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   96篇
  免费   0篇
电工技术   3篇
化学工业   14篇
金属工艺   2篇
机械仪表   5篇
能源动力   12篇
轻工业   3篇
无线电   4篇
一般工业技术   28篇
冶金工业   14篇
原子能技术   1篇
自动化技术   10篇
  2021年   1篇
  2020年   3篇
  2017年   1篇
  2016年   1篇
  2015年   1篇
  2014年   3篇
  2013年   8篇
  2012年   3篇
  2011年   5篇
  2010年   6篇
  2009年   5篇
  2008年   5篇
  2007年   3篇
  2006年   8篇
  2005年   3篇
  2004年   2篇
  2003年   5篇
  2002年   2篇
  2001年   1篇
  2000年   2篇
  1999年   1篇
  1998年   5篇
  1997年   7篇
  1995年   2篇
  1994年   1篇
  1993年   1篇
  1992年   2篇
  1989年   1篇
  1987年   1篇
  1983年   2篇
  1982年   1篇
  1977年   1篇
  1976年   3篇
排序方式: 共有96条查询结果,搜索用时 203 毫秒
1.
Increased activity of the Na(+)-H+ exchanger (NHE-1 isoform) has been observed in cells and tissues from hypertensive humans and animals, including the spontaneously hypertensive rat (SHR). No mutation in NHE-1 DNA sequence or alteration in NHE-1 mRNA and protein expression has been demonstrated in hypertension, indicating that alterations in proteins that regulate NHE-1 activity are responsible for increased activity. The recent finding that NHE-1 phosphorylation in SHR vascular smooth muscle cells (VSMCs) was greater than in Wistar-Kyoto rat (WKY) VSMCs suggested that NHE-1 kinases may represent an abnormal regulatory pathway present in hypertension. To define NHE-1 kinases altered in the hypertensive phenotype. We measured NHE-1 kinase activity by an in-gel-kinase assay using a recombinant glutathione S-transferase NHE-1 fusion protein as a substrate. At least 7 NHE-1 kinases (42 to 90 kD) were present in VSMCs. We studied a 90-kD kinase because it was the major NHE-1 kinase and exhibited differences between SHR and WKY. Comparison of 90-kD kinase activity revealed that SHR VSMCs had increased activity in growth-arrested cells and in cells stimulated by angiotensin II (100 nmol/L for 5 minutes). Activation of the 90-kD kinase by angiotensin II was Ca2+ dependent, PKC independent, and partially dependent on the mitogen-activated protein kinase pathway. These findings indicate that increased activity of a 90-kD NHE-1 kinase is a characteristic of SHR VSMCs in culture and suggest that alterations in the 90-kD NHE-1 kinase and/or proteins that regulate its activity may be a pathogenic component in hypertension in the SHR.  相似文献   
2.
The effects of nonsteroidal anti-inflammatory drugs (NSAIDs), mofezolac, indomethacin, sodium diclofenac, and zaltoprofen, on the production of interleukin-1 receptor antagonist (IL-1ra) were examined in cultured human peripheral blood mononuclear cells (PBMC). Among the NSAIDs tested, mofezolac and sodium diclofenac were found to stimulate the mRNA expression for IL-1ra without affecting the mRNA expression for IL-1 beta. These two drugs also stimulated the secretion of IL-1ra by PBMC in the absence of bacterial lipopolysaccharide (LPS), however, the stimulatory effect of sodium diclofenac diminished in the presence of LPS. Mofezolac suppressed the mRNA expression for IL-1 beta in PBMC stimulated with exogenous IL-1 beta, indicating the secreted IL-1ra in the presence of mofezolac to be biologically active. Since IL-1ra suppresses the function of IL-1, a pro-inflammatory cytokine, the stimulatory effect of such NSAIDs as mofezolac on IL-1ra production could also be one of the mechanisms involved in its anti-inflammatory and antinociceptive actions.  相似文献   
3.
4.
We present conventional detection of 2,4-dinitrophenol (DNP) for using the competitive reaction between DNP and DNP-conjugated albumin onto DNP antibody immobilized quartz crystal microbalance (QCM). This QCM method allows detection of DNP concentration in the range of 0.01 to 100 ng/ml; linear correlation obtains DNP concentration from 1 to 100 ng/ml.  相似文献   
5.
This paper examines the effect of mediated hugs that are achieved with a huggable communication medium on the brain activities of users during conversations. We measured their brain activities with functional near-infrared spectroscopy (NIRS) and evaluated them with two information theoretic measures: permutation entropy, an indicator of relaxation, and multiscale entropy, which captures complexity in brain activation at multiple time scales. We first verify the influence of lip movements on brain activities during conversation and then compare brain activities during tele-conversation through a huggable communication medium with a mobile phone. Our analysis of NIRS signals shows that mediated hugs decrease permutation entropy and increase multiscale entropy. These results suggest that touch interaction through a mediated hug induces a relaxed state in our brain but increases complex patterns of brain activation.  相似文献   
6.
Abstract

A novel adsorbent Zr(IV)-immobilized resin was prepared to remove fluoride ions from tap water and industrial wastewater. In order to enhance both the kinetics and efficiency, large pathways were formed in the resin for fluoride ion adsorption and the Zr(IV)-phosphate complexes were immobilized on the polymer surface by surface-template polymerization. The Zr(IV)-immobilized resin had a fluoride adsorption capacity of 0.30 mmol/g. The morphology of the Zr(IV)-immobilized resin was evaluated by measuring the specific surface area, pore volume, and pore size distribution. The resin possessed large amounts of large macropores with diameters around 300 nm. The molecular structure at the fluoride adsorption sites was investigated by measuring the amounts of phosphorus, zirconium, and fluoride ion in the resin, and developing a model complex using computational chemistry. On the polymer surface, a fluoride ion/Zr(IV)/dioleyl phosphoric acid complex with an ideal F:Zr:P mole ratio of 3:1:3 could be formed.  相似文献   
7.
Fatigue crack initiation and growth characteristics under mixed mode loading have been investigated on aluminum alloys 2017-T3 and 7075-T6, using a newly developed apparatus for mixed mode loading tests. In 2017-T3, the fatigue crack initiation and growth characteristics from a precrack under mixed mode loading are divided into three regions—shear mode growth, tensile mode growth and no growth—on the ΔKIKII plane. The shear mode growth is observed in the region expressed approximately by ΔKII > 3MPa√m and ΔKIIKI > 1.6. In 7075-T6, the condition of shear mode crack initiation is expressed by ΔKII > 8 MPa√m and ΔKIIKI > 1.6, and continuous crack growth in shear mode is observed only in the case of ΔKIKII, 0. The threshold condition of fatigue crack growth in tensile mode is described by the maximum tensile stress criterion, which is given by Δσθmax √2πr 1.6MPa√m, in both aluminum alloys. The direction of shear mode crack growth approaches the plane in which KI decreases and KII increases towards the maximum with crack growth. da/dNKII relations of the curved cracks growing in shear mode under mixed mode loading agree well with the da/dNKII relation of a straight crack under pure mode II loading.  相似文献   
8.
This paper describes control of the coating layer thickness and the crystallite size of the core–shell hybrid particles by controlling the process parameter. The core–shell hybrid particles were prepared using liquid phase deposition (LPD). We confirmed that the homogeneous coating was attained from the result of the zeta potential and the transmission electron microscope (TEM) observation. Furthermore, the coating layer microstructure was estimated using Brunauer–Emmett–Teller (BET) method. The obtained coating layer of titania was estimated using the band gap energy. Results indicate that the blue shift of the band gap energy signifies that the physical property of the hybrid particles was controlled by the coating layer thickness and the crystallite size, which are determined by the processing parameters.  相似文献   
9.
In this paper we clarify directional characteristics of thermal radiation reflection on rough metal surfaces and establish a technique for determining the parameters for heat transfer computation of radiation energy exchange among surfaces. Directional distribution of bidirectional reflectance ρ of surfaces of root‐mean‐square roughness Σ = 0.1 to 1 µm to the irradiation of a visible laser of wavelength λ = 0.6328 µm and to that of an infrared laser of λ = 3.39 µm is investigated experimentally. The optical roughness (Σ/λ) ranges from 0.028 to 1.27. A measure of the magnitude of specular reflection is presented. A model for describing the ρ distribution is presented, and the experimental results of the ρ distribution are analyzed quantitatively and systematically to determine the values of the specular reflection component Rs and the perfect‐diffuse reflection component Rd of the hemispherical reflectance RH, which are input parameters for radiation heat transfer computation. © 2002 Scripta Technica, Heat Trans Asian Res, 31(2): 76–88, 2002; DOI 10.1002/htj.10008  相似文献   
10.
Experiments have been carried out, using a semi-batch reactor equipped with a consecutive sampling device, to clarify the effects of catalysts and vehicles in the coal liquefaction process. The results show that a vehicle has a significant effect during preheating, unlike a catalyst which is not effective at this stage. A catalyst is more effective in promoting liquefaction under reaction conditions of 450°C and ≈ 20 MPa than is a vehicle. A vehicle higher in hydrogen donation increases the yield of oil even if a catalyst is present, providing a multiplier effect. In the development of a direct coal liquefaction process, therefore, selection of a vehicle is as important as that of a catalyst.  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