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   459931篇
  免费   37959篇
  国内免费   21121篇
电工技术   28506篇
技术理论   48篇
综合类   33188篇
化学工业   75061篇
金属工艺   26387篇
机械仪表   29917篇
建筑科学   36499篇
矿业工程   14612篇
能源动力   12832篇
轻工业   30956篇
水利工程   9322篇
石油天然气   28615篇
武器工业   3941篇
无线电   51061篇
一般工业技术   49862篇
冶金工业   22722篇
原子能技术   5075篇
自动化技术   60407篇
  2024年   1585篇
  2023年   6596篇
  2022年   12541篇
  2021年   17571篇
  2020年   13215篇
  2019年   10643篇
  2018年   12424篇
  2017年   13951篇
  2016年   12720篇
  2015年   17864篇
  2014年   22762篇
  2013年   27311篇
  2012年   30147篇
  2011年   33257篇
  2010年   29508篇
  2009年   27991篇
  2008年   27608篇
  2007年   26502篇
  2006年   26534篇
  2005年   23080篇
  2004年   15696篇
  2003年   13665篇
  2002年   12726篇
  2001年   11285篇
  2000年   11163篇
  1999年   11559篇
  1998年   9025篇
  1997年   7638篇
  1996年   7241篇
  1995年   5943篇
  1994年   4808篇
  1993年   3390篇
  1992年   2642篇
  1991年   1965篇
  1990年   1604篇
  1989年   1257篇
  1988年   1028篇
  1987年   624篇
  1986年   494篇
  1985年   311篇
  1984年   240篇
  1983年   177篇
  1982年   179篇
  1981年   110篇
  1980年   131篇
  1979年   64篇
  1978年   24篇
  1977年   34篇
  1976年   40篇
  1973年   17篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Feng  Wenran  Li  Zhen  Chen  Yingying  Chen  Jinyang  Lang  Haoze  Wan  Jianghong  Gao  Yan  Dong  Haitao 《Journal of Materials Science》2022,57(3):1881-1889
Journal of Materials Science - Although chalcogenide materials continue to generate considerable interest due to great potentials for various optoelectronic devices, annealing for a long time in...  相似文献   
2.
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   
3.
4.
5.
In this paper, a novel hybrid structure of Pd doped ZnO/SnO2 heterojunction nanofibers with hexagonal ZnO columns was one step synthesized from electrospun precursor nanofibers. Due to the synergistic effect of hexagonal ZnO, SnO2 and Pd, the structure exhibited excellent hydrogen (H2) gas sensing properties. At low-temperature of 120 °C, the response (Ra/Rg) to 100 ppm H2 gas exceeded 160, the response/recovery time was only 20 s and 6 s respectively and the limit of detection was only 0.5 ppm. Meanwhile, it also had good selectivity for H2 gas and excellent linearity. In addition, the materials were characterized by XRD, FESEM, HRTEM, XPS, and the synthesis mechanism and gas sensing mechanism were proposed.  相似文献   
6.
7.
8.
The effects of cellulose microfibres (CMFs, Average size: 100 ± 5 μm) and cellulose nanofibres (CNFs, Average size: 60 ± 3 nm) on the properties of myofibrillar protein (MP) gels from duck breast meat were studied. The results demonstrated that CMFs and CNFs were mostly connected to MP by non-covalent bonds, the diffusion and cross-linking of MP molecules was promoted, and a denser and more complete gel network was formed. With the increases of CMFs and CNFs concentration (0–10%), the hardness was increased by 13.15% and 19.78% for CMFs10% and CNFs10% gels, respectively, and the elasticity was increased by 40% and 80%, respectively. At the same concentration (0–10%), the increase in gel hardness, viscoelasticity and immobilised water content was greater in the CNFs-MP group than in the CMFs-MP group. The CNFs-MP group had a tighter gel network, and CNFs had a better potential to improve the gelation performance of MP.  相似文献   
9.
10.
Polymer electrets have revealed great potential application in electromechanical devices because of the low weight, large quasi-piezoelectric sensitivity, and excellent flexibility. For an electret, a permanent and macroscopic electric field exists on the surface, principally led by a macroscopic electrostatic charge on the surface or a net orientation of polar groups inside the object. Here, progress in the development of polymer electrets is reviewed. After a brief retrospect of the research courses and those typical polymer electrets that are classified into fluorine polymer and nonfluorine polymer, we present a survey on the charging methods, including corona, soft X-ray, contact, thermal and monoenergetic particle beams. The latest representative applications (i.e., power harvesting, sensors, field effect transistors, and biomedicine) based on polymer electrets are also summarized. Finally, we complete this review with a discussion on perspectives and challenges in this field.  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