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   51篇
  免费   0篇
电工技术   8篇
化学工业   8篇
金属工艺   1篇
建筑科学   1篇
轻工业   4篇
无线电   9篇
一般工业技术   13篇
冶金工业   4篇
原子能技术   1篇
自动化技术   2篇
  2022年   1篇
  2021年   1篇
  2015年   1篇
  2013年   4篇
  2011年   1篇
  2010年   2篇
  2009年   3篇
  2008年   3篇
  2006年   3篇
  2004年   3篇
  2003年   2篇
  2002年   2篇
  2001年   3篇
  2000年   1篇
  1999年   3篇
  1998年   2篇
  1996年   1篇
  1994年   3篇
  1993年   5篇
  1992年   2篇
  1986年   1篇
  1984年   1篇
  1983年   1篇
  1981年   1篇
  1977年   1篇
排序方式: 共有51条查询结果,搜索用时 15 毫秒
1.
Chronic hepatitis C has been demonstrated to be associated with hepatic iron overload, and the hypothesis that the disease activity of hepatitis C is associated with iron cytotoxicity was tested in male volunteer blood donors. Sera with either antibody to hepatitis C virus or hepatitis B surface antigen were selected for determination of ferritin concentration and alanine aminotransferase activity. A correlation between serum ferritin concentration (Y; microgram/l) and alanine aminotransferase activity (X; IU/l) was found in donors with antibody to hepatitis C (log Y = 0.65 x log X + 0.98, r = 0.53, and P < 0.01). The correlation was lower in donors with hepatitis B surface antigen (r = 0.37; P < 0.01). Hepatitis C virus infection probably induces time-dependent iron accumulation associated with the progression of disease activity, while hepatitis B virus infection results in a variety of iron loads with different clinical features. The high disease activity related to hyperferritinemia suggests the presence of iron-induced liver damage in donors with hepatitis C.  相似文献   
2.
3.
Hydrous ruthenium oxide/activated carbon black (RuOx/ACB) composite was synthesized for the first time for supercapacitors by a chemical impregnation method. The RuOx/ACB composite is characterized by thermogravimetric analysis (TGA), field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). The results of TGA and TEM characterization showed that the reaction temperature of composite moved to lower temperature due to the catalytic effect of RuOx. XRD characterization of RuOx/AC illustrated that amorphous hydrous RuOx structure maintained in the composite heated at 150 °C. The equivalent series resistance (ESR) of the composite almost increased with the increase of RuOx content in the composite. The specific capacitance (Csp) of the composite increased with increasing RuOx content in the composite while the Csp of RuOx decreased from 1255.8 to 533.7 F g?1. The above results showed that the utilization of RuOx decreased with higher loading RuOx on ACB.  相似文献   
4.
In positron-emission tomography (PET), to certify that the observed radioactivity in the organ of interest represents the true underlying radioactivity concentration, an experimental/theoretical treatment of factors such as scatter, randoms, reconstruction parameters, recovery coefficients and the cross-calibration procedure is required. Dual isotope experiments used to check the overall tomograph performance are described. It is found that the inclusion of a real-time calibration tube standard in the tomograph field-of-view during scanning compensates for any temporal variation in the machine sensitivity and provides a built-in dead time correction. Reconstruction parameters and recovery coefficients were optimized through phantom experiments. It is shown that results similar to other head and whole body scanners have been achieved  相似文献   
5.
We report the first successful growth of selectively doped In0.53Ga0.47As-InP hcterojunctions by the chloride vapour phase epitaxy, and the observation of TDEG with a maximum electron mobility of 106 000 cm2 V?1 s?1 at 4.2 K.  相似文献   
6.
Antimicrobial activity of nutmeg against Escherichia coli O157   总被引:2,自引:0,他引:2  
We examined the difference between Escherichia coli O157 and non-pathogenic E. coli in their tolerance to spices. Various spices (5 g each) were homogenized at 25 degrees C for 10 min with 5 ml of 70% ethyl alcohol, and the supernatant solutions obtained by centrifugation were used as spice extracts. When the E. coli strains were incubated with each spice extract at concentrations of 0.01% and 0.1%, a noteworthy difference was observed between the O157 and non-pathogenic strains in their tolerance to nutmeg. The populations of the non-pathogenic strains could not be reduced, but those of the O157 strains were remarkably reduced. Antibacterial activity by the nutmeg extract was also found against the enteropathogenic E. coli O111, but not against enterotoxigenic (O6 and O148) and enteroinvasive (O29 and O124) E. coli. When we examined the antibacterial effect of volatile oils in nutmeg on the O157 and non-pathogenic E. coli strains, all O157 strains tested were found to be more sensitive to beta-pinene than non-pathogenic E. coli strains.  相似文献   
7.
We examined the survival and growth of Escherichia coli O157:H7 cells incubated with several seasonings, in comparison with those of non-pathogenic E. coli. The cells were incubated at 25 degrees C for 24 h with several concentrations of NaCl, sucrose, soy sauce, worcester sauce and tomato ketchup, and their survival ratios were determined. The E. coli O157:H7 strains showed relatively higher survival ratios in 0.5-1.0 M sucrose, 25% soy sauce and 12.5-50% worcester sauce than the non-pathogenic strains, but slightly lower survival ratios in 0.5-2.0 M NaCl. A noteworthy difference between E. coli O157:H7 and the non-pathogenic strains was that incubation in the presence of 12.5% soy sauce allowed the growth of E. coli O157:H7 strains but reduced the viable cell numbers of non-pathogenic E. coli strains.  相似文献   
8.
Transparent hydroxyapatite (HA), 99.6% relative density, was prepared by hot isostatic pressing. Optical transmittance of 1 mm thick HA was greater than 60% at 700 nm. Twenty transparent HA plates (10×7×1 mm) were implanted into the medullary cavities of two dogs' femora. At 1 and 2 weeks after implantation the bone marrow derived cells that adhered to the HA surfaces were histochemically examined by light microscopy and scanning electron microscopy. Four types of enzymatic reactions were employed to identify cell types. Alkaline phosphatase was used as a marker for osteoblasts, acid phosphatase and tartrate-resistant acid phosphatase as a marker for osteoclasts and non-specific esterase as a marker for macrophages. Cells adhered to the HA surfaces were a mixed population of osteoblasts, osteoclasts and macrophages. By 2 weeks, the number of osteoblasts increased and formed a bone-like matrix. A small number of osteoclasts formed resorption lacunae on the HA after 2 weeks. By utilizing the transparency of the HA, whole-view of bone matrix formation by osteoblasts and simultaneous resorption of HA by osteoclasts was observed simply and dynamically by light microscopy.  相似文献   
9.
Assuming that photovoltaic (PV) systems are adopted in residential houses under a carbon tax regime, the economic performance of PV systems is investigated from the standpoint of an electric utility. The economic performance is estimated by using the buying price of PV electricity and the PV economic index, which is defined as the ratio of the buying price to the generation cost of the electric utility. Because these values depend on electric power development and operation, the best mix and the operation of power plants are obtained by linear programming subject to restrictions on power generation. Then, the buying price of PV electricity is calculated from the total cost of the electric utility. The buying price means the upper limit at which the electric utility never suffers a loss. The buying price is also compared with the power generation cost. The parameters are the prevalence attainment ratio of PV systems (0 to 100%), the upper limit of newly developed nuclear power plants (0 to 4 GW/10 y), and the generated energy ratio of coal‐fired thermal plants (0 to 15%). Chubu Electric Power Company, Inc. is used as the electric utility. The calculation results show that the buying price of PV electricity increases linearly with increasing carbon tax rate, and its values are 9 and 11.5 yen/kWh when the carbon tax rate is 0 and 25 thousand yen/t‐C, respectively, which does not depend on the prevalence attainment ratio of PV systems and the upper limit of newly developed nuclear power plants. It is not the carbon tax rate but the newly developed nuclear power plant that influences the PV economic index. The values of the PV economic index are 1.35 to 1.45 and 1.50 to 1.60 when the newly developed nuclear power plant capacity is 0 and 4 GW/10 y, respectively. These results show that the economic performance of PV systems is increased by developing nuclear power plants at a certain rate and introducing a carbon tax. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 143(2): 38–49, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10067  相似文献   
10.
Low molecular weight heparin (LMWH)/protamine (P) nano/micro particles (N/MPs) (LMWH/P N/MPs) were applied as carriers for heparin-binding growth factors (GFs) and for adhesive cells including adipose-derived stromal cells (ADSCs) and bone marrow-derived mesenchymal stem cells (BMSCs). A mixture of LMWH and P yields a dispersion of N/MPs (100 nm–3 μm in diameter). LMWH/P N/MPs can be immobilized onto cell surfaces or extracellular matrix, control the release, activate GFs and protect various GFs. Furthermore, LMWH/P N/MPs can also bind to adhesive cell surfaces, inducing cells and LMWH/P N/MPs-aggregate formation. Those aggregates substantially promoted cellular viability, and induced vascularization and fibrous tissue formation in vivo. The LMWH/P N/MPs, in combination with ADSCs or BMSCs, are effective cell-carriers and are potential promising novel therapeutic agents for inducing vascularization and fibrous tissue formation in ischemic disease by transplantation of the ADSCs and LMWH/P N/MPs-aggregates. LMWH/P N/MPs can also bind to tissue culture plates and adsorb exogenous GFs or GFs from those cells. The LMWH/P N/MPs-coated matrix in the presence of GFs may provide novel biomaterials that can control cellular activity such as growth and differentiation. Furthermore, three-dimensional (3D) cultures of cells including ADSCs and BMSCs using plasma-medium gel with LMWH/P N/MPs exhibited efficient cell proliferation. Thus, LMWH/P N/MPs are an adequate carrier both for GFs and for stromal cells such as ADSCs and BMSCs, and are a functional coating matrix for their cultures.  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