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T. E. Phipps Jr. 《Foundations of Physics》1981,11(7-8):633-644
Einstein's second postulate (light-speed constancy) is modified in the following manner:(1) as to motion of light emitters, no modification is made;(2) as to motion of light absorbers, if the absorber moves with velocityv with respect to the observer, that observer will attribute to light the velocity (c+v). It is shown, with reference to the original Einstein train example, that such a modification of the second postulate restores to kinematics a concept of distant simultaneity. Thus is indicated the complicated (acausal) behavior that must be attributed to light in order that the simple behavior earlier attributed
(1)
to matter (nonoccurrence of the Lorentz contraction) may be consistent with all known facts. A reply is made to Grøn's critique
(2)
of the earlier paper on metric standards. It is concluded that further experimental data are needed to decide the simple-light-complicated-matter versus complicated-light-simple-matter issue. 相似文献
16.
Liu F Phipps A Horowitz S Ngo K Cattafesta L Nishida T Sheplak M 《The Journal of the Acoustical Society of America》2008,123(4):1983-1990
This paper presents the development of an acoustic energy harvester using an electromechanical Helmholtz resonator (EMHR). The EMHR consists of an orifice, cavity, and a piezoelectric diaphragm. Acoustic energy is converted to mechanical energy when sound incident on the orifice generates an oscillatory pressure in the cavity, which in turns causes the vibration of the diaphragm. The conversion of acoustic energy to electrical energy is achieved via piezoelectric transduction in the diaphragm of the EMHR. Moreover, the diaphragm is coupled with energy reclamation circuitry to increase the efficiency of the energy conversion. Lumped element modeling of the EMHR is used to provide physical insight into the coupled energy domain dynamics governing the energy reclamation process. The feasibility of acoustic energy reclamation using an EMHR is demonstrated in a plane wave tube for two power converter topologies. The first is comprised of only a rectifier, and the second uses a rectifier connected to a flyback converter to improve load matching. Experimental results indicate that approximately 30 mW of output power is harvested for an incident sound pressure level of 160 dB with a flyback converter. Such power level is sufficient to power a variety of low power electronic devices. 相似文献
17.
Novofumigatonin (1), a new metabolite, has been isolated from Aspergillus novofumigatus. The structure and relative stereochemistry were determined from HR ESI MS, one- and two-dimensional NMR, and single-crystal X-ray analysis. The absolute configuration was assigned using vibrational circular dichroism in combination with density functional calculations. 相似文献
18.
Romain Fardel Lukas Urech Thomas Lippert Claude Phipps James M. Fitz-Gerald Alexander Wokaun 《Applied Physics A: Materials Science & Processing》2009,94(3):657-665
Laser plasma thrusters are a new kind of propulsion system for small satellites, and work with the thrust created by the laser
ablation of a target. Liquid polymer solutions are very promising fuels for such systems, provided that no splashing of the
target occurs, because ejection of droplets strongly decreases the performances of the system. We have investigated the nanosecond
infrared laser ablation of glycidyl azide polymer solutions containing carbon nanoparticles as absorber. Shadowgraphy imaging
revealed two cases, namely splashing regime and solid-like behavior. The transition between both regimes depends on the viscosity
of the solution and on the laser fluence, and is explained by the recoil force acting on the target. Appropriate conditions
to avoid splashing were identified, showing that this liquid polymer solution is a suitable fuel for laser plasma thrusters. 相似文献
19.
The Dirichlet transform is defined for suitable functions by
20.
Gooding KB Higgs R Hodge B Stauffer E Heinz B McKnight K Phipps K Shapiro M Winkler M Ng WL Julian RK 《Journal of the American Society for Mass Spectrometry》2004,15(6):884-892
Approximately 300,000 compounds from selected libraries were screened against a subdomain of a hepatitis C viral (HCV) RNA using a high throughput flow injection mass spectrometry (FIA-MS) method with automated data storage and analysis. Samples contained 2 microM RNA target and 10 microM of each of up to ten ligands. Preliminary studies to optimize operational parameters used the binding of aminoglycosides to the A44 subdomain of bacterial RNA. Binding (confirmed by titration) and sensitivity were maximized within the constraints of the library and throughput. The mobile phase of 5 mM ammonium acetate in 50% isopropanol maintained the noncovalent complexes and provided good detection by electrospray mass spectrometry. Additionally, this composition maximized general solubility of the various classes of compounds including the oligonucleotide and organic library molecules. Cation adduction was insignificant in this screen although some solute and target dependent acetate adduction was observed. The ion trap mass spectrometer provided sufficient mass resolution to identify complexes of RNA with known components of the library. Converted mass spectral data (netCDF) were subjected to two types of statistical evaluation based on binding. The first algorithm identified noncovalent complexes that correlated with the molecular weights of the injected compounds. The second yielded the largest peak in the noncovalent complex region of the spectrum; this spectrum may or may not correlate with expected well components. Sixty-three compounds were confirmed to bind by more stringent secondary testing. Titrations, which were carried out with selected binding compounds, yielded a range of dissociation constants. Biological activity was observed for eleven confirmed binders. 相似文献