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   222篇
  免费   12篇
电工技术   15篇
化学工业   44篇
金属工艺   19篇
机械仪表   3篇
建筑科学   30篇
能源动力   4篇
轻工业   33篇
石油天然气   1篇
无线电   8篇
一般工业技术   27篇
冶金工业   41篇
自动化技术   9篇
  2024年   2篇
  2023年   6篇
  2022年   1篇
  2021年   8篇
  2020年   7篇
  2019年   7篇
  2018年   11篇
  2017年   4篇
  2016年   10篇
  2015年   2篇
  2014年   10篇
  2013年   13篇
  2012年   7篇
  2011年   20篇
  2010年   12篇
  2009年   9篇
  2008年   8篇
  2007年   9篇
  2006年   7篇
  2005年   4篇
  2004年   2篇
  2003年   6篇
  2002年   3篇
  2001年   4篇
  2000年   2篇
  1999年   2篇
  1998年   10篇
  1997年   9篇
  1996年   3篇
  1995年   2篇
  1994年   7篇
  1993年   5篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1989年   6篇
  1988年   2篇
  1987年   2篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1979年   2篇
  1976年   2篇
  1975年   1篇
  1974年   1篇
排序方式: 共有234条查询结果,搜索用时 15 毫秒
71.
A series of medium-scale and large-scale triaxial and unconfined compression tests was conducted in order to evaluate the strength and deformation characteristics and small strain properties of undisturbed well-graded gravelly soils retrieved from three tunnel excavation sites in Toyama prefecture, Japan. Undisturbed gravelly soils were taken by means of a new sampling method using thick water-soluble polymer solutions. The strength and deformation characteristics were evaluated mainly by performing sustained loading and large amplitude unloading and reloading cycles during otherwise monotonic loading at a constant strain rate in drained triaxial compression tests. During isotropic consolidation and shearing, at several stress states, eleven very small vertical cycles were applied to evaluate the quasi-elastic deformation property at small strain levels around 0.001% by static measurement. Dynamic measurements using a pair of accelerometers attached to the side surface of the specimen and wave sources attached to the top cap were also conducted at the same stress levels as static measurements in a single test. Several effects including grading characteristics and pressure level on the difference between the moduli measured statically and dynamically were discussed. The relationship between the small strain and strength properties of undisturbed gravelly soils was evaluated. The small strain properties of air-dried dense Toyoura sand in large-scale triaxial compression tests were also investigated in this study to compare the results of undisturbed gravelly soils.  相似文献   
72.
This paper seeks to determine the trigger of faint heat generation, which was one of the causes of fires in the piles of rubble produced after the 2011 Great East Japan Earthquake. The rubble piles consist of various combustible materials, such as wood, paper and plastics, as well as non‐combustible materials from destroyed buildings. Multiple rubble outdoor storage areas were temporarily set up in the disaster areas to dispose of rubble after it was piled up and separated. However, fires have been occurring in these storage areas since the summer of 2011. One cause of such fires is thought to be the heat generated by fermentation of microorganisms that easily proliferates within the piled up rubble, ultimately resulting in spontaneous ignition. In this study, we collected samples from rubble outdoor storage areas where fires have occurred. We then conducted thermal analyses to obtain basic data, and finally, we developed safety measures to prevent the recurrence of fire. The results revealed that the heat generated during fermentation of rotten tatami and wood chips most likely acts as a trigger causing the fires, given the adiabatic conditions are good. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
73.
Decontamination of lettuce using acidic electrolyzed water   总被引:7,自引:0,他引:7  
The disinfectant effect of acidic electrolyzed water (AcEW), ozonated water, and sodium hypochlorite (NaOCl) solution on lettuce was examined. AcEW (pH 2.6; oxidation reduction potential, 1140 mV; 30 ppm of available chlorine) and NaOCl solution (150 ppm of available chlorine) reduced viable aerobes in lettuce by 2 log CFU/g within 10 min. For lettuce washed in alkaline electrolyzed water (AIEW) for 1 min and then disinfected in AcEW for 1 min, viable aerobes were reduced by 2 log CFU/g. On the other hand, ozonated water containing 5 ppm of ozone reduced viable aerobes in lettuce 1.5 log CFU/g within 10 min. It was discovered that AcEW showed a higher disinfectant effect than did ozonated water significantly at P < 0.05. It was confirmed by swabbing test that AcEW, ozonated water, and NaOCI solution removed aerobic bacteria, coliform bacteria, molds, and yeasts on the surface of lettuce. Therefore, residual microorganisms after the decontamination of lettuce were either in the inside of the cellular tissue, such as the stomata, or making biofilm on the surface of lettuce. Biofilms were observed by a scanning electron microscope on the surface of the lettuce treated with AcEW. Moreover, it was shown that the spores of bacteria on the surface were not removed by any treatment in this study. However, it was also observed that the surface structure of lettuce was not damaged by any treatment in this study. Thus, the use of AcEW for decontamination of fresh lettuce was suggested to be an effective means of controlling microorganisms.  相似文献   
74.
法国硝酸铵化肥工厂爆炸事故介绍及调查   总被引:1,自引:0,他引:1  
2001年9月21日,法国南部城市Toulouse AZF GP化肥工厂发生一起特大爆炸事故。约300t~400t粒状硝酸铵爆炸,29人死亡,约2,500人受伤。事故不仅毁坏大部分厂房,也使方圆几公里的建筑遭受损坏。直接经济损失达23亿欧元。本文作者于2002年3月到现场访问。并且听取了法国政府、大学、研究所及工厂的介绍与事故调查进展情况,并对大规模硝酸铵储存的安全温度(SADT)作了估算。  相似文献   
75.
76.
BACKGROUND: With the onset of eating, the associated rise of dopamine in the lateral hypothalamus (LHA-DA) is thought to regulate quantity of food consumed per meal. Early release of LHA-DA induced by eating is facilitated by oronasal stimulation; we propose that the subsequent LHA-DA response induced by nutrients in the portal vein is dampened by the innervated liver. This was tested by measuring LHA-DA in normal rats: during parenteral feeding to bypass oronasal stimulation, while eating during parenteral feeding, and while eating only. METHODS: Rats had either total liver denervation or sham operation, with placement of a jugular vein catheter and LHA-DA microdialysis cannula. After a 3-week recovery period total liver denervated rats were randomized to parenterally fed, food only, and parenteral plus food groups each with sham-operated controls in which LHA-DA was measured. RESULTS: No difference in LHA-DA release in food only groups occurred between total liver denervated or sham-operated rats. A significantly higher rise in LHA-DA was observed in total liver denervated versus sham-operated rats in parenterally fed (129% +/- 4% versus 116% +/- 2%; p < 0.05) and parenteral plus food (151% +/- 4% versus 134% +/- 4%; p < 0.05) groups. CONCLUSIONS: In total liver denervation versus sham operation, an increase in LHA-DA release occurs during parenteral feeding and eating during parenteral feeding, suggesting that innervated liver inhibits LHA-DA release.  相似文献   
77.
The larval defensive secretions ofLinaeidea aenea Linné andPlagiodera versicolora distincta Baly were identified as plagiolactone and epiplagiolactone. In addition to these compounds, chrysomelidial and the acetates of hexadecanol, octadecanol and (Z)-I 1-eicosenol from the former insect, and plagiodial and epichrysomelidial from latter insect were identified.This is report No. 3 of the Defensive Secretion of Chrysomelid Beetles. Report No. 2 is Sugawara et al., 1979.  相似文献   
78.
    
Alcohols were found to be arylated directly at their α‐C−H bond with aryl halides in the presence of a base and a substoichiometric amount of t‐BuOOt‐Bu through a homolytic aromatic substitution mechanism.

  相似文献   

79.
80.
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