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   1871篇
  免费   110篇
  国内免费   127篇
电工技术   28篇
综合类   205篇
化学工业   373篇
金属工艺   95篇
机械仪表   50篇
建筑科学   5篇
矿业工程   8篇
能源动力   76篇
轻工业   782篇
石油天然气   12篇
无线电   101篇
一般工业技术   209篇
冶金工业   17篇
原子能技术   4篇
自动化技术   143篇
  2024年   8篇
  2023年   89篇
  2022年   94篇
  2021年   95篇
  2020年   93篇
  2019年   73篇
  2018年   47篇
  2017年   52篇
  2016年   74篇
  2015年   38篇
  2014年   118篇
  2013年   109篇
  2012年   198篇
  2011年   209篇
  2010年   185篇
  2009年   208篇
  2008年   102篇
  2007年   154篇
  2006年   26篇
  2005年   9篇
  2004年   13篇
  2003年   9篇
  2002年   12篇
  2001年   16篇
  2000年   4篇
  1999年   9篇
  1998年   4篇
  1996年   3篇
  1995年   5篇
  1994年   5篇
  1993年   2篇
  1992年   2篇
  1991年   4篇
  1990年   3篇
  1989年   1篇
  1988年   6篇
  1987年   7篇
  1986年   10篇
  1985年   4篇
  1984年   3篇
  1982年   2篇
  1980年   1篇
  1978年   1篇
  1976年   1篇
排序方式: 共有2108条查询结果,搜索用时 0 毫秒
991.
《Ceramics International》2022,48(9):12317-12323
Transparent conductive oxide (TCO) films have important applications in many areas. Unfortunately, TCOs are usually fabricated using vacuum and high-temperature methods, preventing them from applications in low-cost flexible devices. In this paper, facile low-temperature sol-gel method is described that can be used to fabricate high-quality TCO films. This study uses lightwave (LW) irradiation (at ~280 °C) with indium-tin-oxide (ITO) as a typical example. Both structure and key properties of ITO films are investigated for different LW irradiation conditions. ITO can be formed via LW irradiation after a period as short as 5 min. Furthermore, it is found that LW irradiation can promote the formation of M ? O framework, effectively remove Cl impurities, and facilitate the elimination of hydroxyl oxygen defects - even at temperatures as low as ~280 °C. The optimal ITO films show excellent electronic properties, including low sheet-resistance (14.5 Ω·sq?1) and high conductivity (1.7 × 103 S cm?1). Moreover, ITO films also show high transmittance (above 87%). Overall, our ITO films have a figure of merit (FOM) of 1.72 × 10?2 Ω?1, which is comparable to (or higher than) those of previous ITO films that were produced using conventional vacuum and high-temperature methods. Our LW irradiation method provides facile and effective approach to produce high-performance TCO films at remarkably low cost. This means these films could be used in affordable flexible large-area devices.  相似文献   
992.
为在遥感图像中提取出来道路信息,利用深度学习技术,引入U2-Net模型进行遥感图像道路分割。相比于传统的道路提取方法,基于U2-Net方法可以实现道路的自动化提取。为验证U2-Net模型分割效果,选取U-Net、DeepLabV3+等近几年较为流行的语义分割方法进行对比试验,并进一步分析U2-Net显著图融合模块中卷积核对道路提取效果的影响。试验结果表明,U2-Net模型能较有效地提取出道路信息,模型在测试集上的平均交并比达到了76.49%,Kappa达到了0.701 2,分割精度优于U-Net、DeepLabV3+等语义分割方法。基于U2-Net模型的深度学习方法可以用于解决遥感图像中的道路分割问题,并具有较好的分割效果。  相似文献   
993.
Lv  Xiaoyi  Tan  Rong  Xu  Xiaoyun  Li  Yanping  Geng  Chao  Fang  Yishan  Tan  CongPing  Cui  Bo  Wang  Lishi 《Journal of Applied Electrochemistry》2022,52(5):895-905
Journal of Applied Electrochemistry - In this contribution, a uniformly distributed CuNi active nanoalloys was obtained on the electrode substrate by one-step facile electrodeposition method, and a...  相似文献   
994.
During lactation, goat milk contains colostrum, transitional milk, mature milk, and end milk. The protein present in goat milk during different lactation periods has different characteristics. This study aimed to characterize the protein profile of goat milk samples obtained at different lactation stages and to identify changes in the physicochemical and functional properties of whey protein and casein from goat milk collected at 1, 3, 15, 100, and 200 d after calving. The results demonstrated that the lactation period had a great influence on the physicochemical and functional properties of goat milk whey protein and casein, especially the protein properties of colostrum on the first day after delivery. The denaturation temperature, hydrophobicity, and turbidity of whey protein were significantly higher on the first day postpartum than at other lactation periods. Correspondingly, the colostrum whey protein also had better functional properties, such as emulsification, oil holding capacity, and foaming properties on the first day postpartum than at other lactation periods. For casein, the turbidity, particle size, water holding capacity, and foaming properties on the first day after delivery were significantly higher than those at other lactation periods, whereas the denaturation temperature, oil holding capacity, and emulsification followed the opposite trend. For both whey protein and casein, the 2 indicators of emulsifying properties, namely, emulsifying activity index and the emulsion stability, also followed an opposite trend relative to lactation stage, whereas the changes in foaming capacity with the lactation period were completely consistent with the change of foaming stability. These findings could provide useful information for the use of goat milk whey protein and casein obtained during different lactation stages in the dairy industry.  相似文献   
995.
The production of an intense beam of polarized hydrogen ions with an ECR ionizer has been investigated. A deuteron tensor polarization of up to 85% of the theoretical value has been observed. The intensity is significantly improved compared to an electron beam ionizer.  相似文献   
996.
固态发酵技术的研究应用现状   总被引:2,自引:0,他引:2  
首先介绍了固态发酵的技术、特点及其优越性,并与液态发酵进行了对比;简要介绍了其最新研究状况及其在食品加工业、资源环境等各领域中的应用;描述了其发展趋势及应用前景。  相似文献   
997.
PAE为活性高分子树脂,固含量越高,稳定性越难控制。该文探讨了一种固含量为35%、低成本PAE的制备方法及与市售增强剂进行比较。结果表明,选择胺/酸摩尔比为1:1~1:1.05,聚酰胺预聚体反应温度为170℃左右,环氧化反应后得到黏度为50~60s的聚酰胺树脂,其干抗张强度优于市售PAE,湿抗张强度相当,保存时间为6个月。  相似文献   
998.
Journal of Materials Science: Materials in Electronics - Recently, lithium–sulfur batteries (LSBs) have attracted much attention due to their high theoretical capacity, low cost, and abundant...  相似文献   
999.
A scalable parallel algorithm for treating two-sided contact in a finite-element multi-physics code (ALE3D) is presented. This method assumes that proximity between the two sides changes continuously, and uses a local search to update proximity relations each cycle. The evolving communication pattern is treated entirely by local, nearest-neighbor communication; there is no global communication. Opening and closing voids, overlapping and intersecting contact surfaces, and a number of other special features are supported.  相似文献   
1000.
Interpretation of magnetic phenomena in rock magnetism requires a good understanding in relationship between magnetic susceptibility and magnetic minerals, particularly magnetite, contained in rocks. Previous studies emphasized on describing such a correlation using a sole expression through statistical analysis. The resultant correlations are generally useful only in qualitative interpretation, but too coarse to simulate quantitative solutions. In this paper, we combine the correlation analysis with neural network techniques to not only identify the correlations between susceptibility and magnetite in rocks but also simulate accurate susceptibilities with respect to the magnetite contents provided. Our study has demonstrated that multilayer perceptron models are capable of producing accurate mappings between susceptibility and magnetite in rocks. However, correlation analysis provides qualitative interpretation for rock magnetism data in identifying the patterns of magnetic behaviours of the rocks. In quantitative simulation, if the required accuracy is not restricted, a general MLP model with existence of noises in training data is the first choice because it does not require statistical data pre-processing for establishing the NN model. If the simulation is to provide solutions as accurate as possible, the MLP model must be trained by noise-filtered datasets. The noise filtering is based on the preliminary correlation analysis. Therefore, these two approaches are mutually complementary, rather than competitive to each other.  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