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81.
The UV–Vis absorption spectra of ribavirin in the absence and presence of calf thymus DNA are presented and discussed in this paper. The molecular structure of ribavirin was investigated by the semiempirical AM1 method, which triggered two polymorphic modifications of the antiviral drug also reported in the literature. Our experimental results point out two types of the binding. The first type involves a non-electrostatic (internal) binding, consisting of the intercalation of drug between the nitrogenous bases of nucleic acid. The second type (an external binding) involves the drug binding to the nucleic acid grooves. In addition, the binding constant of the second process has an order of magnitude greater than the binding constant for the first process, calculated by the Benesi–Hildebrand, Scott, and Scatchard methods, which supposes a 1:1 binding ratio. Also, the interactions of two polymorphic modifications of ribavirin (V1 and V2) with nucleic acids by the molecular mechanic and semiempirical AM1 methods were analyzed. The experimental data pointed out that in the ribavirin–nucleic acid complexes, the 1,2,4-triazole-3-carboxamide chromophore is intercalated between the bases of the nucleic acid sequences, the carboxamidic group is set outside of the nucleic acid sequence toward the major groove, and the 2-hydroxymethyl-tetrahydrofuran-3,4-diol fragment is located in the minor groove. In order to stress the sequence specificity of ribavirin, different models of the nucleic acid sequences containing adenine (A), thymine (T), cytosine (C), and guanine (G) in AAAAAA, TTTTTT, CCCCCC, GGGGGG, ATATAT, CGCGCG, ATCGAT, and CGATCG were used. The theoretical results outline the differences in the contributions of the electrostatic and van der Waals interactions to the total binding energy and the preference of ribavirin for the binding at the sequences of nucleic acids containing adenine and thymine bases.  相似文献   
82.
The sterols and fatty acids contents of 22 extravirgin olive oil samples produced in the Etna area and in other areas of Sicily were determined. Principal component analysis (PCA) of these data provided a ‘scores’ plot where samples produced in the Etna area were clearly grouped and unknown samples could be classified according to their geographical origin. This classification was confirmed by the residual standard deviation values of all samples fitted into a disjoint principal components model derived from Etna oils only. The above results suggest that the DOC (denominazlone di origine controllata) origin mark for Etna extravirgin olive oils can be attributed on the basis of their sterols and fatty acids contents by means of PCA.  相似文献   
83.
A necessity measure is a function n from a Boolean algebra B to the real interval [0,1] such that n(xy) = min{n(x),n(y)} for every x,y ? B and n(0) = 0, n(1) = 1. Necessities are strictly related to Shafer's consonant belief functions and are basic tools when dealing with imprecision and uncertainty. In this article we propose a technique to generate necessities given a collection of items of information quantified by an initial valuation. the method we employ enables us to define conditional necessities in a very natural way and the composition of two necessities by a rule analogous to Dempster's rule. This is obtained by skipping the condition n(0) = 0 and therefore considering necessities with a nonzero “degree of inconsistency.” © 1992 John Wiley & Sons, Inc.  相似文献   
84.
Oxygen scavenger applications in flexible food packaging are still limited due to the difficulty to ensure scavenging activity during storage and throughout the product shelf life. To avoid fast inactivation of the scavenger, multilayer active structures can be realized by inserting the active layer between two or more inert layers. In this work, an unsteady‐state 1D reaction‐diffusion mass transfer model was developed for predicting and optimizing the barrier‐to‐oxygen performance and the physical configurations of the co‐extruded multilayer active films. The film configuration was a three‐layers structure composed of polyethylene terephthalate (PET) as external inert layers, and PET with a polymeric oxygen scavenger as the core reactive layer. Scavenging activity of the multilayer film increased with the reactive layer thickness. Oxygen absorption reaction at short times decreased proportionally with the thickness of the external layers. The most appropriate combinations of inert‐to‐active film thickness were studied and analyzed. © 2017 American Institute of Chemical Engineers AIChE J, 2017  相似文献   
85.
α‐Galactosidase (αGal) is a lysosomal enzyme that hydrolyses the terminal α‐galactosyl moiety from glycosphingolipids. Mutations in the encoding genes for αGal lead to defective or misfolded enzyme, which results in substrate accumulation and subsequent organ dysfunction. The metabolic disease caused by a deficiency of human α‐galactosidase A is known as Fabry disease or Fabry–Anderson disease, and it belongs to a larger group known as lysosomal storage diseases. An effective treatment for Fabry disease has been developed by enzyme replacement therapy (ERT), which involves infusions of purified recombinant enzyme in order to increase enzyme levels and decrease the amounts of accumulated substrate. However, immunoreactivity and IgG antibody formation are major, therapy‐limiting, and eventually life‐threatening complications of ERT. The present study focused on the epitope determination of human α‐galactosidase A against its antibody formed. Here we report the identification of the epitope of human αGal(309–332) recognized by a human monoclonal anti‐αGal antibody, using a combination of proteolytic excision of the immobilized immune complex and surface plasmon resonance biosensing mass spectrometry. The epitope peptide, αGal(309–332), was synthesized by solid‐phase peptide synthesis. Determination of its affinity by surface plasmon resonance analysis revealed a high binding affinity for the antibody (KD=39×10?9 m ), which is nearly identical to that of the full‐length enzyme (KD=16×10?9 m ). The proteolytic excision affinity mass spectrometry method is shown here to be an efficient tool for epitope identification of an immunogenic lysosomal enzyme. Because the full‐length αGal and the antibody epitope showed similar binding affinities, this provides a basis for reversing immunogenicity upon ERT by: 1) treatment of patients with the epitope peptide to neutralize antibodies, or 2) removal of antibodies by apheresis, and thus significantly improving the response to ERT.  相似文献   
86.
87.
Samples of flour derived from an organic wheat seed cultivated in the region Abruzzo (Central Italy) were examined for the detection of aflatoxins, deoxynivalenol, ochratoxin A and zearalenone after storage in the presence of oxygen or under vacuum, for one year. They were analysed by high-performance liquid chromatography with fluorescence detection for aflatoxins, ochratoxin A and zearalenone and with diode array detector for deoxynivalenol. An immunoaffinity column clean-up was applied for all the compounds, except for aflatoxin determination, which required a solid-phase extraction. Recoveries (range: 76–107%) and within-laboratory reproducibility (RSD% < 10.3) met the performance criteria of Commission Regulation (EU) No. 519/2014 amending Commission Regulation (EC) No. 401/2006 for the detection of mycotoxins in foodstuffs. Analytes were below the detection limit of the method, and this result was probably due to the quality of organic seed and good agricultural practices performed for the prevention of mycotoxin formation.  相似文献   
88.
Differentiated thyroid cancers (DTC) are commonly and successfully treated with total thyroidectomy plus/minus radioiodine therapy (RAI). Medullary thyroid cancer (MTC) is only treated with surgery but only intrathyroidal tumors are cured. The worst prognosis is for anaplastic (ATC) and poorly differentiated thyroid cancer (PDTC). Whenever a local or metastatic advanced disease is present, other treatments are required, varying from local to systemic therapies. In the last decade, the efficacy of the targeted therapies and, in particular, tyrosine kinase inhibitors (TKIs) has been demonstrated. They can prolong the disease progression-free survival and represent the most important therapeutic option for the treatment of advanced and progressive thyroid cancer. Currently, lenvatinib and sorafenib are the approved drugs for the treatment of RAI-refractory DTC and PDTC while advanced MTC can be treated with either cabozantinib or vandetanib. Dabrafenib plus trametinib is the only approved treatment by FDA for BRAFV600E mutated ATC. A new generation of TKIs, specifically for single altered oncogenes, is under evaluation in phase 2 and 3 clinical trials. The aim of this review was to provide an overview of the current and future treatments of thyroid cancer with regards to the advanced and progressive cases that require systemic therapies that are becoming more and more targeted on the molecular identity of the tumor.  相似文献   
89.
In the modern electric arc furnace (EAF), more than 40 % of energy comes from chemical sources by fossil fuels: natural gas is used in dedicated burners during the melting of the scrap, while lump coal (mainly anthracite) is added to the basket and pulverized coal is injected as a foaming agent. Within the frame of the European Research Fund for Coal and Steel (RFCS), the ongoing project GREENEAF (RFSR-CT-2009-004) is studying the possibility to replace coal and natural gas in EAF with char and syngas produced by biomass pyrolysis. The best pyrolysis conditions to obtain the proper syngas and char quality have been defined by laboratory tests using biomass available in the surrounding of the partners steel shops. Industrial trials have been performed in three different EAF plants. The results demonstrated the technical feasibility of the approaches, while the economical evaluation has showed the sustainability of replacing the coal with char from biomass in addition to environmental benefits due to CO2 reduction.  相似文献   
90.
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