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   32807篇
  免费   2154篇
  国内免费   32篇
电工技术   233篇
综合类   18篇
化学工业   6566篇
金属工艺   618篇
机械仪表   688篇
建筑科学   919篇
矿业工程   70篇
能源动力   555篇
轻工业   5452篇
水利工程   317篇
石油天然气   116篇
武器工业   5篇
无线电   1237篇
一般工业技术   5632篇
冶金工业   7969篇
原子能技术   131篇
自动化技术   4467篇
  2023年   290篇
  2022年   299篇
  2021年   742篇
  2020年   671篇
  2019年   751篇
  2018年   1342篇
  2017年   1313篇
  2016年   1366篇
  2015年   1044篇
  2014年   1228篇
  2013年   2596篇
  2012年   1928篇
  2011年   1740篇
  2010年   1443篇
  2009年   1282篇
  2008年   1252篇
  2007年   1181篇
  2006年   779篇
  2005年   682篇
  2004年   638篇
  2003年   570篇
  2002年   552篇
  2001年   411篇
  2000年   386篇
  1999年   440篇
  1998年   2375篇
  1997年   1619篇
  1996年   1024篇
  1995年   612篇
  1994年   470篇
  1993年   560篇
  1992年   206篇
  1991年   210篇
  1990年   152篇
  1989年   155篇
  1988年   160篇
  1987年   138篇
  1986年   118篇
  1985年   140篇
  1984年   125篇
  1983年   94篇
  1982年   131篇
  1981年   146篇
  1980年   160篇
  1979年   78篇
  1978年   79篇
  1977年   282篇
  1976年   626篇
  1975年   51篇
  1973年   63篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Journal of Materials Science: Materials in Electronics - Non-volatile organic memory devices were fabricated using polystyrene sulfonate (PSS)?+?nitrogen-doped multi-walled carbon...  相似文献   
2.
3.
4.
5.
6.
The study was conducted to evaluate the effect of non-traditional and highly available and nutrient-dense ingredients in the production of value-added crackers. The crackers were prepared by combining partially defatted chia flour, wheat germ, quinoa, and oat. The antioxidant activity and the polyphenol content were 7.0–8.4 times higher in crackers produced with non-traditional ingredients compared to the control snack. The hydroperoxide value indicated a low oxidative deterioration of the oil. The sample with 10% of partially defatted chia flour was selected for shelf-life test under storage conditions and sensory evaluation. Modified atmosphere exerted a protective effect on the lipid stability regardless of the incorporation of BHT to the formulation. All the evaluated attributes scored highly during consumer acceptance. The formulated cracker presented a relevant content of protein, dietary fibre and omega-3 and -6 fatty acids. Based on these results, the crackers containing non-traditional ingredients resulted in a product with a good potential for both consumer acceptance and outstanding nutritional benefits.  相似文献   
7.
Journal of Porous Materials - The present study reports a systematic analysis of morphology and hydrogen sorption capacity of mesoporous organic-inorganic silica prepared by varying the silica...  相似文献   
8.
Recent advancements in isolation and stacking of layered van der Waals materials have created an unprecedented paradigm for demonstrating varieties of 2D quantum materials. Rationally designed van der Waals heterostructures composed of monolayer transition-metal dichalcogenides (TMDs) and few-layer hBN show several unique optoelectronic features driven by correlations. However, entangled superradiant excitonic species in such systems have not been observed before. In this report, it is demonstrated that strong suppression of phonon population at low temperature results in a formation of a coherent excitonic-dipoles ensemble in the heterostructure, and the collective oscillation of those dipoles stimulates a robust phase synchronized ultra-narrow band superradiant emission even at extremely low pumping intensity. Such emitters are in high demand for a multitude of applications, including fundamental research on many-body correlations and other state-of-the-art technologies. This timely demonstration paves the way for further exploration of ultralow-threshold quantum-emitting devices with unmatched design freedom and spectral tunability.  相似文献   
9.
This study evaluates environmental aggressiveness and atmospheric galvanic corrosivity categories in Chile (Classification of Industrial and Marine ATmospheres test) by installing bolts in electrical transmission towers in the Valparaiso region across four exposure sites: Playa Ancha, San Sebastián, Las Vegas, and San Felipe. Classifications of marine corrosion index (MCI), industrial corrosion index (ICI), and atmospheric corrosion index (ACI) used different galvanic couples: aluminum/steel for MCI, aluminum/copper for ICI, and aluminum/polyethylene for ACI. Corrosion indices varied by season (summer, autumn, winter, and spring), for which couples were exchanged every 3 months. Intraseason variation depended mainly on the meteorochemical variables of the zone, the Cl/SO2 ratio, and the presence of general and pitting corrosion in the aluminum. The results indicate that, regardless of environmental condition, the aluminum in Al/steel (MCI) and Al/copper (ICI) couples presented a higher corrosion rate than when not forming a galvanic couple (ACI). Moreover, under higher environmental chloride, these differences increase. The Playa Ancha station presented the highest ACI.  相似文献   
10.
The Journal of Supercomputing - The increasing number of connected devices and the complexity of Internet of Things (IoT) ecosystems are demanding new architectures for managing and securing these...  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