全文获取类型
收费全文 | 101篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 36篇 |
金属工艺 | 1篇 |
机械仪表 | 1篇 |
建筑科学 | 3篇 |
能源动力 | 22篇 |
轻工业 | 12篇 |
水利工程 | 1篇 |
无线电 | 1篇 |
一般工业技术 | 6篇 |
冶金工业 | 4篇 |
原子能技术 | 1篇 |
自动化技术 | 13篇 |
出版年
2023年 | 1篇 |
2022年 | 10篇 |
2021年 | 10篇 |
2020年 | 4篇 |
2018年 | 3篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 1篇 |
2014年 | 3篇 |
2013年 | 10篇 |
2012年 | 3篇 |
2011年 | 2篇 |
2010年 | 7篇 |
2009年 | 2篇 |
2008年 | 3篇 |
2007年 | 4篇 |
2006年 | 9篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
排序方式: 共有104条查询结果,搜索用时 15 毫秒
51.
The effects of tube bank configuration on forces and heat transfer were investigated for both two-dimensional and three-dimensional gas fluidized beds. Effective dynamic forces and heat transfer coefficients were measured for several tube bank configurations, and it was found that the average forces are smaller than for a single tube. The heat transfer coefficient can be increased by providing sufficient space for particles to descend around both sides of the tube bank. The results provide useful guidelines for optimizing the configuration of tube banks to achieve high heat transfer coefficients while reducing tube erosion due to dynamic forces. 相似文献
52.
The present work aims to show the nonlinear behavior of a PEM fuel cell under different mass transport conditions. Understanding this behavior helps in online state-of-health monitoring and control of a fuel cell stack. To analyze the health of an operating stack, a total harmonic distortion analysis (THDA) system requires only the sum of voltages or currents of the stack to be monitored. A low-frequency current or voltage signal is impressed on the fuel cell stack, and the resulting voltage or current signal is measured. To determine any change in harmonics, the measured signal is processed with a harmonic analyzer. The operational states of individual cells of the fuel cell stack may be inferred from at least one change in the harmonic content of the impressed signal. The mass transport problem related to the cathode and anode is distinguished using mixed-frequency signals. The present study found experimentally that hydrogen starvation is dominantly observed in the harmonic analysis only below a frequency of 15 Hz, whereas air starvation showed harmonic changes at frequencies below 100 Hz. Total harmonic distortions were observed to rise to 2–2.5% under both the starvation conditions but with different frequency signals. 相似文献
53.
Tetsuo Sekine Soichi Takizawa Kohei Uchimura Asako Miyazaki Kyoichiro Tsuchiya 《International journal of molecular sciences》2021,22(15)
The liver has a most indispensable role in glucose and lipid metabolism where we see some of the most serious worldwide health problems. The serine protease prostasin (PRSS8) cleaves toll-like receptor 4 (TLR4) and regulates hepatic insulin sensitivity under PRSS8 knockout condition. However, liver substrate proteins of PRSS8 other than TLR4 and the effect to glucose and lipid metabolism remain unclarified with hepatic elevation of PRSS8 expression. Here we show that high-fat-diet-fed liver-specific PRSS8 transgenic mice improved glucose tolerance and hepatic steatosis independent of body weight. PRSS8 amplified extracellular signal-regulated kinase phosphorylation associated with matrix metalloproteinase 14 activation in vivo and in vitro. Moreover, in humans, serum PRSS8 levels reduced more in type 2 diabetes mellitus (T2DM) patients than healthy controls and were lower in T2DM patients with increased maximum carotid artery intima media thickness (>1.1 mm). These results identify the regulatory mechanisms of PRSS8 overexpression over glucose and lipid metabolism, as well as excessive hepatic fat storage. 相似文献
54.
Influence of the porosity of hydroxyapatite ceramics on in vitro and in vivo bone formation by cultured rat bone marrow stromal cells 总被引:3,自引:0,他引:3
Okamoto M Dohi Y Ohgushi H Shimaoka H Ikeuchi M Matsushima A Yonemasu K Hosoi H 《Journal of materials science. Materials in medicine》2006,17(4):327-336
The in vitro and in vivo osteoblastic differentiation of rat bone marrow stromal cells (MSCs) was assessed on hydroxyapatite disks with 3 different
porosities: 30%, 50%, and 70% (HA30, HA50, and HA70, respectively). MSCs obtained by 10-day culture of fresh bone marrow cells
were subcultured for 2 weeks on 3 kinds of porous HA disks in the presence and absence of dexamethasone (Dex). After 2 weeks
of subculture, alkaline phosphatase (ALP) activity and osteocalcin production of MSCs/HA composites with Dex were higher than
those without, and increased with increasing porosity. The resultant bone tissue grafts “cultured-bone/HA constructs” were
implanted subcutaneously into the backs of syngeneic rats, and harvested 1, 2, and 4 weeks after implantation. At 1 week,
only cultured-bone/HA70 constructs exhibited expanded bone formation. At 2 and 4 weeks, active osteoblasts and progressive
bone formation were observed morphologically in both cultured-bone/HA50 and HA70 constructs. At 4 weeks, bone tissue was observed
even in cultured-bone/HA30 constructs. ALP activity and osteocalcin production also increased with increasing porosity and
time after implantation. In this in vivo model, different scaffold porosity with similar crystal morphology of the apatite phase demonstrated marked differences in
ability to support osteogenesis by implanted rat MSCs. 相似文献
55.
To obtain highly accessible cotton by cyanoethylation with acrylonitrile after pretreatment with swelling agents, the effect of various swelling agents was examined. Swelling agents such as lithium hydroxide, sodium hydroxide, potassium hydroxide, ethylamine, triethylamine, ethylenediamine, piperazine, benzyltrimethylammonium hydroside (BTMOH), urea, dimethyl sulfoxide, dimethylformamide, zinc chloride, and liquid ammonia were examined. It was found that the sodium hydroxide pretreatment or the dual pretreatment with either potassium hydroxide, ethylenediamine, or BTMOH, and sodium hydroxide prior to acrylonitrile treatment gave modified cottons having moisture regain as high as 14%. In such cases, maximum values of moisture regain were observed at the degrees of cyanoethylation of 5–8%. 相似文献
56.
57.
Ishino Yoshizumi; Takahashi-Fujii Asako; Uemori Takashi; Imamura Mitsuo; Kato Ikunoshin 《Protein engineering, design & selection : PEDS》1995,8(11):1171-1175
We studied the 5' 3' exonuclease activity of Bacillus caldotenaxDNA polymerase by site-directed mutagenesis. Among seven mutantsconstructed, two mutant DNA polymerases with an amino acid substitutionof Glyl84 Asp or Glyl92 Asp were confirmed to be deficientin this exonuclease. The two positions corresponded to thoseof the Escherichia coli DNA polymerase I mutants defective in5' 3' exonuclease, polA480ex and polA214. These results provideexperimental support for the proposed amino acid sequence essentialfor the 5' 3' exonuclease activity associated with eubacterialpolymerase Ilike DNA polymerases (family A), includingE.coli and Thermits aquaticus. 相似文献
58.
59.
Takemichi Fukasawa Asako Yoshizaki-Ogawa Atsushi Enomoto Kiyoshi Miyagawa Shinichi Sato Ayumi Yoshizaki 《International journal of molecular sciences》2022,23(12)
Itching can decrease quality of life and exacerbate skin symptoms due to scratching. Itching not only contributes to disease progression but also triggers complications such as skin infections and eye symptoms. Therefore, controlling itching is very important in therapeutic management. In addition to the well-known histamine, IL-31, IL-4 and IL-13 have recently been reported as factors that induce itching. Itching may also be caused by factors other than these histamines. However, we do not know the extent to which these factors are involved in each disease. In addition, the degree of involvement is likely to vary among individuals. To date, antihistamines have been widely used to treat itching and are often effective, suggesting that histamine is more or less involved in itchy diseases. This review discusses the ligand-receptor perspective and describes the dynamics of G protein-coupled receptors, their role as biased agonists, their role as inverse agonists, proactive antihistamine therapy, and drug selection with consideration of impaired performance and anti-PAF effects. 相似文献
60.
Asako Ozaki Eri Kishi Tomoko Ooshima Atsushi Hase Yoko Kawamura 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2016,33(9):1490-1498
Six nanosilver-labelled products and five silver ion (Ag+)-labelled products were investigated to measure the migration of Ag from food-contact plastics, including nanosilver into various food simulants. The products were obtained in Japanese markets in 2012. Zinc (Zn), another major antimicrobial agent, and three harmful metals, cadmium (Cd), lead (Pb) and arsenic (As), were also examined. Ag and Zn were detected in all six nanosilver products at concentrations of 21–200 and 8.4–140 mg kg?1, respectively. These metals were also detected in all five Ag+ products at the same level as nanosilver products. Cd, Pb and As were not detected in any sample. Migrations of Ag and Zn were highest in 4% acetic acid, but also observed in water and 20% ethanol. Big differences were not observed in the migration ratio between nanosilver products and Ag+ products. The ultrafiltration experiments suggested that the Ag that migrated from nanosilver products into 4% acetic acid was in its ionic form, while that into water and 20% ethanol was in its nanoparticle form. 相似文献