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71.
An X-ray crystallographic study of 2,5-dimethyl-3,4-diacetylpyrrole showed that the crystals are monoclinic, space groupP21/n,a = 10·01(3),b = 12·93(3),c = 7·41(2) Å and = 91·5(5) °. The crystal structure was solved by direct methods and refined by least squares to a finalR factor of 0·13. The values determined for the bond distances and angles of the pyrrole ring are in good agreement with the values reported in the literature. However, there are significant changes in the exocyclic bond angles of the atoms of the ring. The planes of the acetyl groups are tilted with respect to the ring plane, forming dihedral angles of 22 ° and 40 °. 相似文献
72.
Griselda Polla María Teresa Garland Ricardo Baggio 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(9):m385-m388
In the title lanthanum complex, {[La(C4H4O5)(H2O)3]NO3}n, the lanthanum cation is immersed in a nine‐coordinate environment provided by a tridentate oxydiacetate (oda) ligand (through two carboxylate and one ether O atoms), three carboxylate O atoms from neighbouring oda ligands and three aqua ligands. The LaO9 polyhedra are interlinked into a tight three‐dimensional framework, which leaves holes where the nitrate anions lodge. The links to the polymeric framework are by an extensive hydrogen‐bonding scheme utilizing all the water H atoms. Thermogravimetric analysis shows that the three coordinated water molecules leave the structure in two well differentiated steps. 相似文献
73.
Miguel Angel Harvey Sebastin Suarez Fabio Doctorovich Fabio D. Cukiernik Ricardo Baggio 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(5):440-444
The CoII cation in poly[[aqua(μ‐benzene‐1,2‐dicarboxylato‐κ3O1,O2:O1)(μ‐4,4′‐bipyridine‐κ2N:N′)cobalt(II)] trihydrate], {[Co(C8H4O4)(C10H8N2)(H2O)]·3H2O}n, is octahedrally coordinated by two N atoms of two 4,4′‐bipyridine ligands, three O atoms from phthalate anions and a fourth O atom from a coordinated water molecule. The packing consists of planes of coordination polymers linked by hydrogen bonds mediated by three solvent water molecules; the linkage is achieved by the water molecules forming intricate oligomeric clusters which also involve the O atoms of the phthalate ligands. 相似文献
74.
Mariana Dennehy Ricardo M. Ferullo Eleonora Freire Ricardo Baggio 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(6):627-631
In the title compound, bis(μ‐1,1‐dioxo‐1,2‐benzothiazole‐3‐thiolato)‐κ3N,S:S;κ3S:N,S‐bis[(1,1‐dioxo‐1,2‐benzothiazole‐3‐thiolato‐κ2N,S)(ethanol‐κO)bismuth(III)] ethanol hemisolvate, [Bi2(C7H4NO2S2)6(C2H5OH)2]·0.5C2H5OH, three independent thiosaccharinate (tsac) anions chelate the metal centre through the endocyclic N and exocyclic S atoms. The complex also presnts two `semicoordination' contacts, one from a pendant ethanol solvent molecule and a second one from an S atom of a centrosymmetrically related molecule. This latter interaction complements two π–π interactions between tsac rings to form a dimeric entity which is the elemental unit that builds up the crystal structure. These dinuclear units are connected to each other via a second type of π–π interaction, generating chains along [11]. Two ethanol molecules, one of them of full occupancy at a general position and semicoordinated to the central cation, and a second one depleted and disordered around a symmetry centre, stabilize the structure. The complex was studied theoretically and the vibrational assignations were confirmed by employing theoretical density functional theory (DFT) methods. 相似文献
75.
M. Enriqueta Díaz de Vivar Sergio Baggio María Teresa Garland Ricardo Baggio 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(9):i79-i82
Orthorhombic Mn(SO3)(H2O)3 has been reinvestigated by single‐crystal X‐ray diffraction in two possible space groups, viz. P212121 (with all atoms in general positions) and Pnma (with the molecule bisected by a mirror plane). The results confirm the lower symmetry assigned in a previous single‐crystal neutron diffraction study. However, the refinement of the P212121 model requires the introduction of racemic twinning and soft positional and displacement restraints for the H atoms. The importance of a scrupulous report on symmetry absence violations as standard policy in crystallographic work is discussed. 相似文献
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Karin Gutkowski Eleonora Freire Ricardo Baggio 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(3):m77-m80
The title complex, {[Pr4(C2H3O2)10(C2O4)(H2O)2]·2H2O}n, was synthesized under hydrothermal conditions from praseodymium acetate and the ionic liquid 1‐butyl‐3‐methylimidazolium chloride via an in situ oxalate‐ligand synthesis. The compound is a two‐dimensional polymer and in the structure presents tightly bound planes parallel to (100), which are in turn linked into a three‐dimensional network by hydrogen bonds involving both coordinated and solvent water molecules. The oxalate anion lies across an inversion centre and acts as a bridge between pairs of Pr atoms within a tetranuclear segment of the polymer. 相似文献
80.
Ana María Atria Gino Corsini Natalia Herrera Maria Teresa Garland Ricardo Baggio 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(5):m169-m172
The two isomorphous title compounds, [M(C5H7N6)2(C9H6O4)2(H2O)2]·4H2O or M2+(Hdap+)2(hpt2−)2(H2O)2·4H2O {where dap is 2,6‐diaminopurine, H2hpt is homophthalic acid [2‐(2‐carboxyphenyl)acetic acid] and M is NiII or CoII}, consist of neutral M2+(Hdap+)2(hpt2−)2(H2O)2 monomers, where the MII cation lies on an inversion centre and its MN2O4 octahedral environment is defined by one N atom (from Hdap+), two O atoms (from one hpt2− dianion and one water molecule) and their inversion images. The structures are unusual in that the Hdap+ cation occurs in an uncommon protonated state (as 2,6‐diamino‐7H‐purin‐1‐ium) and both ligands bind in an unprecedented monodentate fashion. The existence of a large number of donors and acceptors for hydrogen bonding, together with π–π interactions, leads to a rather complex three‐dimensional structure. 相似文献