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101.
102.
Mireille L. Bougeard 《Mathematical Programming》1988,41(1-3):141-159
Using inf-regularization methods, we prove that Morse inequalities hold for some lower-C
2 functions. For this purpose, we first recall some properties of the class of lower-C
2 functions and of their Moreau-Yosida approximations. Then, we establish, under some qualification conditions on the critical points, that it is possible to define a Morse index for a lower-C
2 functionf. This index is preserved by the Moreau-Yosida approximation process. We prove in particular that the Moreau-Yosida approximations are twice continuolusly differentiable around such a critical point which is shown to be a strict local minimum of the restriction off and of its approximations to some affine space. In a last step, Morse inequalities are written for Moreau-Yosida approximations and with the aid of deformation retractions we prove that these inequalities also hold for some lower-C
2 functions. 相似文献
103.
104.
105.
Mireille Wenkin Patricio Ruiz Bernard Delmon Michel Devillers 《Journal of molecular catalysis. A, Chemical》2002,180(1-2):141-159
Bismuth is a well-established promoter of noble metal-based catalysts for the selective liquid phase oxidation of alcohols, aldehydes and carbohydrates with molecular oxygen. Experiments were carried out to improve the understanding of the promoting role of bismuth in bimetallic Pd–Bi catalysts used for the selective oxidation of glucose to gluconate. In relationship with the fact that these catalysts undergo substantial bismuth leaching under the reaction conditions, particular attention was paid to the possible role played by the soluble fraction of bismuth in the oxidative process. Carbon-supported Pd–Bi/C catalysts characterized by various Bi–Pd compositions (0.33≤Bi/Pd≤3.0,10 wt.%Pd+Bi) were prepared from acetate-type precursors, tested under various experimental conditions and analyzed by X-ray diffractometry and X-ray photoelectron spectroscopy (XPS). Whatever the initial catalyst composition, the surface intensity ratio measured by XPS in used catalysts lies in the range 0.4–0.6, suggesting that the dynamic state of the catalyst involves the association of one Bi and two to three Pd atoms. The leaching process and the promoting effect itself are discussed in line with the formation of Bi–glucose and Bi–gluconate complexes present in solution but also as adsorbed species at the catalyst surface. The performances of a monometallic Pd/C catalyst are significantly improved in the presence of adequate amounts of soluble Bi. The involvement of the soluble fraction of bismuth in the overall mechanistic scheme of glucose oxidative dehydrogenation is suggested. The detrimental effect of large amounts of soluble bismuth is attributed to a too extensive adsorption of Bi–glucose complexes on the surface Pd atoms. 相似文献
106.
Meloni S Palma A Schwartz J Kahn A Car R 《Journal of the American Chemical Society》2003,125(26):7808-7809
Metal organic contacts are at the basis of devices such as organic light emitting diodes (OLEDs). Here, we report a theoretical investigation of the chemical interaction between a Mg atom and an organic film made of tris(8-hydroxyquinoline)aluminum (Alq3) molecules. The latter is modeled either by an isolated molecule or by a bulk crystal. Using first-principles molecular dynamics for structural optimization, we find that an isolated Alq3 molecule and a Mg atom form an ion-pair. However, when the metal atom interacts with molecules in a bulk crystalline environment, we find that an organometallic complex is energetically preferred over the ion-pair. The complex formation is an effect of the environment which makes possible the interaction of the metal atom with several adjacent molecules. Here, our calculated O(1s) and N(1s) core level shifts agree well with recent experimental data on Alq3 films exposed to Mg. Our results resolve the apparent contradiction between experiment and predictions made in previous calculations in which a single Alq3 molecule was used to model a thin film. 相似文献
107.
Résumé Les auteurs ont donné un résumé de leurs recherches sur la pyrolyse de 32 substances qui changent de couleur entre 35 et 450° C et qui peuvent s'utiliser comme indicateurs de température. Les courbes de thermolyse ne sont pas reproduites à cause de leur simplicité. Les causes des changements de couleur sont variables. Dans quelques cas, il s'agit d'un changement d'état allotropique (dérivés du mercure) et l'on observe une réversibilité parfaite. Dans d'autres cas, sous l'action d'une reprise d'humidité, on revient à la teinte initiale. Enfin, comme la température de destruction dépend beaucoup du mode de préparation, de la vitesse de chauffe, de l'atmosphère environnante, certaines températures de virage ne doivent pas être considérées comme absolues. C'est pourquoi certaines de nos valeurs s'écartent de celles des auteurs précédents.
En l'honneur du ProfesseurFrite Feigl, pour son 70e anniversaire. 相似文献
Summary The writers have given a résumé of their investigations of the pyrolysis of 32 substances which change color between 35 and 450° C and which can be employed as temperature indicators. The thermolysis curves are not reproduced because of their simplicity. There are various reasons for these changes in color. In some instances a change in allotropic state is involved (mercury derivatives) and a perfect reversibility is observed. In other cases, the initial color is restored because of the recovery of moisture. Finally, since the temperature of destruction depends greatly on the method of preparation, the rate of heating and the surrounding atmosphere, certain color change temperatures should not be regarded as absolute. This explains the divergence of our values from those of previous workers.
Zusammenfassung Über die Untersuchungen der Pyrolyse von 32 Substanzen, die zwischen 35 und 450° C ihre Farbe ändern und daher als Wärmeindikatoren dienen können, wird zusammenfassend berichtet. Die Thermolysekurven sind ihrer Einfachheit wegen nicht wiedergegeben. Die Ursachen der Farbänderung sind unterschiedlich. Mitunter handelt es sich um Polymorphien (Quecksilberverbindungen), die vollständig reversibel sind. In anderen Fällen führt die Wiederaufnahme von Wasser auch zur ursprünglichen Farbe. Da die Zersetzungstemperatur weitgehend von der Art der Darstellung des Präparates, der Geschwindigkeit des Erhitzens, der umgebenden Atmosphäre abhängt, sind manche Umwandlungspunkte nicht als Absolutwerte anzusehen. Aus diesem Grund ergaben sich auch Abweichungen gegenüber Angaben anderer Autoren.
En l'honneur du ProfesseurFrite Feigl, pour son 70e anniversaire. 相似文献
108.
109.
Résumé Le plomb utilisé sous forme d'arbre de Saturne possède une grande réactivité et permet de réduire les nitrates en nitrites. Il s'agit d'une réaction à l'état solide, débutant dès la température ordinaire. On a pu caractériser ainsi la présence de nitrites en mélangeant le plomb avec les nitrates de lithium, sodium, potassium, césium, cuivre, argent, magnésium, calcium, strontium, baryum, zinc, thallium, plomb, cobalt et nickel.
En l'honneur du ProfesseurA. A. Benedetti-Pichler, pour son 70e anniversaire. 相似文献
Summary Lead used in the form of the lead tree has great reactivity and is able to reduce nitrates to nitrites. This involves a solid state reaction and starts at room temperature. In this way it is possible to detect the presence of nitrites after mixing the lead with the following nitrates — Li, Na, K, Cs, Cu, Ag, Mg, Ca, Sr, Ba, Zn, Tl, Pb, Co, Ni.
Zusammenfassung In der Form des Bleibaumes ist Pb sehr reaktionsfähig und reduziert Nitrat zu Nitrit. Dabei handelt es sich um eine Festkörperreaktion, die bei gewöhnlicher Temperatur einsetzt. Nach Vermengen von Blei mit den Nitraten von Li, Na, K, Cs, Cu, Ag, Mg, Ca, Sr, Ba, Zn, Th, Pb, Co und Ni konnte die Anwesenheit von Nitrit festgestellt werden.
En l'honneur du ProfesseurA. A. Benedetti-Pichler, pour son 70e anniversaire. 相似文献
110.
Dr. Aude Sourdon Dr. Magali Gary-Bobo Dr. Marie Maynadier Dr. Marcel Garcia Dr. Jean-Pierre Majoral Dr. Anne-Marie Caminade Dr. Olivier Mongin Dr. Mireille Blanchard-Desce 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(14):3637-3649
The synthesis and the photophysical properties of a new class of fully organic monodisperse nanoparticles for combined two-photon imaging and photodynamic therapy are described. The design of such nanoparticles is based on the covalent immobilization of a dedicated quadrupolar dye that combines excellent two-photon absorbing (2PA) properties, fluorescence and singlet oxygen generation ability, in a phosphorous-based dendrimeric architecture. First, a bifunctional quadrupolar dye bearing two different grafting moieties, a phenol function and an aldehyde function, was synthesized. It was then covalently grafted through its phenol function to a phosphorus-based dendrimer scaffold of generation 1. The remaining aldehyde functions were then used to continue the dendrimer synthesis up to generation 2, introducing finally 24 water-solubilizing triethyleneglycol chains at its periphery. A dendrimer confining 12 photoactive quadrupolar units in its inner scaffold and showing water solubility was thus obtained. Interestingly, the G1 and G2 dendrimers retain some fluorescence as well as significant singlet oxygen production efficiencies while they were found to show very high 2PA cross-sections in a broad range of the NIR biological spectral window. Hydrophilic dendrimer G2 was tested in vitro on breast cancer cells, first in one- and two-photon microscopy, which allowed for visualization of their cell internalization, then in two-photon photodynamic therapy. While being nontoxic in the dark and, more importantly, under exposure to daylight, dendrimer G2 proved to be a very efficient cell-death inducer only under two-photon irradiation in the NIR. 相似文献