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81.
This paper discusses the availability of a two-unit standby redundant repairable system in which the pdf of the life time of the online unit depends on the time it has spent in the standby state before it is switched online. Explicit expressions for the Laplace transforms of the availability and reliability of the system are obtained by identifying suitable regeneration points.
Zusammenfassung In dieser Arbeit wird die Verfügbarkeit eines redundanten 2-Komponentensystems mit heißer Reserve und Reparatur betrachtet. -Die Lebensdauerverteilung der Betriebskomponente hängt von der Länge der Zeit ab, die sie vorher als Reservekomponente verbracht hat. Es werden explizite Ausdrücke der Laplacetransformierten für die Verfügbarkeit und Zuverlässigkeit des Systems ermittelt, indem geeignete Regenerationspunkte verwendet werden.相似文献
82.
Priv.-Doz. Dr. K. -P. Kistner Dr. R. Subramanian 《Mathematical Methods of Operations Research》1974,18(3):117-129
Zusammenfassung Es wird die Zuverlässigkeit eines Systems mit mehreren redundanten Einheiten untersucht, bei dem nicht nur die tätige Einheit, sondern auch die Reserveeinheiten ausfallen und bei dem gestörte Einheiten repariert werden können. Es wird vorausgesetzt, daß die Reparaturzeiten und die Lebensdauern der Reserveeinheiten exponentialverteilt sind, während die Betriebsdauern der tätigen Einheiten, unabhängig von ihrem Alter beim Einsatz, beliebig verteilt sind.Unter diesen Voraussetzungen werden die mittlere Zeit bis zum Ausfall des Systems und die langfristige Verfügbarkeit des Systems explizit für den Fall dreier Einheiten bestimmt.Am Beispiel doppel-exponentialverteilter Betriebsdauern werden die Abhängigkeit dieser Größen von der Reparaturgeschwindigkeit untersucht und die optimale Reparaturrate bestimmt.
Diese Arbeit wurde durch den Sonderforschungsbereich 21 — ökonometrie und Unternehmensforschung — und ein Stipendium der Alexander-von-Humboldt-Stiftung gefördert. 相似文献
Summary We consider the reliability of a repairable system with several stand-by redundant units, where not only the working unit but also the spares are subject to failure. We assume, that repair-times and life-times of spares are exponentially distributed, whereas the time to failure of a working unit is — independent of its age at the time of switch-on — arbitrarily distributed.Using these assumptions, we derive the expected time to system-failure and the steady-state availability explicitely for the case of three redundant units. The example of double-exponentially distributed working-times is used to examine the dependancy of these characteristics on repair-times, and to calculate the optimal repair-rate.
Diese Arbeit wurde durch den Sonderforschungsbereich 21 — ökonometrie und Unternehmensforschung — und ein Stipendium der Alexander-von-Humboldt-Stiftung gefördert. 相似文献
83.
84.
Krishnamurthy E. V. Mahadeva Rao T. Subramanian K. 《Proceedings Mathematical Sciences》1975,81(2):58-79
Proceedings - Mathematical Sciences - A fractional weighted number system, based on Hensel’sp-adic number system, is proposed for constructing a unique code (called Hensel’s code) for... 相似文献
85.
86.
Rotor-assisted population transfer (RAPT) was developed as a method for enhancing MAS NMR sensitivity of quadrupolar nuclei by transferring polarization associated with satellite transitions to the central m=12-->-12 transition. After a single RAPT transfer, there still remains polarization in the satellite transitions that can be transferred to the central transition. This polarization is available without having to wait for the spin system to return to thermal equilibrium. We describe a new RAPT scheme that uses the remaining polarization of the satellites to obtain a further enhancement of the central transition by performing RAPT-enhanced experiments multiple times before waiting for re-equilibration of the spin system. For 27Al (I=5/2) in albite we obtain a multiple RAPT enhancement of 3.02, a 48% increase over single RAPT. For 93Nb (I=9/2) in NaNbO(3) we obtain a multiple RAPT enhancement of 5.76, an 89% increase over single RAPT. We also describe a data processing procedure for obtaining the maximum possible signal-to-noise ratio. 相似文献
87.
Ghorai PK Yashonath S Demontis P Suffritti GB 《Journal of the American Chemical Society》2003,125(23):7116-7123
Previous work on monatomic spherical sorbates has shown the existence of an anomalous peak in self-diffusivity (D) when plotted as a function of size of the diffusant. Molecular dynamics studies on linear molecules of different lengths l in zeolite NaY at 140 and 200 K are reported. It is seen that there is a peak in D as a function of l, suggesting that the levitation effect exists for linear molecules, the simplest member of polyatomics. This is confirmed by the lowering of the activation energy for the molecule whose length l exhibits highest D. Related quantities of interest such as the guest-host interaction energy and preexponential factor are discussed. 相似文献
88.
Tangled, primordial cosmic magnetic fields create small rotational velocity perturbations on the last scattering surface of the cosmic microwave background radiation. For fields which redshift to a present value of B0 = 3 x 10(-9) G, these vector modes are shown to generate polarization anisotropies of order 0.1-4 microK on small angular scales (500相似文献
89.
N. Sankara Subramanian R. Vivek Sabaapathy P. Vickraman G. Vimal Kumar R. Sriram B. Santhi 《Ionics》2007,13(5):323-328
P-type porous silicon (PS) structure has been prepared by anodic electrochemical etching process under optimized conditions.
Photoluminescence studies of the PS structure show emission at longer wavelengths (red) for the excitation at 365 nm. Scanning
electron microscope investigations of the PS surface confirm the formation of uniform porous structure, and the pore diameter
have been estimated as 25 μm. Pd:SnO2/PS/p-Si heterojunction with top gold ohmic contact developed by conventional methods has been used as the sensor device.
Sensing properties of the device towards liquefied petroleum gas (LPG) and NO2 gas have been investigated in an indigenously developed sensor test rig. The response and recovery characteristics of the
sensor device at different operating temperatures show short response time for LPG. From the studies, maximum sensitivity
and optimum operating temperature of the device towards LPG and NO2 gas sensing has been estimated as 69% at 180 °C and 52% at 220 °C, respectively. The developed sensor device shows a short
response time of 25 and 57 s for sensing LPG and NO2 gases, respectively.
Paper presented at the Third International Conference on Ionic Devices (ICID 2006), Chennai, Tamilnadu, India, Dec. 7–9, 2006. 相似文献