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   1562943篇
  免费   32736篇
  国内免费   9943篇
电工技术   38453篇
技术理论   5篇
综合类   10590篇
化学工业   277217篇
金属工艺   67406篇
机械仪表   46001篇
建筑科学   51046篇
矿业工程   12938篇
能源动力   51904篇
轻工业   115735篇
水利工程   16252篇
石油天然气   40462篇
武器工业   699篇
无线电   203284篇
一般工业技术   290615篇
冶金工业   171411篇
原子能技术   34656篇
自动化技术   176948篇
  2021年   17942篇
  2020年   13553篇
  2019年   15979篇
  2018年   17252篇
  2017年   16797篇
  2016年   22749篇
  2015年   19569篇
  2014年   31343篇
  2013年   91003篇
  2012年   38860篇
  2011年   51452篇
  2010年   45742篇
  2009年   53828篇
  2008年   47830篇
  2007年   44749篇
  2006年   47864篇
  2005年   41878篇
  2004年   43277篇
  2003年   43045篇
  2002年   42113篇
  2001年   39172篇
  2000年   37303篇
  1999年   36661篇
  1998年   48284篇
  1997年   41290篇
  1996年   37162篇
  1995年   32005篇
  1994年   29820篇
  1993年   29524篇
  1992年   26690篇
  1991年   23734篇
  1990年   23955篇
  1989年   22904篇
  1988年   21385篇
  1987年   19648篇
  1986年   19025篇
  1985年   22270篇
  1984年   22398篇
  1983年   20367篇
  1982年   19331篇
  1981年   19415篇
  1980年   17977篇
  1979年   18549篇
  1978年   17788篇
  1977年   17451篇
  1976年   18380篇
  1975年   15999篇
  1974年   15554篇
  1973年   15618篇
  1972年   13056篇
排序方式: 共有10000条查询结果,搜索用时 343 毫秒
21.
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   
22.
Refractories and Industrial Ceramics - The paper introduces a promising technology for utilizing a traditional scheme for implementing a flow-through micro-arc oxidation method to restore localized...  相似文献   
23.
Theoretical Foundations of Chemical Engineering - On the basis of the classic concepts of the theory of solid-phase combustion, for the first time, a model with a detailed scheme of chemical...  相似文献   
24.
25.
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   
26.
Multimedia Tools and Applications - Recently, many concepts in technology has been changed. According to the digital transformation trends, Internet of Things (IoT) represents an interested...  相似文献   
27.
In this study, dilute chemical bath deposition technique has been used to deposit CdZnS thin films on soda-lime glass substrates. The structural, morphological, optoelectronic properties of as-grown films have been investigated as a function of different Zn2+ precursor concentrations. The X-ray diffractogram of CdS thin-film reveals a peak corresponding to (002) plane with wurtzite structure, and the peak shift has been observed with the increase of the Zn2+ concentration upon formation of CdZnS thin film. From morphological studies, it has been revealed that the diluted chemical bath deposition technique provides homogeneous distribution of film on the substrate even at a lower concentration of Zn2+. Optical characterization has shown that the transparency of the film is influenced by Zn2+ concentration and when the Zn2+ concentration is varied from 0 M to 0.0256 M, bandgap values of resulting films range from 2.42 eV to 3.90 eV while. Furthermore, electrical properties have shown that with increasing zinc concentration the resistivity of the film increases. Finally, numerical simulation validates and suggests that CdZnS buffer layer with composition of 0.0032 M Zn2+ concentration would be a promising candidate in CIGS solar cell.  相似文献   
28.
Combustion, Explosion, and Shock Waves - Results of a numerical study of mixing, ignition, and combustion of a cold hydrogen jet propagating along the lower wall of a channel parallel to a...  相似文献   
29.
Multimedia Tools and Applications - In this work, a new fuzzy logic-based algorithm is proposed for the enhancement of low light color images. A generalization of a fuzzy set known as an...  相似文献   
30.
Multimedia Tools and Applications - The three-dimensional models of brain tumors serve as diagnostic assistance for physicians, surgeons, and radiologists. The proposed system establishes an...  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