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51.
Paul P. Van Veldhoven Johannes V. Swinnen Murielle Esquenet Guido Verhoeven 《Lipids》1997,32(12):1297-1300
A protocol, based on the use of Pseudomonas lipase, is presented to measure quantitatively the amount of triacylglycerols in extracts from cultured cells or tissues.
Since the lipase also acts on di- and monoacylglycerols, separation of the extracts by thin-layer chromatography is recommended.
In order to allow the lipase-catalyzed hydrolysis to proceed efficiently, lipid extracts or eluates from silica scraping were
mixed with the detergent Thesit [dodecylpoly(ethylene glycol ether)], prior to drying. After dissolution of the dried residues
in water, the amount of triacylglycerols was quantified using Pseudomonas sp. lipase, glycerol kinase, glycerol-phosphate oxidase, and peroxidase. The activity of the latter enzyme was followed either
colorimetrically in the presence of 4-aminoantipyrine and 2,4,6-tribromo-3-hydroxybenzoic acid or fluorimetrically in the
presence of homovanillic acid. 相似文献
52.
Effects of cutting angle,edge preparation,and nano-structured coating on milling performance of a gamma titanium aluminide 总被引:1,自引:0,他引:1
Paolo Claudio Priarone Stefania Rizzuti Luca Settineri Guido Vergnano 《Journal of Materials Processing Technology》2012,212(12):2619-2628
Gamma titanium aluminides are intermetallic alloys. Recently, they have been evaluated as important contenders for structural applications in the automotive and aerospace sectors. This is due to their excellent high-temperature performances and their significantly lower density compared to nickel-based superalloys. In this paper, an analysis of machinability of a gamma TiAl obtained via an electron beam melting (EBM) process is presented. The effects of tool geometry modifications, in terms of cutting tool angles and cutting edge preparation, were investigated. The reduction of radial rake angle and the drag finishing process for cutting edge preparation resulted in an increase of the tool life of the carbide end mills. Nanogradient tool coatings were also observed to affect tool wear during milling tests, and the results highlight that AlSiTiN coating performs better compared to CrAlSiN coating. A post-coating polishing treatment was also taken into account, and it allowed a further reduction of tool wear. The overall results indicate that the machinability of this difficult-to-cut material can be significantly improved by an adjustment of the cutting edge geometry, and by using an AlSiTiN coating system. 相似文献
53.
Silica-supported MoO3 catalysts with MoO3 loadings up to 21% w/w were prepared, characterized and tested in the selective catalytic oxidation (SCO) of ammonia to N2 under dilute conditions. It is found that the catalysts are active and selective in the reaction, and that the catalytic performance increases on increasing the Mo loading. Crystalline MoO3, detected over the silica support, is supposed to be the active species in the reaction. The reactivity of the catalysts is depressed by water addition to the feed at low temperatures and is enhanced by the presence of selected promoters, like Bi and Pb. 相似文献
54.
María D. Hernndez-Alonso Ana R. Almeida Jacob A. Moulijn Guido Mul 《Catalysis Today》2009,143(3-4):326
Anatase-structured Ti1−xZrxO2 materials with x = 0.00, 0.01 and 0.06, were prepared by a reverse microemulsion method, characterized, and tested as catalysts for the selective photo-oxidation of cyclohexane to cyclohexanone. In situ ATR-FTIR spectroscopy was used to evaluate the reaction. Zr incorporation into the anatase lattice enhances the surface acidity of TiO2 without causing any significant structural or electronic modification. As expected, also the stability of surface adsorbed water, i.e. the hydrophilicity, was enhanced. The increase in the Brønsted acidity, together with the higher hydrophilicity, is shown to be detrimental for performance (selectivity and stability) in the selective photo-oxidation of cyclohexane. Apparently potential intrinsic catalytic advantages of having higher acidity are outweighed by (i) the enhanced number of water born OH radicals, inducing non-selective reactions, and (ii) enhanced hydrophilicity leading to slow desorption and consecutive oxidation of cyclohexanone. 相似文献
55.
Highly bright and photostable cyanine dye-doped silica nanoparticles for optical imaging: Photophysical characterization and cell tests 总被引:1,自引:0,他引:1
Ivana Miletto Alessandra Gilardino Pollyanna Zamburlin Simona Dalmazzo Davide Lovisolo Giuseppe Caputo Guido Viscardi Gianmario Martra 《Dyes and Pigments》2010,84(1):121-127
Spherical silica nanoparticles containing fluorescent trimethine indocyanine dyes (λabs = 547 nm, λem = 570 nm) were prepared using a water-in-oil microemulsion method. The nanoparticles were of 50 nm diameter and were almost monodispersed in aqueous solution at pH 5.5. Entrapment of dye molecules in the silica matrix stabilised photoemission over several hours of continuous irradiation. The photoemission intensity of the indocyanine was increased 13-fold over that recorded in solution. As each nanoparticle contained 110 dye molecules, the photoemission brightness of each particle was enhanced by three orders of magnitude. The fluorescent nanoparticles have been tested as imaging tools in in vitro tests. As an example of non-macrophagic cells, a highly differentiated neuronal cell line (GT1-7) was used and the results showed that the prepared nanoparticles can be incorporated into these cells with no apparent toxicity for up to three days. 相似文献
56.
Fabian Essig Lilith Babilon Christoph Vollmuth Alexander M. Kollikowski Mirko Pham Lszl Solymosi Karl Georg Haeusler Peter Kraft Guido Stoll Michael K. Schuhmann 《International journal of molecular sciences》2021,22(20)
High-mobility group box 1 protein (HMGB1) is a damage-associated molecular pattern (DAMP) involved in neutrophil extracellular trap (NET) formation and thrombosis. NETs are regularly found in cerebral thromboemboli. We here analyzed associated HMGB1 expression in human thromboemboli retrieved via mechanical thrombectomy from 37 stroke patients with large vessel occlusion. HMGB1 was detected in all thromboemboli, accounting for 1.7% (IQR 0.6–6.2%) of the total thromboemboli area and was found to be colocalized with neutrophils and NETs and in spatial proximity to platelets. Correlation analysis revealed that the detection of HMGB1 was strongly related to the number of neutrophils (r = 0.58, p = 0.0002) and platelets (r = 0.51, p = 0.001). Our results demonstrate that HMGB1 is a substantial constituent of thromboemboli causing large vessel occlusion stroke. 相似文献
57.
Present assembly systems are often based on rigid, line-based approaches and are hindered in their reconfiguration capability. Line-less Mobile Assembly Systems (LMAS) are a novel approach for assembly organization. They improve flexibility through mobile resources, permitting spatiotemporal freedom in scheduling and resource assignment. This paper presents a method for a priori assessment of LMAS during the early stages of the assembly system design process. The method applies a modified, extended mean value analysis to a closed queuing network representation of LMAS to estimate performance. The method is validated model analysis and comparison on two use cases indicating plausible model behavior. 相似文献
58.
Matthias Bosman Dustin N. Krüger Kasper Favere Callan D. Wesley Cdric H. G. Neutel Birgit Van Asbroeck Owen R. Diebels Bart Faes Timen J. Schenk Wim Martinet Guido R. Y. De Meyer Emeline M. Van Craenenbroeck Pieter-Jan D. F. Guns 《International journal of molecular sciences》2021,22(23)
Clinical and animal studies have demonstrated that chemotherapeutic doxorubicin (DOX) increases arterial stiffness, a predictor of cardiovascular risk. Despite consensus about DOX-impaired endothelium-dependent vasodilation as a contributing mechanism, some studies have reported conflicting results on vascular smooth muscle cell (VSMC) function after DOX treatment. The present study aimed to investigate the effects of DOX on VSMC function. To this end, mice received a single injection of 4 mg DOX/kg, or mouse aortic segments were treated ex vivo with 1 μM DOX, followed by vascular reactivity evaluation 16 h later. Phenylephrine (PE)-induced VSMC contraction was decreased after DOX treatment. DOX did not affect the transient PE contraction dependent on Ca2+ release from the sarcoplasmic reticulum (0 mM Ca2+), but it reduced the subsequent tonic phase characterised by Ca2+ influx. These findings were supported by similar angiotensin II and attenuated endothelin-1 contractions. The involvement of voltage-gated Ca2+ channels in DOX-decreased contraction was excluded by using levcromakalim and diltiazem in PE-induced contraction and corroborated by similar K+ and serotonin contractions. Despite the evaluation of multiple blockers of transient receptor potential channels, the exact mechanism for DOX-decreased VSMC contraction remains elusive. Surprisingly, DOX reduced ex vivo but not in vivo arterial stiffness, highlighting the importance of appropriate timing for evaluating arterial stiffness in DOX-treated patients. 相似文献
59.
Irene Malpartida Maria Angeles Larrubia Vargas Luis J. Alemany Elisabetta Finocchio Guido Busca 《Applied catalysis. B, Environmental》2008,80(3-4):214-225
Pt–Ba–Al2O3 active and selective for NOx storage and selective reduction to N2 has been prepared and tested. Characterization of the parent Al2O3, Pt–Al2O3 and Ba–Al2O3 materials, as well as of Pt–Ba–Al2O3 catalyst in the oxidized, reduced and sulphated state has been performed by FT-IR spectroscopy of low-temperature adsorbed carbon monoxide and of adsorbed acetonitrile. XRD, TEM and XPS analyses have also been performed. Evidence for the predominance of Ba species, which are highly dispersed on the alumina support surface, and may be carbonated or sulphated, has been provided. Competitive interaction of Pt and Ba species with the surface sites of alumina has also been found. 相似文献
60.
Enabling Electrocatalytic Fischer–Tropsch Synthesis from Carbon Dioxide Over Copper-based Electrodes
We report on the discovery that paraffins and olefins up to C6 hydrocarbons can be obtained in CO2 electroreduction at room temperature and atmospheric pressure by application of a commercially available Cu-electrode (Eurofysica), provided pretreatment by electropolishing is avoided. The product distribution follows the Schultz–Flory distribution and, depending on the applied potential, the chain growth probability (α) ranges from 0.23 to 0.31, values lower than those obtained in Fischer–Tropsch synthesis over heterogeneous Co- or Fe-based catalysts. 相似文献