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   3649篇
  免费   102篇
  国内免费   5篇
电工技术   53篇
综合类   11篇
化学工业   830篇
金属工艺   73篇
机械仪表   78篇
建筑科学   229篇
矿业工程   18篇
能源动力   76篇
轻工业   548篇
水利工程   19篇
石油天然气   3篇
无线电   343篇
一般工业技术   669篇
冶金工业   444篇
原子能技术   50篇
自动化技术   312篇
  2021年   34篇
  2020年   31篇
  2019年   42篇
  2018年   38篇
  2017年   44篇
  2016年   71篇
  2015年   77篇
  2014年   82篇
  2013年   124篇
  2012年   161篇
  2011年   145篇
  2010年   112篇
  2009年   130篇
  2008年   122篇
  2007年   133篇
  2006年   143篇
  2005年   115篇
  2004年   100篇
  2003年   82篇
  2002年   89篇
  2001年   67篇
  2000年   54篇
  1999年   65篇
  1998年   123篇
  1997年   99篇
  1996年   62篇
  1995年   66篇
  1994年   62篇
  1993年   46篇
  1992年   60篇
  1991年   49篇
  1990年   42篇
  1989年   50篇
  1988年   51篇
  1987年   60篇
  1986年   53篇
  1985年   45篇
  1984年   57篇
  1983年   51篇
  1982年   43篇
  1981年   51篇
  1980年   41篇
  1979年   42篇
  1978年   41篇
  1977年   44篇
  1976年   55篇
  1975年   29篇
  1974年   28篇
  1973年   33篇
  1971年   32篇
排序方式: 共有3756条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
105.
The cleaning of filter cloths is necessary to avoid prolonged system downtime and strong fouling. Reliable cleaning concepts are central to the removal of residues from the complex surface of filter cloths. Particle residues, in particular, play a decisive role in the sufficiency of the cleaning performance. Consequently, enhanced particle‐removal cleaning concepts based on pulsatile jets for filter cloths have been developed. By varying the cleaning parameters, it has been demonstrated that increased pulse numbers and velocities improve the cleaning performance. Furthermore, this promising cleaning concept cleaned more effectively than conventional methods. The reduction in the amount of detergent needed is an ecological and economic advantage of pulsatile cleaning.  相似文献   
106.
Each film preparation technique affects the physical properties of the resulting coating and thus defines its applicability in modern device construction. In this context solvent based spin coated and solvent‐free physical vapor deposited molecular glass photoresist films are systematically investigated for their dissolution behavior, sensitivity, and overall lithographic performance. These investigations demonstrate that the solvent‐free physical vapor deposition leads to a marked increase in sensitivity. This could be explained by the individual molecule by molecule deposition step producing a more homogeneous distribution of the multicomponent resist system, especially the photoacid generator. In addition, this assumption is supported by former published simulations focusing on aggregate formation within thin films. This work demonstrates that the lithographic sensitivity of multicomponent resist system is an intrinsic parameter to investigate molecular material distribution and indicates that the applied film preparation technique is crucial for the corresponding performance and applicability.  相似文献   
107.
In this work, we show by which mechanism branching of the hydrocarbon chains influences the cloud point of nonionic, ethoxylated surfactants. The temperature-induced separation into a dilute and a concentrated liquid phase is of liquid–gas type and can be explained by the relative probability of endcaps and branching points of the cylindrical micelles in both phases. The influence of branches on the hydrocarbon chains can be easily understood by means of spontaneous and effective packing concepts, while quantification via hydrophilic/lipophilic balance (HLB), hydrophilic-lipophilic difference (HLD), and HLD-Net Average Curvature requires parametrization. The phase equilibrium above the cloud point phenomenon is equivalent to the Winsor I type phase equilibrium, one of the five known phase equilibria in ternary systems.  相似文献   
108.
109.
110.
Through process modelling of surface densified gears produced by powder metallurgy (PM) was established by coupling the modelling of the manufacturing processes surface densification, carburization, and heat treatment. The complete model allows the prediction of the local microstructure and hardness in the gear as well as the appearance and direction of residual stresses in the final part. The structural integrity of the part is governed, on the one hand, by the local material properties and residual stresses and, on the other hand, by the load stresses calculated for typical operating conditions. A simplified hardness dependent Haigh diagram was used to calculate the maximum allowable cyclic stresses for the gear tooth and to derive a local utilization ratio as target entity for optimization of the individual steps of the production chain.  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