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101.
Jonas Boström Valera Veryazov Francesco Aquilante Thomas Bondo Pedersen Roland Lindh 《International journal of quantum chemistry》2014,114(5):321-327
An algorithm for computing analytical gradients of the second‐order Møller–Plesset (MP2) energy using density fitting (DF) is presented. The algorithm assumes that the underlying canonical Hartree–Fock reference is obtained with the same auxiliary basis set, which we obtain by Cholesky decomposition (CD) of atomic electron repulsion integrals. CD is also used for the negative semidefinite MP2 amplitude matrix. Test calculations on the weakly interacting dimers of the S22 test set (Jure?ka et al., Phys. Chem. Chem. Phys. 2006, 8, 1985) show that the geometry errors due to the auxiliary basis set are negligible. With double‐zeta basis sets, the error due to the DF approximation in intermolecular bond lengths is better than 0.1 pm. The computational time is typically reduced by a factor of 6–7. © 2013 Wiley Periodicals, Inc. 相似文献
102.
Fathi F Schlitt M Pedersen DB Kraatz HB 《Langmuir : the ACS journal of surfaces and colloids》2011,27(19):12098-12105
A simple electrochemical method has been proposed for the preparation of silver nanoparticles that can be used for the detection of cyanide. Both the electrochemical behavior and morphology of the Ag nanoparticles have been characterized in the presence of KCN or diethyl cyanophosphonate (DECP) as well as in alkaline media. These were investigated by cyclic voltammetry and scanning electron microscopy (SEM). DECP is a simulant of the chemical warfare agent tabun. 相似文献
103.
Gloriam DE Wellendorph P Johansen LD Thomsen AR Phonekeo K Pedersen DS Bräuner-Osborne H 《Chemistry & biology》2011,18(11):1489-1498
GPRC6A is a Family C G protein-coupled receptor recently discovered and deorphanized by our group. This study integrates chemogenomic ligand inference, homology modeling, compound synthesis, and pharmacological mechanism-of-action studies to disclose two noticeable results of methodological and pharmacological character: (1) chemogenomic lead identification through the first, to our knowledge, ligand inference between two different GPCR families, Families A and C; and (2) the discovery of the most selective GPRC6A allosteric antagonists discovered to date. The unprecedented inference of?pharmacological activity across GPCR families provides proof-of-concept for in?silico approaches against Family C targets based on Family A templates, greatly expanding the prospects of successful drug design and discovery. The antagonists were tested against a panel of seven Family A and C G protein-coupled receptors containing the chemogenomic binding sequence motif where some of the identified GPRC6A antagonists showed some activity. However, three compounds with at least ~3-fold selectivity for GPRC6A were discovered, which present a significant step forward compared with the previously published GPRC6A antagonists, calindol and NPS 2143, which both display ~30-fold selectivity for the calcium-sensing receptor compared to GPRC6A. The antagonists constitute novel research tools toward investigating the signaling mechanism of the GPRC6A receptor at the cellular level and serve as initial ligands for further optimization of potency and selectivity enabling future ex?vivo/in?vivo pharmacological studies. 相似文献
104.
Tommy Sonne Alstrøm Mads Peter Sørensen Niels Falsig Pedersen Søren Madsen 《Acta Appl Math》2011,115(1):63-74
The time-dependent Ginzburg-Landau equation is solved numerically for type-II superconductors of complex geometry using the
finite element method. The geometry has a marked influence on the magnetic vortex distribution and the vortex dynamics. We
have observed generation of giant vortices at boundary defects, suppressing the superconducting state far into the superconductor. 相似文献
105.
Birk T Pedersen KS Piligkos S Thuesen CA Weihe H Bendix J 《Inorganic chemistry》2011,50(12):5312-5314
In the solid state, MnF(salen) forms chains wherein fairly linear fluoride bridges between high-spin Mn(III) centers are observed. We interpret the magnetic properties of these chains by use of the classical Fisher model and by use of the high-temperature expansion approach, as well as by exact matrix diagonalization of the spin Hamiltonian, of model rings. In solution, electron paramagnetic resonance shows the chains to be symmetrically cleaved to monomeric MnF(salen). 相似文献
106.
Sørensen JK Fock J Pedersen AH Petersen AB Jennum K Bechgaard K Kilså K Geskin V Cornil J Bjørnholm T Nielsen MB 《The Journal of organic chemistry》2011,76(1):245-263
In continuation of previous studies showing promising metal-molecule contact properties a variety of C(60) end-capped "molecular wires" for molecular electronics were prepared by variants of the Prato 1,3-dipolar cycloaddition reaction. Either benzene or fluorene was chosen as the central wire, and synthetic protocols for derivatives terminated with one or two fullero[c]pyrrolidine "electrode anchoring" groups were developed. An aryl-substituted aziridine could in some cases be employed directly as the azomethine ylide precursor for the Prato reaction without the need of having an electron-withdrawing ester group present. The effect of extending the π-system of the central wire from 1,4-phenylenediamine to 2,7-fluorenediamine was investigated by absorption, fluorescence, and electrochemical methods. The central wire and the C(60) end-groups were found not to electronically communicate in the ground state. However, the fluorescence of C(60) was quenched by charge transfer from the wire to C(60). Quantum chemical calculations predict and explain the collapse of coherent electronic transmission through one of the fulleropyrrolidine-terminated molecular wires. 相似文献
107.
A wavelength-interrogated waveguide sensor system with a large wavelength range (≈60 nm) is presented. Dynamic measurements of changes in the refractive index of up to 0.33 refractive index units are demonstrated, without the need for mechanical adjustments during measurements. Furthermore, simultaneous detection of the in-coupling of both TE and TM polarization components is realized, which, for example, could be used for online monitoring of both thickness and refractive index of thin adlayers. PACS 42.79; 07.60 相似文献
108.
109.
K. Pedersen T.B. Kristensen T.G. Pedersen P. Morgen Z. Li S.V. Hoffmann 《Applied physics. B, Lasers and optics》2002,74(7-8):677-682
Thin noble metal films (Ag, Au and Cu) on Si (111) have been investigated by optical second-harmonic generation (SHG) in combination
with synchrotron radiation photoemission spectroscopy. The valence band spectra of Ag films show a quantization of the sp-band
in the 4-eV energy range from the Fermi level down to the onset of the d-bands. For Cu and Au the corresponding energy range
is much narrower and quantization effects are less visible. Quantization effects in SHG are observed as oscillations in the
signal as a function of film thickness. The oscillations are strongest for Ag and less pronounced for Cu, in agreement with
valence band photoemission spectra. In the case of Au, a reacted layer floating on top of the Au film masks the observation
of quantum well levels by photoemission. However, SHG shows a well-developed quantization of levels in the Au film below the
reacted layer. For Ag films, the relation between film thickness and photon energy of the SHG resonances indicates different
types of resonances, some of which involve both quantum well and substrate states.
Received: 16 October 2001 / Revised version: 14 March 2002 / Published online: 29 May 2002 相似文献
110.
L.H. Andersen A. Lapierre S.B. Nielsen I.B. Nielsen S.U. Pedersen U.V. Pedersen S. Tomita 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,20(3):597-600
Absorption of gas-phase biomolecules has been studied at the heavy-ion storage ring ELISA. Here we discuss the absorption
characteristics of the chromophores of the Green Fluorescent Protein (GFP). The gas-phase absorption maximum of the deprotonated
chromophore (anion form) is at 479 nm. This is almost identical to one of the two absorption maxima of the protein, being
at 477 nm, which is ascribed to a deprotonated chromophore in the protein. The protonated chromophore (cation form) has a
maximum at 406 nm in the gas phase. We compare the gas-phase results with absorption profiles of GFP and chromophores in liquids,
and argue that the absorption characteristics of GFP are mainly ascribed to intrinsic chemical properties of the chromophore.
Evidently, the special β-can structure of GFP provides shielding of the chromophore from the surroundings without significantly
changing the electronic structure of the chromophore through interactions with amino acid side chains.
Received 28 December 2001 Published online 13 September 2002 相似文献