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201.
202.
An [Hg6O2]-cationic (r) octahedron atomic group has been isolated in a number of mercury oxohalide structures. The octahedron is constructed from two edge-sharing oxo-centered [Hg4O] tetrahedra. For -Hg3O2Cl2, -Hg3O2Cl2, Hg2OI, [Hg2]3O2Cl2, [Hg2]3HgO3Cl2, Hg5O4Cl2, and some other compounds, the geometrical parameters of their crystal structures depend on the dimensions and mutual packing of the cationic r-octahedra and the individual [Hg4O] tetrahedra, if any. 相似文献
203.
204.
Four new two-ligand complexes of copper(II) with 2,2′-bipyridine and one of three different α-hydroxycarboxylic acids (lactic, H2LACO; 2-methyllactic, H2MLACO; and mandelic, H2MANO) were prepared. Complexes 1–3 of general formula [Cu(HL)2(bipy)]·nH2O (HL=monodeprotonated acid), were characterized by elemental analysis, IR, electronic and EPR spectroscopy, magnetic measurements and thermogravimetric analysis. Complexes 1 (HL=HLACO, n=2), 2 (HL=HMLACO, n=1) and 3a (the result of attempted recrystallization of 3, of formula [Cu(HMANO)(bipy)2](HMANO)·H2MANO·CH3CN were studied by X-ray diffractometry. The copper atom is in an elongated, tetragonally distorted octahedral environment in 1 and 2 and in 3a has a coordination polyhedron intermediate between a square pyramid and a trigonal bipyramid, as evaluated in terms of the parameter τ. In 1 and 2 the α-hydroxycarboxylato ligand is bidentate and monoanionic but in 3a there are three forms: a monodentate monoanion, a monoanionic counterion, and a neutral molecule. 相似文献
205.
The Cr-Cr singly-bonded dimers [{η5-RC5H4Cr(CO)3}2] (1, R=Me; 2, R=CO2Et) reacted with an equivalent of elemental selenium in THF at room temperature to give the linear Cr2Se complexes [{η5-RC5H4Cr(CO)2}2Se] (3, R=Me; 4, R=CO2Et), whereas the linear Cr2Se complex (5, R=MeCO) reacted with excess NaBH4, Ph3PCHPh or 2,4-dinitrophenylhydrazine under respective conditions to afford the linear Cr2Se derivatives [{η5-RC5H4Cr(CO)2}2Se] (6, R=MeCH(OH); 7, R=PhCHCMe; 8, R=2,4-(NO2)2C6H3NHNCMe). Similarly, while the butterfly Cr2Se2 complexes [{η5-RC5H4Cr(CO)2}2Se2] (9, R=Me; 10, R=CO2Et) could be produced either by reaction of dimers 1 and 2 with an excess amount of elemental selenium, or by reaction of the linear complexes 3 and 4 with an equivalent of elemental selenium, the butterfly Cr2Se2 derivatives [{η5-RC5H4Cr(CO)2}2Se2] (12, R=MeCH(OH); 13, R=PhCHCMe; 14, R=2,4-(NO2)2C6H3NHNCMe) were yielded by reaction of the butterfly Cr2Se2 complex (11, R=MeCO) with an excess quantity of NaBH4, Ph3PCHPh and 2,4-dinitrophenylhyazine. Both the linear complexes 3, 4, 6-8 and the butterfly complexes 9, 10, 12-14 are new, which have been fully characterized by elemental analysis, spectroscopy and X-ray crystallography. 相似文献
206.
Reaction of powdered Zr with ZrCl4, BaCl2 and Be in suitable proportions in a Ta container at 800°C produces the title compound. Suitable monocrystals for X-ray diffraction were obtained from reactions to which a comparable amount of Hg2Cl2 had been added. The structure of Ba3Zr6Cl18Be is a superstructure of the K2ZrCl6 · Zr6Cl18H type (R3 c, Z = 6; a = 9.6852 (9) Å, c = 52.52 (1) Å; R, Rw = 2.7, 3.2% for 826 independent reflections, 2θ ≤ 50°). Trigonally compressed [Zr6(Be)Cl12i]Cl6a clusters are interconnected by six-coordinate barium atoms that lie in Cla antiprisms (a twisted version of the ZrIV site) while (9 + 3)-coordinate barium substitutes for potassium within chlorine layers. Distortions associated with the size and field of barium are responsible for the superstructure and for differences from other analogues. 相似文献
207.
Molecular mechanism of physical gelation of hydrocarbons by fatty acid amides of natural amino acids
Asish Pal 《Tetrahedron》2007,63(31):7334-7348
A variety of fatty acid amides of different naturally occurring l-amino acids have been synthesized and they are found to form gels with various hydrocarbons. The gelation properties of these compounds were studied by a number of physical methods including FTIR spectroscopy, X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, rheology, and it was found that gelation depended critically on the fatty acid chain length and the nature of the amino acid. Among them l-alanine based gelators were found to be the most efficient and versatile gelators as they self-assemble into a layered structure to form the gel network. Mechanisms for the assembly and formation of gels from these molecules are discussed. 相似文献
208.
The reaction of 2,6‐pyridinedicarboxylic acid ( 1 , LH2) with CeCl3·7H2O and Sm(NO3)3·6H2O in the presence of triethylamine led to the coordination polymer complexes [M(L)(LH)(H2O)2]·4H2O [M = Ce ( 2 ) and Sm ( 3 )]. Both complexes were characterized by elemental analyses, IR spectroscopy and the crystal structures of 2 and 3 . Crystal data for 2 at ?80 °C: monoclinic, space group P21/c, a = 1404.6(1), b = 1122.1(1), c = 1296.1(1) pm, β = 102.09(1)°, Z = 4, R1 = 0.0217 and for 3 at ?80 °C: monoclinic, space group P21/c, a = 1395.1(1), b = 1120.1(1), c = 1282.8(1) pm, β = 102.71(1)°, Z = 4, R1 = 0.019. 相似文献
209.
Huizhang Liu Maria José Calhorda Michael G.B. Drew Josef Novosad Piero Zanello 《Journal of organometallic chemistry》2004,689(17):2808-2819
New Cu(I) and Ag(I) complexes were prepared by reaction of [M(NCCH3)4][X] (M = Cu or Ag; X = BF4 or PF6) with the bidentate chalcogenide ligands Ph2P(E)NHP(E)Ph2 (E = S, S2dppa; E = Se, Se2dppa), and dpspf (1,1′-bis(diphenylselenophosphoryl)ferrocene). Copper and silver behaved differently. While three molecules of either S2dppa and Se2dppa bind to a distorted tetrahedral Cu4 cluster, with deprotonation of the ligand, 1:2 complexes of the neutral ligands are formed with Ag(I), with a tetrahedral coordination of the metal. The [Cu4{Ph2P(Se)NP(Se)Ph2}3]+ clusters assemble as dimers, held together by weak Se?Se distances interactions. Another dimer was observed for the [Ag(dpspf)]+ cation, with two short Ag?Se distances. DFT and MP2 calculations indicated the presence of attracting interactions, reflected in positive Mayer indices (MI). The electrochemistry study of this species showed that both oxidation and reduction took place at silver. 相似文献
210.
Brajagopal Samanta Joy Chakraborty C. R. Choudhury S. K. Dey D. K. Dey S. R. Batten P. Jensen Glenn P. A. Yap Samiran Mitra 《Structural chemistry》2007,18(1):33-41
We have reported herein the synthesis of three new Cu(II) complexes of tri- and tetradentate Schiff base ligands containing
N3 or N4 donor set along with terminal NNN− or SCN− ligands: [L1Cu(NCS)]ClO4 (1), [L2Cu(NCS)2] (2) and [L3Cu(NNN)]ClO4 (3) [L1 = NC5H4C(CH3)=N(CH2)3N=C(CH3)C5H4N, L2= Me2N–(CH2)3–N=C(CH3)C5H4N and L3 = NC5H4CH=N–(CH2)4–N=CHC5H4N]. The complexes have been systematically characterised by elemental, spectroscopic and electrochemical techniques. Antimicrobial
activities of the Schiff base ligands and their metal complexes have been studied using the disc diffusion method on the strains
of Candida tropicalis and Bacillus megaterium. Structures of all the complexes have been unequivocally established from single crystal X-ray diffraction analyses that
show the monomeric units containing a five-coordinated copper center in highly distorted square pyramidal geometry with thiocyanate
or azide anion coordinated as terminal ligand. The complexes 1 and 3 crystallise in monoclinic (P21/c) and 2 in triclinic (P-1) space group, respectively. 相似文献