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21.
Traditionally air quality networks have been carrying out the continuous, on-line measurement of volatile organic compounds (VOC) in ambient air with GC-FID. In this paper some identification and coelution problems observed while using this technique in long-term measurement campaigns are described. In order to solve these problems a GC-MS was set up and operated simultaneously with a GC-FID for C2-C11 VOCs measurement.There are few on-line, unattended, long term measurements of atmospheric VOCs performed with GC-MS. In this work such a system has been optimized for that purpose, achieving good repeatability, linearity, and detection limits of the order of the GC-FID ones, even smaller in some cases. VOC quantification has been made by using response factors, which is not frequent in on-line GC-MS. That way, the identification and coelution problems detected in the GC-FID, which may led to reporting erroneous data, could be corrected.The combination of GC-FID and GC-MS as complementary techniques for the measurement of speciated VOCs in ambient air at sub-ppbv levels is proposed. Some results of the measurements are presented, including concentration values for some compounds not found until now on public ambient air VOC databases, which were identified and quantified combining both techniques. Results may also help to correct previously published VOC data with wrongly identified compounds by reprocessing raw chromatographic data.  相似文献   
22.
Background: Genetic risk scores (GRSs) have partially improved the understanding of the etiology of moderate hypertriglyceridemia (HTG), which until recently was mainly assessed by secondary predisposing causes. The main objective of this study was to assess whether this variability is due to the interaction between clinical variables and GRS. Methods: We analyzed 276 patients with suspected polygenic HTG. An unweighted GRS was developed with the following variants: c.724C > G (ZPR1 gene), c.56C > G (APOA5 gene), c.1337T > C (GCKR gene), g.19986711A > G (LPL gene), c.107 + 1647T > C (BAZ1B gene) and g.125478730A > T (TRIB gene). Interactions between the GRS and clinical variables (body mass index (BMI), diabetes mellitus, diet, physical activity, alcohol consumption, age and gender) were evaluated. Results: The GRS was associated with triglyceride (TG) concentrations. There was a significant interaction between BMI and GRS, with the intensity of the relationship between the number of alleles and the TG concentration being greater in individuals with a higher BMI. Conclusions: GRS is associated with plasma TG concentrations and is markedly influenced by BMI. This finding could improve the stratification of patients with a high genetic risk for HTG who could benefit from more intensive healthcare interventions.  相似文献   
23.
Monitoring the hydrolysis or disappearance of starch by the starch iodine test is a simple procedure for determining the maturity of cider apples, but it does not indicate the exact amount of starch present. So far, studies of starch in apples have dealt exclusively with dessert apples. In this paper the relationship between the visual starch index, the dark‐coloured surface area and the real starch content was studied in two varieties of cider apple commonly used in Normandy (France). Starch determination in cider apples required adapting the protocol provided by the Boehringer enzymatic kit. The work led to proposing a simplified index with five scales instead of 10. This index gives the correspondences between the new and old scales as well as the probable starch contents for each new scale. © 2002 Society of Chemical Industry  相似文献   
24.
Applied Intelligence - The17 Sustainable Development Goals (SDGs) established by the United Nations Agenda 2030 constitute a global blueprint agenda and instrument for peace and prosperity...  相似文献   
25.
A considerable number of nonlinear industrial loads employ three-phase inductive filters to reduce their peak currents and mitigate the conduction of harmonic currents into the supply system. In modeling and analysis of this kind of filter, the fact that-for reasons of economy-they consist of a single block where the three electrical phases share the same magnetic core instead of having three single-phase reactors is often overlooked. Since the three windings are coiled in the same plane, the central magnetic limb of the core has a lower magnetic reluctance than do the lateral limbs. Moreover, this undesired effect is increased by the existence of internal magnetic couplings. The above phenomenon, which might, at first sight, be considered negligible, will become noticeable in real electrical facilities because of the particular operating conditions of three-phase inductive filters. The aim of this paper is, thus, to present a new model for three-limb core three-phase inductive filters that includes all the above parasitic effects and to describe its practical application in order to assess the magnitude of the errors produced by traditional models when estimating real filter behavior.  相似文献   
26.
The attachment glycoprotein (G) of respiratory syncytial virus (RSV) is synthesized as two mature forms: a membrane-anchored form and a smaller secreted form. Mutant cDNAs were constructed that encoded one or the other form of the protein and were expressed in recombinant vaccinia viruses (rVV). Mice were immunized with rVV by dermal scarification or i.p. injection to determine the contribution of the membrane-anchored and secreted forms of the G protein on the augmentation of pulmonary pathology seen following RSV challenge. Mice scarified with rVV expressing the membrane-anchored G protein had a markedly reduced pulmonary eosinophilic response following RSV challenge compared with mice scarified with rVV expressing either wild-type or secreted G protein. The induction of pulmonary eosinophilia in rVV-primed mice was also dependent upon the route of vaccination. An eosinophilic response was not observed in any groups of mice immunized i.p. with rVV expressing any of the different forms of the G protein. The difference in pulmonary pathology observed between dermal scarification or i.p. vaccinated mice was not reflected in a difference in cytokine production by splenocytes from vaccinated and challenged mice restimulated with RSV in vitro. Both groups produced significant levels of IL-4 and IL-5. These data suggest that the local APCs and lymphoid environment, together with the form of the G protein, influence pulmonary pathology following RSV challenge.  相似文献   
27.
BACKGROUND: In this study the antimicrobial effectiveness of oregano and sage essential oils (EOs) incorporated into two different matrices, whey protein isolate (WPI) and cellulose‐based filter paper, was analysed. RESULTS: Antimicrobial properties of WPI‐based films containing oregano and sage EOs were tested against Listeria innocua, Staphylococcus aureus and Salmonella enteritidis. Oregano EO showed antimicrobial activity against all three micro‐organisms. The highest inhibition zones were against L. innocua. However, sage EO did not show antimicrobial activity against any of the micro‐organisms. Antimicrobial activity was confirmed for both EOs using cellulose‐based filter paper as supporting matrix, although it was significantly more intense for oregano EO. Inhibition surfaces were significantly greater when compared with those of the WPI films. This finding is likely due to the higher porosity and diffusivity of the active compounds in the filter paper. CONCLUSION: The interactions between the EOs and the films have a critical effect on the diffusivity of the active compounds and therefore on the final antimicrobial activity. As a result, to obtain active edible films, it is necessary to find the equilibrium point between the nature and concentration of the active compounds in the EO and the formulation of the film. Copyright © 2010 Society of Chemical Industry  相似文献   
28.
Biodegradable self‐reinforced films of poly (3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) and PHBV microparticles were prepared through the solvent casting method (srPHBV). Differential scanning calorimetry (DSC), wide angle X‐ray scattering (WAXS) and polarized optical microscopy results confirmed the nucleating effect of PHBV microparticles. WAXS proved that diffractograms of PHBV and srPHBV‐6 films at room temperature contain the main characteristic diffraction peaks of an orthorhombic α‐type crystalline structure. Small angle X‐ray scattering (SAXS) showed a similar decrement rate of long spacing in PHBV and srPHBV films. SAXS/WAXS data revealed that when the amount of filler was increased, lamellae thickness grew. Transmission electron microscopy images illustrated well filler dispersion in the srPHBV films. Scanning electron microscopy results exhibited a significant reduction in porosity for srPHBV films once the PHBV microparticles were added. Atomic force microscopy analysis showed higher surface roughness after filler incorporation. Samples of srPHBV films showed higher barrier properties against water vapor, oxygen, and carbon dioxide. Combined properties of srPHBV films revealed the possibility of being suitable candidates for food packaging applications. POLYM. ENG. SCI., 59:E120–E128, 2019. © 2018 Society of Plastics Engineers  相似文献   
29.
Biomimetic materials with biomechanical properties resembling those of native tissues while providing an environment for cell growth and tissue formation, are vital for tissue engineering (TE). Mechanical anisotropy is an important property of native cardiovascular tissues and directly influences tissue function. This study reports fabrication of anisotropic cell‐seeded constructs while retaining control over the construct's architecture and distribution of cells. Newly synthesized poly‐4‐hydroxybutyrate (P4HB) is fabricated with a dry spinning technique to create anelastomeric fibrous scaffold that allows control of fiber diameter, porosity, and rate ofdegradation. To allow cell and tissue ingrowth, hybrid scaffolds with mesenchymalstem cells (MSCs) encapsulated in a photocrosslinkable hydrogel were developed. Culturing the cellularized scaffolds in a cyclic stretch/flexure bioreactor resulted in tissue formation and confirmed the scaffold's performance under mechanical stimulation. In vivo experiments showed that the hybrid scaffold is capable of withstanding physiological pressures when implanted as a patch in the pulmonary artery. Aligned tissue formation occurred on the scaffold luminal surface without macroscopic thrombus formation. This combination of a novel, anisotropic fibrous scaffold and a tunable native‐like hydrogel for cellular encapsulation promoted formation of 3D tissue and provides a biologically functional composite scaffold for soft‐tissue engineering applications.  相似文献   
30.
The performance assessment of wind farms requires the acquisition of accurate power and wind speed data of each turbine. Nowadays, the nacelle anemometry is widely studied as an option for power performance verification. Therefore, systems to detect the nacelle anemometer faults in a wind farm in operation are necessary for maintenance purposes. In this paper, we propose a method to detect wind speed deviations of the nacelle anemometers by comparing them with the nearby anemometers. This comparison is made through an approach to estimate the wind speed in each nacelle. The approach is based on the discretization of wind speed data using the bin method. The key issue of this proposal is the estimation of the anemometer deviations considering the range of data with lower uncertainty. To this end, an average uncertainty model per bin and direction sector has been integrated into the method. The tests show that using wind speeds higher than 4.5 m s ? 1 gives the lowest uncertainty. Data from two wind farms have been used to test this method, and the obtained results have allowed the detection of problematic anemometers. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
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