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Serhiy Z. Malynych Alexander Tokarev Stephen Hudson John Ballato Konstantin G. Kornev 《Journal of magnetism and magnetic materials》2010,322(14):1894-1897
Imaging of micro- and nanofluidics is a challenge since the size of the channels is so small that the installment of additional optical and mechanical switches is very difficult. The size of the device and associated increase in viscous dissipation constitute another constraint. In response to these limitations, this work proposes and demonstrates the manipulation of light by adding a functional lens to control the light on demand. In the present work, this lens is realized by filling a hollow fiber with a colloid of superparamagnetic Fe3O4 nanoparticles. When the propagation of light is perpendicular to the magnetic field, this lens stretches the circular beam into a ribbon yielding a larger visible area. Potentially, one can apply a rotating magnetic field thus illuminating a larger spot size or creating other beam geometries. Such composite fibers might also be of value for Faraday isolation and other magneto-optic effects in optical fibers. 相似文献
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The notion of dimension as a quantitative characteristic of space geometry is discussed. It is supposed that hadrons created in interactions between particles and nuclei can be considered sets of points possessing fractal properties in the three-dimensional phase space (p T , η, ?). The Hausdorff-Besicovich dimension D F is considered the most natural characteristic for determining the fractal dimension. Different methods for determining the fractal dimension are compared: box counting (BC), P-adic coverage (PaC), and system of equations of P-adic coverage (SePaC). A procedure for choosing optimum values of parameters of the considered methods is presented. These parameters are shown to be able to reconstruct the fractal dimension D F , number of levels N lev, and fractal structure with maximal efficiency. The features of the PaC- and SePaC-methods in the analysis of fractals with independent branching are noted. 相似文献
36.
Ihor Ketsman Ya.B. Losovyj A. Sokolov Zhenjun Wang J.I. Brand 《Applied Surface Science》2008,254(14):4308-4312
An increase in the density of states between the oxygen 2p bands and the Fermi level is seen with increasing Gd concentrations. In addition, for the Gd-doped HfO2 films, the Gd 4f photoexcitation peak at 5.5 eV below the valence band maximum was identified using resonant photoemission. Electrical measurements show pronounced rectification properties for lightly-doped Gd:HfO2 films on p-Si and for heavily-doped Gd:HfO2 films on n-Si, suggesting a crossover from n-type to p-type behavior with increasing doping level. In addition, there is an increase in the reverse bias current with neutron irradiation. 相似文献
37.
Ihor R. Muts Vasyl I. Zaremba Dr. Ute Ch. Rodewald Dipl.‐Ing. Rainer Pöttgen Prof. Dr. 《无机化学与普通化学杂志》2008,634(1):56-60
New auride Ca3Au3In was synthesized from the elements in a sealed tantalum tube in a high‐frequency furnace. Ca3Au3In was investigated by X‐ray powder and single crystal diffraction: ordered Ni4B3 type, Pnma, a = 1664.1(6), b = 457.3(2), c = 895.0(3) pm, wR2 = 0.0488, 1361 F2 values, and 44 variables. The three crystallographically independent boron positions of the Ni4B3 type are occupied by the gold atoms, while the four nickel sites are occupied by calcium and indium in an ordered manner. All gold atoms have trigonal prismatic coordination, i.e. Ca6 prisms for Au1 and Au2 and Ca4In2 prisms for Au3. While the Au3 atoms are isolated, we observe Au1–Au1 and Au2–Au2 zig‐zag chains at Au–Au distances of 292 and 284 pm. These slabs resemble the CrB type structure of CaAu. Consequently Ca3Au3In can be considered as a ternary auride. Together the Au2, Au3 and indium atoms build up a three‐dimensional [Au2In] polyanionic network (281–293 pm Au–In) in which the chains of Au1 centered trigonal prisms are embedded. The crystal chemical similarities with the structures of Ni4B3, CaAuIn, and CaAu are discussed. 相似文献
38.
K. L. Tokarev M. A. Kiskin A. A. Sidorov G. G. Aleksandrov V. N. Ikorskii I. P. Suzdalev V. M. Novotortsev I. L. Eremenko 《Russian Chemical Bulletin》2008,57(6):1209-1214
The mononuclear complexes (η3-terpy)M(Piv)2·MeCN (M = Fe
ii
(3) and Co
ii
(4), and Piv is the pivalate anion) were synthesized by the reactions of polymeric iron(ii) and cobalt(ii) pivalates with 2,2′:6′,2″-terpyridine (terpy). The oxidation of compound 3 affords the pentanuclear heterospin iron(ii,iii) complex (η3-terpy)Fe5(μ4-O)(μ3-OH)(μ-OH)2(μ-Piv)7(η1-Piv)2 (5). All compounds were characterized by X-ray diffraction.
Dedicated to the 90th anniversary of the L. Ya. Karpov Institute of Physical Chemistry.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1186–1190, June, 2008. 相似文献
39.
Motornov M Sheparovych R Tokarev I Roiter Y Minko S 《Langmuir : the ACS journal of surfaces and colloids》2007,23(1):13-19
Hybrid brushes composed of two liquid polymers, poly(dimethylsiloxane) (PDMS) and a highly branched ethoxylated polyethylenimine (EPEI), were synthesized on Si wafers by the "grafting to" method and by applying a combinatorial approach (fabrication of gradient brushes). The combinatorial approach revealed a strong effect of "layer assisted tethering", which allowed us to synthesize hybrid brushes twice as thick as the reference homopolymer brushes. The hybrid brushes are stable thin films that can rapidly and reversibly switch between hydrophilic and hydrophobic states in water and air, respectively. The switching in water affects a rapid release of amino functional groups which can be used to regulate adhesion and reactivity of the material. The switching in air rapidly returns the brush to a hydrophobic state. The hybrid brush is hydrophilic because of two mechanisms: (1) exposure of EPEI chains to the brush-water interface under water, and (2) retention of some fraction of water via swollen EPEI chains (the EPEI chains swell by 2-3 times), which are conserved by a PDMS cap in air. The hybrid brush is wettable under water, and at the same time, the brush is nonwettable in air because water droplets are trapped in a metastable state when the water contact angle is above 90 degrees . 相似文献
40.
The electrochemical gate based on a chemical signal-responsive membrane was assembled on a Au electrode surface. The polyelectrolyte gel membrane was capable to bind cholesterol because of the hydrogen bonding between cholesterol and the polymer backbone resulting in the gel swelling. The membrane channels were reversibly closed and opened upon addition and washing out cholesterol, respectively. Thus, the electrochemical process of a soluble redox probe, [Fe(CN)(6)](3-/4-), at the membrane-modified electrode was reversibly switched "on-off" by the cyclic addition and washing out cholesterol. The electrochemical reaction was also tuned by the variation of the concentration of the added cholesterol that controlled the extent of the channels closing. The switchable and tuneable operation of the chemically controlled electrochemical gate was characterized by Faradaic impedance spectroscopy and atomic force microscopy, indicating that the extent of the pores opening and closing is controlled by the concentration of the membrane-associated cholesterol. The chemical-responsive electrochemical gate was suggested to be a part of future biochemical/electrochemical systems with logic operations. 相似文献