetraaquamanganese(II)] tetrahydrate, [Mn2(C7H2O6)2(H2O)8]·4H2O, (III), the metal ions and the organic ligands form a cyclic centrosymmetric Mn2(C7H2O6)2 unit, and these units are linked into a complex three‐dimensional framework structure containing 12 independent O—H...O hydrogen bonds. There are two independent CuII ions in tetraaqua(4‐oxo‐4H‐pyran‐2,6‐dicarboxylato)copper(II), [Cu(C7H2O6)(H2O)4], (IV), and both lie on centres of inversion in the space group P; the metal ions and the organic ligands form a one‐dimensional coordination polymer, and the polymer chains are linked into a three‐dimensional framework containing eight independent O—H...O hydrogen bonds. Diaqua(4‐oxo‐4H‐pyran‐2,6‐dicarboxylato)cadmium monohydrate, [Cd(C7H2O6)(H2O)2]·H2O, (V), forms a three‐dimensional coordination polymer in which the organic ligand is coordinated to four different Cd sites, and this polymer is interwoven with a complex three‐dimensional framework built from O—H...O hydrogen bonds. 相似文献