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71.
Erik Pieter van Geest Sina Katharina Götzfried David M. Klein Nadiya Salitra Sorraya Popal Yurii Husiev Corjan J. Van der Griend Xuequan Zhou Maxime A. Siegler Gregory F. Schneider Sylvestre Bonnet 《Photochemistry and photobiology》2023,99(2):777-786
Photosubstitutionally active ruthenium complexes show high potential as prodrugs for the photoactivated chemotherapy (PACT) treatment of tumors. One of the problems in PACT is that the localization of the ruthenium compound is hard to trace. Here, a ruthenium PACT prodrug, [Ru(3)(biq)(STF-31)](PF6)2 (where 3 = 3-(([2,2′:6′,2″-ter- pyridin]-4′-yloxy)propyl-4-(pyren-1-yl)butanoate) and biq = 2,2′-biquinoline), has been prepared, in which a pyrene tracker is attached via an ester bond. The proximity between the fluorophore and the ruthenium center leads to fluorescence quenching. Upon intracellular hydrolysis of the ester linkage, however, the fluorescence of the pyrene moiety is recovered, thus demonstrating prodrug cellular uptake. Further light irradiation of this molecule liberates by photosubstitution STF-31, a known cytotoxic nicotinamide phosphoribosyltransferase (NAMPT) inhibitor, as well as singlet oxygen via excitation of the free pyrene chromophore. The dark and light cytotoxicity of the prodrug, embedded in liposomes, as well as the appearance of blue emission upon uptake, were evaluated in A375 human skin melanoma cells. The cytotoxicity of the liposome-embedded prodrug was indeed increased by light irradiation. This work realizes an in vitro proof-of-concept of the lock-and-kill principle, which may ultimately be used to design strategies aimed at knowing where and when light irradiation should be realized in vivo. 相似文献
72.
In the past years, many dynamic systems often referred to as "molecular machines" have been elaborated. They are generally set in motion by external stimuli like chemical, electrochemical, or photochemical reactions. Light irradiation seems particularly promising since the input signal can be switched on and off fast and readily on a very small place. In this tutorial review, we will highlight recent advances in the design and synthesis of various ruthenium(II) complexed rotaxanes, catenanes, scorpionates or macrocycles. In these compounds, one part of the system is set in motion by photochemically expelling a given chelate. We will discuss the behaviour of various topologically non-trivial systems like catenanes and rotaxanes as well as acyclic and macrocyclic models. 相似文献
73.
Li Kong Sven H. C. Askes Sylvestre Bonnet Dr. Alexander Kros Dr. Frederick Campbell 《Angewandte Chemie (International ed. in English)》2016,55(4):1396-1400
Membrane fusion results in the transport and mixing of (bio)molecules across otherwise impermeable barriers. In this communication, we describe the temporal control of targeted liposome–liposome membrane fusion and contents mixing using light as an external trigger. Our method relies on steric shielding and rapid, photoinduced deshielding of complementary fusogenic peptides tethered to opposing liposomal membranes. In an analogous approach, we were also able to demonstrate precise spatiotemporal control of liposome accumulation at cellular membranes in vitro. 相似文献
74.
The two ligands 1 (4'-(3-anisylphenyl)-2,2';6',2' '-terpyridine) and 2 (2-mesityl-8-anisyl-1,10-phenanthroline) (Scheme 2) were synthesized and coordinated to ruthenium. The corresponding complexes Ru(1)(2)(L)n+, where L = Cl-, CH3CN, or C5H5N, have been fully characterized. Notably, the hindering mesityl group of the phenanthroline ligand was shown to lie opposite to the monodentate ligand L both in solution and in the solid state. Upon irradiation in acetonitrile or pyridine, quantitative isomerization of the complex occurred, which consisted of a 90 degrees rotation of the bidentate chelate. In the new isomers the mesityl group was shown to pi stack to the coordinated monodentate ligand with the anisyl group of the phen (1,10-phenanthroline) lying on the other side of the ruthenium atom. The back reaction was performed by heating the photochemical isomers of the complexes in DMSO and exchanging the DMSO with chloride anion, acetonitrile, or pyridine. The stability of the ruthenium(II)-pyridine bond was used in order to inscribe the Ru(terpy)(phen) motif in a molecular ring. Functionalization of the ligands and subsequent cyclization reaction on the complex were performed on the two isomers of Ru(1)(2)(C5H5N)2+. Four macrocyclic complexes including the Ru(terpy)(phen)(py)n+ moiety were obtained and characterized. A (CH2)18 alkane chain or polyethylene glycol chain formed the flexible part of the ruthena-macrocycles. Upon visible light irradiation a dramatic geometrical changeover of the cyclic complex took place, which could be reversed thermally. 相似文献
75.
76.
The appearance of an endothermic annealing peak in semicrystalline poly(phenylene sulphide) and semicrystalline poly(ethylene
terephthalate) after annealing at or above the cold-crystallization temperature is investigated by temperature-modulated differential
scanning calorimetry, thermo-mechanical analysis and dynamic-mechanical analysis. The results indicate relaxation processes
in the interlamellar amorphous phase, which is in a strongly constrained state after cold crystallization. During the annealing
treatments rearranging processes take place. These processes result in a separation of the amorphous phase into an interlamellar
relaxed and a “pseudo-crystalline” phase.
Received: 27 October 1998 Accepted in revised form: 19 January 1999 相似文献
77.
A. Bonnet B. Lestriez J. P. Pascault H. Sautereau 《Journal of Polymer Science.Polymer Physics》2001,39(3):363-373
The intractable, high‐temperature‐resistant thermoplastics (TPs) polyphenylenether (PPE) and polyetherimide (PEI) were processed by dissolution into epoxy–amine precursors and a subsequent reaction of the precursors. Because the TP concentration was higher than the critical concentration, the phase separation produced a dispersion of crosslinked thermoset (TS) particles into a TP matrix. The morphology of the blends was examined with transmission electron microscopy and dynamic mechanical thermal spectroscopy, which showed completion of the phase separation. The interfacial adhesion at the TP‐matrix/TS‐particle interface was estimated on TP/TS bilayers to be 10 J/m2 in PEI blends, whereas it was 70 J/m2 in PPE blends, where there is strong evidence for in situ grafting between PPE phenolic chain ends and glycidyl functions of the reactive TS. Yielding in the compressive mode occurred at an intermediate yield stress between the components' values, and the anelastic deformation was separated from the plastic deformation. Fractures in the tensile mode occurred through debonding at the matrix/particle interfaces and coalescence of these defects, which led to microcrack formation and brittle failure. Mode I fracture toughness was, therefore, higher for PPE blends than for PEI blends, a result of the higher interfacial adhesion. However, a decrease from pure TP was observed. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 363–373, 2001 相似文献
78.
Isothermal rates of reaction during the cure of epoxy‐amine/thermoplastic blends were studied. Epoxy‐amine reaction induces a phase separation. Experimental results show that when TP concentration is higher than 30 wt% an increase of reaction rate is observed after phase separation. A modelling of the kinetics of each phase before and after phase separation, shows that in the epoxy‐amine rich phase, gelation occurs for a conversion close to 0.6. Rheological behaviour was studied during the cure. The viscosity was found greatly dependent of the morphology, the epoxy amine conversion and of the evolution of the phase composition. Modelling of the viscosity using simple relations gives a good fit of the experimental results during the cure. 相似文献
79.
The investigation into the luminescence properties of a lanthanide-binding peptide, derived from the Ca-binding loop of the parvalbumin, and modified by incorporating a 1,8-naphthalimide (Naph) chromophore at the N-terminus is described. Here, the Naph is used as a sensitising antenna, which can be excited at lower energy than classical aromatic amino acids, such as tryptophan (the dodecapeptide of which was also synthesised and studied herein). The syntheses of the Naph antenna, its solid phase incorporation into the dodecapeptide, and the NMR investigation into the formation of the corresponding lanthanide complexes in solution is presented. We also show that this Naph antenna can be successfully employed to sensitize the excited states of both europium and terbium ions, the results of which was used to determined the stability constants of their formation complexes, and we demonstrated that our peptide 'loop' can selectively bind these lanthanide ions over Ca(II). 相似文献
80.
Frégeau MO Jacquet D Morjean M Bonnet E Chbihi A Frankland JD Rivet MF Tassan-Got L Dechery F Drouart A Nalpas L Ledoux X Parlog M Ciortea C Dumitriu D Fluerasu D Gugiu M Gramegna F Kravchuk VL Marchi T Fabris D Corsi A Barlini S 《Physical review letters》2012,108(12):122701
An atomic clock based on x-ray fluorescence yields has been used to estimate the mean characteristic time for fusion followed by fission in reactions 238U + 64Ni at 6.6 MeV/A. Inner shell vacancies are created during the collisions in the electronic structure of the possibly formed Z=120 compound nuclei. The filling of these vacancies accompanied by a x-ray emission with energies characteristic of Z=120 can take place only if the atomic transitions occur before nuclear fission. Therefore, the x-ray yield characteristic of the united atom with 120 protons is strongly related to the fission time and to the vacancy lifetimes. K x rays from the element with Z=120 have been unambiguously identified from a coupled analysis of the involved nuclear reaction mechanisms and of the measured photon spectra. A minimum mean fission time τ(f)=2.5×10(-18) s has been deduced for Z=120 from the measured x-ray multiplicity. 相似文献