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   699篇
  免费   54篇
  国内免费   5篇
电工技术   11篇
综合类   27篇
化学工业   143篇
金属工艺   33篇
机械仪表   21篇
建筑科学   28篇
矿业工程   7篇
能源动力   37篇
轻工业   91篇
水利工程   13篇
石油天然气   24篇
武器工业   1篇
无线电   61篇
一般工业技术   116篇
冶金工业   50篇
原子能技术   8篇
自动化技术   87篇
  2023年   16篇
  2022年   17篇
  2021年   38篇
  2020年   20篇
  2019年   29篇
  2018年   32篇
  2017年   21篇
  2016年   22篇
  2015年   29篇
  2014年   28篇
  2013年   53篇
  2012年   42篇
  2011年   36篇
  2010年   25篇
  2009年   44篇
  2008年   26篇
  2007年   25篇
  2006年   28篇
  2005年   16篇
  2004年   8篇
  2003年   11篇
  2002年   19篇
  2001年   11篇
  2000年   9篇
  1999年   16篇
  1998年   18篇
  1997年   11篇
  1996年   17篇
  1995年   13篇
  1994年   11篇
  1993年   7篇
  1992年   7篇
  1991年   3篇
  1990年   2篇
  1989年   2篇
  1988年   3篇
  1987年   4篇
  1985年   5篇
  1984年   2篇
  1983年   5篇
  1982年   2篇
  1980年   2篇
  1979年   2篇
  1978年   2篇
  1977年   2篇
  1976年   2篇
  1974年   2篇
  1973年   3篇
  1972年   3篇
  1961年   1篇
排序方式: 共有758条查询结果,搜索用时 109 毫秒
1.
Mobile Networks and Applications - 5G/6G communication are first generation high speed wireless communication network which integrates the aerial data, terrestrial data and maritime data via...  相似文献   
2.
Metal Science and Heat Treatment - The effect of solid boronizing at 950°C for 2 and 4 h on the phase composition, microstructure, hardness and abrasive wear of steel AISI 304L is studied...  相似文献   
3.
Two-dimensional MoS2 nanoparticles (2D-nps) exhibit artificial enzyme properties that can be regulated at bio-nanointerfaces. We discovered that protein lipase is able to tune the peroxidase-like activity of MoS2 2D-nps, offering low-nanomolar, label-free detection and identification in samples with unknown identity. The inhibition of the peroxidase-like activity of the MoS2 2D-nps was demonstrated to be concentration dependent, and as low as 5 nm lipase was detected with this approach. The results were compared with those obtained with several other proteins that did not display any significant interference with the nanozyme behavior of the MoS2 2D-nps. This unique response of lipase was characterized and exploited for the successful identification of lipase in six unknown samples by using qualitative visual inspection and a quantitative statistical analysis method. The developed methodology in this approach is noteworthy for many aspects; MoS2 2D-nps are neither labeled with a signaling moiety nor modified with any ligands for signal readout. Only the intrinsic nanozyme activity of the MoS2 2D-nps is exploited for this detection approach. No analytical equipment is necessary for the visual detection of lipase. The synthesis of the water-soluble MoS2 2D-nps is low costing and can be performed in bulk scale. Exploring the properties of 2D-nps and their interactions with biological materials reveals highly interesting yet instrumental features that offer the development of novel bioanalytical approaches.  相似文献   
4.
5.
To the flow produced in particle-suspension by a rotating disk of infinite extent,the asymptotic behavior at infinity is analyzed.A corresponding series solution is presented.It isshown that this approach yields widely valid solutions of high accuracy for all the cases in whichthat suction or weak injection at the disk surface exists.For the cases that strong injection or par-ticle-free band exists,the series method fails.  相似文献   
6.
本文介绍了InP、InGaAs、InGaP、InGaAsP等的光压港(PVS)。并把InGaAsP(在特定组份下)的PVS与FFT—PL谱进行了比较;分析和讨论了PVS测试的局限性和复杂性;指出了对多层异质结构材料,只有把器件结构、外延工艺、ECV测试等结合起来,才可能正确地理解PVS给出的测试结果。  相似文献   
7.
The operation of a petroleum refinery at TÜPRA . Tütünçiftlik was assessed using the pinch-design method. By making use of heat integration in the heat-exchange network, appreciable amounts of energy can be saved as a result of a capital investment having a pay-back period of about 6·5 months.  相似文献   
8.
本文论述了黑釉铁锈花产品的坯釉料组成及制作工艺.井对黑釉铁锈花产品的起源、形成机理进行了探讨分析。  相似文献   
9.
Knowledge and Information Systems - Developing effective and efficient data stream classifiers is challenging for the machine learning community because of the dynamic nature of data streams. As a...  相似文献   
10.

Shear connectors play a prominent role in the design of steel-concrete composite systems. The behavior of shear connectors is generally determined through conducting push-out tests. However, these tests are costly and require plenty of time. As an alternative approach, soft computing (SC) can be used to eliminate the need for conducting push-out tests. This study aims to investigate the application of artificial intelligence (AI) techniques, as sub-branches of SC methods, in the behavior prediction of an innovative type of C-shaped shear connectors, called Tilted Angle Connectors. For this purpose, several push-out tests are conducted on these connectors and the required data for the AI models are collected. Then, an adaptive neuro-fuzzy inference system (ANFIS) is developed to identify the most influencing parameters on the shear strength of the tilted angle connectors. Totally, six different models are created based on the ANFIS results. Finally, AI techniques such as an artificial neural network (ANN), an extreme learning machine (ELM), and another ANFIS are employed to predict the shear strength of the connectors in each of the six models. The results of the paper show that slip is the most influential factor in the shear strength of tilted connectors and after that, the inclination angle is the most effective one. Moreover, it is deducted that considering only four parameters in the predictive models is enough to have a very accurate prediction. It is also demonstrated that ELM needs less time and it can reach slightly better performance indices than those of ANN and ANFIS.

  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