首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   404篇
  免费   51篇
  国内免费   5篇
电工技术   1篇
化学工业   158篇
机械仪表   9篇
建筑科学   8篇
能源动力   6篇
轻工业   123篇
水利工程   8篇
石油天然气   3篇
武器工业   5篇
无线电   14篇
一般工业技术   57篇
冶金工业   30篇
原子能技术   2篇
自动化技术   36篇
  2024年   3篇
  2023年   6篇
  2022年   12篇
  2021年   41篇
  2020年   13篇
  2019年   16篇
  2018年   28篇
  2017年   23篇
  2016年   16篇
  2015年   23篇
  2014年   22篇
  2013年   31篇
  2012年   36篇
  2011年   45篇
  2010年   22篇
  2009年   18篇
  2008年   20篇
  2007年   11篇
  2006年   11篇
  2005年   9篇
  2004年   5篇
  2003年   9篇
  2002年   4篇
  2001年   12篇
  2000年   2篇
  1999年   2篇
  1998年   4篇
  1997年   2篇
  1996年   4篇
  1995年   1篇
  1993年   2篇
  1992年   1篇
  1990年   1篇
  1988年   1篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1968年   1篇
排序方式: 共有460条查询结果,搜索用时 31 毫秒
51.
52.
Marcela Safarova  Jaroslav Kusy 《Fuel》2005,84(17):2280-2285
Pyrolysis tests were performed under laboratory conditions, simulating possible processes in the burning of brown coal mines. These tests focused on gaseous products of thermal decomposition of coal and how their concentrations changed depending on pyrolysis temperature. Results obtained can help to quantify the contributions of particular gases to overall explosiveness of a gaseous mixture and can explain the process of explosive gas release during conflagration.  相似文献   
53.
54.
Oxidized cellulose: An application in the form of sorption filter materials   总被引:1,自引:0,他引:1  
Oxidized cellulose (oxycellulose) was very effectively used in the form of filter sheets to remove some metal ions from water and from aqueous solutions. Furthermore, oxycellulose was applied in an ion‐exchange column and in a batch process. The mechanisms of the sorption process inside oxycellulose as well as the kinetics of sorption were studied. A comparison of oxycellulose and other adsorption components such as zeolites and ion‐exchange resins was made. The affinity of oxycellulose to metal ions was determined to be in the following order: Cd2+, Zn2+ > Ni2+ ? Ca2+ > Mg2+ ? Na+. The use of oxycellulose was very effective, especially in the form of sorption filters, because this allowed us to use a simple filtration process. Moreover, the specific loading amount of the filter cake was higher for filtration than for the column process under comparable conditions. Oxycellulose in a glass column behaved similarly to an ion‐exchange resin. It showed approximately constant efficiency until the sorption capacity of the adsorbent was exhausted, and then it suddenly dropped. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   
55.
An electrochemical sensor was applied for investigating the immobilized rat brain acetylcholinesterase inhibition by chlorofos. Two alternative routes were explored as response-generating reactions: (i) direct electrochemical oxidation of thiocholine produced upon acetylthiocholine enzymatic hydrolysis and (ii) reduction of the produced thiocholine with hexacyanoferrate (III), followed by hexacyanoferrate (II) electrochemical detection. The advantages of the direct way are simplicity and higher sensitivity compared to the indirect one, which however avoids the interferences because of the lower potential applied.Enzyme inhibition was identified as competitive, the increasing from 1.31 to 1.43 mmol L−1 with chlorofos concentration in the range 0.2-1.0 mmol L−1 and the maximal rate of the enzyme reaction remaining constant (Imax = 579.30 ± 5.71 μA) in the presence of chlorofos. The inhibition constant was calculated using the Dixon method (KI = 10.07 mmol L−1).The suppression of the acetylcholinesterase activity by the inhibitor, expressed as current decrease at a constant substrate concentration, was exploited for chlorofos quantification optimized by the design of experiments methodology. Optimal response was obtained for an acetylthiocholine concentration of 0.2 mmol L−1, at 26 °C and pH 7.  相似文献   
56.
The objective of this study was to evaluate the oil extraction process from walnut seeds by pressing followed by extraction with supercritical CO2. In pressing experiments, a factorial arrangement was conducted in order to study the combined effects of seed moisture content (2.5%, 4.5% and 7.5%) and pressing temperature (25, 50 and 70 °C) on oil recovery and quality parameters. For all conditions tested, the oil quality compared well with that of cold-pressed walnut oil. Oil recovery increased significantly as moisture content raised. Highest oil recovery (89.3%) was obtained at 7.5% moisture content and 50 °C temperature. The cake resulting from pressing at these conditions was extracted with CO2 in a high pressure pilot plant with single stage separation and solvent recycle. The effects of two different pressures (200 and 400 bar) and temperatures (50 and 70 °C) with regard to oil yield and quality, and time required for extraction were analyzed. At each condition, the extraction rate changed with the mass of solvent and extraction time. At first, the mass of oil extracted was determined by the oil solubility in CO2 and a linear relationship was observed, where the slope results in the solubility of oil in CO2 at the experiment conditions. After that, the extraction rate was governed by solubility and diffusion, and continuously decreased with time. The colour changed along the extraction from a whitish clear product to a yellow one. Tocopherol and carotenoid contents were significantly higher than those obtained by pressing. Extraction conditions did not affect significantly the fatty acid composition.  相似文献   
57.
The inhibitory effect of some plant oil aromatics against three strains of Arcobacter butzleri, two strains of Arcobacter cryaerophilus, and one strain of Arcobacter skirrowii was evaluated. When MICs were determined using the broth macrodilution method, cinnamaldehyde was most inhibitory followed by thymol, carvacrol, caffeic acid, tannic acid, and eugenol (P < 0.001). Sublethal concentrations of the three most potent plant oil aromatics also were examined. Overall, cinnamaldehyde was the most bacteriostatic against all arcobacters tested except A. butzleri when these strains were exposed to the MIC25 of this aromatic aldehyde. The bacteriostatic activities of thymol and carvacrol were concentration and species dependent.  相似文献   
58.
Apical membrane antigen 1 is a microneme protein which plays an indispensable role during Apicomplexa parasite invasion. The detailed mechanism of AMA-1 molecular interaction with its receptor on bovine erythrocytes has not been completely defined in Babesia bovis. This study was focused on identifying the minimum B. bovis AMA-1-derived regions governing specific and high-affinity binding to its target cells. Different approaches were used for detecting ama-1 locus genetic variability and natural selection signatures. The binding properties of twelve highly conserved 20-residue-long peptides were evaluated using a sensitive and specific binding assay based on radio-iodination. B. bovis AMA-1 ectodomain structure was modelled and refined using molecular modelling software. NetMHCIIpan software was used for calculating B- and T-cell epitopes. The B. bovis ama-1 gene had regions under functional constraint, having the highest negative selective pressure intensity in the Domain I encoding region. Interestingly, B. bovis AMA-1-DI (100YMQKFDIPRNHGSGIYVDLG119 and 120GYESVGSKSYRMPVGKCPVV139) and DII (302CPMHPVRDAIFGKWSGGSCV321)-derived peptides had high specificity interaction with erythrocytes and bound to a chymotrypsin and neuraminidase-treatment sensitive receptor. DI-derived peptides appear to be exposed on the protein’s surface and contain predicted B- and T-cell epitopes. These findings provide data (for the first-time) concerning B. bovis AMA-1 functional subunits which are important for establishing receptor-ligand interactions which could be used in synthetic vaccine development.  相似文献   
59.
The study was conducted to evaluate the effect of non-traditional and highly available and nutrient-dense ingredients in the production of value-added crackers. The crackers were prepared by combining partially defatted chia flour, wheat germ, quinoa, and oat. The antioxidant activity and the polyphenol content were 7.0–8.4 times higher in crackers produced with non-traditional ingredients compared to the control snack. The hydroperoxide value indicated a low oxidative deterioration of the oil. The sample with 10% of partially defatted chia flour was selected for shelf-life test under storage conditions and sensory evaluation. Modified atmosphere exerted a protective effect on the lipid stability regardless of the incorporation of BHT to the formulation. All the evaluated attributes scored highly during consumer acceptance. The formulated cracker presented a relevant content of protein, dietary fibre and omega-3 and -6 fatty acids. Based on these results, the crackers containing non-traditional ingredients resulted in a product with a good potential for both consumer acceptance and outstanding nutritional benefits.  相似文献   
60.
Transcatheter embolization is a minimally invasive procedure that uses embolic agents to intentionally block diseased or injured blood vessels for therapeutic purposes. Embolic agents in clinical practice are limited by recanalization, risk of non-target embolization, failure in coagulopathic patients, high cost, and toxicity. Here, a decellularized cardiac extracellular matrix (ECM)-based nanocomposite hydrogel is developed to provide superior mechanical stability, catheter injectability, retrievability, antibacterial properties, and biological activity to prevent recanalization. The embolic efficacy of the shear-thinning ECM-based hydrogel is shown in a porcine survival model of embolization in the iliac artery and the renal artery. The ECM-based hydrogel promotes arterial vessel wall remodeling and a fibroinflammatory response while undergoing significant biodegradation such that only 25% of the embolic material remains at 14 days. With its unprecedented proregenerative, antibacterial properties coupled with favorable mechanical properties, and its superior performance in anticoagulated blood, the ECM-based hydrogel has the potential to be a next-generation biofunctional embolic agent that can successfully treat a wide range of vascular diseases.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号