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711.
Let S′ be the class of tempered distributions. For ƒ ∈ S′ we denote by J
−α
ƒ the Bessel potential of ƒ of order α. We prove that if J
−α
ƒ ∈ BMO, then for any λ ∈ (0, 1), J
−α
(f)λ ∈ BMO, where (f)λ = λ−n
f(φ(λ−1)), φ ∈ S. Also, we give necessary and sufficient conditions in order that the Bessel potential of a tempered distribution of order
α > 0 belongs to the VMO space. 相似文献
712.
Marc de la Asunción Luis Castillo Juan Fernández-Olivares Oscar García-Pérez Antonio González Francisco Palao 《Annals of Operations Research》2007,155(1):391-415
An interleaved integration of the planning and scheduling process is presented with the idea of including soft temporal constraints
in a partial order planner that is being used as the core module of an intelligent decision support system for the design
forest fire fighting plans. These soft temporal constraints have been defined through fuzzy sets. This representation allows
us a flexible representation and handling of temporal information. The scheduler model consists of a fuzzy temporal constraints
network whose main goal is the consistency checking of the network associated to each partial order plan. Moreover, we present
a model of estimating this consistency, and show the monitoring and rescheduling capabilities of the system. The resulting
approach is able to tackle problems with ill defined knowledge, to obtain plans that are approximately consistent and to adapt
the execution of plans to unexpected delays.
This work has been partially supported under the project MCyT TIC2002-04146-C05-2 and the contract NET033957 with the Andalusian
Regional Government. 相似文献
713.
In the present paper, the ionic conductivity and the dielectric relaxation properties on the poly(vinyl alcohol)-CF3COONH4 polymer system have been investigated by means of impedance spectroscopy measurements over wide ranges of frequencies and
temperatures. The electrolyte samples were prepared by solution casting technique. The temperature dependence of the sample’s
conductivity was modeled by Arrhenius and Vogel-Tammann-Fulcher (VTF) equations. The highest conductivity of the electrolyte
of 3.41×10 − 3 (Ωcm) − 1 was obtained at 423 K. For these polymer system two relaxation processes are revealed in the frequency range and temperature
interval of the measurements. One is the glass transition relaxation (α-relaxation) of the amorphous region at about 353 K and the other is the relaxation associated with the crystalline region
at about 423 K. Dielectric relaxation has been studied using the complex electric modulus formalism. It has been observed
that the conductivity relaxation in this polymer system is highly non-exponential. From the electric modulus formalism, it
is concluded that the electrical relaxation mechanism is independent of temperature for the two relaxation processes, but
is dependent on composition. 相似文献
714.
Quírico A. Castillo José M. Padrón Lukasz Wojtas Mehdi Keramane Evelyn A. Germosén 《Tetrahedron letters》2019,60(25):1640-1642
A new germacrane-type sesquiterpene lactone, koanolide A (1), was isolated from the aerial parts of Koanophyllon gibbosum. The new structure was elucidated using spectroscopic and spectrometric data analyses, including 1D and 2D NMR. The absolute configuration of compound 1 was established by X-ray crystallography. The antiproliferative activity of 1 was studied in a panel of six representative human solid tumor cell lines and showed GI50 values ranging from 0.34 to 20 μM. 相似文献
715.
An experimental study was conducted to examine the effects of surface roughness and adverse pressure gradient (APG) on the
development of a turbulent boundary layer. Hot-wire anemometry measurements were carried out using single and X-wire probes in all regions of a developing APG flow in an open return wind tunnel test section. The same experimental conditions
(i.e., T
∞, U
ref, and C
p) were maintained for smooth, k
+ = 0, and rough, k
+ = 41–60, surfaces with Reynolds number based on momentum thickness, 3,000 < Re
θ < 40,000. The experiment was carefully designed such that the x-dependence in the flow field was known. Despite this fact, only a very small region of the boundary layer showed a balance
of the various terms in the integrated boundary layer equation. The skin friction computed from this technique showed up to
a 58% increase due to the surface roughness. Various equilibrium parameters were studied and the effect of roughness was investigated.
The generated flow was not in equilibrium according to the Clauser (J Aero Sci 21:91–108, 1954) definition due to its developing nature. After a development region, the flow reached the equilibrium condition as defined
by Castillo and George (2001), where Λ = const, is the pressure gradient parameter. Moreover, it was found that this equilibrium condition can be used
to classify developing APG flows. Furthermore, the Zagarola and Smits (J Fluid Mech 373:33–79, 1998a) scaling of the mean velocity deficit, U
∞δ*/δ, can also be used as a criteria to classify developing APG flows which supports the equilibrium condition of Castillo
and George (2001). With this information a ‘full APG region’ was defined. 相似文献
716.
Geldbach TJ Zhao D Castillo NC Laurenczy G Weyershausen B Dyson PJ 《Journal of the American Chemical Society》2006,128(30):9773-9780
The biphasic hydrosilylation of 1-hexadecene with siloxane B9800 in a range of ionic liquids is reported. Of the ionic liquids tested, [C(4)py][BF(4)] and [C(4)-3-pic][BF(4)] offer the optimum compromise between activity and catalyst retention. Several platinum precatalysts were screened, of which K(2)PtCl(4) and Pt(PPh(3))(4) were found to give the best performance; the former provides the highest activity, while the latter offers higher stability and recyclability, and depending on the conditions, both can afford either homogeneous or soluble nanoparticle catalysts as the active species. A number of reaction parameters were varied, and the effects of oxygen, water, and chloride impurities on the reaction were studied. In addition, since nanoparticle catalysts were observed, various strategies to stabilize nanoparticles were screened, but none of them resulted in a superior catalytic system. 相似文献
717.
Beobide G Castillo O Luque A García-Couceiro U García-Terán JP Román P 《Inorganic chemistry》2006,45(14):5367-5382
The synthesis, crystal structure, and magnetic behavior of nine transition-metal complexes based on pyrazine-2,5-dicarboxylato (pz25dc) and pyrazine-2,3-dicarboxylato (pz23dc) ligands are reported. The pz25dc ligand displays a bis-bidentate coordination mode, with the carboxylate groups almost coplanar with the pyrazine ring, to afford polymeric 1-D chains [Mn(1), Fe(2), Zn(3), and Cu(4 and 5)] and discrete dimeric entities [Mn(6)] when the 1,10-phenanthroline (phen) blocking ligand is used to avoid further polymerization. The nonplanar pz23dc ligand chelates to a unique copper center, while it bridges another one or two metal centers via the remaining carboxylate group, leading to 1-D polymeric chains (7), ladder chains (8), and sheets (9). The crystal packing of the metal-organic frameworks of compounds 4-9 generates voids which are occupied by assembled water molecules. The different water cluster patterns (tapes, four-membered discrete rings, and chains for compounds 6, 8, and 9, respectively) and their role in the cohesiveness of supramolecular architectures are analyzed. Thermogravimetric and variable-temperature X-ray powder diffraction studies have revealed the occurrence of reversible dehydration processes in compounds 6, 8, and 9. Furthermore, the magnetic behavior of these compounds has been studied in order to analyze the capability of the pyrazine ring to transmit magnetic interactions. 相似文献
718.
Carlos?DíazEmail author Paola?Castillo Maria?Luisa?Valenzuela 《Journal of Cluster Science》2005,16(4):515-522
Thermal treatment in air of the organometallic polymer
(1) results in the formation of nanometer-size metal oxide particles. Cr particles in the 35–85 nm range, mostly 54 nm, immersed
in an phosphorus oxides matrix were found. ATG studies in air suggest that the formation of the nanostructures occurs in four
steps, the first involving loss of the carbonyl groups of the Cr(CO)5 fragment. The following steps involve the oxidation of the organic matter and finally the oxidation of the chromium to give
the pyrolytic product. The use of these kinds of organometallic polymers as precursors for a general and potential new route
to materials having metal/metal oxide nanostructures is discussed. 相似文献
719.
Rodríguez-Morales S Zhou X Salari H Castillo R Breen PJ Compadre CM 《Journal of chromatography. A》2005,1062(2):285-289
Cetylpyridinium chloride (CPC) has been found to be effective in reducing microbial contamination in apples. A sensitive and specific HPLC method was developed to determine CPC residues in apples treated with CPC. This method involves ion exchange solid-phase extraction, and the use of stearylpyridinium chloride (SPC) as internal standard. Limit of quantitation, was 0.5 microg/ml of CPC for the apple ethanolic extracts. The observed residues in apple (2.35-4.35 microg/g of apple) were lower than those previously reported for chicken and beef. The method is specific, sensitive, reproducible and accurate. 相似文献
720.
Paul Castillo Bernardo Cockburn Dominik Schö tzau Christoph Schwab. 《Mathematics of Computation》2002,71(238):455-478
We study the convergence properties of the -version of the local discontinuous Galerkin finite element method for convection-diffusion problems; we consider a model problem in a one-dimensional space domain. We allow arbitrary meshes and polynomial degree distributions and obtain upper bounds for the energy norm of the error which are explicit in the mesh-width , in the polynomial degree , and in the regularity of the exact solution. We identify a special numerical flux for which the estimates are optimal in both and . The theoretical results are confirmed in a series of numerical examples.