【摘 要】
：
随着改革开放的不断深化，乡镇企业、外向型企业、卫星城镇的崛起，社会经济发展对公路交通的要求越来越高，全社会更加注重时效。我国公路质量差、通行能力低、混合交通严重、车速
论文部分内容阅读
随着改革开放的不断深化，乡镇企业、外向型企业、卫星城镇的崛起，社会经济发展对公路交通的要求越来越高，全社会更加注重时效。我国公路质量差、通行能力低、混合交通严重、车速慢，已不适应社会经济发展的需要，严重困扰了社会经济效益的提高。为了从根本上改变中国公路交?
With the continuous deepening of reform and opening up, the demand for road traffic by the development of township and village enterprises, export-oriented enterprises and satellite cities and towns has become higher and higher, and society as a whole has been paying more attention to timeliness. China’s poor road quality, low capacity, mixed traffic serious, slow speed, has not adapted to the needs of social and economic development, seriously harassed the improvement of social and economic benefits. In order to fundamentally change China’s road traffic?
其他文献
Various physiological rhythms strongly influence cognitive performances by means of changing brain oscillations, especially the theta and gamma rhythms.In t
早春及冬季保护地黄瓜常出现化瓜现象,即雌花开放后,花蒂黄化萎缩,子房不再生长膨大。化瓜影响早熟性,使早期产量及总产量受损失,直接影响经济效益,成为黄瓜生产上的一大难
Prolonged voluntary abdominal breathing (VAB) is considered a basic component of Zen meditation.We previously demonstrated that prolonged VAB using visual f
1983～1985年对辽宁地区常栽培的16个青椒品种的耐贮性做了比较试验,经三年7次品种比较,初步筛选出麻辣三道筋油椒、世界冠军、茄门、三道筋油椒、巴彦和12—2等耐贮性较好的品
林业和治沙产业是集社会效益、生态效益和经济效益于一体的特殊产业,肩负着环境建设和经济发展的双重使命。国家为扶持林业发展和推动防治沙漠化工程建设,分别从1986年和199
β-amyloid (Aβ) deposition is considered to be partly responsible for cognitive dysfunction in Alzheimers disease (AD).Down-regulation of c-AMP responsive
Introduction β-arrestin2, abundantly distributed in central nervous system, promotes endocytosis of G protein-coupled receptors and the formation of signal
许多研究者先后发现零上低温冷害,将首先使植物细胞受到伤害。Christiansen,1970,Lyons,1973等研究指出,当植物遭受零上低温侵害后,植物细胞膜透性显著提高。细胞膜透性加大
近年来平菇在国内外有着广泛的栽培,被人们誉为食用菌的后起之秀。我们于1981-1982年在新疆阜康县天山北麓的每天池自然保护区多次采集到野生平菇,经组织分离获得纯菌株,编