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561.
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
562.
M. Sc. Marc Duchardt Prof. Dr. Uwe Ruschewitz Prof. Dr. Stefan Adams Prof. Dr. Stefanie Dehnen Prof. Dr. Bernhard Roling 《Angewandte Chemie (International ed. in English)》2018,57(5):1351-1355
Highly conductive solid electrolytes are crucial to the development of efficient all‐solid‐state batteries. Meanwhile, the ion conductivities of lithium solid electrolytes match those of liquid electrolytes used in commercial Li+ ion batteries. However, concerns about the future availability and the price of lithium made Na+ ion conductors come into the spotlight in recent years. Here we present the superionic conductor Na11Sn2PS12, which possesses a room temperature Na+ conductivity close to 4 mS cm?1, thus the highest value known to date for sulfide‐based solids. Structure determination based on synchrotron X‐ray powder diffraction data proves the existence of Na+ vacancies. As confirmed by bond valence site energy calculations, the vacancies interconnect ion migration pathways in a 3D manner, hence enabling high Na+ conductivity. The results indicate that sodium electrolytes are about to equal the performance of their lithium counterparts. 相似文献
563.
具有高锂离子迁移数和良好可加工性能的锂快离子导体对于全固态电池的发展非常重要。然而,现有的锂快离子导体主要限制于硬质陶瓷,目前尚无柔性聚合物类型的锂快离子导体被报道。在这个工作中,我们报告了一种通过三种不同有机单体的自由基聚合反应形成的三元无规共聚单离子快离子导体(SISC)。该SISC中包含丰富的锂离子传输位点和具有阴离子锚定功能的阴离子受体。此外,三种不同单体的共聚反应带来低结晶度和低玻璃化转变温度(Tg),有利于链段运动,从而获得小的锂离子传输的活化能(Ea)。电化学测试结果表明,该SISC的室温离子电导率和锂离子迁移数分别达到1.29 mS∙cm−1和0.94。将SISC与锂金属负极和多种正极(包括LiFePO4、LiCoO2和硫化聚丙烯腈(SPAN))原位聚合,组装得到的全固态电池具有良好的电化学稳定性。其中,Li||LiFePO4全固态电池表现出高达8C的倍率性能和良好的循环寿命(在0.5C倍率下稳定循环 > 700圈)。这项工作提供了一种新颖的聚合物基快离子导体设计理念,对于发展高性能全固态电池具有重要意义。 相似文献
564.
Otaciro R. Nascimento Claudio J. Magon Jose Fernando Lima Jose Pedro Donoso Eglantina Benavente Jaime Paez Vladimir Lavayen Maria Angelica Santa Ana Guillermo Gonzalez 《Journal of Sol-Gel Science and Technology》2008,45(2):195-204
In this work we report results from continuous-wave (CW) and pulsed electron paramagnetic resonance (EPR) and proton nuclear
magnetic resonance (NMR) studies of the vanadium pentoxide xerogel V2O5:nH2O (n ≈ 1.6). The low temperature CW-EPR spectrum shows hyperfine structure due to coupling of unpaired V4+ electron with the vanadium nucleus. The analysis of the spin Hamiltonian parameters suggests that the V4+ ions are located in tetragonally distorted octahedral sites. The transition temperature from the rigid-lattice low-temperature
regime to the high temperature liquid-like regime was determined from the analysis of the temperature dependence of the hyperfine
splitting and the V4+ motional correlation time. The Electron Spin Echo Envelope Modulation (ESEEM) data shows the signals resulting from the interaction
of 1H nuclei with V4+ ions. The modulation effect was observed only for field values in the center of the EPR absorption spectrum corresponding
to the single crystals orientated perpendicular to the magnetic field direction. At least three protons are identified in
the xerogel by our magnetic resonance experiments: (I) the OH groups in the equatorial plane, (ii) the bound water molecules
in the axial V=O bond and (iii) the free mobile water molecules between the oxide layers. Proton NMR lineshapes and spin-lattice
relaxation times were measured in the temperature range between 150 K and 323 K. Our analysis indicates that only a fraction
of the xerogel protons contribute to the measured conductivity. 相似文献
565.
Quaranta A Lachaud F Herrero C Guillot R Charlot MF Leibl W Aukauloo A 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(29):8201-8211
The synthesis and characterisation of [Ru(bpy)2(PhenImHPh)]2+ where PhenImHPh represents the 2-(3,5-di-tert-butylphenyl)imidazo[4,5-f][1,10]phenanthroline ligand are described. The compounds issued from the three different protonic states of the imidazole ring [Ru(bpy)2(PhenImPh)]+ (I), [Ru(bpy)2(PhenImHPh)]2+ (II) and [Ru(bpy)2(PhenImH2Ph)]3+ (III) were isolated and spectroscopically characterised. The X-ray structures of [Ru(bpy)2(PhenImPh)](PF6)H2O.6 MeOH, [Ru(bpy)2(PhenImHPh)](NO3)2H2O.3 MeOH and [Ru(bpy)2(PhenImH2Ph)](PF6)3 5 H2O are reported. Electrochemical data obtained on these complexes indicate almost no potential shift for the Ru(III/II) redox couple. Therefore a Coulombic effect between the imidazole ring and the metal centre can be ruled out. The monooxidised forms of I and II have been characterised by EPR spectroscopy and are reminiscent of the presence of a radical species. The emission properties of the parent compound [Ru(bpy)2(PhenImHPh)]2+ were studied as a function of pH and both the lifetimes and intensities decreased upon deprotonation. Photophysical properties, investigated in the absence and presence of an electron acceptor (methylviologen), were distinctly different for the three compounds. Transient absorption features indicate that unique excited states are involved. Theoretical data obtained from DFT calculations in water on the three protonic forms are presented and discussed in the light of the experimental results. 相似文献
566.
Investigations of the electrotransport and thermodynamic properties of CsH2PO4 and composite systems (1 ? x)CsH2PO4?xSiO2 (x=0–0.5) synthesized on the basis of silicon dioxide with different magnitude of the specific surface area are conducted while varying the partial pressure of water vapor. It is demonstrated that the superionic phase transition, which is observed in CsH2PO4 at a temperature of 230°C, has nothing to do with the process of dehydration. A strong surface interaction of the salt with the matrix is discovered in composites of different compositions synthesized on the basis of uniformly porous silicon dioxides with specific surface areas of 41–520 m2 g?1 and the value of pH ~7. The interaction is found to lead to dehydration and to small values of conductivity in the systems heated to temperatures in excess of 230°C. An analysis of the dehydration products is conducted and conditions conducive to the existence of phases with certain compositions are determined. 相似文献
567.
Yunfei Cheng Hailei Zhao Deqiang Teng Fushen Li Xionggang Lu Weizhong Ding 《Journal of membrane science》2008
BaCo0.7Fe0.3−xNbxO3−δ (BCFN, x = 0–0.2) were prepared by the conventional solid state reaction process. The crystal structure, electrical conductivity and oxygen desorption property were studied by X-ray diffraction (XRD), different thermal analysis (DTA), four-terminal direct current conductivity and oxygen temperature programmed desorption (O2-TPD), respectively. At x = 0.08–0.20, BCFN have a cubic perovskite structure, while it exhibits the hexagonal structure for x = 0.00 and the mixed phases of cubic perovskite with trace amount of hexagonal for x = 0.05. BCFN shows good structure stability in 5%H2 + Ar reducing atmosphere, and it is enhanced with the increased Nb-doping content. The electrical conductivity of BCFN increases with increasing temperature and decreases with the Nb substitution content for iron. BCFN exhibits a p-type semiconductor and obeys the thermally activated small polarons hopping mechanism. The oxygen fluxes increase with the working temperature and the COG flow rate, but decrease with increasing Nb content. The flux of BCFN (x = 0.08) with 1.0 mm thickness membrane reaches 25.77 ml min−1 cm−2 at 875 °C, higher than most of the reported materials. 相似文献
568.
Dense mixed proton and electron conducting membrane made of BaCe0.95Nd0.05O3-δ(BCNd5)was prepared by pressing followed by sintering.X-ray diffraction(XRD)was used to characterize the phase structure of both the powder and the sintered membranes.The microstructure of the sintered membranes was studied by scanning electron microscopy(SEM).Hydrogen permeation through the BCNd5 membrane was studied using a high temperature permeator.The hydrogen permeation fluxes under wet conditions are higher than those under dry conditions,which is due to H hopping via surface OH groups.At 925℃,a hydrogen permeation flux of 0.02 mL/min cm2 was obtained under wet condition.which recommends BCNd5 as a potential material for hydrogen-selective membranes. 相似文献
569.
570.
Ba(Pr1−xZrx)1−yYyO3−δ materials were obtained by a two-step process of mechanical activation followed by annealing at 1250 °C. Guidelines for correlations between structure and composition, and their role on stability were characterised as a function of atmosphere, with special emphasis on degradation by carbonation in CO2-rich atmospheres, or upon redox changes. The role of humidity on these degradation processes was also analysed by taking into account differences between wet and dry atmospheres with regards to the onset of secondary phases and structural changes. Thermodynamic calculations were used to predict 2-phase and 3-phase equilibria in contact with CO2-rich atmospheres and to obtain corresponding stability diagrams. The thermodynamic calculations were also used as guidelines for the progress of carbonation in isothermal conditions, and also with variable temperature, namely on cooling carbonate free materials from high temperatures, or on re-heating under CO2. 相似文献