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281.
A Study of Overheating of Thermostatically Controlled TiO2 Thin Films by Using Raman Spectroscopy 下载免费PDF全文
Dr. Juan Jesús Gallardo Dr. Javier Navas Dr. David Zorrilla Dr. Rodrigo Alcántara Diego Valor Dr. Antonio Sánchez‐Coronilla Dr. Norge Cruz Hernández Dr. Concha Fernández‐Lorenzo Prof. Dr. Joaquín Martín‐Calleja 《Chemphyschem》2015,16(18):3949-3958
In this study a classic Raman spectroscopy method is applied and the intensity ratio of Stokes and anti‐Stokes peaks is used to measure the temperature of thermostatically controlled TiO2 thin films. In addition, three mathematical formulae are used and analyzed to estimate the temperature of the TiO2 thin films. Overheating of the samples above the thermostatically controlled temperature was observed while recording the Raman spectra, with a temperature increase of up to 30 K being detected. DFT‐periodic calculations showed that the anatase (101) surface had a smaller band gap than bulk anatase. Thus, it can absorb the laser radiation with a wavelength of 532 nm that is used in the experimental setup. Part of the absorbed photon energy transfers into phonon energy, heating up the anatase phase, thus leading to the heating of the samples. Moreover, overheating of the samples indicates that the experimental method used in this study can lead to deviations in their real absolute temperature values. 相似文献
282.
A Non‐Invasive NMR Method Based on Histidine Imidazoles to Analyze the pH‐Modulation of Protein–Nucleic Acid Interfaces 下载免费PDF全文
Dr. Isabel Cruz‐Gallardo Dr. Rebecca Del Conte Dr. Adrián Velázquez‐Campoy Dr. Sofía M. García‐Mauriño Dr. Irene Díaz‐Moreno 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(20):7588-7595
A useful 2J(N?H) coupling‐based NMR spectroscopic approach is proposed to unveil, at the molecular level, the contribution of the imidazole groups of histidines from RNA/DNA‐binding proteins on the modulation of binding to nucleic acids by pH. Such protonation/deprotonation events have been monitored on the single His96 located at the second RNA/DNA recognition motif (RRM2) of T‐cell intracellular antigen‐1 (TIA‐1) protein. The pKa values of the His96 ionizable groups were substantially higher in the complexes with short U‐rich RNA and T‐rich DNA oligonucleotides than those of the isolated TIA‐1 RRM2. Herein, the methodology applied to determine changes in pKa of histidine side chains upon DNA/RNA binding, gives valuable information to understand the pH effect on multidomain DNA/RNA‐binding proteins that shuttle among different cellular compartments. 相似文献
283.
Selected tandem mass spectrometry (MS/MS) ion monitoring (SMIM) is the most suitable scanning mode to detect known peptides in complex samples when an ion-trap mass spectrometer is the instrument used for the analysis. In this mode, the MS detector is programmed to perform continuous MS/MS scans on one or more selected precursors, either during a selected time interval, or along the whole chromatographic run. MS/MS spectra are recorded, so virtual multiple reaction monitoring chromatogram traces for the different fragment ions can be plotted. In this work, a shotgun proteomics approach was applied to the detection of previously characterized species-specific peptides from different seafood species. The proposed methodology makes use of high intensity focused ultrasound-assisted trypsin digestion for ultra fast sample preparation, peptide separation and identification by reverse phase capillary LC coupled to an ion-trap working in the SMIM scanning mode. This methodology was applied to the differential classification of seven commercial, closely related, species of Decapoda shrimps proving to be an excellent tool for seafood product authentication, which may be used by fisheries and manufacturers to provide a fast and effective identification of the specimens, guaranteeing the quality and safety of foodstuffs to consumers. 相似文献
284.
Karola Böhme Inmaculada C. Fernández‐No Manuel Pazos José M. Gallardo Jorge Barros‐Velázquez Benito Cañas Pilar Calo‐Mata 《Electrophoresis》2013,34(6):877-887
The present study aims to compare two molecular technologies, 16S rRNA sequencing and MALDI‐TOF MS, for bacterial species identification in seafood. With this aim, 70 reference strains from culture collections, including important seafood‐borne pathogenic and spoilage bacterial species, and 50 strains isolated from commercial seafood products, were analysed by both techniques. Genomic analysis only identified the species of 50% of the isolated strains, proving to be particularly poor at identifying members of the Pseudomonas and Bacillus genera. In contrast, MALDI‐TOF MS fingerprinting identified 76% of the strains at the species level. The mass spectral data were submitted to the SpectraBank database ( http://www.spectrabank.org ), making this information available to other researchers. Furthermore, cluster analysis of the peak mass lists was carried out with the web application SPECLUST and the calculated groupings were consistent with results determined by a phylogenetic approach that is based on the 16S rRNA sequences. However, the MALDI‐TOF MS analysis demonstrated more discriminating potential that allowed for better classification, especially for the Pseudomonas and Bacillus genera. This is of importance with respect to the varying pathogenic and spoilage character at the intragenus and intraspecies level. In this sense, MALDI‐TOF MS demonstrated to be a competent bacterial typing tool that extends phenotypic and genotypic approaches, allowing a more ample classification of bacterial strains. 相似文献
285.
Application of a potentiometric electronic tongue as a classification tool in food analysis 总被引:3,自引:0,他引:3
This paper reports on the application of a potentiometric sensor array to the food analysis field, in order to distinguish simple tastes and to classify food samples. This array is formed by a set of non-specific all-solid-state potentiometric sensors and has been used in combination with principal component analysis (PCA) for the classification of food samples in batch and in flow injection mode. First attempt was to classify synthetic samples prepared with controlled variability. Once this ability is proven, satisfactory classification results are presented for commercial waters, orange-based drinks and tea samples. An interesting correlation is achieved between the natural juice content and its first calculated component, which allows for a very simple tool for screening purposes. 相似文献
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