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11.
Kastelein RA Hagedoorn M Au WW de Haan D 《The Journal of the Acoustical Society of America》2003,113(2):1130-1137
The underwater hearing sensitivity of a striped dolphin was measured in a pool using standard psycho-acoustic techniques. The go/no-go response paradigm and up-down staircase psychometric method were used. Auditory sensitivity was measured by using 12 narrow-band frequency-modulated signals having center frequencies between 0.5 and 160 kHz. The 50% detection threshold was determined for each frequency. The resulting audiogram for this animal was U-shaped, with hearing capabilities from 0.5 to 160 kHz (8 1/3 oct). Maximum sensitivity (42 dB re 1 microPa) occurred at 64 kHz. The range of most sensitive hearing (defined as the frequency range with sensitivities within 10 dB of maximum sensitivity) was from 29 to 123 kHz (approximately 2 oct). The animal's hearing became less sensitive below 32 kHz and above 120 kHz. Sensitivity decreased by about 8 dB per octave below 1 kHz and fell sharply at a rate of about 390 dB per octave above 140 kHz. 相似文献
12.
13.
The sorption kinetics for the removal aldehydes from aqueous solutions with Amberlite XAD-16 and MPP particles impregnated
with Primene JM-T was investigated. A model, accounting for the simultaneous mass transfer and chemical reaction, is developed
to describe the process. It is based on the analogy to the diffusion and reaction in a stagnant liquid sphere, but corrected
for the porosity and particle properties influencing the diffusion. The developed model describes the kinetic behavior of
the process in the low concentration region rather well. However, in the high concentration region, larger discrepancies are
observed. Initially, the influence of the flow rate was investigated to eliminate the effect of the external mass transfer.
The influence of the particle morphology was investigated for both physical and reactive sorption. Physical sorption experiments
were used to determine the factor τ that takes the particle properties influencing the diffusion into account. It was shown that the diffusion is faster in XAD-16
than in MPP impregnated systems. Reaction rate constant k
x
was determined by fitting the model to the experimental data. Sorption of benzaldehyde appears to be significantly slower
(k
x
∼10−4 l/mol s) than the sorption of pentanal (k
x
∼10−3 l/mol s) due to the slower chemical reaction. The influence of the particle size was investigated for the sorption of pentanal
with XAD-16. It was observed that the particle size does influence the diffusion term, but does not have an effect on the
reaction rate. On the other hand, the extractant loading influences the reaction rate slightly in the low concentration region,
whereas the initial concentration of the solute has more pronounced effect. 相似文献
14.
John H.J. Einmahl Laurens de Haan Ashoke Kumar Sinha 《Stochastic Processes and their Applications》1997,70(2):143-171
Let (X1, Y1), (X2, Y2),…, (Xn, Yn) be a random sample from a bivariate distribution function F which is in the domain of attraction of a bivariate extreme value distribution function G. This G is characterized by the extreme value indices and its spectral measure or angular measure. The extreme value indices determine both the marginals and the spectral measure determines the dependence structure. In this paper, we construct an empirical measure, based on the sample, which is a consistent estimator of the spectral measure. We also show for positive extreme value indices the asymptotic normality of the estimator under a suitable 2nd order strengthening of the bivariate domain of attraction condition. 相似文献
15.
16.
Sea and Wind: Multivariate Extremes at Work 总被引:4,自引:0,他引:4
Multivariate extreme value theory is used to estimate the probability of failure of a sea-wall near the town of Petten in
Noord Holland, The Netherlands. The sample consists of 828 observations of still water levels and wave heights collected during
storm events over a 13-year period. The paper sketches the probabilistic and statistical theory behind the estimation procedures
used.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
17.
Jan R. de Dobbelaere Erica L. van Zeeventer Jan W. de Haan Henk M. Buck 《Theoretical chemistry accounts》1975,38(3):241-244
INDO calculations have been performed for the activated complex of the [1, 5] H.-shift in 1,3-cyclohexadiene and 1,3,5-cycloheptatriene. During the migration in the cyclohexadiene system a homoconjugation was calculated between the carbon atoms C1 and C5. For cycloheptatriene it could be demonstrated that one double bond does not participate in the reaction. Activation enthalpies are related to (homo)conjugation in the transition state of the reaction for cyclic conjugated dienes and trienes. The electron density on the migrating hydrogen can be related to the electron affinity of the ring system in the transition state.[/p] 相似文献
18.
Limit theory for multivariate sample extremes 总被引:4,自引:0,他引:4
19.
Lambertus J. F. Broer Ritzo E. de Haan 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1958,9(5-6):162-172
Zusammenfassung Es ist eine Methode für die Messung eines schwankenden Staudruckes entwickelt worden. Das Ger?t besteht aus Staurohr, Verbindungsrohr,
piezo-elektrischem Druckaufnehmer und elektrischem Filter. Die aerodynamischen, mechanischen und elektrischen Eigenschaften
des Systems werden besprochen und eine Eichmethode beschrieben.
Das ausgeführte Ger?t besitzt eine nahezu geradlinige Eichkurve bis 800 Hz und eignet sich für die Turbulenzmessungen hinter
verschiedenen Gittern. Die Ergebnisse stimmen befriedigend mit Hitzdrahtmessungen überein.
Laboratorium voor Aero- en Hydrodynamica van de Technische Hogeschool te Delft (Mededeling no. 87). 相似文献
Laboratorium voor Aero- en Hydrodynamica van de Technische Hogeschool te Delft (Mededeling no. 87). 相似文献
20.