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   172723篇
  免费   14961篇
  国内免费   8204篇
电工技术   10839篇
技术理论   15篇
综合类   13544篇
化学工业   27591篇
金属工艺   9759篇
机械仪表   11279篇
建筑科学   13027篇
矿业工程   5077篇
能源动力   5003篇
轻工业   14895篇
水利工程   3043篇
石油天然气   10181篇
武器工业   1470篇
无线电   18201篇
一般工业技术   19667篇
冶金工业   7447篇
原子能技术   1833篇
自动化技术   23017篇
  2024年   374篇
  2023年   2774篇
  2022年   4679篇
  2021年   6979篇
  2020年   5354篇
  2019年   4432篇
  2018年   4983篇
  2017年   5675篇
  2016年   4824篇
  2015年   6886篇
  2014年   8870篇
  2013年   10445篇
  2012年   11785篇
  2011年   13014篇
  2010年   11526篇
  2009年   10896篇
  2008年   10766篇
  2007年   10163篇
  2006年   9955篇
  2005年   8317篇
  2004年   5778篇
  2003年   5046篇
  2002年   4872篇
  2001年   4165篇
  2000年   3893篇
  1999年   3823篇
  1998年   3042篇
  1997年   2397篇
  1996年   2240篇
  1995年   1832篇
  1994年   1475篇
  1993年   1083篇
  1992年   860篇
  1991年   658篇
  1990年   482篇
  1989年   385篇
  1988年   302篇
  1987年   202篇
  1986年   152篇
  1985年   112篇
  1984年   72篇
  1983年   53篇
  1982年   63篇
  1981年   49篇
  1980年   54篇
  1979年   22篇
  1977年   8篇
  1976年   10篇
  1970年   5篇
  1959年   8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.
3.
4.
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   
5.
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   
6.
Yang  Annan  Li  Bo  Yang  Mao  Yan  Zhongjiang  Xie  Yi 《Wireless Networks》2021,27(1):809-823
Wireless Networks - In this paper, a grouping-based uplink orthogonal frequency division multiple access (OFDMA) random access method is studied which can improve users’ satisfaction in the...  相似文献   
7.
8.
A digital light processing (DLP) technology has been developed for 3D printing lead-free barium titanate (BTO) piezoelectric ceramics. By comparing the curing and rheological properties of slurries with different photosensitive monomer, a high refractive index monomer acryloyl morpholine (ACMO) was chosen, and a design and preparation method of BTO slurry with high solid content, low viscosity and high curing ability was proposed. By further selecting the printing parameters, the single-layer exposure time was reduced and the forming efficiency has been greatly improved. Sintered specimens were obtained after a nitrogen-air double-step debinding and furnace sintering process, and the BTO ceramics fabricated with 80 wt% slurry shows the highest relative density (95.32 %) and piezoelectric constant (168.1 pC/N). Furthermore, complex-structured BTO ceramics were prepared, impregnated by epoxy resin and finally assembly made into hydrophones, which has significance for the future design and manufacture of piezoelectric ceramic-based composites that used in functional devices.  相似文献   
9.
10.
Sun  Junli  Wang  Huaibin  Li  Yang  Zhao  Min 《Journal of Porous Materials》2021,28(3):889-894
Journal of Porous Materials - Co3O4 has been widely investigated as a promising candidate anode material for lithium-ion batteries. We report on the porous Co3O4 column synthesized via a simple...  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