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981.
《Journal of Coordination Chemistry》2012,65(15):2426-2440
AbstractIn the present study, the oxidative dissolution of metallic copper has been explored with the intention to prepare some new complexes with urotropine (hmta) and triethylenediamine (dabco) ligands. All the compounds synthesized were characterized by single-crystal X-ray diffraction and Raman spectroscopy. Reactions performed in a DMSO/CuCl2?2H2O mixture resulted in [(μ-Cl)2CuI(hdabco+)CuI(μ-Cl)(κS-DMSO)]n and [CuICl(hmta)2] complexes. Their isostructural bromide analogs [(μ-Br)2CuI(hdabco+)CuI(μ-Br)(κS-DMSO)]n and [CuIBr(hmta)2] were prepared by the reaction of elemental copper with respective ligands in a DMSO/CBr4 mixture. Early interrupted reaction of the copper wire with the DMSO/CBr4/dabco solution resulted in an appearance of crystals of the [CuI2Br2(CO)2(dabco)]n carbonyl complex on the copper surface. It arises with the participation of in situ formed carbon monoxide. Despite the identical stoichiometry, the crystal structure of the [Cu2Br2(CO)2(dabco)]n complex is markedly different from that of a known [Cu2Cl2(CO)2(dabco)]n analog. 相似文献
982.
《Journal of Coordination Chemistry》2012,65(2):218-225
By using the flexible bis(triazole) ligand 1,2-bis(1,2,4-triazol-1-yl)ethane (bte), a polyoxometalate-templated compound, [Zn2(bte)4(SiW12O40)]·2H2O (1), was synthesized under hydrothermal conditions. The compound was characterized by single-crystal X-ray diffraction, elemental analyses, IR spectroscopy, photoluminescence spectroscopy, and cyclic voltammetry. Compound 1 is constructed from two motifs: the [SiW12O40]4? polyanion and a bi-nuclear metal-organic circle [Zn2(bte)2]4+. The polyanion exerts a template role, inducing the formation of the bi-nuclear circle. The circles build a 1-D circle connecting circle chain through sharing the same Zn ions. Adjacent circles in the chain are vertical with each other. The template polyanion is surrounded by four circles from four different 1-D chains, forming a 3-D supramolecular structure. 相似文献
983.
《Journal of Coordination Chemistry》2012,65(4):612-623
Two metal–organic coordination polymers, [Cu3(4-bpcb)2(1,2,4-btc)2(H2O)2] (1) and [Cu3(3-bpcb)3(btec)1.5] (2), have been synthesized from hydrothermal reaction of copper chloride with mixed ligands [4-bpcb?=?N,N′-bis(4-pyridinecarboxamide)-1,4-benzene, 3-bpcb?=?N,N′-bis(3-pyridinecarboxamide)-1,4-benzene, 1,2,4-H3btc?=?1,2,4-benzenetricarboxylic acid, and H4btec?=?1,2,4,5-benzenetetracarboxylic acid]. X-ray diffraction analysis reveals that 1 exhibits a 2-D layer structure and 2 possesses a three-dimensional (3-D) network. In 1 and 2, CuII ions are connected by bridging 1,2,4-btc or btec to form 2-D polymeric layers. Cu-1,2,4-btc layer does not propagate into a 3-D coordination framework in 1 due to 4-bpcb showing monodentate coordination (via ligation of only one pyridyl nitrogen). In 2, Cu-btec 2-D layers are further extended into a 3-D network with (64.82)3 topology by 3-bpcb ligand in μ 2-bridging coordination (via ligation of two pyridyl nitrogens). The different structures of the two complexes illustrate the influence of different polycarboxylates and N-donor positions of organic ligands on the formation of such coordination architectures. Moreover, the thermal properties and electrochemical properties of the copper complexes bulk-modified carbon paste electrodes have been studied. 相似文献
984.
《Journal of Coordination Chemistry》2012,65(2):125-134
Abstract The complex [Sm(H3L)(NO3)(H2O)](NO3)2 · H2O was synthesized by the (2+3) condensation of tris(2-aminoethyl)amine with 2,6-diformyl-4-chlorophenol in the presence of Sm3+. Its crystal structure has been determined. In the complex the coordination number of Sm3+ is nine. A water molecule is encapsulated in the cryptate as a guest, confirmed by electrospray mass spectrometry, thermal analysis and the X-ray crystal structure. 相似文献
985.
《Journal of Coordination Chemistry》2012,65(1-2):73-80
Abstract Reaction of [Co(CNC6H3Et2-2,6)5]BF4 with bidentate phosphines leads to monosubstituted Co(I) complexes, [Co(CNC6H3Et2-2,6)4(L-L)]BF4, where L-L = Ph2P(CH2)n PPh2, n = 1-4,6; Ph2PCH2-CH2AsPh2, Ph2PC6H4PPh2-p, Ph2PCH[dbnd]CHPPh2-trans. Reaction conditions are such that disubstitution would be possible, but bidentate bridging to form bimetallic complexes is not favoured. Comparison of v([sbnd]N°C) IR, electronic spectra, and molar conductivities with values for [Co(CNC6H3Et2-2,6)4L]X, where X = ClO4, BF4; L = monodentate triarylphosphine; indicates that these new complexes must also be five-coordinate Co(I) complexes, in which the potentially bidentate phosphine ligands are coordinated through only one P atom. Structures are approximately trigonal bipyramidal in solution and the solid state, with the phosphine ligand occupying an axial position. 相似文献
986.
《Journal of Coordination Chemistry》2012,65(19):3481-3491
[Cu(L)(NO3)2] (1) and [Cu(L)(H2O)2](SCN)2 (2) [L?=?3,14-diethyl-2,6,13,17-tetraazatricyclo(16.4.0.07,12)docosane] have been prepared and structurally characterized by single-crystal X-ray diffraction at 100?K. For these constrained macrocycle complexes, copper(II) exists in a tetragonally distorted octahedral environment with the four nitrogen atoms of the macrocyclic ligands and two oxygen atoms from either nitrate or water in axial positions. The macrocyclic ligands in both complexes adopt the most stable trans-III conformation. The Cu–N distances are 2.021(2)–2.047(2)?Å and typical but the axial ligands are weakly coordinating, with Cu–O bond lengths, 2.506(2)?Å for 1 and 2.569(2)?Å for 2, due to the pseudo Jahn–Teller effect. The crystals are stabilized by a 3-D network by intra and intermolecular hydrogen bonds that are formed among the secondary nitrogen hydrogen atoms and nitrate in 1, and intermolecular hydrogen bonds are formed by water and thiocyanates in 2. The electronic absorption and IR spectral properties are also discussed. 相似文献
987.
Dr. Matthias W. Löble María Casimiro Dr. Dominique T. Thielemann Dr. Pascual Oña‐Burgos Prof. Dr. Ignacio Fernández Prof. Dr. Peter W. Roesky Prof. Dr. Frank Breher 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(17):5325-5334
2D 1H,89Y heteronuclear shift correlation through scalar coupling has been applied to the chemical‐shift determination of a set of yttrium complexes with various nuclearities. This method allowed the determination of 89Y NMR data in a short period of time. Multinuclear NMR spectroscopy as function of temperature, PGSE NMR‐diffusion experiments, heteronuclear NOE measurements, and X‐ray crystallography were applied to determine the structures of [Y5(OH)5(L ‐Val)4(Ph2acac)6] ( 1 ) (Ph2acac=dibenzoylmethanide, L ‐Val=L ‐valine), [Y( 2 )(OTf)3] ( 3 ), and [Y2( 4 )(OTf)5] ( 5 ) ( 2 : [(S)P{N(Me)N?C(H)Py}3], 4 : [B{N(Me)N?C(H)Py}4]?) in solution and in the solid state. The structures found in the solid state are retained in solution, where averaged structures were observed. NMR diffusion measurements helped us to understand the nuclearity of compounds 3 and 5 in solution. 1H,19F HOESY and 19F,19F EXSY data revealed that the anions are specifically located in particular regions of space, which nicely correlated with the geometries found in the X‐ray structures. 相似文献
988.
Dr. Jean‐François Létard Dr. Saket Asthana Helena J. Shepherd Dr. Philippe Guionneau Dr. André E. Goeta Naohiko Suemura Ryuta Ishikawa Prof. Sumio Kaizaki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(19):5924-5934
A comprehensive study of the magnetic and photomagnetic behaviors of cis‐[Fe(picen)(NCS)2] (picen=N,N′‐bis(2‐pyridylmethyl)1,2‐ethanediamine) was carried out. The spin‐equilibration was extremely slow in the vicinity of the thermal spin‐transition. When the cooling speed was slower than 0.1 K min?1, this complex was characterized by an abrupt thermal spin‐transition at about 70 K. Measurement of the kinetics in the range 60–70 K was performed to approach the quasi‐static hysteresis loop. At low temperatures, the metastable HS state was quenched by a rapid freezing process and the critical T(TIESST) temperature, which was associated with the thermally induced excited spin‐state‐trapping (TIESST) effect, was measured. At 10 K, this complex also exhibited the well‐known light‐induced excited spin‐state‐trapping (LIESST) effect and the T(LIESST) temperature was determined. The kinetics of the metastable HS states, which were generated from the freezing effect and from the light‐induced excitation, was studied. Single‐crystal X‐ray diffraction as a function of speed‐cooling and light conditions at 30 K revealed the mechanism of the spin‐crossover in this complex as well as some direct relationships between its structural properties and its spin state. This spin‐crossover (SCO) material represents a fascinating example in which the metastability of the HS state is in close vicinity to the thermal spin‐transition region. Moreover, it is a beautiful example of a complex in which the metastable HS states can be generated, and then compared, either by the freezing effect or by the LIESST effect. 相似文献
989.
Uptake for lead, copper, cadmium, nickel and manganese from aqueous solution using the Moringa oleifera seeds biomass (MOSB) and amine-based ligand (ABL) was investigated. Experiments on two synthetic multi-solute systems revealed that MOSB performed well in the biosorption and followed the decreasing orders Pb(II) > Cu(II) > Cd(II) > Ni(II) > Mn(II) and Zn(II) > Cu(II) > Ni(II). The general trend of the heavy metal ions uptake by the amine-based ligand followed decreased in the order Mn > Cd > Cu > Ni > Pb, which is the reverse trend for what was observed for MOSB. Comparing the single- and multi-metal solutions, there was no clear effect in the biosorption capacity of MOSB suggesting the presence of sufficient active binding sites for all metal ions studied. The MOSB performance is also not affected by pH in the range 3.5–8. 相似文献
990.
《Physics and Chemistry of Liquids》2012,50(6):641-648
The complex formation reaction between N,N′-bis(2-pyridylmethylidene)-1,2-diiminoethane (BPIE) di-Schiff base ligand as an electron donor and iron(III) chloride as an electron acceptor have been studied spectrophometrically in methanol at 28°C. The values of equilibrium constants, K and molar absorptivities, ε were obtained from the Benesi–Hildebrand, Scott and Foster–Hammick–Wardley equations. The results indicate the formation of 1?:?1 charge transfer complex. The absorption band energy of the complex, E CT, the ionization potential of the BPIE Schiff base ligand, I D, and the Gibbs energy changes of the above reaction, ΔG 0, were calculated. Finally, the kinetics of the complex formation reaction were studied and was found to be second-order in each reactant. The values of the rate constants of the forward and reverse reactions k 1 and k ?1 were determined. 相似文献