全文获取类型
收费全文 | 151篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
化学 | 85篇 |
力学 | 4篇 |
数学 | 6篇 |
物理学 | 58篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 1篇 |
2013年 | 8篇 |
2012年 | 5篇 |
2011年 | 5篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 10篇 |
2007年 | 6篇 |
2006年 | 7篇 |
2005年 | 9篇 |
2004年 | 10篇 |
2003年 | 4篇 |
2002年 | 6篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1963年 | 1篇 |
1935年 | 2篇 |
排序方式: 共有153条查询结果,搜索用时 15 毫秒
81.
S. Puledda A. Marconi 《International journal of environmental analytical chemistry》2013,93(4):209-220
Abstract In this paper, the method that utilizes the X-ray diffraction technique combined with a procedure for X-ray absorption correction, already applied to chrysotile, was extended to the quantitative determination of microgram quantities of four types of amphibolic asbestos. These are: crocidolite, amosite, tremolite and anthophyllite. The effectiveness of the absorption correction procedure, based on the use of a silver membrane filter, was tested for crocidolite by preparing standards of this substance in three different matrices and comparing their diffractometric responses with those of pure analyte standards. These experimental data were also used to calculate the mass absorption coefficients of the matrices, which were compared with both the theoretical values and the values obtained in previous experiments where chrysotile was used as the analyte. The limits of detection of the four pure amphiboles, and crocidolite in matrix were established, and a detailed study of the most common interferences that disturb the analytical peaks of the four amphiboles, was performed. 相似文献
82.
Moreno C.H. Marconi M.C. Shlyaptsev V.N. Rocca J.J. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1999,27(1):6-7
A sequence of high resolution shadowgrams that map the evolution of the plasma of a 380 μm diameter microcapillary discharge was obtained using a very compact 46.9 nm laser. These images are the first plasma diagnostics data obtained using a table-top soft X-ray laser 相似文献
83.
The synthesis of new segmented polyurethanes containing different amounts of N,N-diethylaminoethyl-N′-2,2 hydroxymethylpropionamide, and able to bind, after suitable quaternization, high amounts of heparin, is described. The quaternization is carried out on organic solutions of the polymers. Polymers have been characterized by spectroscopic techniques (transmission and reflectance IR and 1H and 13C NMR), molecular weight measurements and differential scanning calorimetry. The heparin content of the polymer films was determined by a colorimetric system, and its biological activity was evaluated in vitro by activated partial thromboplastin time (APTT) measurements. The distribution of heparin on the surface and in bulk of the heparinized films was evaluated by scanning electron microscopy (SEM) combined with X-ray energy dispersive spectroscopy. 相似文献
84.
We define a lattice Boltzmann model of solid, deformable suspensions immersed in a fluid itself described in terms of the lattice Boltzmann method. We discuss the rules governing the internal dynamics of the solid object as well as the rules specifying the interaction between solid and fluid particle. We perform a numerical drag experiment to validate the model. Finally we consider the case of a population of flexible chains in suspension in a shear stress flow and study the influence on the velocity profile. 相似文献
85.
Albertini E Raggi L Vagnini M Sassolini A Achilli A Marconi G Cartechini L Veronesi F Falcinelli M Brunetti BG Miliani C 《Analytical and bioanalytical chemistry》2011,399(9):2987-2995
We report the development of a suitable protocol for the identification of the biological origin of binding media on tiny samples from ancient paintings, by exploitation of the high specificity and high sensitivity offered by the state-of-the art DNA analysis. In particular, our aim was to molecularly characterize mitochondrial regions of the animal species traditionally employed for obtaining glues. The model has been developed using aged painting models and then tested to analyze the organic components in samples from the polychrome terracotta Madonna of Citerna by Donatello (1415-1420), where, by GC-MS and FTIR spectroscopy, animal glues and siccative oils were identified. The results obtained are good in terms of both sensibility and specificity of the method. First of all, it was possible to confirm that Donatello used animal glue for the preparation of the painted layers of the Madonna of Citerna and, specifically, glue derived from Bos taurus. Data obtained from sequencing confirm that each sample contains animal glue, revealing that it was mostly prepared from two common European taurine lineages called T2 and T3. There is one remarkable exception represented by one sample which falls into a surviving lineage of the now extinct European aurochs. 相似文献
86.
87.
Pérez-Junquera A Marconi VI Kolton AB Alvarez-Prado LM Souche Y Alija A Vélez M Anguita JV Alameda JM Martín JI Parrondo JM 《Physical review letters》2008,100(3):037203
We study both experimentally and theoretically the driven motion of domain walls in extended amorphous magnetic films patterned with a periodic array of asymmetric holes. We find two crossed-ratchet effects of opposite sign that change the preferred sense for domain wall propagation, depending on whether a flat or a kinked wall is moving. By solving numerically a simple phi(4) model we show that the essential physical ingredients for this effect are quite generic and could be realized in other experimental systems involving elastic interfaces moving in multidimensional ratchet potentials. 相似文献
88.
Gu T Ceroni P Marconi G Armaroli N Nierengarten JF 《The Journal of organic chemistry》2001,66(19):6432-6439
Assemblies of four oligophenylenevinylene moieties arising from a calix[4]arene core, i.e., calix[4]oligophenylenevinylenes, have been prepared by Heck-type cross-coupling reactions of styrene derivatives with a tetraiodinated cone-calix[4]arene precursor. Photophysical studies in solution have revealed that there are electronic ground state interactions between the covalently bonded OPV moieties. The absorption spectra of the calix[4]oligophenylenevinylenes are significantly different from those obtained by summing the spectra of four model units and their emission is red-shifted when compared to the corresponding model compounds. Electrochemical studies have shown that the redox processes of the four OPV subunits do not take place at the same potentials indicating also a strong electronic interaction among them in the calix[4]oligophenylenevinylenes. 相似文献
89.
Moreno CH Marconi MC Kanizay K Rocca JJ Uspenskii YA Vinogradov AV Pershin YA 《Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics》1999,60(1):911-917
We have used a tabletop soft-x-ray laser and a wave-front division interferometer to probe the plasma of a pinch discharge. A very compact capillary discharge-pumped Ne-like Ar laser emitting at 46.9 nm was combined with a wave division interferometer based on Lloyd's mirror and Sc-Si multilayer-coated optics to map the electron density in the cathode region of the discharge. This demonstration of the use of tabletop soft-x-ray laser in plasma interferometry could lead to the widespread use of these lasers in the diagnostics of dense plasmas. 相似文献
90.
U. Marini Bettolo Marconi N. H. March 《International journal of quantum chemistry》1981,20(3):693-704
The self-consistent relativistic Thomas–Fermi theory of heavy positive ions with N electrons and nuclear charge Ze is shown to lead to a chemical potential μ which has the scaling property with ? = α2Z2, α being the fine structure constant. Combining this with the Layzer–Bahcall expansion for the total energy E(Z, N), namely, it is proved that the coefficients Enm (N) at large N have the asymptotic behavior Nn–2m/3#1/3. The corresponding result for the scaling of the relativistic Thomas–Fermi energy is Scaling properties of the higher order terms in Enm (N) and E(Z, N) are also proposed. 相似文献