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   32922篇
  免费   2161篇
  国内免费   27篇
电工技术   224篇
综合类   18篇
化学工业   6542篇
金属工艺   615篇
机械仪表   694篇
建筑科学   924篇
矿业工程   70篇
能源动力   553篇
轻工业   5562篇
水利工程   311篇
石油天然气   114篇
武器工业   5篇
无线电   1236篇
一般工业技术   5636篇
冶金工业   8006篇
原子能技术   123篇
自动化技术   4477篇
  2023年   289篇
  2022年   301篇
  2021年   743篇
  2020年   659篇
  2019年   749篇
  2018年   1352篇
  2017年   1311篇
  2016年   1369篇
  2015年   1045篇
  2014年   1229篇
  2013年   2594篇
  2012年   1942篇
  2011年   1739篇
  2010年   1438篇
  2009年   1285篇
  2008年   1254篇
  2007年   1176篇
  2006年   784篇
  2005年   673篇
  2004年   634篇
  2003年   565篇
  2002年   551篇
  2001年   406篇
  2000年   383篇
  1999年   438篇
  1998年   2377篇
  1997年   1619篇
  1996年   1026篇
  1995年   618篇
  1994年   471篇
  1993年   562篇
  1992年   202篇
  1991年   207篇
  1990年   153篇
  1989年   158篇
  1988年   161篇
  1987年   136篇
  1986年   120篇
  1985年   141篇
  1984年   125篇
  1983年   96篇
  1982年   139篇
  1981年   147篇
  1980年   159篇
  1979年   81篇
  1978年   80篇
  1977年   289篇
  1976年   626篇
  1975年   53篇
  1973年   78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