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排序方式: 共有139条查询结果,搜索用时 15 毫秒
41.
In two independent experiments, we have measured the Rayleigh factor of tert-butanol-water mixtures as a function of concentration. Our results are in strong disagreement with those of Vuks and Shurapova in that we find only a single maximum in the Rayleigh factor at mole fraction 0.125 in alcohol. We find that the Rayleigh factors of solutions in the immediate vicinity of 0.03 mole fraction of alcohol depend strongly upon the purity of the components and treatment of the solutions prior to measurement. A possible explanation for this behavior is given. 相似文献
42.
J. Jolly 《Journal of Quantitative Spectroscopy & Radiative Transfer》1978,20(5):503-518
The absolute concentrations of the argon-ion states of the configurations 3d, 4s, 4p, 4p′, 4d and 5s have been measured for a pulsed laser discharge whose plasma parameters have been previously determined. For the resonant levels, the measurements were made by a self-absorption technique and for other levels by absolute spectroscopic observations. Variations of the populations of these levels as functions of discharge current and filling pressure (i.e. electron temperature and density) permitted calculations of the total excitation and de-excitation rate coefficients due to electrons as functions of temperature for each laser level. For excitation, collisions with the fundamental and long-lived states were taken into account while, for de-excitation, superelastic, excitation and ionization collisions were considered. 相似文献
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Amorphous silicon films are deposited by radio-frequency plasma-enhanced chemical-vapor deposition (RF-PECVD) with different n-doping rates. The amorphous films are subsequently crystallized using either solid phase crystallization (SPC) or rapid thermal annealing (RTA). We compare the effect of the n-doping rate on some properties of the microcrystalline silicon films obtained with both techniques. In the SPC process, the time required for the beginning of the crystallization decreases with increasing phosphorus doping. Moreover, doped films present slightly higher crystal size than intrinsic films but the doping rate does not significantly influence the grain size. For RTA, the doping rate decreases the crystallization temperature and increases significantly the crystal size. Whatever the doping rate, the average grain sizes obtained by RTA are larger than those obtained by SPC. The electrical resistance of the crystallized films also depends on the crystallization process: RTA films present a lower dark conductivity than SPC films. These results are discussed taking into account the different kinetics of both crystallization techniques and the role played by the silicon dangling bonds and their charge states on the crystal growth. 相似文献
45.
In this paper, a lower bound estimate on the uniform radius of spatial analyticity is established for solutions to the incompressible, forced Navier–Stokes system on an \(n\) -torus. This estimate matches previously known estimates provided that a certain bound on the initial data is satisfied. In particular, it is argued that for two-dimensional (2D) turbulent flows, the initial data is guaranteed to satisfy this hypothesized bound on a significant portion of the 2D global attractor, in which case, the estimate on the radius matches the best known one found in Kukavica (1998). A key feature in the approach taken here is the choice of the Wiener algebra as the phase space, i.e., the Banach algebra of functions with absolutely convergent Fourier series, whose structure is suitable for the use of the so-called Gevrey norms. We note that the method can also be applied with other phase spaces such as that of the functions with square-summable Fourier series, in which case the estimate on the radius matches that of Doering and Titi (1995). It can then similarly be shown that for three-dimensional (3D) turbulent flows, this estimate holds on a significant portion of the 3D weak attractor. 相似文献
46.
We present diverse reconfigurable complex 3D twister vortex superlattice structures in a large area embedded with tunable vortex spirals as well as dark rings, threaded by vortex helices. We demonstrate these tunable complex chiral vortex superlattices by the superposition of relatively phase engineered plane waves. The generated complex 3D twister lattice vortex structures are computationally as well as experimentally analyzed using various tools to verify the presence of phase singularities. Our observation indicates the application-specific flexibility of our approach to tailor the transverse superlattice spatial irradiance profile of these longitudinally whirling vortex-cluster units and dark rings. 相似文献
47.
Peptide Modifications Differentially Alter G Protein‐Coupled Receptor Internalization and Signaling Bias 下载免费PDF全文
Veronika Mäde Stefanie Babilon Dr. Navjeet Jolly Lizzy Wanka Dr. Kathrin Bellmann‐Sickert Dr. Luis E. Diaz Gimenez Dr. Karin Mörl Prof. Dr. Helen M. Cox Prof. Dr. Vsevolod V. Gurevich Prof. Dr. Annette G. Beck‐Sickinger 《Angewandte Chemie (International ed. in English)》2014,53(38):10067-10071
Although G protein‐coupled receptors (GPCRs) are targeted by more clinically used drugs than any other type of protein, their ligand development is particularly challenging. Humans have four neuropeptide Y receptors: hY1R and hY5R are orexigenic, while hY2R and hY4R are anorexigenic, and represent important anti‐obesity drug targets. We show for the first time that PEGylation and lipidation, chemical modifications that prolong the plasma half‐lives of peptides, confer additional benefits. Both modifications enhance pancreatic polypeptide preference for hY2R/hY4R over hY1R/hY5R. Lipidation biases the ligand towards arrestin recruitment and internalization, whereas PEGylation confers the opposite bias. These effects were independent of the cell system and modified residue. We thus provide novel insights into the mode of action of peptide modifications and open innovative venues for generating peptide agonists with extended therapeutic potential. 相似文献
48.
Rajdip Roy Dr. Jolly Deb Dr. Siddhartha Sankar Jana Prof. Parthasarathi Dastidar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(47):15320-15324
A simple strategy for designing salt‐based supramolecular gelators comprised of various nonsteroidal anti‐inflammatory drugs (NSAIDs) and amantadine (AMN) (an antiviral drug) has been demonstrated using a supramolecular synthon approach. Single‐crystal and powder X‐ray diffraction established the existence of the well‐studied gel‐forming 1D supramolecular synthon, namely, primary ammonium monocarboxylate (PAM) synthon in all the salts. Remarkably five out of six salts were found to be capable of gelling methyl salicylate (MS)—an important ingredient in commercially available topical gels; one such selected biocompatible salt displayed an anti‐inflammatory response in prostaglandin E2 (PGE2) assay, thereby indicating their plausible biomedical applications. 相似文献
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In the presence of a bis (η3-allyl)palladium-bisdicyclohexylphosphinoethane catalyst allene and CO2 cooligomerize to give a mixture of esters, a lactone and polymer. 相似文献