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61.
Nicolas Bulidon Valérie Deydier Frederic Bumbieler Claude Duret-Thual Christophe Mendibide Didier Crusset 《工业材料与腐蚀》2021,72(1-2):154-165
Since 2014, the concept developed for the disposal of high-level radioactive waste in the French deep geological repository project Cigéo includes a cement-based grout material. This cement-based grout material will be injected between the casing and the claystone to neutralize the potential acidity resulting from the claystone oxidation induced by the drilling process of the disposal cell. In these conditions of pH (around 10.5) and temperature (90°C, maximum expected during the disposal), the metallic materials could be sensitive to stress corrosion cracking (SCC). In this project, different environments (aerated or deaerated, at room temperature or at 90°C) and synthetic solutions are considered to reproduce the different periods expected during the long life repository. The project is based on electrochemical measurements (polarization curves to define the SCC critical domain of potentials), slow strain rate tensile tests, and long-term immersion for crack initiation and propagation tests. 相似文献
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63.
Geoffray Labar Cédric Bauvois Dr. Franck Borel Dr. Jean‐Luc Ferrer Dr. Johan Wouters Prof. Didier M. Lambert Prof. 《Chembiochem : a European journal of chemical biology》2010,11(2):218-227
2‐Arachidonoylglycerol plays a major role in endocannabinoid signaling, and is tightly regulated by the monoacylglycerol lipase (MAGL). Here we report the crystal structure of human MAGL. The protein crystallizes as a dimer, and despite structural homologies to haloperoxidases and esterases, it distinguishes itself by a wide and hydrophobic access to the catalytic site. An apolar helix covering the active site also gives structural insight into the amphitropic character of MAGL, and likely explains how MAGL interacts with membranes to recruit its substrate. Docking of 2‐arachidonoylglycerol highlights a hydrophobic and a hydrophilic cavity that accommodate the lipid into the catalytic site. Moreover, we identified Cys201 as the crucial residue in MAGL inhibition by N‐arachidonylmaleimide, a sulfhydryl‐reactive compound. Beside the advance in the knowledge of endocannabinoids degradation routes, the structure of MAGL paves the way for future medicinal chemistry works aimed at the design of new drugs exploiting 2‐arachidonoylglycerol transmission. 相似文献
64.
65.
In-situ fabrication of polyacrylate-silver nanocomposite through photoinduced tandem reactions involving eosin dye 总被引:1,自引:0,他引:1
A silver-acrylate nanocomposite was prepared using a novel one-pot strategy involving eosin dye as visible sensitizer and an amine derivative as radicals' source. The mechanism highlighted by steady state photolysis and time-resolved absorption spectroscopy lies on the initial formation of a strong ion-pair complex between eosin and Ag+. Upon visible irradiation, the excited triplet state of the metal complex efficiently abstracts a hydrogen atom from the amine and produces an α-aminoalkyl radical. In acrylate monomer matrix, such a strong reactive species initiates a free radical photopolymerization and also provides the reduction of the silver cation. Through this ‘in-situ’ fabrication method, the kinetics formation of the nanocomposite and its detailed structural analysis are characterized by UV-visible, real-time FTIR absorption spectroscopy and by transmission electron microscopy. 相似文献
66.
Shiming Xie Chen Song Zexin Yu Shaowu Liu Frédéric Lapostolle Didier Klein Chunming Deng Min Liu Hanlin Liao 《Journal of the European Ceramic Society》2021,41(1):535-543
Suspension plasma spraying (SPS) as a potential technique to prepare thermal barrier coatings (TBCs) has been attracting more and more attention. However, most reports on SPS were carried out in the atmosphere. Given the unique features of in-flight particles and plasma jets under low pressure, the resulting coatings are expected to be different from those under atmospheric pressure. In this article, yttria-stabilized zirconia (YSZ) thermal barrier coatings were prepared using suspension plasma spraying under different environmental pressures. The results show that as the environmental pressure decreased, the column-like structural coating turned into a vertical crack segmented structure, as well as a dramatic decrease in surface roughness. More nanoparticle agglomerates were formed in the coating under lower environmental pressures. The real porosity of the coating increased with a decrease in environmental pressure. 相似文献
67.
Ali Bougatef Naima Nedjar-Arroume Rozenn Ravallec-Plé Yves Leroy Didier Guillochon Ahmed Barkia Moncef Nasri 《Food chemistry》2008
The angiotensin I-converting enzyme (ACE) inhibitory activities of protein hydrolysates prepared from heads and viscera of sardinelle (Sardinella aurita) by treatment with various proteases were investigated. Protein hydrolysates were obtained by treatment with Alcalase®, chymotrypsin, crude enzyme preparations from Bacillus licheniformis NH1 and Aspergillus clavatus ES1, and crude enzyme extract from sardine (Sardina pilchardus) viscera. All hydrolysates exhibited inhibitory activity towards ACE. The alkaline protease extract from the viscera of sardine produced hydrolysate with the highest ACE inhibitory activity (63.2 ± 1.5% at 2 mg/ml). Further, the degrees of hydrolysis and the inhibitory activities of ACE increased with increasing proteolysis time. The protein hydrolysate generated with alkaline proteases from the viscera of sardine was then fractionated by size exclusion chromatography on a Sephadex G-25 into eight major fractions (P1–P8). Biological functions of all fractions were assayed, and P4 was found to display a high ACE inhibitory activity. The IC50 values for ACE inhibitory activities of sardinelle by-products protein hydrolysates and fraction P4 were 1.2 ± 0.09 and 0.81 ± 0.013 mg/ml, respectively. Further, P4 showed resistance to in vitro digestion by gastrointestinal proteases. The amino acid analysis by GC/MS showed that P4 was rich in phenylalanine, arginine, glycine, leucine, methionine, histidine and tyrosine. The added-value of sardinelle by-products may be improved by enzymatic treatment with visceral serine proteases from sardine. 相似文献
68.
Didier Dupont Giuseppina Mandalari Daniel Molle Julien Jardin Joëlle Léonil Richard M. Faulks Martin S. J. Wickham E. N. Clare Mills Alan R. Mackie 《Molecular nutrition & food research》2010,54(6):767-780
IgE‐mediated allergy to milk and egg is widespread in industrialised countries and mainly affects infants and young children. It may be connected to an incomplete digestion of dietary proteins causing an inappropriate immune response in the gut. In order to study this, a biochemical model of infant gastroduodenal digestion has been developed, which has reduced levels of protease (eightfold for pepsin and tenfold for trypsin and chymotrypsin), phosphatidylcholine and bile salts, compared with the adult model. This model has been used to study the behaviour of three characterised food‐relevant proteins (bovine β‐lactoglobulin (β‐Lg), β‐casein (β‐CN) and hen's egg ovalbumin), all of which are relevant cows' milk and hens' egg allergens. Digestion products were characterised using electrophoresis, immunochemical techniques and MS. These showed that ovalbumin and β‐CN were digested more slowly using the infant model compared with the adult conditions. Resistant fragments of β‐CN were found in the infant model, which correspond to previously identified IgE epitopes. Surprisingly, β‐Lg was more extensively degraded in the infant model compared with the adult one. This difference was attributed to the tenfold reduction in phosphatidylcholine concentration in the infant model limiting the protective effect of this phospholipid on β‐Lg digestion. 相似文献
69.
Ali Bougatef Naima Nedjar-Arroume Laïla Manni Rozenn Ravallec Ahmed Barkia Didier Guillochon Moncef Nasri 《Food chemistry》2010
In order to utilise sardinelle (Sardinellaaurita) protein by-products, which is normally discarded as industrial waste in the process of fish manufacturing, heads and viscera proteins were hydrolysed by different proteases to obtain antioxidative peptides. All hydrolysates showed different degrees of hydrolysis and varying degrees of antioxidant activities. Hydrolysate generated with crude enzyme extract from sardine (Sardinapilchardus) displayed high antioxidant activity, and the higher DPPH radical-scavenging activity (87 ± 2.1% at 2 mg/ml) was obtained with a degree of hydrolysis of 6%. This hydrolysate was fractionated by size exclusion chromatography on a Sephadex G-25 into eight major fractions (P1–P8). Fraction P4, which exhibited the highest DPPH scavenging activity, was then fractionated by reversed-phase high performance liquid chromatography (RP-HPLC). Seven antioxidant peptides were isolated. The molecular masses and amino acids sequences of the purified peptides were determined using ESI-MS and ESI-MS/MS, respectively. Their structures were identified as Leu-His-Tyr, Leu-Ala-Arg-Leu, Gly-Gly-Glu, Gly-Ala-His, Gly-Ala-Trp-Ala, Pro-His-Tyr-Leu and Gly-Ala-Leu-Ala-Ala-His. The first peptide displayed the highest DPPH radical-scavenging activity (63 ± 1.57%; at 150 μg/ml) among these peptides. 相似文献
70.
Structural and biochemical characteristics of bovine intramuscular connective tissue and beef quality 总被引:1,自引:0,他引:1
Annabelle Dubost Didier Micol Brigitte Picard Claire Lethias Donato Andueza Dominique Bauchart Anne Listrat 《Meat science》2013
The aim of the study was to evaluate the impact of structural and biochemical characteristics of muscle intramuscular connective tissue on beef quality. The experimental design was based on three muscles of three breeds sampled as fresh material and cooked at 55 °C (Longissimus thoracis and Semimembranosus) or at 70 °C (Semimembranosus and Biceps femoris) for quality assessment. The results showed that muscle characteristics influence beef quality differently from one muscle to another. In grilled LT, proteoglycan content contributed negatively to juiciness, and intramuscular lipids were linked positively to tenderness, flavour, residues and overall liking scores. In grilled SM, cross-link and lipid contents were involved in beef quality. In BF cooked to 70 °C, perimysial branch points were negatively linked to tenderness. In SM cooked to 70 °C, perimysial area was involved in beef quality. These results should allow a better understanding of the factors involved in background toughness, in juiciness and flavour of meat. 相似文献