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111.
Diffusion of monatomic guest species within confined media has been understood to a good degree due to investigations carried
out during the past decade and a half. Most guest species that are of industrial relevance are actually polyatomics such as,
for example, hydrocarbons in zeolites. We attempt to investigate the influence of non-spherical nature of guest species on
diffusion. Recent molecular dynamics (MD) simulations of motion of methane in NaCaA and NaY, benzene in NaY and one-dimensional
channels AlPO4−5, VPI−5 and carbon nanotube indicate interesting insights into the influence of the host on rotational degrees of freedom
and orientational properties. It is shown that benzene in one-dimensional channels where the levitation parameter is near
unity exhibits translational motion opposite to what is expected on the basis of molecular anisotropy. Rotational motion of
benzene also possesses rotational diffusivities aroundC
6
and C2axes opposite to what is expected on the basis of molecular geometry. Methane shows orientational preference for 2+ 2 or 1
+ 3 depending on the magnitude of the levitation parameter. 相似文献
112.
113.
Let 1 ≤ p ≤ ∞. A subset K of a Banach space X is said to be relatively p ‐compact if there is an 〈xn 〉 ∈ ls p (X) such that for every k ∈ K there is an 〈αn 〉 ∈ lp ′ such that k = σ∞n=1 αn xn . A linear operator T: X → Y is said to be p ‐compact if T (Ball (X)) is relatively p ‐compact in Y. The set of all p ‐compact operators Kp (X, Y) from X to Y is a Banach space with a suitable factorization norm κp and (Kp , κp ) is a Banach operator ideal. In this paper we investigate the dual operator ideal (Kd p , κd p ). It is shown that κd p (T) = πp (T) for all T ∈ B (X, Y) if either X or Y is finite‐dimensional. As a consequence it is proved that the adjoint ideal of Kd p is Ip ′, the ideal of p ′‐integral operators. Further, a composition/decomposition theorem Kd p = Πp K is proved which also yields that (Πmin p )inj = Kd p . Finally, we discuss the density of finite rank operators in Kd p and give some examples for different values of p in this respect. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
114.
A scheme to execute an n-bit Deutsch-Jozsa (DJ) algorithm using n qubits has been implemented for up to three qubits on an NMR quantum computer. For the one- and the two-bit Deutsch problem,
the qubits do not get entangled, and the NMR implementation is achieved without using spin-spin interactions. It is for the
three-bit case, that the manipulation of entangled states becomes essential. The interactions through scalar J-couplings in NMR spin systems have been exploited to implement entangling transformations required for the three bit DJ algorithm. 相似文献
115.
Anil Kumar 《Journal of Chemical Sciences》1986,97(1):1-7
The distribution of nickel and cobalt species has been computed, based on the pH-dependent model of Zirino and Yamamoto. The
media used in the pH range of 7 to 9 are natural waters like fresh water, sea water and a mixture of them at different compositions,
at 25°C temperature and 1 atm pressure. In fresh water, both nickel and cobalt dominate as free cations at lower pH, and as
carbonato complexes at higher pH. In sea water, chloro complexes are significant. In mixtures of the two kinds of water, as
might be found in a totally mixed estuary, chloro complexes are important, varying slowly with pH. Sea water plays an important
role in complexation. The present results are in excellent agreement with experimental data obtained by the resin exchange
method. 相似文献
116.
Raphaël Trouillon Zachary Combs Bhavik Anil Patel Danny O’Hare 《Electrochemistry communications》2009,11(7):1409-1413
Stability of sensors in biosamples is a critical issue and can be mitigated by membranes. The effect of different membranes (Nafion, cellulose acetate, chitosan, fibronectin, PSS/PL) on the electrochemistry of an outer-sphere redox couple (ruthenium II/III hexaammine) and on the electrocatalytic reduction of dissolved oxygen are described. Biofouling has been induced by albumin solutions. Results demonstrate good performances of fibronectin in all situations investigated. Other membranes do not provide a satisfactory protection from biofouling and some of them, PSS/PL in particular, seriously disturb electrochemical mechanisms. 相似文献
117.
Anjan Biswas Abhijit Bandyopadhyay Nikhil K. Singha Anil K. Bhowmick 《Journal of polymer science. Part A, Polymer chemistry》2008,46(24):8023-8040
Direct sulfonation and styrene‐mediated sulfonation were carried out onto metallocene‐based poly(ethylene‐co‐octene) (POE) and poly(ethylene‐co‐butene) (PBE) elastomers to impart polarity on the completely nonpolar rubbery matrices and to prepare a new class of elastomer. The influence of styrene‐grafting and pendant chain length on the degree of sulfonation was also studied. The effects of sulfonation, styrene grafting and styrene‐mediated sulfonation at their optimized levels on various physicomechanical properties were thoroughly investigated, and the resultant properties were correlated with structures of the modified elastomers. Higher extent of sulfonic acid groups were introduced through direct sulfonation in comparison with the styrene‐mediated sulfonation, whereas better thermal and mechanical properties were obtained through styrene‐mediated sulfonation in comparison with the direct sulfonation process. PBE had shown higher degree of sulfonation and percentage grafting than POE. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 8023–8040, 2008 相似文献
118.
Temperature dependent molar conductances and fluidities of bisulfate and ethyl sulfate anion-based ionic liquids were measured. The extent of dissociation of the ionic liquids was estimated from the Walden plot in term of ionicity. The ionicity mainly depends on the magnitude of Coulombic forces, altered by the anion’s Lewis basicity. Aqueous solutions of aprotic ionic liquids, in general, possesses ionicity in the range of ≈70–99%. This article reveals that the substitution of the anion by bisulfate and ethylsulfate reduces the ionicity of aqueous solution of these ionic liquids to the range of 10–37%. This is very close to that exhibited by some of the protic ionic liquids and phosphonium based ionic liquids with sweetner anions. The concentration dependent molar conductance of these ionic liquids has been fitted to Mahiuddin and Ismail’s equation. To our surprise, the molar conductances of bisulfate-based aprotic ionic liquids are remarkably high, even though these ionic liquids possess lower ionicity. 相似文献
119.
In the Ni(II)–S(IV)–O2 system in the region of pH > 8.4, both Ni(II) and S(IV) are simultaneously autoxidized, and when sulfur is consumed fully NiOOH precipitates. At pH > 8.4, ethanol has no effect on the rate, whereas ammonia strongly inhibits the reaction when pH > 7.0. The kinetics of the reaction, in both the presence and the absence of ethanol, is defined by the rate law where k is the rate constant, KO is the equilibrium constant for the adsorption of O2 on ? Ni(OH)2 particle surface. In ammonia buffer, the factor F is defined by where K, KOH, K1, K2, K3, and K4 are the stability constants of NiSO3, NiOH+, Ni(NH3)2+, Ni(NH3), Ni(NH3), and Ni(NH3), respectively. In unbuffered medium, the factor F reduces to The values of k and Ksp were found to be (1.3 ± 0.08) × 10?1 s?1 and (4.2 ± 3.5) × 10?16, respectively, at 30°C. A nonradical mechanism that assumes the adsorption of both SO32? and O2 on the ? Ni(OH)2 particle surface has been proposed. At pH ≤ 8.2, Ni(II) displays no catalytic activity for sulfur(IV)‐autoxidation and it is also not oxidized to NiOOH. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 464–478, 2010 相似文献
120.
JPC – Journal of Planar Chromatography – Modern TLC - A rapid and reliable high-performance thin-layer chromatographic method has been established for analysis of prednisolone in a... 相似文献