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   167620篇
  免费   14445篇
  国内免费   8154篇
电工技术   9694篇
技术理论   6篇
综合类   13025篇
化学工业   27170篇
金属工艺   9890篇
机械仪表   11270篇
建筑科学   12864篇
矿业工程   4991篇
能源动力   4744篇
轻工业   12475篇
水利工程   3083篇
石油天然气   9968篇
武器工业   1335篇
无线电   18923篇
一般工业技术   18757篇
冶金工业   7816篇
原子能技术   1958篇
自动化技术   22250篇
  2024年   655篇
  2023年   2481篇
  2022年   4488篇
  2021年   6201篇
  2020年   4872篇
  2019年   4065篇
  2018年   4392篇
  2017年   4995篇
  2016年   4732篇
  2015年   6486篇
  2014年   8148篇
  2013年   9777篇
  2012年   10963篇
  2011年   11756篇
  2010年   10555篇
  2009年   10227篇
  2008年   10073篇
  2007年   9606篇
  2006年   9838篇
  2005年   8429篇
  2004年   6076篇
  2003年   5597篇
  2002年   5980篇
  2001年   5301篇
  2000年   4294篇
  1999年   4034篇
  1998年   2984篇
  1997年   2491篇
  1996年   2377篇
  1995年   1996篇
  1994年   1582篇
  1993年   1059篇
  1992年   902篇
  1991年   637篇
  1990年   514篇
  1989年   403篇
  1988年   329篇
  1987年   224篇
  1986年   153篇
  1985年   122篇
  1984年   92篇
  1983年   74篇
  1982年   59篇
  1981年   47篇
  1980年   43篇
  1979年   30篇
  1978年   9篇
  1977年   12篇
  1976年   15篇
  1959年   9篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Zhao  Jiandong  Lei  Wei  Li  Zijian  Zhao  Dongfeng  Han  Mingmin  Hou  Xiaoqing 《Multimedia Tools and Applications》2022,81(4):4753-4780
Multimedia Tools and Applications - The crowding in bus is an important factor affecting passenger satisfaction and bus dispatching level. However, how to use video images to detect crowding...  相似文献   
2.
Tang  Haina  Zhao  Xiangpeng  Ren  Yongmao 《Wireless Networks》2022,28(3):1197-1202
Wireless Networks - Geolocation is important for many emerging applications such as disaster management and recommendation system. In this paper, we propose a multilayer recognition model (MRM) to...  相似文献   
3.
Ripe carambolas are hard to store and transport, while freeze-dried ones are easy to store. However, its long production time leads to higher costs. This study shows that high hydrostatic pressure (HHP) treatment could shorten the freeze-drying time of carambola slices. After HHP treatment (25–250 MPa), the drying time of the fresh sample can be shortened by 33.3–44.4% and the distribution of water and pigment in tissues is much uniform. With the increment of the pressure, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging rate are increased. At 250 MPa, the total phenolic content (TPC) increased from 11.34 to 13.36 mg GAE g−1, and the total flavonoid content (TFC) of the control sample was increased from 10.77 to 12.73 mg RE g−1. Compared with the untreated sample, HHP treatment can enhance the flavour and shorten the freeze-drying time. This work guides the application of HHP technology for drying food processing.  相似文献   
4.
In this work, the composition-dependent point defect types and formation energies of RE2Hf2O7 (RE = La, Ce, Pr, Nd, Pm, Sm, Eu and Gd) as well as the oxygen diffusion behavior are systematically investigated by first-principles calculations. The possible defect reactions and dominant defect complexes under stoichiometric and non-stoichiometric conditions are revealed. It is found that O Frenkel pairs are the predominant defect in stoichiometric pyrochlore hafnates. Hf-RE cation anti-site defects, accompanied by RE vacancies and/or oxygen interstitials, are stable in the non-stoichiometric case of HfO2 excess. On the other hand, RE-Hf anti-site defects together with oxygen vacancies and/or RE interstitials are preferable in the case of RE2O3 excess. The energy barriers for the migration along the VO48f - VO48f pathway of pyrochlore hafnates were calculated to be between 0.81 eV and 0.89 eV. Based on these results, a defect engineering strategy is proposed and the pyrochlore hafnates investigated here are predicted to exhibit potential oxygen ionic conductivity.  相似文献   
5.
Fan  Deng-Ping  Huang  Ziling  Zheng  Peng  Liu  Hong  Qin  Xuebin  Van Gool  Luc 《国际自动化与计算杂志》2022,19(4):257-287
Machine Intelligence Research - This paper aims to conduct a comprehensive study on facial-sketch synthesis (FSS). However, due to the high cost of obtaining hand-drawn sketch datasets, there is a...  相似文献   
6.
Zhao  Ziyu  Lin  Haitao  Ma  Pibo 《Applied Composite Materials》2022,29(4):1675-1694
Applied Composite Materials - In this paper, the low-velocity impact deformation behavior of biaxial warp-knitted flexible composite was investigated. A simplified finite element model (FEM) of the...  相似文献   
7.
8.
Food Science and Biotechnology - Various hilling materials (rice hulls, pine sawdust, and perlite) were compared to produce sprout vegetables using beach silvertop (Glehnia littoralis Fr. Schm. ex...  相似文献   
9.
International Journal of Information Security - Machine learning techniques have been widely used and shown remarkable performance in various fields. Along with the widespread utilization of...  相似文献   
10.
Zhang  Nan  Zhao  Man  Liu  Guangfa  Wang  Jiaoyang  Chen  Yunzhi  Zhang  Zhengjian 《Journal of Materials Science》2022,57(19):8687-8700
Journal of Materials Science - A green modification method for effectively enhancing toughness of PLA was established. Herein, alkaline lignin (LG) was firstly alkylated with dodecane, and then...  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