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121.
Summers RJ Bailey PJ Roberts B 《The Journal of the Acoustical Society of America》2010,128(6):3667-3677
In an isolated syllable, a formant will tend to be segregated perceptually if its fundamental frequency (F0) differs from that of the other formants. This study explored whether similar results are found for sentences, and specifically whether differences in F0 (ΔF0) also influence across-formant grouping in circumstances where the exclusion or inclusion of the manipulated formant critically determines speech intelligibility. Three-formant (F1 + F2 + F3) analogues of almost continuously voiced natural sentences were synthesized using a monotonous glottal source (F0 = 150 Hz). Perceptual organization was probed by presenting stimuli dichotically (F1 + F2C + F3; F2), where F2C is a competitor for F2 that listeners must resist to optimize recognition. Competitors were created using time-reversed frequency and amplitude contours of F2, and F0 was manipulated (ΔF0 = ± 8, ± 2, or 0 semitones relative to the other formants). Adding F2C typically reduced intelligibility, and this reduction was greatest when ΔF0 = 0. There was an additional effect of absolute F0 for F2C, such that competitor efficacy was greater for higher F0s. However, competitor efficacy was not due to energetic masking of F3 by F2C. The results are consistent with the proposal that a grouping "primitive" based on common F0 influences the fusion and segregation of concurrent formants in sentence perception. 相似文献
122.
We propose some formulations of the notion of “operational independence” of two subsystems S
1,S
2 of a larger quantum system S and clarify their relation to other independence concepts in the literature. In addition, we indicate why the operational
independence of quantum subsystems holds quite generally, both in nonrelativistic and relativistic quantum theory. 相似文献
123.
E. A. Goode W. H. Summers und A. Schachkeldjan 《Fresenius' Journal of Analytical Chemistry》1934,98(3-4):137
Ohne Zusammenfassung 相似文献
124.
Morphology of periodic nanostructures for photonic crystals grown by glancing angle deposition 总被引:1,自引:1,他引:0
An enhancement of the glancing angle deposition (GLAD) technique called PhiSweep was used to grow slanted columns of silicon and titanium dioxide onto patterned substrates. The PhiSweep technique involves periodically rotating the substrate back and forth during the deposition process, which reduces column fanning caused by anisotropy in the shadowing conditions. The patterned substrates consisted of a tetragonal array of hillocks with 100, 200, and 300 nm periodicities and were fabricated using electron beam lithography. The PhiSweep method alters the tilt angle of the slanted columns compared with those grown using traditional GLAD. We present a derivation of the tilt angle of the slanted columns as a function of the parameters of the PhiSweep technique. The tilt angles of the silicon and titanium dioxide films were measured and agree with the predicted values. The films fabricated using the PhiSweep method are compared with similar films grown using traditional GLAD. The PhiSweep technique produced films with substantially less column fanning than those grown by traditional GLAD. This reduction in column fanning has extended the size range over which periodic GLAD structures, such as square spiral photonic crystals, can be grown. 相似文献
125.
126.
127.
The random vortex method of Chorin1 provides a numerical simulation of high-Reynolds number flow in two dimensions. The method can be used to model the viscous interaction of wind with a surface-mounted obstacle of arbitrary cross-section. In this paper the method has been used to investigate the flow of wind over common building shapes; an inlet profile is chosen to represent the stationary aspects of the atmospheric boundary layer. The evolution of flow over a short time-interval after flow initialization is depicted, and a mean value of pressure coefficient, Cp, is calculated over the building perimeter. Some comparison is made with published wind-tunnel measurements for the case of a surface-mounted square-section block and for a building model with 10° roof pitch. 相似文献
128.
Paper-based biosensors represent a disruptive technology by providing instantaneous and low-cost diagnostics for health and environmental applications. The lack of sensitivity can be an obstacle for this technology to compete with traditional analytical instrumentations. Aiming to improve the sensitivity of a paper-based colorimetric biosensor, we have applied colloids engineering in combination with filtration to lower the paper substrate backgrounds and optimize the immobilization of bio-molecules on paper. A model system consisting of an enzyme, alkaline phosphatase (ALP), and an inorganic colloid, calcium carbonate (CC), flocculated by a cationic dimethylamino-ethyl-methacrylate polyacrylamide (CPAM), demonstrated that the optimized CC flocs are best for enhancing the detecting sensitivity of ALP. The CC floc structure on paper was optimized by modulating its structure in suspension. Subsequently, the filtration process and the wicking ability of paper enabled to freeze the deposited CC structure inherited from the suspension. The incorporation of biomolecules into the CC before immobilizing on paper through filtration provided not only a better microenvironment, but also a higher surface density of immobilized biomolecules. The ALP detection limit of 117 fmol per zone (5 mm circle) in the current study was fifty times lower than that of the common soaking method for biomolecule immobilization. The minimum amount of biomolecules per unit substrate area required for detection was lowered by over an order of magnitude, compared with spotting methods (i.e. inkjet printing). The improvement was also demonstrated by the steepest slope of standard curve, the lowest background, and the highest activity of the bioactive paper probed with the diluted BCIP/NBT liquid substrates. 相似文献
129.
It is shown that in a relativistic quantum field theory satisfying Wightman's axioms, there are no nontrivial field-like operators, or even bilinear forms, associated to a two (or less)-dimensional spacelike plane in Minkowski space. This generalizes Wightman's result that fields can not be defined as operators at a point and stands in contrast to Borchers' result that field operators can be associated with one-dimensional timelike planes. 相似文献
130.
Photoconductivity has been measured from the F+ absorption band in electron and proton irradiated SrO. The measurements were made over the spectral range from 2 to 4 eV and over the temperature range from 65 to 180 K. The photocurrent excited in the F+ band appears to be carried by electrons and has a thermal activation energy of about 0.10 eV. 相似文献