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排序方式: 共有2172条查询结果,搜索用时 15 毫秒
71.
V. P. Sergeev E. P. Plygan' E. A. Ivashchenko N. I. Vagin N. N. Baglei 《Fibre Chemistry》2002,34(6):433-439
Surgical sutures with antimicrobial and fungicidal properties in which not only the capillary effect was eliminated but the atraumatic indexes were also improved were developed. The easier threading of the sutures in the suture needle also indicates that atraumatic domestic sutures corresponding to the current requirements of medicine have been obtained. 相似文献
72.
Novel monomers 1a, 1b, in which a phosphonate function is incorporated in both aromatic rings, were synthesized from the addition reaction of tetraisopropyl [2,2′-disulfanyl-5,5′-thiodiphenyl]-1,1′-diphosphonate and diisopropyl (2-sulfanylphenyl)-1-phosphonate with the glycidylmethacrylate. Free radical homo- and copolymerizations of phosphonate monomers containing methacrylate groups were first carried out in bulk and in THF solution. They offered (co)polymers for potential use in dental resins, in high yields and moderate to high inherent viscosities. The components and structure of the (co)polymers were confirmed by FTIR, SEC, 1H, 31P NMR spectra.
Thermal analysis by using differential scanning calorimetry indicated an amorphous structure of the (co)polymers obtained by polymerization in solution. Upon UV-radiation the composite resins have been synthesized by cross-linking reaction. 相似文献
73.
Low‐Temperature Chemical Synthesis of High‐Purity Diacylglycerols (DAG) from Monoacylglycerols (MAG)
A chemical method was developed for low‐temperature synthesis of DAG from MAG followed by an easy purification procedure in order to obtain high‐purity DAG. Solvent‐assisted and solvent‐free reaction conditions were used, combined with different catalysts (sodium methoxide, p‐toluenesulfonic acid, methanesulfonic acid, and sulfuric acid). All reactions were performed at 35 and 70 °C. By increasing both acidity and polarity of the catalyst the equilibrium shifts towards the formation of DAG. When using sulfuric acid in solvent‐assisted condition at 70 °C, 88 % conversion was obtained after 20 min of reaction (77 % w/w DAG in the reaction mixture after evaporation of the solvent). After purifying by means of column chromatography, 96 % pure DAG were obtained. The overall yield of DAG was 81 %. 相似文献
74.
75.
Sustainable Oxidative Cleavage of Vegetable Oils into Diacids by Organo-Modified Molybdenum Oxide Heterogeneous Catalysts 下载免费PDF全文
Aimé Serge Ello Amir Enferadi-kerenkan Albert Trokourey Trong-On Do 《Journal of the American Oil Chemists' Society》2017,94(12):1451-1461
Exploiting vegetable oils to produce industrially valuable diacids via an eco‐friendly process requires an efficient and recyclable catalyst. In this work, a novel catalytic system based on organo‐modified molybdenum trioxide was synthesized by a green hydrothermal method in one simple step, using Mo powder as precursor, hydrogen peroxide, and amphiphilic surfactants cetyltrimethylammonium bromide (CTAB) and tetramethylammonium bromide (TMAB) as capping agents. The synthesized materials were first characterized by different techniques including XRD, SEM, TGA, and FT‐IR. Interestingly, various morphologies were obtained depending on the nature of the surfactants and synthetic conditions. The synthesized catalysts were employed in oxidative cleavage of oleic acid, the most abundant unsaturated fatty acid, to produce azelaic and pelargonic acids with a benign oxidant, H2O2. Excellent catalytic activities resulting in full conversion of initial oleic acid were obtained, particularly for CTAB‐capped molybdenum oxide (CTAB/Mo molar ratio of 1:3) that gave 83 and 68% yields of production of azelaic and pelargonic acids, respectively. These are the highest yields that have been obtained for this reaction by heterogeneous catalysts up to now. Moreover, the CTAB‐capped catalyst could be conveniently separated from the reaction mixture by simple centrifugation and reused without significant loss of activity up to at least four cycles. 相似文献
76.
Brigitte Mouanda Veronique Eyeffa Serge Palacin 《Journal of Applied Electrochemistry》2009,39(3):313-320
An agarose gel was used as an electrochemical cell to graft vinylic polymer layers on conductive surfaces by electro-initiated
radical electrografting of various water-soluble and hydrophobic vinylic monomers in the presence of diazonium ions. The process
was followed by in situ electrochemical measurements and the resulting grafted layer was characterized by infrared (IRRAS)
and photoelectron (XPS) spectroscopy.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
77.
Serge Laplante Nathalie Souchet Piotr Bryl 《European Journal of Lipid Science and Technology》2009,111(2):135-141
Among the fat fish species available from Eastern Quebec (Canada), whole Atlantic mackerel (Scomber scombrus) and herring (Clupea harengus) represent abundant fishery resources which are currently under‐utilized. They have relatively high contents of oil and coenzyme Q10 (CoQ10) in their tissues, which could be valuable for nutraceutical applications. Therefore, two low‐temperature extraction processes were compared for the recovery of oil and CoQ10 from these resources, such as enzymatic hydrolysis using Protamex? and supercritical CO2 (SCO2) using fish lyophilizates. The results revealed that highest yields of oil and CoQ10 were obtained using the enzymatic hydrolysis process with mackerel. Whatever the process used, CoQ10 concentrations were higher in herring oil, due mainly to a more selective extraction of CoQ10 over that of the oil. The highest CoQ10 recovery rates (extraction efficiencies) were obtained using the enzymatic hydrolysis process with both types of fish, but also the SCO2 process with herring under some conditions. For mackerel, the lower CoQ10 recovery rates obtained from the SCO2 process were explained by its more important matrix effect. An economic assessment of both processes revealed that the enzymatic hydrolysis extraction process would be the most promising for up‐scaling the recovery of oil and CoQ10 from these resources. 相似文献
78.
79.
Trappeniers M Goormans S Van Beneden K Decruy T Linclau B Al-Shamkhani A Elliott T Ottensmeier C Werner JM Elewaut D Van Calenbergh S 《ChemMedChem》2008,3(7):1061-1070
alpha-GalCer (also known as KRN7000) is an immunomodulatory glycolipid that is known to potently activate invariant natural killer T (NKT) cells upon CD1d-mediated stimulation. Because Th1 and Th2 cytokines, which are released after alpha-GalCer presentation, antagonize each other's effects, alpha-GalCer analogues that induce a biased Th1/Th2 response are highly awaited. In this context, we report the synthesis and in vitro evaluation of alpha-Gal-D-xylo-Cer and two alpha-Gal-L-lyxo-Cer analogues, one with the natural acyl chain, the other with a truncated chain. 相似文献
80.
Radiometric layer-by-layer analysis has been used to study the grain-boundary diffusion of Co in submicrocrystalline Mo produced by severe plastic deformation using high-pressure torsion. It has been found that, under severe plastic deformation, nonequilibrium grain boundaries have been formed, which are ultrafast diffusion paths. During annealing, the recovery of nonequilibrium grain boundaries takes place. The properties of boundaries that underwent the recovery were shown to be close to those of boundaries originated by recrystallization in coarse-grained Mo. As the annealing temperature increases, the fraction of nonequilibrium boundaries decreases; and beginning from 823 K, there are no more nonequilibrium boundaries in the structure. 相似文献