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91.
Palacios MA Mota AJ Ruiz J Hänninen MM Sillanpää R Colacio E 《Inorganic chemistry》2012,51(13):7010-7012
The first examples of pentanuclear heterotrimetallic [(LnNi)(2)Ru] [Ln(3+) = Gd (1) and Dy (2)] complexes were prepared and magnetostructurally characterized. They exhibit ferromagnetic interactions, leading to a high-magnetic-moment ground state. 相似文献
92.
Gabriel P. Paternain Mikko Salo Gunther Uhlmann 《Geometric And Functional Analysis》2012,22(5):1460-1489
We show that for a simple surface with boundary the attenuated ray transform in the presence of a unitary connection and a skew-Hermitian Higgs field is injective modulo the natural obstruction for functions and vector fields. We also show that the connection and the Higgs field are uniquely determined by the scattering relation modulo a gauge transformation. The proofs involve a Pestov type energy identity for connections together with holomorphic gauge transformations which arrange the curvature of the connection to have definite sign. 相似文献
93.
Katja Lappalainen Mikko Manninen Ville Alopaeus Juhani Aittamaa John Dodds 《Transport in Porous Media》2009,77(1):17-40
Capillary pressure is considered in packed-beds of spherical particles. In the case of gas–liquid flows in packed-bed reactors,
capillary pressure gradients can have a significant influence on liquid distribution and, consequently, on the overall reactor
performance. In particular, capillary pressure is important for non-uniform liquid distribution, causing liquid spreading
as it flows down the packing. An analytical model for capillary pressure–saturation relation is developed for the pendular
and funicular regions and the factors affecting capillary pressure in the capillary region are discussed. The present model
is compared to the capillary pressure models of Grosser et al. (AIChE J., 34:1850–1860, 1988) and Attou and Ferschneider (Chem.
Eng. Sci., 55:491–511, 2000) and to the experiments of Dodds and Srivastava (Part Part Syst. Charact., 23:29–39, 2006) and
Dullien et al. (J. Colloid Interface Sci., 127:362–372, 1989). The non-homogeneity of real packings is considered through
particle size and porosity distributions. The model is based on the assumption that the particles are covered with a liquid
film, which provides hydrodynamic continuity. This makes the model more suitable for porous or rough particles than for non-porous
smooth particles. The main improvements of the present model are found in the pendular region, where the liquid dispersion
due to capillary pressure gradients is most significant. The model can be used to improve the hydrodynamic models (e.g., CFD
and cellular automata models) for packed-bed reactors, such as trickle-bed reactors, where gas, liquid, and solid phases are
present. Models for such reactors have become quite common lately (Sáez and Carbonell, AIChE J., 31:52–62, 1985; Holub et al.,
Chem. Eng. Sci, 47, 2343–2348, 1992; Attou et al., Chem. Eng. Sci., 54:785–802, 1999; Iliuta and Larachi, Chem. Eng. Sci.,
54:5039–5045, 1999, IJCRE 3:R4, 2005; Narasimhan et al., AIChE J., 48:2459–2474, 2002), but they still lack proper terms causing
liquid dispersion. 相似文献
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Vladimir A. Sivakov Dr. Katja Höflich Michael Becker Dr. Andreas Berger Dr. Thomas Stelzner Dr. Kai‐Erik Elers Dr. Viljami Pore Dr. Mikko Ritala Prof. Dr. Silke H. Christiansen Dr. 《Chemphyschem》2010,11(9):1995-2000
A new method to prepare plasmonically active noble metal nanostructures on large surface area silicon nanowires (SiNWs) mediated by atomic layer deposition (ALD) technology has successfully been demonstrated for applications of surface‐enhanced Raman spectroscopy (SERS)‐based sensing. As host material for the plasmonically active nanostructures we use dense single‐crystalline SiNWs with diameters of less than 100 nm as obtained by a wet chemical etching method based on silver nitrate and hydrofluoric acid solutions. The SERS active metal nanoparticles/islands are made from silver (Ag) shells as deposited by autometallography on the core nanoislands made from platinum (Pt) that can easily be deposited by ALD in the form of nanoislands covering the SiNW surfaces in a controlled way. The density of the plasmonically inactive Pt islands as well as the thickness of noble metal Ag shell are two key factors determining the magnitude of the SERS signal enhancement and sensitivity of detection. The optimized Ag coated Pt islands on SiNWs exhibit great potential for ultrasensitive molecular sensing in terms of high SERS signal enhancement ability, good stability and reproducibility. The plasmonic activity of the core‐shell Pt//Ag system that will be experimentally realized in this paper as an example was demonstrated in numerical finite element simulations as well as experimentally in Raman measurements of SERS activity of a highly diluted model dye molecule. The morphology and structure of the core‐shell Pt//Ag nanoparticles on SiNW surfaces were investigated by scanning‐ and transmission electron microscopy. Optimized core–shell nanoparticle geometries for maximum Raman signal enhancement is discussed essentially based on the finite element modeling. 相似文献
96.
Marjo Kettunen Riitta J. Silvennoinen Nikolay Houbenov Antti Nykänen Janne Ruokolainen Jani Sainio Viljami Pore Marianna Kemell Mikael Ankerfors Tom Lindström Mikko Ritala Robin H. A. Ras Olli Ikkala 《Advanced functional materials》2011,21(3):510-517
Chemical vapor deposition of a thin titanium dioxide (TiO2) film on lightweight native nanocellulose aerogels offers a novel type of functional material that shows photoswitching between water‐superabsorbent and water‐repellent states. Cellulose nanofibrils (diameters in the range of 5–20 nm) with native crystalline internal structures are topical due to their attractive mechanical properties, and they have become relevant for applications due to the recent progress in the methods of their preparation. Highly porous, nanocellulose aerogels are here first formed by freeze‐drying from the corresponding aqueous gels. Well‐defined, nearly conformal TiO2 coatings with thicknesses of about 7 nm are prepared by chemical vapor deposition on the aerogel skeleton. Weighing shows that such TiO2‐coated aerogel specimens essentially do not absorb water upon immersion, which is also evidenced by a high contact angle for water of 140° on the surface. Upon UV illumination, they absorb water 16 times their own weight and show a vanishing contact angle on the surface, allowing them to be denoted as superabsorbents. Recovery of the original absorption and wetting properties occurs upon storage in the dark. That the cellulose nanofibrils spontaneously aggregate into porous sheets of different length scales during freeze‐drying is relevant: in the water‐repellent state they may stabilize air pockets, as evidenced by a high contact angle, in the superabsorbent state they facilitate rapid water‐spreading into the aerogel cavities by capillary effects. The TiO2‐coated nanocellulose aerogels also show photo‐oxidative decomposition, i.e., photocatalytic activity, which, in combination with the porous structure, is interesting for applications such as water purification. It is expected that the present dynamic, externally controlled, organic/inorganic aerogels will open technically relevant approaches for various applications. 相似文献
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100.
We formulate a sufficient condition for the existence of a consistent price system (CPS), which is weaker than the conditional full support condition (CFS). We use the new condition to show the existence of CPSs for certain processes that fail to have the CFS property. In particular this condition gives sufficient conditions, under which a continuous function of a process with CFS admits a CPS, while the CFS property might be lost. 相似文献