全文获取类型
收费全文 | 742篇 |
免费 | 42篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 4篇 |
综合类 | 5篇 |
化学工业 | 206篇 |
金属工艺 | 21篇 |
机械仪表 | 16篇 |
建筑科学 | 20篇 |
能源动力 | 51篇 |
轻工业 | 80篇 |
水利工程 | 5篇 |
石油天然气 | 7篇 |
无线电 | 80篇 |
一般工业技术 | 130篇 |
冶金工业 | 48篇 |
原子能技术 | 3篇 |
自动化技术 | 116篇 |
出版年
2024年 | 6篇 |
2023年 | 14篇 |
2022年 | 39篇 |
2021年 | 79篇 |
2020年 | 37篇 |
2019年 | 49篇 |
2018年 | 62篇 |
2017年 | 39篇 |
2016年 | 43篇 |
2015年 | 26篇 |
2014年 | 36篇 |
2013年 | 47篇 |
2012年 | 42篇 |
2011年 | 50篇 |
2010年 | 30篇 |
2009年 | 37篇 |
2008年 | 20篇 |
2007年 | 20篇 |
2006年 | 12篇 |
2005年 | 8篇 |
2004年 | 9篇 |
2003年 | 7篇 |
2002年 | 8篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1998年 | 10篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1995年 | 8篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1956年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有792条查询结果,搜索用时 15 毫秒
11.
Linux malware can pose a significant threat—its (Linux) penetration is exponentially increasing—because little is known or
understood about Linux OS vulnerabilities. We believe that now is the right time to devise non-signature based zero-day (previously
unknown) malware detection strategies before Linux intruders take us by surprise. Therefore, in this paper, we first do a
forensic analysis of Linux executable and linkable format (ELF) files. Our forensic analysis provides insight into different
features that have the potential to discriminate malicious executables from benign ones. As a result, we can select a features’
set of 383 features that are extracted from an ELF headers. We quantify the classification potential of features using information
gain and then remove redundant features by employing preprocessing filters. Finally, we do an extensive evaluation among classical
rule-based machine learning classifiers—RIPPER, PART, C4.5 Rules, and decision tree J48—and bio-inspired classifiers—cAnt
Miner, UCS, XCS, and GAssist—to select the best classifier for our system. We have evaluated our approach on an available
collection of 709 Linux malware samples from vx heavens and offensive computing. Our experiments show that ELF-Miner provides more than 99% detection accuracy with less than 0.1% false alarm rate. 相似文献
12.
Nazrin S. N. Umar S. A. Halimah M. K. Marian M. M. Najwa Z. W. Jufa M. S. Syahirah M. T. Zuhasanah Z. Azlan M. N. Geidam I. G. Boukhris Imed Kebaili Imen 《Journal of Inorganic and Organometallic Polymers and Materials》2022,32(7):2513-2526
Journal of Inorganic and Organometallic Polymers and Materials - Copper oxide doped TeO2–B2O3 glass system with empirical formula;... 相似文献
13.
Adil Farooq Arfa Iqbal Nosheen Fatima Rana Misha Fatima Tuba Maryam Farhat Batool Zahra Rehman Farid Menaa Shabia Azhar Afrah Nawaz Faheem Amin Zuhair M. Mohammedsaleh Salma Saleh Alrdahe 《International journal of molecular sciences》2022,23(6)
Chronic liver disease (CLD) is a global threat to the human population, with manifestations resulting from alcohol-related liver disease (ALD) and non-alcohol fatty liver disease (NAFLD). NAFLD, if not treated, may progress to non-alcoholic steatohepatitis (NASH). Furthermore, inflammation leads to liver fibrosis, cirrhosis, and hepatocellular carcinoma. Vitexin, a natural flavonoid, has been recently reported for inhibiting NAFLD. It is a lipogenesis inhibitor and activates lipolysis and fatty acid oxidation. In addition, owing to its antioxidant properties, it appeared as a hepatoprotective candidate. However, it exhibits low bioavailability and low efficacy due to its hydrophobic nature. A novel rat model for liver cirrhosis was developed by CCL4/Urethane co-administration. Vitexin encapsulated liposomes were synthesized by the ‘thin-film hydration’ method. Polyethylene glycol (PEG) was coated on liposomes to enhance stability and stealth effect. The diseased rats were then treated with vitexin and PEGylated vitexin liposomes, administered intravenously and orally. Results ascertained the liposomal encapsulation of vitexin and subsequent PEG coating to be a substantial strategy for treating liver cirrhosis through oral drug delivery. 相似文献
14.
Muhammad U. Farooq Xiangxue Zhang Yanan Guan Wenyao Chen Jinghong Zhou Jing Zhang Gang Qian Xuezhi Duan Xinggui Zhou Weikang Yuan 《American Institute of Chemical Engineers》2023,69(1):e17932
Methyl methacrylate (MMA) is an important monomer for the production of acrylic plastics and polymer dispersions. In this study, we demonstrate a strategy to synergize the electronic and geometric effects of the Au/CeO2 catalyst, achieving three orders of magnitude improvement in reaction rate for the oxidative esterification of methacrolein to MMA. The electronic properties of Au in terms of the valence electron population of 5d states are decoupled from the redox ability and acid–base properties of catalyst support as the main cause for the significant increase in the specific activity of the active site. Moreover, the Au edge site is identified as the main active site for this reaction, whose number reaches the maximum for the 1.6 nm-sized Au particles. Hence, the synergism between the electronic (lower valence electron population of 5d states) and geometric (more edge active sites) promotions of the Au-10/CeO2 catalyst contributes to the highest catalytic activity. 相似文献
15.
Taruna Singh Nazia Umar Khan Sheikh Shreaz Athar Adil Hashmi 《Polymer Engineering and Science》2013,53(12):2650-2658
Bioactive metal cobalt containing sunflower oil‐based polyesteramide resin was developed by condensation polymerization reaction among oil‐derived sunflower fatty amide diol, adipic acid, and cobalt chloride. Microwave‐assisted synthesis was used throughout the reaction as it enhances reaction rate, gives higher yield, and greater purity of the products. Spectroscopic techniques, such as Fourier transform infrared spectroscopy and proton‐nuclear magnetic resonance, have been used to establish the structure of the polymers. Presence of cobalt in polymer has been confirmed through atomic absorption spectroscopy. Standard laboratory methods such as acid value, hydroxyl value, saponification value, iodine value, specific gravity, and viscosity were used to study the physicochemical characteristics of the polymers. Thermal behavior of the polymer was analyzed using thermogravimetry/differential thermal analysis. The synthesized polymers were evaluated for their biological activity. This study indicates that the synthesized polymer has significant antifungal activity against Candida, including azole‐resistant strains, advocating further investigation for clinical applications in the treatment of fungal infections. POLYM. ENG. SCI., 53:2650–2658, 2013. © 2013 Society of Plastics Engineers 相似文献
16.
Reza Haghpanah Ricky Nilam Arvind Rajendran Shamsuzzaman Farooq Iftekhar A. Karimi 《American Institute of Chemical Engineers》2013,59(12):4735-4748
A systematic analysis of several vacuum swing adsorption (VSA) cycles with Zeochem zeolite 13X as the adsorbent to capture CO2 from dry, flue gas containing 15% CO2 in N2 is reported. Full optimization of the analyzed VSA cycles using genetic algorithm has been performed to obtain purity‐recovery and energy‐productivity Pareto fronts. These cycles are assessed for their ability to produce high‐purity CO2 at high recovery. Configurations satisfying 90% purity‐recovery constraints are ranked according to their energy‐productivity Pareto fronts. It is shown that a 4‐step VSA cycle with light product pressurization gives the minimum energy penalty of 131 kWh/tonne CO2 captured at a productivity of 0.57 mol CO2/m3 adsorbent/s. The minimum energy consumption required to achieve 95 and 97% purities, both at 90% recoveries, are 154 and 186 kWh/tonne CO2 captured, respectively. For the proposed cycle, it is shown that significant increase in productivity can be achieved with a marginal increase in energy consumption. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4735–4748, 2013 相似文献
17.
Qasim Ali Farooq Anwar Muhammad Ashraf Nazamid Saari Rashida Perveen 《International journal of molecular sciences》2013,14(1):818-835
This study was carried out to appraise whether or not the exogenous application of a potential osmoprotectant, proline, could ameliorate the adverse effects of drought stress on maize seed and seed oil composition, as well as oil antioxidant activity. Water stress reduced the kernel sugar, oil, protein and moisture contents and most of the seed macro- and micro-elements analyzed in both maize cultivars but it increased the contents of seed fiber and ash. Water stress increased the oil oleic acid content with a subsequent decrease in the amount of linoleic acid, resulting in an increased oil oleic/linoleic ratio for both maize cultivars. However, no variation was observed in oil stearic and palmitic acids content due to water stress. A considerable drought induced an increase in seed oil α-, γ-, δ- and total tocopherols and flavonoids were observed in both maize cultivars. However, oil phenolic and carotenoid content as well as 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging activity decreased. Foliar-applied proline significantly increased the content of seed sugar, oil, protein, moisture, fiber and ash in both maize cultivars under well irrigated and water deficit conditions. Furthermore, exogenous application of proline increased the oil oleic and linoleic acid contents. The concentrations of antioxidant compounds namely phenolics, carotenoids, flavonoids and tocopherols estimated in the seed oil increased due to foliar-applied proline under water deficit conditions that was positively correlated with the enhanced oil DPPH free radical scavenging activity. Moreover, the increase in the contents of these antioxidant compounds and oil antioxidant activity due to the foliar application of proline was noted to be more pronounced under water deficit conditions. 相似文献
18.
Sulfur dioxide, zwitterionic monomer, 3-(N,N-diallylammonio)propanesulfonate and a hydrophobic monomer N,N-diallyl-N-octadecylammonium chloride were cycloterpolymerized in dimethyl sulfoxide using azobisisobutyronitrile (AIBN) as the initiator to afford water-insoluble polysulfobetaines (PSB) in excellent yields. The PSBs were converted into the corresponding anionic polyelectrolyte (APE) by treatment with 1 equiv. of sodium hydroxide. Treating the pH-responsive PSB polymers with different equivalents of NaOH varied the zwitterionic and anionic charge densities in the polymer chain. The polymer chains with zwitterionic fraction greater than 0.5 were found to be insoluble in water. The solution properties of the APE and PSB/APE systems containing varying amount of the hydrophobic monomers in the range 0-10 mol% were investigated by viscometric techniques. It was found that PSB/APE polymer with a ratio of 33:67 for the zwitterionic and anionic fractions in the polymer chains, respectively, gave the highest viscosity value. The polymer concentration (C*HA) of around 1 g/dl was required for the manifestation of significant hydrophobic associations. The polymer solutions exhibited sharp increase in viscosity with increasing polymer concentrations in salt (NaCl)-free as well as salt-added solutions. The presence of sodium chloride is shown to enhance intermolecular associations in polymers having hydrophobes in the lower mol% range, whereas, intramolecular associations were manifested in polymers containing higher proportions of the hydrophobes. 相似文献
19.
Sea urchin-like nanostructures of ZnO consisting of ZnO nanowires with blunt faceted ends were grown on Si (100) substrates by oxidation of metallic Zn at 600 °C. ZnO nanowires having a diameter of 30–60 nm and length of 2–4 Μm were in similar shape with uniform diameter along its entire length with well faceted blunt ends. X-ray diffraction and transmission electron microscope analysis showed that the as-grown nanostructures were highly crystalline with wurtzite hexagonal structure having lattice constants of a=b=3.25 å and c=5.21 å. Room temperature photoluminescence (PL) measurements showed a weak near band-edge emission at 380 nm, but a strong green emission at 500–530 nm. A model for vapor-solid (VS) growth mechanism of ZnO nanowires was presented, in which nucleation of ZnO is crucial for the growth of the nanostructures. 相似文献
20.
Effect of tartrazine dye on micellisation of cationic surfactants: conductometric,spectrophotometric, and tensiometric studies 下载免费PDF全文
The interactions between anionic dye (tartrazine) and cationic surfactants (dodecyltrimethylammonium bromide and cetyltrimethylammonium bromide) have been studied by conductometric, spectrophotometric, and tensiometric techniques. The conductance and surface tension of dodecyltrimethylammonium bromide and cetyltrimethylammonium bromide in pure water as well as in aqueous tartrazine when plotted with surfactant concentration gave values of the critical micelle concentration at different temperatures. As well as increasing the length of the carbon chain of surfactants, the presence of tartrazine reduces the critical micelle concentration. From specific conductivity data, the counterion dissociation constant, standard free energy, enthalpy, entropy of micellisation, surface excess concentration, surface tension at critical micelle concentration, minimum area per molecule, surface pressure at critical micelle concentration, and Gibbs energy of adsorption were evaluated. Spectroscopic studies reveal that the binding of dye to micelles brings a bathochromic shift in dye absorption spectra that indicates dye–surfactant interaction. 相似文献