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71.
72.
《应用光谱学评论》2013,48(2):245-261
Abstract The effects of reactive oxygen species on cell function and health have driven the development of numerous detection methodologies to assess oxidative stress. In this article, we review the detection of reactive oxygen species by fluorescence microscopy and flow cytofluorometry over the last seven years. Emphasis is placed on the variety of sample matrices analyzed and the diverse biomedical questions and oxidative stress mediated diseases that benefit from the information provided by these fluorescence-based analytical techniques. 相似文献
73.
用多形核白细胞-鲁米诺化学发光法测定具有超氧化物歧化酶(SOD)和过氧化氢酶(CAT)双功能模拟酶-金属卟啉(四磺酸基苯基铁卟啉、四磺酸基苯基铜卟啉、四磺酸基苯基锰卟啉、四磺酸基苯基钴卟啉)对呼吸爆发所产生的活性氧的影响,结果表明,模拟酶对爆发反应中细胞发光产生抑制,即对活性氧有清除作用;且同一物质随着浓度由10^-7-10^-5mol/L,上升而增强。 相似文献
74.
Study of typical space wave–particle coupling events possibly related with seismic activity 下载免费PDF全文
Based on the DEMETER satellite, we found two space wave-particle coupling events during February 2010 that took place in the range of the McIlwain parameter L (1.27-- 1.37). There are strong spatial and temporal correlation between the particle bursts (PBs) and the electromagnetic disturbances of the coupling events. The two PBs show different energy spectrum characteristics, while the corresponding electromagnetic disturbances concentrated on different frequency ranges. In agreement with the prediction of the theory of wave-particle interaction, we conclude that the two wave-particle inter- actions can be probably explained as follows: one is electron-dominant precipitation with energy of 0.09 MeV,-~0.2 MeV induced by a VLF electromagnetic wave with the frequencies of 14 kHz,-20 kHz, and another is proton-dominant precip- itation with energies of 0.65 MeV--2.85 MeV induced by a VLF electromagnetic wave with the frequency of ≤ 100 Hz. For the first time, these particle bursts' origins, from electrons or protons detected by the Instrument for the Detection of Particles (IDP) on board, are inferred by theoretical calculation, although the instrument has no ability to identify the particle species. 相似文献
75.
Qiao Xu Sheng-Yi Liu Xue-Lan Guo Pei-Wu Li Hong Chen Yuan-Di Zhao 《Analytica chimica acta》2009,632(1):21-8458
Oxidative burst is the rapid and transient production of large amounts of reactive oxygen species, including superoxide anion, hydrogen peroxide (H2O2), and hydroxyl radical. A rapid and simple technique was employed for in vivo detection of oxidative burst in oilseed rape (Brassica napus L.) leaves, using a modified electrode. Platinum (Pt) micro-particles were dispersed on a Pt electrode, coated with a poly (o-phenylenediamine) film. This exhibited high sensitivity, selectivity and stability in H2O2 detection. Amperometry was used to obtain satisfactory linear relationships between reductive current intensities and H2O2 concentrations at −0.1 V potential in different electrolytes. This electrode was used in vivo to detect oxidative burst in oilseed rape following fungal infection. Oxidative bursts induced by infection of the fungal pathogen Sclerotinia sclerotiorum (Lib.) de Bary exhibited notably different mechanisms between a susceptible and a resistant glucose oxidase-transgenic genotype. 相似文献
76.
We calculate the red damping wing of Gunn-Peterson trough taking the evolution of the neutral fraction into consideration
and take a clear look at the ionized region around the ionizing sources. We get the result that the damping wing flux feature
is mainly determined by the neutral hydrogen outside the ionized bubble and the cut off in the damping wing would be useful
to get the size of the ionized bubble. We also fit the red damping wing of the recently discovered high redshift GRB080913
and find that the ionized bubble is too small to create apparent cut off in the spectrum of this burst.
Supported by the National Natural Science Foundation of China (Grant Nos. 10673034 and 10621303) and the National Basic Research
Program of China (Grant No. 2007CB815404) 相似文献
77.
Laser-induced plasmas are investigated during laser micro structuring of a C 75 steel alloy using laser bursts that consist of nanosecond laser pulses under atmospheric pressure. The influence of the laser burst mode — single and collinear double pulses — on plasma dynamics and ablation efficiency is investigated for burst energies in the millijoule regime. Electron density and excitation temperatures measured as a function of time. The results are compared with published data looking for changes of the plasma parameters scaling with the burst energy over two orders of magnitude. For collinear double pulses at burst energies of 1–2 mJ an increase of the ablation rate by a factor of three to four compared to single pulses was observed. 相似文献
78.
Alain Meli Lannang Denis Kehdinga Sema Simplice J. N. Tatsimo V. F. Tsague Tankeu Hycienth F. Tegha Jean Duplex Wansi 《Natural product research》2018,32(9):1033-1038
One new depsidone, polyanthadepsidone A (1), together with four known compounds were isolated from the dichloromethane extract of the leaves of Garcinia polyantha. The structures of all compounds were determined by comprehensive analyses of their 1D and 2D NMR and EI mass spectral data. All the isolates exhibited suppressive effect on phagocytosis response upon activation with serum opsonised zymosan in the IC50 range of 4.5–23.80 μM, tested in vitro for oxidative burst studies of whole blood. 相似文献
79.
Experimental investigation of the time and temperature dependences of the process of relaxation of excited silver chloride has been carried out by the method of a photostimulated burst of luminescence. It is found that the relaxation process can be divided into two components, the rates of which differ by an order of magnitude. The activation energies of these processes of 0.03 and 0.06 eV correspond to the thermal ionization energies of electrons from shallow traps. Thermally activated relocalization of charges from shallow to deep traps in the process of relaxation has been revealed. The depth of a corresponding trap appeared equal to 0.17 eV. A model of a crystal phosphor has been suggested that contains five levels in the forbidden band: a hole center of recombination (luminescence), a deep electron trap, two shallow electron traps located at a depth of 0.03 and 0.06 eV from the bottom of the conductivity band, and a hole trap located at a height of 0.17 eV from the valence band top. Within the framework of this model, we can qualitatively explain the time and temperature dependences of stored light sums. We have shown the possibility of applying the method of a photostimulated burst of luminescence to investigation of the processes of relaxation of electron excitations in crystals to establish the relaxation mechanisms. 相似文献
80.