全文获取类型
收费全文 | 17430篇 |
免费 | 2018篇 |
国内免费 | 481篇 |
专业分类
电工技术 | 412篇 |
综合类 | 273篇 |
化学工业 | 5393篇 |
金属工艺 | 442篇 |
机械仪表 | 623篇 |
建筑科学 | 248篇 |
矿业工程 | 89篇 |
能源动力 | 3471篇 |
轻工业 | 1531篇 |
水利工程 | 29篇 |
石油天然气 | 67篇 |
武器工业 | 31篇 |
无线电 | 2897篇 |
一般工业技术 | 3438篇 |
冶金工业 | 206篇 |
原子能技术 | 263篇 |
自动化技术 | 516篇 |
出版年
2024年 | 38篇 |
2023年 | 585篇 |
2022年 | 1492篇 |
2021年 | 1754篇 |
2020年 | 866篇 |
2019年 | 748篇 |
2018年 | 672篇 |
2017年 | 802篇 |
2016年 | 788篇 |
2015年 | 804篇 |
2014年 | 1071篇 |
2013年 | 1077篇 |
2012年 | 1089篇 |
2011年 | 1536篇 |
2010年 | 1010篇 |
2009年 | 888篇 |
2008年 | 777篇 |
2007年 | 738篇 |
2006年 | 571篇 |
2005年 | 424篇 |
2004年 | 316篇 |
2003年 | 287篇 |
2002年 | 258篇 |
2001年 | 200篇 |
2000年 | 167篇 |
1999年 | 108篇 |
1998年 | 173篇 |
1997年 | 124篇 |
1996年 | 76篇 |
1995年 | 51篇 |
1994年 | 59篇 |
1993年 | 45篇 |
1992年 | 39篇 |
1991年 | 51篇 |
1990年 | 33篇 |
1989年 | 38篇 |
1988年 | 26篇 |
1987年 | 21篇 |
1986年 | 22篇 |
1985年 | 25篇 |
1984年 | 20篇 |
1983年 | 13篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 12篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1975年 | 3篇 |
1951年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
《Food Control》2017
The sanitising effect of low concentration neutralised electrolysed water (LCNEW, pH: 7.0, free available chlorine (FAC): 4 mg/L) combined with ultrasound (37 kHz, 80 W) on food contact surface was evaluated. Stainless steel coupon was chosen as attachment surface for Escherichia coli ATCC 25922, Pichia pastoris GS115 and Aureobasidium pullulans 2012, representing bacteria, yeast and mold, respectively. The results showed that although LCNEW itself could effectively reduce survival population of E. coli ATCC 25922, P. pastoris GS115 and low concentration A. pullulans 2012 in planktonic status, LCNEW combined with ultrasound showed more sanitising efficacy for air-dried cells on coupons, with swift drops: 2.2 and 3.1 log CFU/coupon reductions within 0.2 min for E. coli ATCC 25922 and P. pastoris GS115, respectively and 1.0 log CFU/coupon reductions within 0.1 min for A. pullulans 2012. Air-dried cells after treatment were studied by atomic force microscopy (AFM)/optical microscopy (OM) and protein leakage analyses further. All three strains showed visible cell damage after LCNEW and LCNEW combined with ultrasound treatment and 1.41 and 1.73 μg/mL of protein leakage were observed for E. coli ATCC 25922 and P. pastoris GS115, respectively after 3 min combination treatment, while 6.22 μg/mL of protein leakage for A. pullulans 2012 after 2 min combination treatment. For biofilms, LCNEW combined with ultrasound also significantly reduced the survival cells both on coupons and in suspension for all three strains. The results suggest that LCNEW combined with ultrasound is a promising approach to sanitise food equipment. 相似文献
952.
《Food Control》2017
The antibacterial properties of Se NPs were investigated against four foodborne pathogens (Escherichia coli O157:H7, Staphylococcus aureus, Salmonella, and Listeria monocytogenes). The cytotoxicity of Se NPs was also studied using the Caco-2 cell line. Se NPs at concentrations of 10 μg/mL or higher exhibited dose-dependent antimicrobial properties against S. aureus, but not on the other three pathogens. Se NPs also exhibited various degrees of toxicity on Caco-2 cells after 24 h of exposure. Cellular shrinkage and irregular shapes of treated bacterial cells indicated that the antimicrobial effects of Se NPs are bacteriostatic, not bactericidal. This is the first study to investigate the antimicrobial activity of Se NPs against important foodborne pathogens. The results of this study demonstrate that Se NPs can be used as an antimicrobial agent to inhibit the growth of S. aureus and can be potentially used for food safety applications. 相似文献
953.
954.
955.
Ahmad Umar 《Nanoscale research letters》2009,4(9):1004-1008
Dye-sensitized solar cells (DSSCs) were fabricated by using well-crystallized ZnO nanocombs directly grown onto the fluorine-doped
tin oxide (FTO) via noncatalytic thermal evaporation process. The thin films of as-grown ZnO nanocombs were used as photoanode
materials to fabricate the DSSCs, which exhibited an overall light to electricity conversion efficiency of 0.68% with a fill
factor of 34%, short-circuit current of 3.14 mA/cm2, and open-circuit voltage of 0.671 V. To the best of our knowledge, this is first report in which thin film of ZnO nanocombs
was used as photoanode materials to fabricate the DSSCs. 相似文献
956.
Photovoltaics: Quantification of Nano‐ and Mesoscale Phase Separation and Relation to Donor and Acceptor Quantum Efficiency,Jsc, and FF in Polymer:Fullerene Solar Cells (Adv. Mater. 25/2014)
下载免费PDF全文
![点击此处可从《Advanced materials (Deerfield Beach, Fla.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Wei Ma John R. Tumbleston Long Ye Cheng Wang Jianhui Hou Harald Ade 《Advanced materials (Deerfield Beach, Fla.)》2014,26(25):4399-4399
957.
Analyzing the behaviors of virtual cells (VCs) and traditional manufacturing systems: Ant colony optimization (ACO)-based metamodels 总被引:1,自引:0,他引:1
Saadettin Erhan Kesen M. Duran Toksari Zülal Güngör Ertan Güner 《Computers & Operations Research》2009
The aim of this paper is two fold. First we investigate the three different types of systems, namely cellular layout (CL), process layout (PL) and virtual cells (VCs). VCs are addressed by using family-based scheduling rule, developed by a part allocation algorithm in a PL. Simulation is used to compare three types of systems under the performance metrics such as mean flow time and mean tardiness. Results indicate that VCs have better responsiveness in terms of the performance metrics. Second we develop a new ant colony optimization-based metamodels fed by existing simulation runs to represent the prospective simulation runs, which require a lot of time and effort. Regression metamodels, which allow us to obtain much faster results, are seen to be promising to estimate the systems behaviors. 相似文献
958.
James R. Wilson Anh T. Duong Hsun-Yi Chen Daniel R. Mumm 《Journal of power sources》2010,195(7):1829-1840
Composite La0.8Sr0.2MnO3 (LSM)-Y2O3-stabilized ZrO2 (YSZ) cathodes with compositions ranging from 30:70 to 70:30 wt.% LSM:YSZ were studied both electrochemically and microstructurally. Polarization resistance was lowest for the 50 wt.% YSZ composition, and increased symmetrically as the composition deviated from this value. Serial-sectioning using focused ion beam-scanning electron microscopy was implemented to reconstruct the three-dimensional cathode microstructure. Various averaged structural parameters were determined versus composition, including phase volume fractions, surface area densities, total triple-phase boundary (TPB) densities, interfacial curvatures, phase tortuosities, and the levels of phase connectivity. Typically >90% of the pore and YSZ networks were found to be intra-connected to the surrounding phase, but the LSM networks showed lower connected fractions, as low as 37.5% for a LSM weight fraction of 30%. The composition dependences of the total TPB density and electrochemically-active TPB density (i.e., TPB's on three fully intra-connected phases) were shown to agree reasonably well with simple “sphere-packing” structural models. An electrochemical model that accounted for the linear-specific resistance of TPB's, phase intra-connectivity, and oxygen ion transport in the YSZ as influenced by its tortuosity, was found to provide reasonable agreement with the measured polarization resistance versus composition. 相似文献
959.
Pt-Ru/C catalyst (12 wt%) was prepared by the incipient wetness impregnation method followed by a redox heat-treatment. Transmission electron microscopy (TEM) results revealed uniformly distributed metallic crystallites of Pt-Ru alloy nanoparticles (dPtRu = 2.1 ± 1.0 nm). The effect of redox treatments of the impregnated catalysts on methanol oxidation reaction (MOR) was examined by cyclic voltammetry (CV). The MOR activity of the PtRu/C was significantly improved after each oxidation step of the redox treatment cycles. The enhanced catalytic activity was found to be quite stable in chronoamperometry (CA) measurements. CV, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) results strongly suggested that the improved catalytic activity was due to the formation of a stable c-RuOx (x = 2-3) domain during the oxidation treatments. A bifunctional based mechanism was proposed for the MOR on the oxidized PtRu/C catalysts. Formation of Ru-OH species on the surface of c-RuOx domains was suggested as stale sites for the oxidation of carbon monoxide adsorbed on the Pt catalytic sites. 相似文献
960.