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101.
Ohne Zusammenfassung 相似文献
102.
J. A. Le Clerc und W. L. Dubois 《Fresenius' Journal of Analytical Chemistry》1905,44(8-9):579-580
Ohne Zusammenfassung 相似文献
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Abstract The melting curve of NaCl0.5Br0.5 has been measured under pressure up to 4.5 GPa. The melting temperatures of Ag and NaCl have been used to determine the pressure in the sample at its melting temperature. 相似文献
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The effect of additive noise on a static front that connects a stable homogeneous state with an also stable but spatially periodic state is studied. Numerical simulations show that noise induces front propagation. The conversion of random fluctuations into direct motion of the front's core is responsible of the propagation; noise prefers to create or remove a bump, because the necessary perturbations to nucleate or destroy a bump are different. From a prototype model with noise, we deduce an adequate equation for the front's core. An analytical expression for the front velocity is deduced, which is in good agreement with numerical simulations. 相似文献
108.
Nouredine Zekri Khadidja Khelloufi Lotfi Zekri Bernard Porterie Ahmed Kaiss Jean-Pierre Clerc 《Physics letters. A》2012
Non-equilibrium front propagation in a two-dimensional network modelling wildfire propagation was studied. The model includes deterministic long-range interactions due to radiation and a time weighting procedure. Three weight-dependent propagation regimes were found: dynamical, static, and non-propagative. The dynamical regime shows saturation for small weight values and a percolation transition area depending on the weight and size of the interaction domain. From the scaling interface exponents, the model seems to belong to the dynamical percolation universality class. In the limit of static regime it belongs to the random deposition class. 相似文献
109.
Marie-Louisa Ramaroson Claude Koutouan Jean-Jacques Helesbeux Valrie Le Clerc Latifa Hamama Emmanuel Geoffriau Mathilde Briard 《Molecules (Basel, Switzerland)》2022,27(23)
Phenylpropanoids and flavonoids are specialized metabolites frequently reported as involved in plant defense to biotic or abiotic stresses. Their biosynthetic accumulation may be constitutive and/or induced in response to external stimuli. They may participate in plant signaling driving plant defense responses, act as a physical or chemical barrier to prevent invasion, or as a direct toxic weapon against microbial or insect targets. Their protective action is described as the combinatory effect of their localization during the host’s interaction with aggressors, their sustained availability, and the predominance of specific compounds or synergy with others. Their biosynthesis and regulation are partly deciphered; however, a lot of gaps in knowledge remain to be filled. Their mode of action on microorganisms and insects probably arises from an interference with important cellular machineries and structures, yet this is not fully understood for all type of pests and pathogens. We present here an overview of advances in the state of the art for both phenylpropanoids and flavonoids with the objective of paving the way for plant breeders looking for natural sources of resistance to improve plant varieties. Examples are provided for all types of microorganisms and insects that are targeted in crop protection. For this purpose, fields of phytopathology, phytochemistry, and human health were explored. 相似文献
110.
A. Rousset L. Clerc A. C. Vajpei B. Gillot F. Jemmali 《Journal of Thermal Analysis and Calorimetry》1987,32(3):845-855
Non-isothermal and isothermal TG studies on the cation distribution in submicronic titanomagnetites; Fe3–xTixO4 with 02O3. The DTA results show that the temperature of oxidation of Fe2+ to Fe3+ ions is increased, whereas the temperature of phase change is decreased with increasing titanium substitution. The kinetics of oxidation is found to be governed by the law of diffusion for variable working conditions and for different extents of the vacancies created at the solid-gas interface. The diffusion of iron(II) ions located at octahedral sites proceeds with a lower activation energy than that of iron(II) ions located at tetrahedral sites. Diffusion rates were discerned to be composition-dependent and the variations can be identified with the distribution of the iron ions in sublattices.
Paper presented at the World Conference on Thermal Analysis, Madeira (Portugal), 1986. 相似文献
Zusammenfassung Es wird über nicht-isotherme und isotherme TG-Untersuchungen der Kationenverteilung in submikronen Titanomagnetiten (Fe3–x Ti x O4 mit 0<x<0.82) berichtet. Titanomagnetite mitx<0.61 konnten unter 500° zu Titan-substituierten Magnetiten oxydiert werden, die eine größere Leerstellenkonzentration als-Fe2O3 aufweisen. Die DTA-Ergebnisse zeigen, daß die zur Oxydation von Fe2+- zu Fe3+-Ionen notwendige Temperatur mit zunehmender Titansubstitution ansteigt, die Phasenübergangstemperatur dagegen absinkt. Die Kinetik der Oxydation ist unter verschiedenen Arbeitsbedingungen und bei unterschiedlichen Konzentrationen der an der Fest-Gas-Grenzfläche gebildeten Fehlstellen diffusionsbestimmt. Die Aktivierungsenergie der Diffusion von an den oktaedrischen Stellen lokalisierten Fe(II)-Ionen ist geringer als die von tetraedrisch koordinierten Fe(II)-Ionen. Diffusionsgeschwindigkeiten werden als von der Konzentration abhängig erkannt und die Variationen können mit der Verteilung der Eisenionen im Subgitter identifiziert werden.
Fe3–x Ti x O4 c 0<x<0.82. x< 0.61 500° , -Fe2O3. , , . , — . , , . , .
Paper presented at the World Conference on Thermal Analysis, Madeira (Portugal), 1986. 相似文献