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151.
N,N -Dimethylglycinato Complexes of Platinum(IV) The aquapentachloroplatinic acid (H3O)-[PtCl5(H2O)] · 2(18-cr-6) · 6 H2O ( 1 ) reacts with N,N-dimethylglycine (Me2glyH) to give cis-[PtCl2(N,O-Me2gly)2] · (18-cr-6) ( 6 ) and (Me2glyH2)[PtCl4(N,O-Me2gly)] ( 7 ). Complexes 6 and 7 are characterized by microanalysis, 1H-NMR and IR spectroscopy as well as by X-ray structure analysis. In both complexes the N,N-dimethylglycinato ligands are N,O-coordinated. In 6 , the amino groups are mutually trans and the carboxylato groups are cis (configuration index: OC-6–22). In the crystal, there are only weak C–H…O interactions between the N-methyl groups of the [PtCl2(N,O-Me2gly)2] complex and the oxygen atoms of the crown ether (shortest C…O contacts: 3.10(2) Å and 3.21(2) Å). In the solid state, 7 exhibits strong cation-anion interactions: The carboxyl group of the cation (Me2glyH2)+ forms a strong O–H…O bridge to the exocyclic oxygen atom of the carboxylate group of the glycinato ligand (O…O 2.61(1) Å). 相似文献
152.
Ca9Cl8(BC2)2 was obtained by solid state reaction of a mixture of CaCl2, Ca, B and C. The structure was solved by single crystal X-ray structure determination. Ca9Cl8(BC2)2 crystallizes in the orthorhombic space group Cmcm (No. 63, a = 1162.91(8) pm, b = 1341.59(10) pm and c = 1208.62(9) pm, Z = 4). The most striking element of the title compound is the bent BC25– unit that is surrounded by a bicapped trigonal prismatic arrangement of calcium ions. 相似文献
153.
Synthesis and Molecular Structure of [Li(THF)4][{(CO)4Mo}2(μ-PPh2)(μ-PPh2PPh2)]: The First Compound with an 1,3-Dimetalla-cyclopentaphosphane Ring [Mo(CO)4(NBD)] (NBD = norbornadiene) reacts with LiPPh2 and PPh2PPh2 in THF at –80 °C to give [Li(THF)4][{(CO)4Mo}2(μ-PPh2)(μ-PPh2PPh2)] ( 1 ). 1 exhibits an A2X coupling pattern in the 31P NMR spectrum. A crystal structure determination showed the presence of bridging phosphanido (PPh2) and diphosphane ligands (PPh2PPh2). The central Mo2P3 five-membered ring adopts a half-chair conformation and thus resembles an inorganic cyclopentane. 相似文献
154.
Olaf Reckeweg Andreas Baumann Hermann A. Mayer Jochen Glaser H.-Jürgen Meyer 《无机化学与普通化学杂志》1999,625(10):1686-1692
On the Coexistence of Tetragonal and Monoclinic CaC2: Structural and Spectroscopic Studies on Alkaline Earth Metal Acetylides, MC2 (M = Ca, Sr, Ba) The alkaline earth acetylides CaC2, SrC2 and BaC2 can be considered to occur in three polymorphic structures each. The monoclinic low-temperature form, the tetragonal form, and the cubic high-temperature form. No deviation from axial symmetry is obtained for the C22– ions in the tetragonal structure determinations, as confirmed by X-ray single-crystal structures and 13C MAS NMR studies. The CaC2 samples prepared by us were always a mixture of monoclinic and tetragonal phase. Their Raman spectra exhibited two distinct C2 streching vibrations. Problems arising from the coexistence of these two phases for the interpretation of 13C MAS NMR spectra are discussed. 相似文献
155.
Herbi K. Dreiner Sven Heinemeyer Olaf Kittel Ulrich Langenfeld Arne M. Weber Georg Weiglein 《The European Physical Journal C - Particles and Fields》2009,62(3):547-572
Within the Minimal Supersymmetric Standard Model (MSSM) we systematically investigate the bounds on the mass of the lightest
neutralino. We allow for non-universal gaugino masses and thus even consider massless neutralinos, while assuming in general
that R-parity is conserved. Our main focus is on laboratory constraints. We consider collider data, precision observables, and also
rare meson decays to very light neutralinos. We then discuss the astrophysical and cosmological implications. We find that
a massless neutralino is allowed by all existing experimental data and astrophysical and cosmological observations. 相似文献
156.
We subject the baby Skyrme model to a Moyal deformation, for unitary or Grassmannian target spaces and without a potential term. In the Abelian case, the radial BPS configurations of the ordinary noncommutative sigma model also solve the baby Skyrme equation of motion. This gives a class of exact analytic noncommutative baby Skyrmions, which have a singular commutative limit but are stable against scaling due to the noncommutativity. We compute their energies, investigate their stability and determine the asymptotic two-Skyrmion interaction. 相似文献
157.
Robert D. Shannon Olaf Medenbach Philippe Ghosez 《Journal of solid state chemistry》2009,182(10):2762-2768
The refractive indices of ZrW2O8, measured at wavelengths of 435.8-643.8 nm, were used to calculate nD at λ=589.3 nm and n∞ at λ=∞ from a one-term Sellmeier equation. Refractive indices, nD and dispersion values, A, are, respectively, 1.8794 and 114×10−16 m2. The high dispersion, relative to other molybdates, tungstates and Zr-containing compounds, is attributed to the low value of Eo=7.7 eV and mean cation coordination number. Total electronic polarizabilities, αtotal, were calculated from n∞ and the Lorenz-Lorentz equation. The unusually large difference between the observed polarizability of 20.087 Å3 and the calculated total polarizability αT of 17.59 Å3 (Δ=+12.4%) is attributed to (1) a large M-O-W angle, (2) a high degree of W 5d-O(terminal) 2p and Zr nd-O 2p hybridization, and (3) unusually high oxygen displacement factors, B(O), normalized to B(W). 相似文献
158.
In this work we investigate the material behaviour of steel 51CrV4 in classical uniaxial strain controlled tension tests of different strain rates interposed by relaxation steps, in which the equilibrium stress observed is significantly smaller than the stresses seen in slowest strain rate test. Also, some cyclic experiments with different strain rates and amplitudes were done to analyze the hysteresis behaviour of the material. Against this background of experimental data the modeling possibilties of two models are explored: the Lion model and the Chaboche model with kinematic hardening ansatz. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
159.
The Fluid-Structure-Interactions (FSI) for technological constructions on sea are becoming nowadays very important in view of growing consumption of renewable energy sources. Exceptionally the offshore wind farms are exposed to extreme weather conditions due to breaking and non-breaking wave loads. This work presents numerical Finite-Volume-Method (FVM) analysis of fluid and structure interactions with water waves impact on elastic solid structures. We develop a Free Surface-Structure-Interaction (FSSI) solver in OpenFAOM [1] with multi-regional mesh deformation. A two dimensional numerical water impact model on a damping element prototype of an offshore wind turbin tower is investigated. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
160.
Rotthaus O Thomas F Jarjayes O Philouze C Saint-Aman E Pierre JL 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(26):6953-6962
The two tetradentate ligands H(2)L and H(2)L(Me) afford the slightly distorted square-planar low-spin Ni(II) complexes 1 and 2, which comprise two coordinated phenolate groups. Complex 1 has been electrochemically oxidized into 1(+), which contains a coordinated phenoxyl radical, with a contribution from the nickel orbital. In the presence of pyridine, 1(+) is converted into 1(Py) (+), an octahedral phenolate nickel(III) complex with two pyridines axially coordinated: An intramolecular electron transfer (valence tautomerism) is promoted by the geometrical changes, from square planar to octahedral, around the metal center. The tetradentate ligand H(2)L(Me), in the presence of pyridine, and the hexadentate ligand H(2)L(Py) in CH(2)Cl(2) afford, respectively, the octahedral high-spin Ni(II) complexes 2(Py) and 3, which involve two equatorial phenolates and two axially coordinated pyridines. At 100 K, the one-electron-oxidized product 2(Py) (+) comprises a phenoxyl radical ferromagnetically coupled to the high-spin Ni(II) ion, with large zero-field splitting parameters, while 3(+) involves a phenoxyl radical antiferromagnetically coupled to the high-spin Ni(II) ion. 相似文献