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101.
Mireille Content François Lemay Pierre Leroux 《Journal of Combinatorial Theory, Series A》1980,28(2):169-190
This paper proposes a general setting for Möbius inversion which includes the cases of locally finite partially ordered sets and monoids with the finite decomposition property (f.d.p.). The unifying concept is that of categories with the f.d.p., called Möbius categories, which we characterize in four different ways. The established theory of incidence algebras, Möbius functions, product formulas, reduced algebras, etc., is carried over. Furthermore, the study of functors between Möbius categories yields results in two directions: firstly, inspired from the substitution of formal power series is the construction of a homomorphism between incidence algebras which allows the transfer of Möbius inversions; secondly, surjective functors often give rise to a reduced incidence algebra, thus shedding new light on many important reduced algebras in combinatorial theory. 相似文献
102.
Mireille Leleyter Pierre Joyes Marie-Claire Cadeville 《Journal of Physics and Chemistry of Solids》1983,44(8):779-787
The intensities of emission of NipCn+(p = 1–3) and NiCn? secondary ions given by two alloys: Ni3C and NiC 5% at. C, show off a saw-toothed behaviour according to the parity of the number n of carbon atoms. Maxima occur when n is odd for NiCn+ ions and when n is even in the other cases (p = 2, 3; negative ions). Besides, the influence of the carbon concentration in the alloy can be observed.The alternations of NiCn+ and Ni2Cn+ ions can be interpreted from Pitzer and Clementi model (the clusters are supposed to be linear). Thus it can be found greater stabilities for NiC2k+1 and Ni2C2k chains than for NiC2k and Ni2C2k+1 chains respectively, which very well agrees with the “correspondence rule” between the emissions of different species of ions and their electronic properties. 相似文献
103.
104.
Porrès L Mongin O Katan C Charlot M Pons T Mertz J Blanchard-Desce M 《Organic letters》2004,6(1):47-50
[structure: see text] Novel octupolar fluorophores derived from the symmetrical functionalization of a triphenylamine core with strong acceptor peripheral groups via phenylene-ethynylene linkers have been synthesized and shown to exhibit high fluorescence quantum yields, very large TPA cross-sections in the red-NIR region, and suitable photostability. 相似文献
105.
Z‐Shaped Pyrrolo[3,2‐b]pyrroles and Their Transformation into π‐Expanded Indolo[3,2‐b]indoles 下载免费PDF全文
Rafał Stężycki Dr. Marek Grzybowski Guillaume Clermont Prof. Mireille Blanchard‐Desce Prof. Dr. Daniel T. Gryko 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(15):5198-5203
Sterically hindered 1,4‐dihydropyrrolo[3,2‐b]pyrroles possessing ortho‐(arylethynyl)phenyl substituents at positions‐2 and ‐5 were efficiently synthesized through a sila‐Sonogashira reaction. These unique Z‐shaped dyes showed relatively strong fluorescence in solution. Detailed optimization revealed that, in the presence of InCl3, these alkynes readily undergo an intramolecular double cyclization to give hexacyclic products bearing an indolo[3,2‐b]indole skeleton in remarkable yields. Steady‐state UV–visible spectroscopy revealed that upon photoexcitation, the prepared Z‐shaped alkynes undergo mostly radiative relaxation leading to high fluorescence quantum yields. In the case of 7,14‐dihydrobenzo[g]benzo[6,7]indolo[3,2‐b]indoles, we believe that the substantial planarization of geometry in the excited state, is the underlying reason for the observed large Stokes shifts. The presence of additional electron‐withdrawing groups makes it possible to further alter the photophysical properties. The two‐photon absorption cross‐section values of both families of dyes were found to be modest and the nature of the excited state responsible for two‐photon absorption appeared to be strongly affected by the presence of peripheral groups. Serendipitous synthesis of unusual double‐Z‐shaped alkyne by Sonogashira and Glaser coupling is also reported. 相似文献
106.
Dr. Céline Le Droumaguet Aude Sourdon Dr. Emilie Genin Dr. Olivier Mongin Dr. Mireille Blanchard‐Desce 《化学:亚洲杂志》2013,8(12):2984-3001
A series of octupolar fluorophores built from a triphenylamine (TPA) core connected to electron‐withdrawing (EW) peripheral groups through conjugated spacers has been synthesized. Their photoluminescence, solvatochromism, and two‐photon absorption (2PA) properties were systematically investigated to derive structure–property relationships. All derivatives exhibit two 2PA bands in the 700–1000 nm region: a first band at low energy correlated with a core‐to‐periphery intramolecular charge transfer that leads to an intense 1PA in the blue‐visible range, and a second more intense band at higher energy due to an efficient coupling of the branches through the TPA core. Increasing the strength of the EW end groups or the length of the conjugated spacers and replacing triple‐bond linkers with double bonds induces both enhancement and broadening of the 2PA responses, thereby leading to cross‐sections up to 2100 GM at peak and higher than 1000 GM over the whole 700–900 nm range. All derivatives exhibit intense photoluminescence (PL) in low‐ to medium‐polarity environments (with quantum yields in the 0.5–0.9 range) and display a strong positive solvatochromic behavior (with Lippert–Mataga specific shifts ranging from 15 000 to 27 500 cm?1), triple bonds, and phenyl moieties in the conjugated spacers, thereby leading to larger sensitivities than those of double bonds and thienyl moieties. More hydrophilic derivatives were also shown to be biocompatible, to retain their 2PA and PL properties in biological conditions, and finally to be suitable as polarity sensors for multiphoton cell imaging. 相似文献
107.
The ability to probe surface reactivity on a local scale has led to a new insight into the comprehension of the electrochemical reactivity in relation with the microstructure of the surface. Among the different techniques developed in recent years, local electrochemical impedance spectroscopy has the advantage of using a transient approach to locally characterize a stationary electrochemical system without the need to add any redox mediator in solution, which is a great advantage for the study of different systems.In this review, particular attention is paid to the different ways of measuring the local impedance, and the technique implementing a local current measurement in solution is deeply discussed. This local electrochemical impedance spectroscopy journey also encompasses a discussion about technical and experimental limitations. 相似文献
108.
Summary Molecular Hartree-Fock equations for iteration-variation calculations in momentum space based on trial functions expressed as linear combinations of spherical Gaussian functions are obtained. They are applied to the hydrogen molecule to test their validity. The significant improvements brought by a first iteration are accessed through an asymptotic analysis. 相似文献
109.
Edward Beaumont Jean‐Christophe Lambry Dr. Anne‐Claire Robin Pavel Martasek Prof. Mireille Blanchard‐Desce Dr. Anny Slama‐Schwok Dr. 《Chemphyschem》2008,9(16):2325-2331
We have recently designed a nanotrigger (NT), a photoactive molecule addressing the NADPH sites of proteins. This nanotrigger has a 103 times larger two‐photon cross‐section compared to the ubiquitous NADPH cofactor. In this work, we tested whether two‐photon excitation of the bound NT to NADPH sites may be used to initiate enzymatic catalysis by appropriate electron injection. To establish proof of principle, we monitored the ultrafast absorption of NT bound to the fully active endothelial NO‐Synthase (eNOS) following excitation by one and two‐photons at 405 and 810 nm, respectively. Electron injection from NT* to FAD in eNOS initiated the catalytic cycle in 15±3 ps at both exciting wavelengths. The data proved for the first time that electron transfer can be promoted by two‐photon excitation. We also show that the nanotrigger decays faster in homogeneous solvents than in the NADPH site of proteins, suggesting that hindered environments modified the natural decay of NT. The nanotrigger provides a convenient way of synchronizing an ensemble of proteins in solution with a femtosecond laser pulse. The ability of NT to initiate NOS catalysis by two‐photon excitation may be exploited for controlled and localized release of free NO in cells with enhanced spatial and temporal resolution. 相似文献
110.
Valérie Lebret Laurence Raehm Jean-Olivier Durand Monique Smaïhi Martinus H. V. Werts Mireille Blanchard-Desce Delphine Méthy-Gonnod Catherine Dubernet 《Journal of Sol-Gel Science and Technology》2008,48(1-2):32-39
Two-photon dye-doped mesoporous silica nanoparticles (NPs) have been conjugated with folic acid (FA) in order to obtain efficient nanotools for bioimaging of cancer cells. The surface of the NPs was first functionalized with 3-aminopropyltriethoxysilane. The amine-covered NPs were subsequently reacted with an activated ester derivative of FA. Cytotoxicity studies performed with MCF7 and HeLa cancer cells demonstrate that these functionalized NPs are much less cytotoxic than the non-functionalized NPs against both cell lines. Unfortunately, the grafting of FA enables the formation of charge transfer complexes between the two-photon dye and FA which leads to quenching of the fluorescence of the NPs. Hence although these NPs cannot be used for biomaging purposes, they offer interesting potentialities if the two-photon dye used can be replaced by a two-photon fluorophore which do not interact with FA or if the interaction between the encapsulated dye and FA can be prevented by using a suitable spacer between the surface and the FA moiety. 相似文献