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991.
992.
993.
Andreas Heerwig Ulrike Müller Fabian Nitsche Prof. Dr. Michael Ruck 《无机化学与普通化学杂志》2012,638(10):1462-1467
A new family of quaternary phases with the general sum formula Cu3+δBi5–δSe8–2δX2+2δ (X = Cl, Br) was discovered by slow cooling of high temperature melts. Cu3.58(1)Bi4.42(1)Se6.84(2)Cl3.16(2) (δ = 0.58) and Cu4.52(1)Bi3.48(1)Se4.96(2)Br5.04(2) (δ = 1.52) crystallize isostructural in the orthorhombic space group type Pnnm with a = 1332.3(1)/1340.2(3) pm, b = 1683.7(2)/1717.2(1) pm, and c = 406.2(1)/407.1(2) pm. The new structure type resembles in some aspects the hollandite as well as the pavonite type. A framework of face‐ and edge‐sharing anion polyhedra around Bi3+ cations hosts Cu+ cations. The characteristic motif is an infinite band of polyhedra that has the width of five polyhedra, with three octahedra being enclosed by capped trigonal prisms. The octahedrally coordinated Bi3+ cations are partially substituted by Cu+ (in octahedra faces), while Se2– anions are replaced by X–. The sulfide iodide Cu3.33(2)Bi2S3.33(2)I2.67(2) crystallizes in the monoclinic space group C2/m with a = 2803.6(9) pm, b = 409.9(1) pm, c = 1058.0(3) pm, and β = 110.68(2)°. Double strands of face‐sharing [BiS1/1S2/2I4/4] as well as [BiS3/3I2/2(S0.33/I0.67)2/2] polyhedra run along [010]. In between them, the Cu+ cations are spread over numerous closely spaced sites. They define a ladder‐shaped continuous path for ion conduction along [010]. 相似文献
994.
Fabian Kallmeier Dr. Beata Dudziec Dr. Torsten Irrgang Prof. Dr. Rhett Kempe 《Angewandte Chemie (International ed. in English)》2017,56(25):7261-7265
The development of reactions that convert alcohols into important chemical compounds saves our fossil carbon resources as alcohols can be obtained from indigestible biomass such as lignocellulose. The conservation of our rare noble metals is of similar importance, and their replacement by abundantly available transition metals, such as Mn, Fe, or Co (base or nonprecious metals), in key technologies such as catalysis is a promising option. Herein, we report on the first base-metal-catalyzed synthesis of pyrroles from alcohols and amino alcohols. The most efficient catalysts are Mn complexes stabilized by PN5P ligands whereas related Fe and Co complexes are inactive. The reaction proceeds under mild conditions at catalyst loadings as low as 0.5 mol %, and has a broad scope and attractive functional-group tolerance. These findings may inspire others to use Mn catalysts to replace Ir or Ru complexes in challenging dehydrogenation reactions. 相似文献
995.
Fabian Weiss Prof.Dr. Frank Kubel Dr. Óscar Gálvez Dr. Markus Hoelzel Dr. Stewart F. Parker Philipp Baloh Dr. Riccardo Iannarelli Dr. Michel J. Rossi Prof. Dr. Hinrich Grothe 《Angewandte Chemie (International ed. in English)》2016,55(10):3276-3280
The composition of high‐altitude ice clouds is still a matter of intense discussion. The constituents in question are ice and nitric acid hydrates, but the exact phase composition of clouds and its formation mechanisms are still unknown. In this work, conclusive evidence for a long‐predicted phase, alpha‐nitric acid trihydrate (alpha‐NAT), is presented. This phase was characterized by a combination of X‐ray and neutron diffraction experiments, allowing a convincing structure solution. Furthermore, vibrational spectra (infrared and inelastic neutron scattering) were recorded and compared with theoretical calculations. A strong interaction between water ice and alpha‐NAT was found, which explains the experimental spectra and the phase‐transition kinetics. On the basis of these results, we propose a new three‐step mechanism for NAT formation in high‐altitude ice clouds. 相似文献
996.
M. Sc. Fabian Spitzer Dr. Christian Graßl Dr. Gábor Balázs M. Sc. Eva M. Zolnhofer Prof. Dr. Karsten Meyer Prof. Dr. Manfred Scheer 《Angewandte Chemie (International ed. in English)》2016,55(13):4340-4344
A study of P4 transformations at low‐valent iron is presented using β‐diketiminato (L) FeI complexes [LFe(tol)] (tol=toluene; L=L1 ( 1 a ), L2 ( 1 b ), L3 ( 1 c )) with different combinations of aromatic and backbone substituents at the ligand. The products [(LFe)4(μ4‐η2:η2:η2:η2‐P8)] (L=L1 ( 2 a ), L2 ( 2 b )) containing a P8 core were obtained by the reaction of 1 a,b with P4 in toluene at room temperature. Using a slightly more sterically encumbered ligand in 1 c results in the formation of [(L3Fe)2(μ‐η4:η4‐P4)] ( 2 c ), possessing a cyclo‐P4 moiety. Compounds 2 a – c were comprehensively characterized and their electronic structures investigated by SQUID magnetization and 57Fe Mössbauer spectroscopy as well as by DFT methods. 相似文献
997.
Abdellah Henni Abdallah Merrouche Laid Telli Amina Karar Fabian I. Ezema Hichem Haffar 《Journal of Solid State Electrochemistry》2016,20(8):2135-2142
Indium-doped zinc oxide nanorods were electrochemically deposited at low temperature on ITO substrates. The synthesized ZnO-arrayed layers were investigated by using X-ray diffraction, scanning electron microscopy, UV–vis transmittance, electrochemical impedance spectroscopy, and photocurrent spectroscopy. X-ray diffraction analysis demonstrates that the electrodeposited films are crystalline and present the hexagonal Würtzite ZnO phase with preferential (002) orientation. The ZnO films obtained forms aligned hexagonal nanorods, and depending on the increasing In concentration, the surface morphologies of the films are changed. The ln-doped ZnO nanorods (NRs) are well-aligned with the c-axis being perpendicular to the substrates when the ln concentration was between 0 and 2 at.%. of In, the grown films with In contents up to 4 at.%, changes in the optical band gap from 3.31 to 3.39 eV, and the blue shift in the band gap energy was attributed to the Burstein–Moss effect. The effect of In concentration on the photocurrent generated by films shows that the obtained thin films can be used as a photovoltaic material. Changes in the photocurrent response and the electronic disorder were also discussed in the light of In doping. It was found that the carrier density of IZO thin films varied between 1.06?×?1018 and 1.88?×?1018 cm?3 when the In concentration was between 0 and 4 at.%. 相似文献
998.
999.
Eric Miguel Tridas Christopher Allemang Fabian Mast J Mark Anthony Rudiger Schlaf 《Journal of mass spectrometry : JMS》2015,50(7):938-943
In this study a novel fabrication method for a radio frequency (RF) ion funnel is presented. RF ion funnels are important devices for focusing ion clouds at low vacuum conditions for mass spectrometry or deposition‐related applications. Typically, ion funnels are constructed of stainless steel plate ring electrodes with a decreasing diameter where RF and direct current potentials are applied to the electrodes to focus the ion cloud. The presented novel design is based on a flexible circuit board that serves both as the signal distribution circuit and as the electrodes of the ion funnel. The flexible circuit board is rolled into a 3D printed scaffold to create a funnel shape with ring electrodes formed by the copper electrodes of the flexible circuit board. The design is characterized in direct comparison with a conventional steel‐plate electrode design. The discussed results show that the new funnel has similar performance to the conventionally designed funnel despite much lower manufacturing costs. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
1000.
Norma K. Minar Dr. Kun Hou Christian Westermeier Dr. Markus Döblinger Dr. Jörg Schuster Fabian C. Hanusch Dr. Bert Nickel Prof. Dr. Geoffrey A. Ozin Prof. Dr. Thomas Bein 《Angewandte Chemie (International ed. in English)》2015,54(26):7577-7581
A highly‐ordered 3D covalent fullerene framework is presented with a structure based on octahedrally functionalized fullerene building blocks in which every fullerene is separated from the next by six functional groups and whose mesoporosity is controlled by cooperative self‐assembly with a liquid‐crystalline block copolymer. The new fullerene‐framework material was obtained in the form of supported films by spin coating the synthesis solution directly on glass or silicon substrates, followed by a heat treatment. The fullerene building blocks coassemble with a liquid‐crystalline block copolymer to produce a highly ordered covalent fullerene framework with orthorhombic Fmmm symmetry, accessible 7.5 nm pores, and high surface area, as revealed by gas adsorption, NMR spectroscopy, small‐angle X‐ray scattering (SAXS), and TEM. We also note that the 3D covalent fullerene framework exhibits a dielectric constant significantly lower than that of the nonporous precursor material. 相似文献