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991.
T W Sloan 《The Journal of the Operational Research Society》2004,55(6):647-656
In many environments, product yield is heavily influenced by equipment condition. Despite this fact, previous research has either focused on the issue of maintenance, ignoring the effect of equipment condition on yield, or has focused on the issue of production, omitting the possibility of actively changing the machine state. We formulate a Markov decision process model of a single-stage production system in which demand is random. The product yield has a binomial distribution that depends on the equipment condition, which deteriorates over time. The objective is to choose simultaneously the equipment maintenance schedule as well as the quantity to produce in a way that minimizes the sum of expected production, backorder, and holding costs. After proving some results about the structural properties of the optimal policy, numerical problems are used to compare this method to the typical approach of solving the maintenance and production problems sequentially. The results show that the simultaneous solution provides substantial gains over the sequential approach. In the cases studied, the proposed method resulted in an average cost savings of approximately 18%. 相似文献
992.
S. Yu. Ketkov H. L. Selzle E. W. Schlag S. N. Titova L. V. Kalakutskaya 《Optics and Spectroscopy》2004,97(4):567-571
Two-color photoionization of nickelocene molecules cooled in a supersonic jet is performed using a tunable nanosecond pulsed laser. The first stage of the multiphoton excitation is the transition from the highest occupied molecular orbital of nickelocene to the lowest Rydberg level. Conditions are found under which molecular ions (η 5-C5H5)2Ni+ are the only product of the multiphoton ionization in the one-color experiment. Irradiation of an excited molecule by an intense pulse of another laser increases significantly the yield of molecular ions. The dependence of the yield of (η5-C5H5)2Ni+ ions on the frequency of the second laser makes it possible to determine the adiabatic ionization potential of nickelocene as 6.138±0.012eV. 相似文献
993.
994.
E. B. Kudashev 《Acoustical Physics》2003,49(5):545-549
It is shown that, in hydrodynamic noise measurements in the presence of acoustic noise acting upon the pressure fluctuation receiver, spatial filtering methods should provide the best results. Active methods are developed for suppressing the acoustic noise that affects a miniature receiver in the course of turbulent pressure fluctuation measurements. The methods are based on complicating the structure of the measuring transducer by introducing an extra compensating sensing element whose characteristics are identical with those of the main sensing element. The spatial filtering of small-scale turbulent pressure fluctuations by a finite-size electroacoustic transducer is used as the basis for the development of noise-compensated measuring systems, as well as methods of measuring the turbulent pressure fluctuations by receivers with noise compensation. A numerical study of the wave-number filtering of acoustic noise in wall pressure measurements by a noise-compensated receiver is performed. 相似文献
995.
C. Bizdadea C.C. Ciobîrc E.M. Cioroianu S.O. Saliu S.C. Sraru 《Annalen der Physik》2003,12(9):543-571
The local and manifestly covariant Lagrangian interactions in four spacetime dimensions that can be added to a “free” model that describes a generic matter theory and an abelian BF theory are constructed by means of deforming the solution to the master equation on behalf of specific cohomological techniques. 相似文献
996.
997.
Kvon Z. D. Tkachenko V. A. Plotnikov A. E. Sablikov V. A. Renard V. Portal J. C. 《JETP Letters》2004,79(1):36-39
JETP Letters - An experimental study of the two-, three-, and four-terminal resistance of a ballistic wire is carried out. The wire is fabricated on the basis of high-mobility 2D electron gas in an... 相似文献
998.
G. E. Volovik 《JETP Letters》2004,79(3):101-105
According to the Multiple Point Principle, our Universe is on the coexistence curve of two or more phases of the quantum vacuum. The coexistence of different quantum vacua can be regulated by the exchange of the global fermionic charges between the vacua, such as baryonic, leptonic, or family charge. If the coexistence is regulated by the baryonic charge, all the coexisting vacua exhibit the baryonic asymmetry. Due to the exchange of the baryonic charge between the vacuum and matter, which occurs above the electroweak transition, the baryonic asymmetry of the vacuum induces the baryonic asymmetry of matter in our Standard Model phase of the quantum vacuum. The present baryonic asymmetry of the Universe indicates that the characteristic energy scale, which regulates the equilibrium coexistence of different phases of quantum vacua, is about 106 GeV. 相似文献
999.
Delauré B. Beck M. Golovko V. V. Kozlov V. Phalet T. Schuurmans P. Severijns N. Vereecke B. Versyck S. Beck D. Quint W. Ames F. Reisinger K. Forstner O. Deutsch J. Bollen G. Schwarz S. 《Hyperfine Interactions》2003,150(1-4):91-105
We present data from three seasons of experimental field work designed to recreate ancient Andean coastal ceramic firing techniques. Based on the recent discovery of two different archaeological ceramic production sites in the La Leche river valley of northern coastal Peru, the opportunity arose to apply Mössbauer spectroscopy and other analytical methods to reconstruct ancient firing procedures. Two sets of firings took place in 1993 and 1997 in Batán Grande using a partially restored Formative kiln from about 800 BC, local hardwood and cow dung as fuel. A third experiment followed in 2000 after the discovery of a Middle Sicán ceramics workshop in use between ca. AD 950 and 1050 at Huaca Sialupe, where an exact replica of an ancient kiln was built from local clay, and fired with local wood and cow dung. Additionally, inverted urns found at Huaca Sialupe were tested for their potential use as furnaces for metal working. Mössbauer spectroscopy was used to compare the physical and chemical state of specimens produced in the field experiments with ancient ceramics and with specimens produced in controlled laboratory experiments. 相似文献
1000.
We analyze the characteristics of a three-frequency spatial parametric soliton formed by virtue of the cascade frequency tripling in quadratic, periodically poled crystals. A variational approach and a method of averaging are developed, which make it possible to describe analytically, with good accuracy, the characteristics of the spatial solitons studied numerically. 相似文献