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   132952篇
  免费   12491篇
  国内免费   7645篇
电工技术   9300篇
技术理论   7篇
综合类   9755篇
化学工业   19739篇
金属工艺   7964篇
机械仪表   8662篇
建筑科学   9787篇
矿业工程   3959篇
能源动力   4255篇
轻工业   9042篇
水利工程   3001篇
石油天然气   5646篇
武器工业   1425篇
无线电   17284篇
一般工业技术   15145篇
冶金工业   6421篇
原子能技术   1914篇
自动化技术   19782篇
  2024年   427篇
  2023年   1634篇
  2022年   3310篇
  2021年   4991篇
  2020年   3686篇
  2019年   3101篇
  2018年   3407篇
  2017年   3861篇
  2016年   3636篇
  2015年   5214篇
  2014年   6738篇
  2013年   8297篇
  2012年   9411篇
  2011年   10494篇
  2010年   9526篇
  2009年   9249篇
  2008年   9362篇
  2007年   8925篇
  2006年   8277篇
  2005年   6586篇
  2004年   5046篇
  2003年   4383篇
  2002年   4497篇
  2001年   3808篇
  2000年   2887篇
  1999年   2181篇
  1998年   1851篇
  1997年   1431篇
  1996年   1177篇
  1995年   973篇
  1994年   769篇
  1993年   625篇
  1992年   444篇
  1991年   380篇
  1990年   343篇
  1989年   309篇
  1988年   234篇
  1987年   206篇
  1986年   177篇
  1985年   145篇
  1984年   128篇
  1983年   99篇
  1982年   87篇
  1981年   78篇
  1980年   95篇
  1979年   57篇
  1978年   63篇
  1977年   66篇
  1976年   79篇
  1975年   44篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.
Wan  Huan  Wang  Hui  Scotney  Bryan  Liu  Jun  Ng  Wing W. Y. 《Multimedia Tools and Applications》2020,79(39-40):29327-29352
Multimedia Tools and Applications - In many real-world classification problems there exist multiple subclasses (or clusters) within a class; in other words, the underlying data distribution is...  相似文献   
84.
In the past two decades, brain science and robotics have made gigantic advances in their own fields, and their interactions have generated several interdisciplinary research fields. First, in the ‘understanding the brain by creating the brain’ approach, computational neuroscience models have been applied to many robotics problems. Second, such brain-motivated fields as cognitive robotics and developmental robotics have emerged as interdisciplinary areas among robotics, neuroscience and cognitive science with special emphasis on humanoid robots. Third, in brain–machine interface research, a brain and a robot are mutually connected within a closed loop. In this paper, we review the theoretical backgrounds of these three interdisciplinary fields and their recent progress. Then, we introduce recent efforts to reintegrate these research fields into a coherent perspective and propose a new direction that integrates brain science and robotics where the decoding of information from the brain, robot control based on the decoded information and multimodal feedback to the brain from the robot are carried out in real time and in a closed loop.  相似文献   
85.
86.
This study assessed the collection efficiency (CE) of two popularly used sampling devices (BioSampler and Coriolis sampler) for fungal aerosols. Phosphate‐buffered saline (PBS) supplemented with or without surfactant (Tween‐20, Tween‐80, or Triton X‐100) and antifoam agent was prepared and used as collection liquids. The agar impactor (BioStage) was simultaneously operated with liquid‐based samplers to collect fungi from seven sites located at a university building, public library, and animal farming. Fungal concentrations determined by liquid samplers were divided by those by BioStage, and the ratio values represented CE. Results indicate that the CE of BioSampler was superior to that of Coriolis (P = 0.0001) and the PBS containing surfactant collected fungi better than that without surfactant (P < 0.0001), whereas antifoam agent showed no influence (P = 0.8). Moreover, fungal concentrations determined by BioSampler with surfactant‐added PBS were statistically indifferent from those by BioStage (P > 0.05) with a Spearman correlation coefficient of 0.81‐0.83 (P < 0.01). In addition to sampler and collection liquid, sampling location was also identified as a significant CE factor (P = 0.006), implying potential influences by fungal genera in the studied fields. Overall, BioSampler with surfactant‐supplemented PBS (eg, Triton X‐100) is recommended considering the great CE and compatibility with a variety of analytical assays.  相似文献   
87.
Microsystem Technologies - Recently, nonlinear system identification has received increasingly more attention due to its promising applications in engineering fields. It has become a challenging...  相似文献   
88.
Sustainable biocomposites have gained considerable interest as an alternative to conventional composites in recent years due to their cost-effectiveness and environmental friendliness. The aim of this study was to investigate the performance and durability behavior of biocomposites from sustainable biocarbon (BC) as compared to conventional established fillers. The poly(butylene terephthalate) (PBT) and its composites reinforced with BC, talc, and glass fiber (GF) were prepared and the durability performances was investigated. The study showed that BC/PBT biocomposites provided a lighter weight alternative to traditionally used fillers. After undergoes thermo-oxidative aging, the mechanical properties of BC/PBT biocomposite were deteriorated. The GF/PBT showed the most stable in retaining its mechanical properties in comparison to the talc/PBT and BC/PBT. The aging behavior and mechanism of the PBT composites were discussed. This study provides further insight on the durability-related properties progression of biocomposites as compared to traditional used fillers. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47722.  相似文献   
89.
With the continuous development of the Internet of Things technology and the proposal of “Made in China 2025”, the construction of IoT applicat  相似文献   
90.
张俊  赵辰洋 《低温建筑技术》2021,43(12):129-132
结构的安全性是结构防止破坏倒塌的能力,是结构工程重要的质量指标.老工业基地中的厂房主体结构安全性评价,对于厂房加固改造起到了关键性作用.文中通过对某工业厂房主体结构大量现场勘验、隐患排查及检测数据,结合结构验算,从承载能力、损伤等几方面对该老旧工业厂房的安全性进行了评价与分析,并详细介绍了检测鉴定的流程,为以后类似的老旧工业厂房的检测鉴定提供参考.  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