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71.
Melinda VargováGustav Plesch Ulrich F. Vogt Miroslav ZahoranMichal Gorbár Karol Jesenák 《Applied Surface Science》2011,257(10):4678-4684
TiO2 thick films deposited on macroporous reticulated Al2O3 foams with pore size of 10 ppi and 15 ppi were prepared using dip coating from slurries of Aeroxide® P25 nanopowder and precipitated titania. All prepared films have sufficiently good adhesion to the surface of the substrate also in case of strongly cracked films. No measurable release of deposited TiO2 after repeated photocatalytic cycles was observed. The photocatalytic activity was characterized as the rate of mineralization of aqueous phenol solution under irradiation of UVA light by TOC technique. The best activity was obtained with Aeroxide® P25 coated Al2O3 foam with the pore size of 10 ppi, annealed at 600 °C. The optimal annealing temperature for preparation of films from precipitated titania could be determined at 700 °C. Films prepared by sol-gel deposition technique were considerably thinner compared to coatings made of suspensions and their photocatalytic activity was significantly smaller. 相似文献
72.
We describe an electoral system for distributing seats in a parliament. It gives proportionality for the political parties and close to proportionality for constituencies. The system suggested here is a version of the system used in Sweden and other Nordic countries with permanent seats in each constituency and adjustment seats to give proportionality on the national level. In the national election of 2010 the current Swedish system failed to give proportionality between parties. We examine here one possible cure for this unwanted behavior. The main difference compared to the current Swedish system is that the number of adjustment seats is not fixed, but rather dynamically determined to be as low as possible and still insure proportionality between parties. 相似文献
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74.
Feichtinger Gustav Andreas J. Novak 《Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences》2013,19(3):197-211
In this paper we present a simple time-continuous behavioural model of habit formation. Addictive behaviour is damped by a threshold which adapts itself to the habit. This adaptive behaviour of the threshold may lead to periodic fluctuations of the consumption rate, the habit and the threshold. It turns out that both a low adjustment rate of the threshold as well as a steep consumption function favour oscillatory patterns. 相似文献
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77.
Márcio D. Lima Mônica J. de Andrade Viera Skákalová Felipe Nobre Carlos P. Bergmann Siegmar Roth 《固体物理学:研究快报》2007,1(4):165-167
A method for the production of transparent carbon nanotube networks (CNTNs) over transparent substrates was developed. In this method, CNTNs were grown directly in the target surface by applying the catalyst in specific zones of the substrate through lithographic techniques. The networks can be also transferred from the original substrate to other surfaces. The newly grown carbon nanotubes have a very high aspect ratio (>50000). Thus far, networks with an optical transmittance of 94% at 550 nm and a surface resistivity of 3.6 kΩ/sq have been produced. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
78.
It is shown that the electron temperature in low pressure discharges can be estimated from the drift velocity of the ions towards the wall. Velocity measurements by resonant laser light scattering lead to electron temperatures consistent with such values obtained by probe measurements. 相似文献
79.
V. Šepelák I. Bergmann A. Feldhoff P. Heitjans F. J. Litterst K. D. Becker 《Hyperfine Interactions》2005,165(1-4):81-87
The single-step synthesis of nanosized MgFe2O4 and NiFe2O4 via mechanochemical processing of binary oxide precursors is followed by 57Fe Mössbauer spectroscopy. Quantitative information is provided on both ionic and spin configurations in mechanosynthesized spinels. The response of the mechanosynthesized ferrite nanoparticles to changes in temperature is also studied. 相似文献
80.
T. P. Martin T. Bergmann H. Göhlich T. Lange 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1991,19(4):25-29
Intensity anomalies (magic numbers) have been observed in the mass spectra of sodium clusters containing up to 22 000 atoms. For small clusters (Na n ,n≤1500) the anomalies appear to be due to the filling of electronic shells (groups of subshells having the same energy). The shells can be characterized rather well by a pseudoquantum-number, indicating the possible existence of a symmetry higher than spherical. The mass spectra of larger clusters (1500≤n≤22 000) are well explained by the completion of icosahedral or cuboctahedral shells of atoms. The fact that the two types of shells (electron and atom) occur in distinct and non-overlapping size intervals might indicate the existence of a “liquid” to “solid” transition in going from small to large clusters. 相似文献