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   424篇
  免费   10篇
  国内免费   4篇
电工技术   10篇
综合类   6篇
化学工业   29篇
金属工艺   15篇
机械仪表   15篇
建筑科学   9篇
矿业工程   9篇
能源动力   1篇
轻工业   167篇
水利工程   21篇
石油天然气   8篇
武器工业   1篇
无线电   24篇
一般工业技术   79篇
冶金工业   20篇
自动化技术   24篇
  2024年   1篇
  2022年   1篇
  2021年   3篇
  2020年   2篇
  2019年   2篇
  2018年   3篇
  2017年   5篇
  2016年   4篇
  2015年   3篇
  2014年   7篇
  2013年   4篇
  2012年   38篇
  2011年   58篇
  2010年   19篇
  2009年   11篇
  2008年   34篇
  2007年   20篇
  2006年   32篇
  2005年   24篇
  2004年   30篇
  2003年   21篇
  2002年   30篇
  2001年   11篇
  2000年   8篇
  1999年   13篇
  1998年   3篇
  1997年   7篇
  1996年   3篇
  1995年   9篇
  1994年   5篇
  1993年   4篇
  1992年   2篇
  1991年   2篇
  1990年   2篇
  1989年   3篇
  1988年   1篇
  1986年   1篇
  1984年   3篇
  1983年   1篇
  1980年   1篇
  1959年   2篇
  1958年   2篇
  1957年   1篇
  1954年   1篇
  1948年   1篇
排序方式: 共有438条查询结果,搜索用时 15 毫秒
11.
主要研究电脑鼠走迷宫的算法,主要包括迷宫生成算法、原始全迷宫搜索算法和修正后的泛洪算法.改进后的算法可以搜索到从起点到终点的所有可行路径中的一条最佳路径,以实现快速、高效求解迷宫的目的.  相似文献   
12.
一种粒子群优化原型模式修正力度的协同分类方法   总被引:1,自引:0,他引:1  
协同模式识别是一种有着抗噪声、抗缺损、强鲁棒性等诸多优良特性的模式识别方法,其中原型模式的选取模式识别结果有着决定性的作用,其选取直接决定着模式识别的结果和效果,各种方法中信息反馈修正的方法能获得较的效果,但易出现信息饱和的问题;提出了一种粒子群优化修正力度的处理机制,能有效改善此问题,获得最优原型;改进的算法应用于纹理和鼻咽癌细胞图像识别,结果表明,该方法能有效地提高协同神经网络的识别率和可靠性,且识速度也有提高.  相似文献   
13.
液压盘式刹车作为石油钻机的关键装置,其质量的好坏直接关系到钻井作业能否安全实施。因此,急需制定一个高水平的石油钻机液压盘式刹车标准。阐述了将制动力矩确定为液压盘式刹车型号主参数的根据和技术内涵,确定了石油钻机液压盘式刹车型号的表示方法。介绍了液压盘式刹车的制动方式、制动力矩的确定方法及制动力矩公式中载荷的取值方法,得到了SY/T6727—2008《石油钻机液压盘式刹车》标准的基本参数。  相似文献   
14.
介绍了新车型产品设计阶段,涂装的涂胶密封工艺同步工程分析内容.结合典型实例,对影响涂胶密封效果、涂胶施工等问题的产品结构提出合理的优化建议,以有效提升车身密封结构的工艺合理性和施工性,也为后续汽车涂装的涂胶密封同步工程分析工作提供借鉴.  相似文献   
15.
Goat milk fat includes several branched chain fatty acids (BCFAs), like 4-methyloctanoic acid, which when free, are responsible for goaty flavor. This flavor limits the market opportunities for goat milk. Prior research showed that cyclodextrins (CDs) can reduce goaty flavor, presumably by binding free fatty acids. This research extends that observation. In odor ranking trials in citrate buffer at pH 4.8, β-CD concentrations between 0% and 0.35% were increasingly effective in reducing odor intensity due to 4-methyloctanoic acid, but only when present in high molar excess. α-CD was also effective, but γ-CD was not. In lipase-treated goat milk only β-CD was effective but at much lower molar excess, a difference potentially explained by several factors. One was that BCFAs bind to CDs in marked preference to their straight chain isomers. Displacement experiments with phenolphthalein disproved that hypothesis. The ability of β-CD to reduce goaty flavor intensity extended to yogurt. An analytical panel showed that flavor of goat yogurt was reduced by addition of β-CD, but only if added before heating and fermentation. A hedonic trial showed that consumers preferred unsweetened and sweet/vanilla-flavored goat yogurt more when β-CD was included, P = 0.004 and 0.016, respectively. Males liked all yogurts more than females (P < 0.01), but there was a treatment × gender interaction (P = 0.016) for sweet/vanilla yogurt: sweet/vanilla masked the goaty flavor for males but not females. This results parallels previously demonstrated gender effects for sheepmeat flavor caused by BCFAs. PRACTICAL APPLICATION: β-Cyclodextrin masks goaty flavor in yogurt, and with its GRAS status means it could be used in commercial goat yogurts and similar products so the real or perceived nutritional advantages of goat milk are not lost to goaty flavor.  相似文献   
16.
Scientists have recently studied the frequency and possible forms of clinical manifestations of cross-reactivity to food among 239 of Abakan at the age from 6 month to 15 years with skin, respiratory and combined manifestation of atopy It was proved that risk factors of development of cross-reactivity to food occur among 80% of children who have various forms of allergic diseases moreover the cross allergic reactions between the foodstuffs most frequently occur with the gastrointestinal and with skin forms of food allergy and the cross allergic reactions between the pollen and food allergens more frequently occut with the respiratory forms of atopy and dermorespiratory syndrome. Considerably more rarely this type of reactions is discovered between the epidermal and food allergens, which most frequently were revealed with the dermatorespiratory syndrome.  相似文献   
17.
邹刚 《水力发电》2006,32(7):42-44
湾坝河水电站闸基坐落在第四纪砂砾石覆盖层上,属于软基上建闸。为了确保闸坝基础能满足坝基稳定、承载、变形的要求,设计上采用了振冲法对覆盖层进行加固处理。该工程振冲加固技术的施工方法、技术措施、质量控制措施可供类似工程参考。  相似文献   
18.
白禅寺电航工程7号闸底板混凝土是在流动水下浇筑的,混凝土浇筑完毕后,水下部分混凝土相当于第四系覆盖层,混凝土与基岩接触面有淤沙,为使7号闸底板混凝土达到常态下浇筑混凝土的性态而进行了补强灌浆处理,介绍了混凝土补强灌浆的施工方法,施工措施,检查手段并对其质量进行了评价。  相似文献   
19.
The effects of supplementation with grass silage and replacement of some corn in the concentrate with soybean meal (SBM) on milk production, and milk fatty acid (FA) profiles were evaluated in a replicated 4 × 4 Latin square study using 16 dairy cows grazing pasture composed of ryegrass, Kentucky bluegrass, and white clover. Each experimental period lasted for 3 wk. The 4 dietary treatments were PC, 20 h of access to grazing pasture, supplemented with 6 kg/d of corn-based concentrate mixture (96% corn; C); PCSB, 20 h of access to grazing pasture, supplemented with 6 kg/d of corn- and SBM-based concentrate mixture (78% corn and 18% SBM; CSB); SC, 7 h of access to grazing pasture during the day and 13 h of ad libitum access to grass silage at night, supplemented with 6 kg/d of C concentrate; and SCSB, 7 h of access to grazing pasture during the day and 13 h of ad libitum access to grass silage at night, supplemented with 6 kg/d of CSB concentrate. The concentrate mixtures were offered twice each day in the milking parlor and were consumed completely. Grass silage supplementation reduced dietary crude protein and concentration of total sugars, and dietary SBM inclusion increased dietary crude protein concentration and decreased dietary starch concentration. Milk yield and energy-corrected milk were increased by SBM supplementation of cows with access to grass silage. Milk protein concentration was lower in cows offered grass silage, regardless of whether SBM was fed. Dietary SBM inclusion tended to increase milk fat concentration. Plasma urea N was reduced by silage feeding and increased by SBM supplementation. Supplementation with grass silage overnight could represent a useful strategy for periods of lower pasture availability. Dietary inclusion of SBM in solely grazing cows had no effects on milk production and composition, exacerbated the inefficient capture of dietary N, and increased diet cost. Grass silage supplementation affected milk FA profiles, increasing both the FA derived from de novo synthesis and those derived from rumen microbial biomass, and decreasing the sum of C18 FA (mostly derived from diet or from mobilization of adipose tissue reserves). Milk fat concentrations of conjugated linoleic acid cis-9, trans-11, vaccenic acid (18:1 trans-11), and linolenic acid (18:3n-3) were unaffected by grass silage supplementation, suggesting that partial replacement of pasture by unwilted grass silage does not compromise the dietary quality of milk fat for humans.  相似文献   
20.
This paper considers the design of a software sensor (or soft-sensor) for the on-line estimation of the biological activities of a colony of aerobic micro-organisms acting on activated sludge processes, where the carbonaceous waste degradation and nitrification processes are taken into account. These bioactivities are intimately related to the dissolved oxygen concentration. Two factors that affect the dynamics of the dissolved oxygen are the respiration rate or the oxygen uptake rate (OUR) and the oxygen transfer function (K(l)a). These items are challenging topics for the application of recursive identification due the nonlinear characteristic of the oxygen transfer function, and to the time-varying feature of the respiration rate. In this work, OUR and the oxygen transfer function are estimated through a software sensor, which is based on a modified version of the discrete extended Kalman filter. Numerical simulations are carried out in a predenitrifying activated sludge process benchmark and the obtained results demonstrate the applicability and efficiency of the proposed methodology, which should provide a valuable tool to supervise and control activated sludge processes.  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