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961.
J. Burgess D. L. Davies A. J. Grist J. A. Hall S. A. Parsons 《Monatshefte für Chemie / Chemical Monthly》1994,125(5):515-523
Summary Solvent effects on thecharge-transfer bands of a series of thiocyanato-tetraazamacrocycle-manganese(III) complexes are reported, and discussed in terms of the donor and acceptor (hydrogen-bonding) properties of the respective solvents. The piezochromic behaviour of one of these complexes is also described.
Solvatochromie von Thiocyanato-Tetraazamakrocyclo-Mangan(III) — Komplexen
Zusammenfassung Die Auswirkung von Lösungsmitteleffekten auf diecharge-transfer — Banden einer Reihe von Thiocyanato-Tetraazamakrocyclo-Mangan(III) — Komplexen wird im Zusammenhang mit den Donor- und Akzeptoreigenschaften des Lösungsmittels diskutiert. Das piezochrome Verhalten eines der Komplexe wird beschrieben.相似文献
962.
963.
We have developed a microdialysis sampling technique coupled on-line with simultaneous electrothermal atomic absorption spectrometry (SIMAAS) for the continuous monitoring of copper (Cu), manganese (Mn), nickel (Ni), and selenium (Se) in saline solutions and in cell suspensions. These trace elements are considered to be those associated most significantly with oxidative stress in biological systems. We employed ultrapure saline (0.9% NaCl) as the perfusate and, thus, the dialysate samples contained a high concentration of salt in the matrix. The use of modifiers [Pd coupled with Mg(NO3)2] prevented the target elements from undergoing evaporation at a pyrolysis temperature of 1200 °C, a process that effectively eliminated interference from NaCl. The excellent linearity, detection limits, and precision of the SIMAAS technique allowed the Cu, Mn, Ni, and Se concentrations to be determined in saline. For the on-line microdialysis-SIMAAS system, the ultrapure saline was perfused at a flow rate of 1 μL/min. The probe recoveries of Cu, Mn, Ni, and Se in saline were 57.9, 65.0, 65.5, and 67.9%, respectively. A standard saline solution was measured continuously by the on-line system to ensure long-term stability; each measurement fell within a range of two standard deviations. We determined the on-line spiked recoveries of Cu, Mn, Ni, and Se (101.3, 88.8, 91.3, and 98.5%, respectively) by adding a spiking standard into the stirred saline. The spiked recoveries (Cu, 37.5%; Mn, 3.8%; Ni, 71.1%; Se, 33.8%) were also determined through on-line spiking of a standard into the stirred cell suspension; these values demonstrate that Cu, Mn, and Se were depleted in the cell suspension, but Ni was not. The use of this on-line microdialysis-SIMAAS system permitted the in situ, dynamic, and continuous monitoring of Cu, Mn, Ni, and Se in cell suspensions at a temporal resolution of 20 min. 相似文献
964.
Taher Yousefi Ahmad Nozad Golikand Mohammad Hossein MashhadizadehMustafa Aghazadeh 《Current Applied Physics》2012,12(1):193-198
Manganese dioxide (MnO2) nanowires with diameter about 30-70 nm is achieved via a two-step process: first, template-free cathodic electrodeposition from aqueous solution of Mn(NO3)2 on steel substrate and followed by heat treatment. The temperature-annealed sample was studied by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) methods and Fourier transform infrared (FT-IR) spectroscopy. The electrochemical performance of the MnO2 sample was studied by cyclic voltammetry (CV) and chronopotentiometry in Na2SO4 solutions. The sample showed excellent supercapacitive behavior. The specific capacitance (SC) of 237 F g−1 in a potential window of 0-0.9V was obtained at the scan rate of 2 mV s−1. The SC calculated from the chronopotentiometry data is about 246 F g−1. The SC was decreased by 16% after 1000 cycles. 相似文献
965.
Shishir Ghosh Faruque Ahmed Rafique Al-Mamun Daniel T. Haworth Sergey V. Lindeman Tasneem A. Siddiquee Dennis W. Bennett Shariff E. Kabir 《Journal of chemical crystallography》2009,39(8):595-602
Abstract Treatment of Mn2(CO)10 with 2-thiazoline-2-thiol in the presence of Me3NO at room temperature afforded the dimanganese complexes [Mn2(CO)7(μ-NS2C3H4)2] (1) and [Mn2(CO)6(μ-NS2C3H4)2] (2) in 51 and 34% yields, respectively. Compound 1 was quantitatively converted into 2 when reacted with one equiv of Me3NO. Reaction of 1 with triphenylphosphine at room temperature furnished the mononuclear complex [Mn(CO)3(PPh3)(κ
2-NS2C3H4)] (3) in 66% yield. All three new complexes have been characterized by elemental analyzes and spectroscopic data together with
single crystal X-ray diffraction studies for 1 and 3. Compound 1 crystallizes in the orthorhombic space group Pbca with a = 12.4147(2), b = 16.2416(3), c = 19.0841(4) ?, β = 90°, Z = 8 and V = 3848.01(12) ?3 and 3 crystallizes in the monoclinic space group P 21/n with a = 10.41730(10), b = 14.7710(2), c = 14.9209(2) ?, β = 91.1760(10)°, Z = 4 and V = 2295.45(5) ?3.
Graphical Abstract Two new dimanganese complexes [Mn2(CO)7(μ-NS2C3H4)2] (1) and [Mn2(CO)6(μ-NS2C3H4)2] (2) were formed when [Mn2(CO)10] was treated with 2-thiazoline-2-thiol in the presence of Me3NO. Compound 2 reacts with PPh3 to give the monomeric complex [Mn(CO)3(PPh3
)(κ
2-NS2C3H4)]. The structures of 1 and 3 were established by crystallography. Shishir Ghosh, Faruque Ahmed, Rafique Al-Mamun, Daniel T. Haworth, Sergey V. Lindeman,
Tasneem A. Siddiquee, Dennis W. Bennett, Shariff E. Kabir Investigations of 2-thiazoline-2-thiol as a ligand: Synthesis and
X-ray structures of [Mn2(CO)7(μ-NS2C3H4)2] and [Mn(CO)3
(PPh3)(κ
2-NS2C3H4)].
相似文献
966.
Shreya Mukherjee Matthew R. DanielsRashmi Bagai Khalil A. AbboudGeorge Christou Christos Lampropoulos 《Polyhedron》2010
The use of carboxylates in the synthesis of 3d/4f clusters, with or without a second organic ligand, has afforded a series of tetranuclear M2Gd2 complexes (M = Fe or Mn), and two new trinuclear M2Gd (M = Fe or Mn) molecular compounds. Only one of these, [Mn2Gd2O2(O2CBut)8(HO2CBut)4] (1), does not contain a multidentate chelate ligand. Two other similar tetranuclear clusters were synthesized from the use of triethanolamine (teaH3) and 1,1,1-tris(hydroxymethyl)ethane (thmeH3). [Mn2Gd2(OH)2(O2CPh)4(NO3)2(teaH)2] (2) has very similar structure with 1, bearing a defective incomplete double-cubane core bridged by μ3-O atoms, whereas in the core of [NHEt3]2[Fe2Gd2(O2CPh)4(thme)2(NO3)4] (3) the thme3− ligand caps the two incomplete cubane units, providing the triply-bridging alkoxides needed for bridging. Two new oxide-centered triangular clusters were synthesized bearing the Schiff-based chelate 2-{[2-(dimethylamino)ethyl]methylamino}ethanol (dmemH), namely [Fe2GdO(O2CBut)2(dmem)2(NO3)3] (4), and [Mn2GdO(O2CBut)2(dmem)2(NO3)3] (5). Magnetic susceptibility measurements and/or reduced magnetization studies established that complexes 1 and 3 have an S = 5 ground state, complex 2 has S = 4, and complexes 4 and 5 are S = 7/2 in their ground states. These complexes portray the feasibility of obtaining products bearing metal cores commonly found in homometallic clusters, even when these include metals with completely different coordination chemistry and electronic structure, such as lanthanides. 相似文献
967.
The dissolution of [(CH3)N]2Na[MnN(CN)5]·H2O in water results in the dissociation of the labile trans-CN ligand to form [MnN(H2O)(CN)4]2−(aq). The formed aqua complex reacts rapidly with a number of nucleophiles such as NCS− and N3−. Here we report the single crystal X-ray structure of the reaction products of as well as the equilibrium and kinetic behaviour of [MnN(H2O)(CN)4]2− in solution. 相似文献
968.
Phase equilibria studies of the system K2SO4–MnSO4–H2O published revealed discrepancies between the data presented in the literature regarding the solid phases formed at ambient temperatures. The solubility in the system at 298 K and 313 K was determined. At 298 K, the existence of the double salt K2SO4·3MnSO4·5H2O and of MnSO4·H2O was confirmed. The examinations at 313 K showed the formation of the stable solid phases MnSO4·H2O, K2SO4·2MnSO4, K2SO4·MnSO4·1.5H2O, K2SO4 and the formation of a metastable phase K2SO4·MnSO4·2H2O. 相似文献
969.
Svetlana G. Baca Helen Stoeckli-Evans Christina Ambrus Stanislav T. Malinovskii Iurii Malaestean Nicolae Gerbeleu Silvio Decurtins 《Polyhedron》2006,25(18):3617-3627
Two new μ3-oxo-centered trinuclear manganese complexes, one of them a homo-valence (1) pivalate complex and the other a mixed-valence (2) pivalate complex (where Im = imidazole, 1-MeIm = 1-methylimidazole), have been synthesized and characterized by IR spectroscopy, thermogravimetric analysis, X-ray crystallography and magnetochemistry. Complexes 1 and 2 are μ3-oxo-trinuclear compounds with the three manganese atoms bridged by six pivalate groups. At each axial position there is an Im (1) or 1-MeIm (2) molecule. In both compounds, the manganese coordination geometry is slightly distorted octahedral, consisting of the oxygen of the central triangle, four oxygen atoms from bridging pivalate ligands, and a terminal Im or 1-MeIm nitrogen atom. The crystal packing of 1 involves hydrogen bonding between complex cations [Mn3O(Piv)6(Im)3]+ and outersphere pivalate ions, whereas in compound 2 interactions of the C–Hπ type, formed by both the aromatic and methyl C–H groups of 1-MeIm molecules, are present. Magnetic studies reveal that both compounds represent antiferromagnetically coupled, spin-frustrated triangular systems exhibiting weak to moderate exchange coupling constants. 相似文献
970.