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   616篇
  免费   13篇
  国内免费   20篇
电工技术   14篇
综合类   38篇
化学工业   37篇
金属工艺   27篇
机械仪表   176篇
建筑科学   45篇
矿业工程   4篇
能源动力   29篇
轻工业   3篇
水利工程   1篇
石油天然气   30篇
武器工业   3篇
无线电   24篇
一般工业技术   80篇
冶金工业   9篇
原子能技术   1篇
自动化技术   128篇
  2024年   1篇
  2023年   6篇
  2022年   2篇
  2021年   17篇
  2020年   19篇
  2019年   14篇
  2018年   6篇
  2017年   11篇
  2016年   11篇
  2015年   23篇
  2014年   47篇
  2013年   44篇
  2012年   54篇
  2011年   53篇
  2010年   42篇
  2009年   37篇
  2008年   27篇
  2007年   38篇
  2006年   30篇
  2005年   33篇
  2004年   20篇
  2003年   40篇
  2002年   16篇
  2001年   8篇
  2000年   7篇
  1999年   8篇
  1998年   7篇
  1997年   7篇
  1996年   9篇
  1995年   2篇
  1994年   1篇
  1993年   3篇
  1991年   2篇
  1990年   2篇
  1988年   1篇
  1983年   1篇
排序方式: 共有649条查询结果,搜索用时 156 毫秒
71.
减振器是一种一次性使用的能量吸收装置。它完全靠材料的塑性变形来吸收快速掉棒时产生的冲击能量。由于它的工作原理和与之串联的油压缓冲器截然不同,故当后者失效时可作为第二道安全屏障。本设计通过简单估算对不同尺寸,特别是不同形状试样的冲击韧性进行比较,直接利用材料的α_k值对特定几何特性的减振器材料作了筛选。  相似文献   
72.
运用Solid works&COSMOS有限元分析软件,建立翻车机转子有限元模型并进行分析,计算了翻车机转子的应力分布状况,并进行静强度校核,找出了翻车机转子出现结构变形的原因.  相似文献   
73.
This research is designed to help researchers and policy makers ground their work in the reality of how US consumers are thinking and behaving with respect to automotive fuel economy. Our data are from semi-structured interviews with 57 households across nine lifestyle “sectors.” We found no household that analyzed their fuel costs in a systematic way in their automobile or gasoline purchases. Almost none of these households track gasoline costs over time or consider them explicitly in household budgets. These households may know the cost of their last tank of gasoline and the unit price of gasoline on that day, but this accurate information is rapidly forgotten and replaced by typical information. One effect of this lack of knowledge and information is that when consumers buy a vehicle, they do not have the basic building blocks of knowledge assumed by the model of economically rational decision-making, and they make large errors estimating gasoline costs and savings over time.  相似文献   
74.
Waterborne (WB) products are of growing importance in the car refinishes market. Especially WB basecoats are gaining increased market share during the last couple of years. The introduction of WB two-pack primers, fillers, clearcoats and single stage topcoats is hampered, however due to the lack of suited binder systems.

In this paper, new approaches will be presented for two-pack binder systems. A number of topics will be discussed in more detail: the design of the binders, the involved chemistry, the incorporation of stabilizing and reactive groups, the functionality and miscibility of the hardener. Based on these variables, the most important properties have been studied: film formation, reactivity, potlife and paint properties like hardness, appearance and water and solvent resistance. During the investigation, model studies have also been applied.

It is shown that some binder systems offer very attractive features in which a number of properties can be tuned, e.g. amine-functional emulsions combined with acetoacetate-functional hardeners result in an excellent level of properties suited for primer/filler application.

These binder systems have been used as the starting points for product development that resulted in new prototypes of low VOC WB products with a very attractive overall performance.  相似文献   

75.
0 INTRODUCTIONA metal pushing belt-p1anetary gear continuouslyvariable transbossion was invented by Macey andVahabzadeh in l987[1]. The most retnarkablecharacteristic of this tusAnssion is a wider rahorange than a conventional metal pushing beltcontinuously variable transndssion, and without areversal planeop gear, the transmission ratio range isconhnuously expanded from positive ratio to negahveratio through a zero ratio. So a metal pushing belt-planetary gear continuously variable tran…  相似文献   
76.
曾智勇 《山东内燃机》2009,(1):14-17,23
青藏高原环境的恶劣,使得青藏发电车上柴油发电装置的燃油系统设计面临一系列问题。本文针对设计过程中所面临的各项高原环境特有的问题,逐步展开对燃油系统部件的设计,并在设计中合理有效的解决了这些问题。  相似文献   
77.
针对某型轿车麦弗逊前悬架在实际中定位参数变化幅度过大的问题,提出了基于ADAMS/Car的麦弗逊前悬架参数模型。通过对运动学参数、质量特性参数、力学特性参数和外界参数分析,建立了悬架系统仿真精确模型,并选取双侧车轮同向跳动工况进行仿真。同时,分析了车轮上下跳动过程中该悬架定位参数的变化规律以及对悬架性能的影响,得出了该悬架参数的合理性及存在的不足。对此,进行悬架参数优化,解决了实际中存在的缺陷,改善了悬架系统性能。  相似文献   
78.
便携式汽车清洗器的研究   总被引:1,自引:0,他引:1  
随着国民经济的发展,生活节奏的加快,汽车越来越多地进入了个人的家庭,洗车市场也空前的庞大。但目前市场上的洗车方法均存在一些缺点,所以设计一种便携、环保、快速的洗车设备,具有重大的现实意义。便携式汽车清洗器的设计是在理论设计的基础上,通过模拟实验验证并完善。  相似文献   
79.
文章介绍了以互补分裂谐振环和一系列沟道组成的LHM为单元的零阶谐振系统(ZOR),并给出了此系统共振频率和导纳斜率参数的确定方法。描述了由带有J-变案频器的ZOR组成的带通滤波器的设计方法。  相似文献   
80.
In this study, two different nano-silica particles (hydrophilic, Aerosil TT600 and hydrophobic, Aerosil R972) were selected in order to provide the most transparent, UV-absorbent nano-clearcoats. These nano-silica particles were used to improve and optimize properties of 2-pack polyurethane clearcoats based on acrylic polyol. Micro-PIXE analysis was employed to illustrate distribution of nano-silica in the polyurethane matrix. Physical and chemical degradations were investigated via spectrophotometry and FTIR spectroscopy.Additionally, thermal stability and the ability of the clearcoats to resist simulated car wash conditions were also studied. Contrary to belief, coatings loaded with hydrophilic nano-silica which are more UV-absorbent had less durability in UV-B/H2O accelerated tests.  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