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201.
202.
A Stable Aluminacyclopropene LAl(η2‐C2H2) and Its End‐On Azide Insertion to an Aluminaazacyclobutene
203.
Combinatorial inequalities and some of their geometrical consequences are generalized. The result of the Theorem is the best
possible one.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
204.
Mo(CO)6 can be useful as a precursor for the preparation of Mo and MoSx nanoparticles on a Au(1 1 1) substrate. On this surface the carbonyl adsorbs intact at 100 K and desorbs at temperatures lower than 300 K. Under these conditions, the dissociation of the Mo(CO)6 molecule is negligible and a desorption channel clearly dominates. An efficient dissociation channel was found after dosing Mo(CO)6 at high temperatures (>400 K). The decomposition of Mo(CO)6 yields the small coverages of pure Mo that are necessary for the formation of Mo nanoclusters on the Au(1 1 1) substrate. At large coverages of Mo (>0.15 ML), the dissociation of Mo(CO)6 produces also C and O adatoms. Mo nanoclusters bonded to Au(1 1 1) exhibit a surprising low reactivity towards CO. Mo/Au(1 1 1) surfaces with Mo coverages below 0.1 ML adsorb the CO molecule weakly (desorption temperature<400 K) and do not induce C–O bond cleavage. These systems, however, are able to induce the dissociation of thiophene at temperatures below 300 K and react with sulfur probably to form MoSx nanoparticles. The formed MoSx species are more reactive towards thiophene than extended MoS2(0 0 0 2) surfaces, MoSx films or MoSx/Al2O3 catalysts. This could be a consequence of special adsorption sites and/or distinctive electronic properties that favor bonding interactions with sulfur-containing molecules. 相似文献
205.
Vojtech Novohradsky Anna Rovira Cormac Hally Alex Galindo Gloria Vigueras Albert Gandioso Marie Svitelova Roger Bresolí‐Obach Hana Kostrhunova Lenka Markova Jana Kasparkova Santi Nonell Jos Ruiz Viktor Brabec Vicente Marchn 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(19):6377-6381
Although cyclometalated IrIII complexes have emerged as promising photosensitizers for photodynamic therapy, some key drawbacks still hamper clinical translation, such as operability in the phototherapeutic window and reactive oxygen species (ROS) production efficiency and selectivity. In this work, a cyclometalated IrIII complex conjugated to a far‐red‐emitting coumarin, IrIII–COUPY, is reported with highly favourable properties for cancer phototherapy. IrIII–COUPY was efficiently taken up by HeLa cells and showed no dark cytotoxicity and impressive photocytotoxicity indexes after irradiation with green and blue light, even under hypoxia. Importantly, a clear correlation between cell death and intracellular generation of superoxide anion radicals after visible light irradiation was demonstrated. This strategy opens the door to novel fluorescent photodynamic therapy agents with promising applications in theragnosis. 相似文献
206.
pH‐Responsive Hybrid Organic–Inorganic Ruthenium Nanoparticles for Controlled Release of Doxorubicin
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Hana Buchtelova Vladislav Strmiska Simona Dostalova Petr Michalek Sona Krizkova Pavel Kopel David Hynek Lukas Richtera Vojtech Adam Zbynek Heger 《Particle & Particle Systems Characterization》2017,34(11)
The current study aims at preparing biocompatible hybrid organic–inorganic ruthenium core–shell nanostructures (RuNPs) coated with polyvinylpyrrolidone (PVP) and polyoxyethylene stearate (POES). Thereafter, the core/shell RuNPs are loaded with doxorubicin (to form RuPDox) with a loading efficiency > 60%. RuPDox possesses exceptional stability and pH‐responsive release kinetics with approx. 50% release of doxorubicin at up to 1 h exposure to an acidic endosomal environment. The cytotoxic effects of RuPDox are tested in vitro against breast cancer (MDA‐MB‐231), ovarian cancer (A2780), and neuroblastoma (UKF‐NB‐4) cells. Notably, although RuNPs have slight cytotoxicity only, RuPDox causes a synergistic enhancement of cytotoxicity when compared to free doxorubicin. Significant increase in free radicals formation, enhanced activity of executioner caspases 3/7, and higher expression of p53 and metallothionein is further identified due to the RuPDox treatment. Single‐cell gel electrophoresis reveals no additional contribution of RuNPs to genotoxicity of doxorubicin. Moreover, RuPDox promotes significantly increased stability of doxorubicin in human plasma and pronounced hemocompatibility assayed on human red blood cells. The results imply a high potential of biocompatible hybrid RuNPs with PVP‐POES shell as versatile nanoplatforms to enhance the efficiency of cancer treatment. 相似文献
207.
Morales-Juárez J Cea-Olivares R Moya-Cabrera MM Jancik V García-Montalvo V Toscano RA 《Inorganic chemistry》2005,44(20):6924-6926
The novel M[(OPPh2)2N]2.nTHF (M = Sr (2), Ba (3)) complexes were prepared and characterized. Upon exposure to atmospheric oxygen, 2 and 3 were transformed to the dinuclear species Sr2-[(OPPh2)2N]4.2C3H6O3 (4) and Ba(2)[(OPPh2)2N]4.2C4H8O3 (5), respectively. Compounds 4 and 5 contain coordinated carboxylic acids obtained from the oxidative degradation of DME and THF, respectively, which were used as solvents for crystallization. 相似文献
208.
Koutna M Janisch R Unucka M Svobodnik A Mornstein V 《Photochemistry and photobiology》2004,80(3):531-534
Low-power lasers are commonly used in human medicine for treatment of various pathological conditions, but mechanisms of their healing effects are still poorly understood. The results of this study provide information related to these effects at the cellular level. Two different protozoan species, Euglena gracilis and Tetrahymena thermophila, were used to study changes in locomotion behavior in response to low-power lasers. The cells were irradiated at 830 and 650 nm generated by a semiconductor laser (99 J/cm2, 360 mW) and a laser pointer (0.75 J/cm2, 5 mW), respectively, and their locomotion was recorded by a TV camera and analyzed using computer software. Exposure to laser light, regardless of the wavelength, resulted in increased cell velocity in both species (P <0.001). Exposure to 650 nm produced an equal increase in median cell velocity in both E. gracilis (19.0%) and T. thermophila (18.2%), and some increase persisted in the postirradiation 30 s period. Irradiation by the 830 nm laser resulted in a markedly higher response in Tetrahymena (29.4%) than in Euglena (15.2%), and the two median values remained increased after irradiation was discontinued. Different reactions found in the species studied and some mechanisms underlying the response of cells to radiation are discussed. 相似文献
209.
Measurements of the absolute temperature are analyzed in this paper by means of a method which enables to suppress the noise of the amplifier. The theoretical analysis is made and the relation between the time of integration and the error of this statistical measurement is derived. The RC filter is used instead of the integrator and the relation between the error of the measurement and the time constant of the filter is derived. 相似文献
210.
F.M. Hoffmann E.V. Obrien J. Hrbek R.A. De Paola 《Journal of Electron Spectroscopy and Related Phenomena》1983,29(1):301-305
The adsorption of cyclopentane on Ru(001) has been studied using Electron Energy Loss Spectroscopy (EELS) and Thermal Desorption Mass Spectroscopy (TDMS). Thermal desorption shows with increasing coverage a chemisorbed first layer desorbing at 180 K with subsequent multilayer formation. The vibrational spectrum of the first chemisorbed layer is characterized by a C-H soft mode at 2610 cm?1. This mode is ascribed to a C-H-metal interaction, which is also responsible for the dehydrogenation to cyclopentene upon annealing to 200 K. It appears that a geometrical fit between the molecule and the metal substrate is not necessary for this type of interaction. Coadsorbed oxygen suppresses the C-H-metal interaction. This is believed to be due to site-blocking or ligand effects of oxygen on the three-fold hollow sites of Ru(001). 相似文献