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301.
Dr. Jordi-Amat Cuello-Garibo Catriona C. James Dr. Maxime A. Siegler Dr. Samantha L. Hopkins Dr. Sylvestre Bonnet 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(5):1260-1268
Cyclometallated ruthenium complexes typically exhibit red-shifted absorption bands and lower photolability compared to their polypyridyl analogues. They also have lower symmetry, which sometimes makes their synthesis challenging. In this work, the coordination of four N,S bidentate ligands, 3-(methylthio)propylamine (mtpa), 2-(methylthio)ethylamine (mtea), 2-(methylthio)ethyl-2-pyridine (mtep), and 2-(methylthio)methylpyridine (mtmp), to the cyclometallated precursor [Ru(bpy)(phpy)(CH3CN)2]+ (bpy=2,2′-bipyridine, Hphpy=2-phenylpyridine) has been investigated, furnishing the corresponding heteroleptic complexes [Ru(bpy)(phpy)(N,S)]PF6 ([ 2 ]PF6–[ 5 ]PF6, respectively). The stereoselectivity of the synthesis strongly depended on the size of the ring formed by the Ru-coordinated N,S ligand, with [ 2 ]PF6 and [ 4 ]PF6 being formed stereoselectively, but [ 3 ]PF6 and [ 5 ]PF6 being obtained as mixtures of inseparable isomers. The exact stereochemistry of the air-stable complex [ 4 ]PF6 was established by a combination of DFT, 2D NMR, and single-crystal X-ray crystallographic studies. Finally, [ 4 ]PF6 was found to be photosubstitutionally active under irradiation with green light in acetonitrile, which makes it the first cyclometallated ruthenium complex capable of undergoing selective photosubstitution of a bidentate ligand. 相似文献
302.
Frdric Buron Nuno Rodrigues Thibault Saurat Marie Aude Hiebel Stphane Bourg Pascal Bonnet Reine Nehm Philippe Morin Nathalie Percina Justine Corret Batrice Valle Remy le Guevel Marie-Lise Jourdan Hlne Bndetti Sylvain Routier 《Molecules (Basel, Switzerland)》2021,26(17)
This work describes the synthesis, enzymatic activities on PI3K and mTOR, in silico docking and cellular activities of various uncommon 2,4,7 trisubstituted pyrido[3,2-d]pyrimidines. The series synthesized offers a chemical diversity in C-7 whereas C-2 (3-hydroxyphenyl) and C-4 groups (morpholine) remain unchanged, in order to provide a better understanding of the molecular determinants of PI3K selectivity or dual activity on PI3K and mTOR. Some C-7 substituents were shown to improve the efficiency on kinases compared to the 2,4-di-substituted pyrimidopyrimidine derivatives used as references. Six novel derivatives possess IC50 values on PI3Kα between 3 and 10 nM. The compounds with the best efficiencies on PI3K and mTOR induced micromolar cytotoxicity on cancer cell lines possessing an overactivated PI3K pathway. 相似文献
303.
304.
Dr. Rémy Jouclas Dr. Sophie Laine Dr. Svetlana V. Eliseeva Dr. Jérémie Mandel Dr. Frédéric Szeremeta Dr. Pascal Retailleau Dr. Jiefang He Jean-François Gallard Agnès Pallier Dr. Célia S. Bonnet Prof. Dr. Stéphane Petoud Dr. Philippe Durand Dr. Éva Tóth 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(16):e202317728
Applying a single molecular probe to monitor enzymatic activities in multiple, complementary imaging modalities is highly desirable to ascertain detection and to avoid the complexity associated with the use of agents of different chemical entities. We demonstrate here the versatility of lanthanide (Ln3+) complexes with respect to their optical and magnetic properties and their potential for enzymatic detection in NIR luminescence, CEST and T1 MR imaging, controlled by the nature of the Ln3+ ion, while using a unique chelator. Based on X-ray structural, photophysical, and solution NMR investigations of a family of Ln3+ DO3A-pyridine model complexes, we could rationalize the luminescence (Eu3+, Yb3+), CEST (Yb3+) and relaxation (Gd3+) properties and their variations between carbamate and amine derivatives. This allowed the design of probes which undergo enzyme-mediated changes detectable in NIR luminescence, CEST and T1-weighted MRI, respectively governed by variations in their absorption energy, in their exchanging proton pool and in their size, thus relaxation efficacy. We demonstrate that these properties can be exploited for the visualization of β-galactosidase activity in phantom samples by different imaging modalities: NIR optical imaging, CEST and T1-weighted MRI. 相似文献
305.
Many semicrystalline polymers undergo a process of aging when they are stored at temperatures higher than their glass-transition
temperature (T
g). Syndiotactic polypropylene was quenched from the melt to −40 °C, crystallized from the glassy state at 20 or 40 °C and
stored at the respective temperature for different aging times up to 7200 h. A significant increase in the tensile modulus
and stress at yield and a decrease in strain at yield were observed for both aging temperatures. Differential scanning calorimetry
(DSC) scans of aged material showed an endothermic annealing peak 15–30 °C above the previous aging temperature, the maximum
temperature and enthalpic content of which increased with aging time. The position and the shape of the melting peak were
not affected by aging. Scans of the storage modulus obtained from dynamic mechanical analyser measurements indicated a softening
process starting at about 20 °C above the aging temperature and correlating with the annealing peak detected by DSC. Density
measurements and wide-angle X-ray scattering investigations revealed that neither the crystallinity increased significantly
nor did the crystal structure change. So the observed property changes induced by aging are attributed to microstructural
changes within the amorphous phase. Furthermore, it could be shown by annealing experiments carried out at 60 °C, that aging
above T
g is, analogous to aging below T
g (physical aging), a thermoreversible process.
Received: 18 September 2000 Accepted: 2 January 2001 相似文献
306.
Matthieu Pélingre Dr. Meriem Smadhi Abed Bil Dr. Véronique Bonnet Prof. José Kovensky 《ChemistryOpen》2021,10(4):493-496
The synthesis of pure difunctionalized hexa-, hepta- and octamaltosides was performed by one-pot chemical reaction from perbenzoylated cyclodextrin. Oligomaltosides with azide, propargyl or allyl on reducing end and an unprotected hydroxyl group on non-reducing end were obtained from perbenzoylated α-, β- and γ-cyclodextrin with 12 to 48 % yields. 相似文献
307.
Katrin Krüger Virginia Lüdke Jonathan Pettinger Luke Ashton Laetitia Bonnet Cherie A. Motti Johann Lex Michael Oelgemöller 《Tetrahedron letters》2018,59(14):1427-1430
The photochemistry of several phthalimido acetamides and phthaloyl dipeptide esters has been investigated. Their photocyclization ability strongly depended on the substitution pattern of the amide linker group. While secondary amide-derived starting materials were largely unreactive, the corresponding tertiary amide-linked derivatives furnished the desired cyclic peptide model compounds in acceptable to good yields (41–80%). The structurally related ester-linked model derivatives also remained unreactive upon irradiation. Preferential hydrogen-abstraction from the E-cis-substituent is suggested to explain the observed differences in cyclization ability. 相似文献
308.
Nadiège Nomède-Martyr Elodie Disa Katia Guérin Pierre Bonnet Marc Dubois 《Comptes Rendus Chimie》2018,21(8):791-799
Beneficial effects of fluorination on the stability of carbon nanofibre (CNF) dispersion in organic solvents as a function of time are evidenced. Because of their excellent friction properties, fluorinated CNFs (CF0.85) can be used as nanoparticles of tribo-active phase in lubrication; however, they have to be added into a matrix. We have shown that mixtures of CF0.85 are more stable than CNF solutions. Investigations by ultraviolet–visible spectroscopy have been carried out 2 h after sonication and after an ageing of 4 months. Hansen solubility theory was used, and after ageing, tribological and Raman spectroscopy experiments showed no significant modification of physicochemical properties of the CF0.85. 相似文献
309.
310.
Glass transition temperature of glucose, sucrose, and trehalose: an experimental and in silico study 总被引:2,自引:0,他引:2
Simperler A Kornherr A Chopra R Bonnet PA Jones W Motherwell WD Zifferer G 《The journal of physical chemistry. B》2006,110(39):19678-19684
Isothermal-isobaric molecular dynamics simulations are used to calculate the specific volume of models of different amorphous carbohydrates (glucose, sucrose, and trehalose) as a function of temperature. Plots of specific volume vs temperature exhibit a characteristic change in slope when the amorphous systems change from the glassy to the rubbery state. The intersection of the regression lines of data below (glassy state) and above (rubbery state) the change in slope provides the glass transition temperature (T(g)). These predicted glass transition temperatures are compared to experimental T(g) values as obtained from differential scanning calorimetry measurements. As expected, the predicted values are systematically higher than the experimental ones (about 12-34 K) as the cooling rates of the modeling methods are about a factor of 10(12) faster. Nevertheless, the calculated trend of T(g) values agrees exactly with the experimental trend: T(g)(glucose) < T(g)(sucrose) < T(g)(trehalose). Furthermore, the relative differences between the glass transition temperatures were also computed precisely, implying that atomistic molecular dynamics simulations can reproduce trends of T(g) values in amorphous carbohydrates with high quality. 相似文献