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151.
A.D. Jana R. Saha A.K. Ghosh S. Manna J. Ribas N. Ray Chaudhuri G. Mostafa 《Polyhedron》2009,28(14):3065-3077
Four coordination polymeric complexes, [{Cu2(aepn)2Pt(CN)4·H2O}(H2O){Pt(CN)4}]n, (1), [{Cu(dpt)2Pt(CN)4}]n (2), [{Cu(dien)Pt(CN)4}]n (3) and [{Cu(iprdien)Pt(CN)4}]n (4) (where aepn = N-(2-aminoethyl)-1,3-propanediamine, dpt = 3,3′-imino bispropylamine, dien = diethylenetriamine, iprdien = N′-isopropyldiethylenetriamine), have been synthesized and characterized by X-ray single crystal structure determination and variable temperature magnetic measurements. The formation of the supramolecular assemblies has been rationalized and it has been shown that competition between coordinative forces and hydrogen bonding interactions is crucial in the determination of final solid-state packing. A zig-zag/helical 1D chain (2 and 3) appears when the chelating amine at the Cu(II) center is capable of forming the maximum number of hydrogen bonds, on the other hand when one or more of the amine sites are blocked, due to the prevention of the maximization of hydrogen bonding, (4,2) ribbons (1 and 4) appear. Variable temperature magnetic measurement shows the presence of weak antiferromagnetic interactions in all the complexes. 相似文献
152.
Zala Mahendrasinh Sujit B. Kumar E. Suresh Joan Ribas 《Transition Metal Chemistry》2010,35(6):757-763
A new pyridylpyrazole-containing tetradentate ligand, namely N,N-bis(3,5-dimethylpyrazol-1-ylmethyl)aminomethylpyridine (L), and two of its binuclear azido-bridged complexes, [Ni2(L)2(N3)2](ClO4)2·2EtOH (1) and [Cu2(L)2(N3)2](ClO4)2 (2), have been synthesized and characterized by physico-chemical and spectroscopic methods. The crystal structures of both
complexes are reported. Each metal atom in the complexes has a MN6 coordination environment with distorted octahedral geometry. Variable-temperature magnetic susceptibility measurements for
complex (1) show typical antiferromagnetic behavior with J value −84.5 ± 1.3 cm−1, whereas complex (2) has no magnetic interactions. 相似文献
153.
The azido-bridged manganese complex of formula [Mn(tptz)(mu(1,1)-N3)2]n [1; tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine] has been synthesized and characterized by single-crystal X-ray diffraction analysis and a low-temperature magnetic study. The complex 1 crystallizes in the orthorhombic space group Pbcn, with a = 17.911(5) A, b = 15.804(5) A, c = 6.6538(18) A, and Z = 4. The Mn atoms are coordinated by three N atoms of the tptz ligands and connected to each other by double end-on (EO) azide ligands, forming a neutral 1D chain. The adjacent 1D chains are connected by face-to-face pi-pi-stacking interactions and C-H...pi interactions of pyridine rings of the tptz ligands, which leads to the formation of a supramolecular 2D sheet structure. Temperature- and field-dependent magnetic analyses reveal dominant intrachain ferromagnetic interactions with EO azide-bridge and weak interchain antiferromagnetic interactions with overall metamagnetic behavior having 3D magnetic ordering at 2.7 K. The critical field is approximately 80 G, at which the interlayer antiferromagnetic ground-state switches to a ferromagnetic state. 相似文献
154.
Tamayo A Escriche L Lodeiro C Ribas-Ariño J Ribas J Covelo B Casabó J 《Inorganic chemistry》2006,45(19):7621-7627
The complete halide series of Ni(II) complexes containing the tetradentate macrocyclic ligand 3,11-dithia-7,17-diazabicyclo[11.3.1]heptadeca-1(17),13,15-triene (L), was fully characterized by X-ray diffraction. The fluoro, chloro, and bromo complexes are dinuclear species with formula [{Ni(L)}2(mu-X)2]2+ (X = halide), whereas only mononuclear species with formula [Ni(Y)(solv)(L)]n+ (Y = halide or solvent molecule), were obtained with I. To date, the fluoro derivative is the first nonorganometallic coordination compound containing the Ni(mu-F)2Ni core. The magnetic properties of these halo complexes have been studied. Intramolecular interactions were observed in the three dinuclear complexes, being antiferromagnetic in the fluoro derivative and ferromagnetic in both the chloro and bromo ones. The two iodo derivatives are paramagnetic species, as would be expected for mononuclear octahedral Ni(II) complexes. Density functional theory calculations led us to relate the magnetic behaviors of these compounds to the values of the corresponding Ni-X-Ni(i) angle. The analysis of the singly occupied molecular orbitals gave a clear comprehension of the different magnetic exchange interactions found in these Ni(II) complexes. 相似文献
155.
The treatment of alpha-H-p-H-PTM (PTM = polychlorotriphenylmethane) with oleum 65% followed by deprotonation and oxidation leads to the isolation of a novel pure organic radical PTMSO3H x 3 H2O x 0.5 hexane (2). The X-ray diffraction of 2 reveals a layered structure with disordered H2O molecules between facing sulfonic acid groups. We have explored the coordination abilities of the sulfonate derivative using different metals. The treatment of 2 with mild bases yields the sulfonate radical PTMSO3Na x H2O (3). On the other hand, the new compound [Cu(py)2(H2O)4](PTMSO3)2 x 2 H2O x 2 EtOH (4) has been crystallized using Cu(II) as the metallic counterion in the presence of pyridine. The structure reveals a solvent-separated ion-pair-type compound, with no direct coordination of the metal ion with the sulfonate group, and the formation of organic layers between layers of transition metal complexes. This situation has been overcome by favoring the stabilization of the sulfonate group over the Cu(II) center by changing the pyridine ligand to cyclam. This has led to compound [Cu(cyclam)](PTMSO3)2 x 6 EtOH (5a), in which the sulfonate group acts as a monodentate axial ligand for the Cu(II) center. We have observed a single-to-single crystal rearrangement from 5a to [Cu(cyclam)](PTMSO3)2 (5b) because of the loss of the solvent of crystallization, without significant modification of the metal coordination environment. All species have been structurally and magnetically characterized, and the magnetic coupling between the organic radicals and the metal paramagnetic centers is discussed. 相似文献
156.
A novel heterometallic 3d-4f metal-azido complex of mixed ligands, showing unprecedented structure type and interesting magnetic properties, has been hydrothermally synthesized and characterized. 相似文献
157.
A new end-on azide-bridged dimeric Mn(III) complex has been synthesized by using the tridentate N-isonicotinamidosalicylaidimine ligand. Magnetic studies show that the complex has a high-spin ground state of S = 4 and is ac out-of-phase frequency-dependent. 相似文献
158.
159.
Sarkar S Datta A Mondal A Chopra D Ribas J Rajak KK Sairam S M S Pati SK 《The journal of physical chemistry. B》2006,110(1):12-15
Synthesis, structural characteristics, magnetic studies and DFT calculations in Ni(II) dinuclear complexes containing two bridging N3- and an O-H...O linkage reveal the existence of ferromagnetic interactions between Ni(II) centers via N3- ligands and antiferromagnetic interactions through the H-bonded moiety. The overall magnetic behavior of the system depends on the delicate balance between these two competing interactions. 相似文献
160.
Jordi Ribas‐Arino Dr. Motoyuki Shiga Dr. Dominik Marx Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(23):4190-4193
The time is ripe : A general theoretical framework based on force‐transformed potential energy surfaces rationalizes the intriguing results of recent experiments in the emerging field of covalent mechanochemistry.