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   6601篇
  免费   543篇
  国内免费   6篇
电工技术   64篇
化学工业   1555篇
金属工艺   157篇
机械仪表   173篇
建筑科学   267篇
矿业工程   22篇
能源动力   210篇
轻工业   928篇
水利工程   45篇
石油天然气   44篇
无线电   517篇
一般工业技术   1527篇
冶金工业   494篇
原子能技术   32篇
自动化技术   1115篇
  2024年   28篇
  2023年   65篇
  2022年   79篇
  2021年   200篇
  2020年   196篇
  2019年   159篇
  2018年   315篇
  2017年   341篇
  2016年   388篇
  2015年   232篇
  2014年   308篇
  2013年   670篇
  2012年   361篇
  2011年   438篇
  2010年   356篇
  2009年   329篇
  2008年   344篇
  2007年   312篇
  2006年   222篇
  2005年   188篇
  2004年   152篇
  2003年   142篇
  2002年   140篇
  2001年   81篇
  2000年   77篇
  1999年   68篇
  1998年   131篇
  1997年   94篇
  1996年   84篇
  1995年   66篇
  1994年   45篇
  1993年   38篇
  1992年   28篇
  1991年   29篇
  1990年   28篇
  1989年   22篇
  1988年   34篇
  1987年   18篇
  1986年   23篇
  1985年   30篇
  1984年   14篇
  1983年   19篇
  1982年   24篇
  1981年   21篇
  1980年   17篇
  1979年   23篇
  1978年   12篇
  1977年   18篇
  1976年   23篇
  1974年   14篇
排序方式: 共有7150条查询结果,搜索用时 15 毫秒
991.
992.
In this study, the flow parameters of Reiner–Philippoff nanofluid flow with high-order slip properties, activation energy, and bioconvection have been analyzed using artificial neural networks (ANNs). Local Nusselt number (LNN), local Sherwood number (LSN), and motile density number (MDN) are considered as flow parameters. Numerical values have been obtained by numerical methods using flow equations. To estimate the flow parameters, three different ANN models have been designed. The Levenberg–Marquardt training algorithm is used in multilayer perceptron network models with 10 neurons in the hidden layers. In all, 70% of the data set has been used for training the models, 15% for validation, and 15% for testing. The performance analysis of the network models has been made by calculating the determined performance parameters. The R values for the LNN, LSN, and MDN parameters have been calculated as 0.99261, 0.98769, and 0.99102, respectively, and the average deviation values are −0.65%, 0.06%, and −0.11%, respectively. The attained outcomes showed that the ANNs can predict the LNN, LSN, and MDN, which are the flow parameters of the Reiner–Philippoff nanofluid flow, with high accuracy.  相似文献   
993.
994.
Neural Computing and Applications - In this paper we introduce an efficient soft demapping method for amplitude phase shift keying (APSK) constellations using extreme learning machine (ELM). The...  相似文献   
995.
996.
997.
Küçük  Ö.  Eraslan  O.  Eskitascioglu  G.  Belli  S. 《Strength of Materials》2020,52(2):317-324
Strength of Materials - The aims of this finite elemental stress analysis (FEA) study were to evaluate the effects of loading direction, crown coverage, and adjacent teeth on stress distribution in...  相似文献   
998.
In this study, the use of Cu and Ni interlayers have been investigated for functional core-rim composite part production with WC-Co 9?wt-% feedstock/steel. For this purpose, different experiments have been performed and joining condition, shear strength and microstructure of the intermediate region have been examined. It has been found that AISI 4340 insert/WC-Co have been joined and 85.8?MPa shear strength achieved, but high speed steel insert has not joined. Moreover, it has been determined that better results are obtained with Ni interlayer. Under the same conditions, when the 40?µm Ni interlayer has been used between AISI 4340 core and WC-Co rim, shear strength has been increased approximately twice and has been 162.7?MPa.  相似文献   
999.
The aim of this study was to develop alginate and zein films containing natamycin, a natural antifungal agent, in order to limit/prevent the mould growth on the surface of kashar cheeses. The films were prepared by casting, and characterized in terms of antimicrobial and mechanical properties (tensile strength, elongation-at-break, and elastic modulus), and their morphology was examined by scanning electron microscopy (SEM). Mechanical properties of the zein films were found to be weaker than the alginate films. SEM analysis indicated that alginate films have a more regular structure than zein films, and a more homogenous distribution was observed at lower concentrations of natamycin. The antifungal activities of both films increased as the natamycin concentration (100, 200, 500, 1000, 2000, and 4000 ppm) increased; however, alginate films exhibited relatively high antifungal activity. The effects of films on the shelf life of kashar cheeses inoculated with Aspergillus niger and Penicillium camemberti were investigated during their storage under refrigerator conditions for 45 days. At high-natamycin concentrations, zein films showed higher antifungal activity against both fungi at the end of the storage period.  相似文献   
1000.
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