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   5603篇
  免费   533篇
  国内免费   3篇
电工技术   15篇
综合类   1篇
化学工业   1941篇
金属工艺   42篇
机械仪表   115篇
建筑科学   229篇
矿业工程   10篇
能源动力   144篇
轻工业   1840篇
水利工程   55篇
石油天然气   38篇
无线电   207篇
一般工业技术   722篇
冶金工业   156篇
原子能技术   9篇
自动化技术   615篇
  2024年   16篇
  2023年   72篇
  2022年   278篇
  2021年   434篇
  2020年   226篇
  2019年   253篇
  2018年   250篇
  2017年   253篇
  2016年   285篇
  2015年   202篇
  2014年   311篇
  2013年   466篇
  2012年   432篇
  2011年   465篇
  2010年   343篇
  2009年   336篇
  2008年   283篇
  2007年   254篇
  2006年   180篇
  2005年   137篇
  2004年   125篇
  2003年   91篇
  2002年   80篇
  2001年   42篇
  2000年   49篇
  1999年   49篇
  1998年   36篇
  1997年   26篇
  1996年   22篇
  1995年   12篇
  1994年   16篇
  1993年   15篇
  1992年   10篇
  1991年   5篇
  1990年   5篇
  1989年   17篇
  1988年   8篇
  1987年   12篇
  1986年   5篇
  1985年   9篇
  1984年   8篇
  1983年   2篇
  1982年   3篇
  1981年   2篇
  1980年   4篇
  1979年   1篇
  1978年   4篇
  1977年   3篇
  1976年   2篇
排序方式: 共有6139条查询结果,搜索用时 78 毫秒
831.
832.
833.
The cover image is based on the Research Article Study of the physical and chemical changes during the maturation of three cocoa clones, EET8, CCN51, and ICS60 by Andrés F Cubillos Bojacá et al., DOI: 10.1002/jsfa.9882 . Cover image ©AGROSAVIA Images.

  相似文献   

834.
Spontaneously foaming oil systems have been formulated from water-in-oil emulsions by the controlled release and entrapment of gas in emulsified water droplets contained within the oil. The cascade of events leading to their formation is as follows: Two Span 60-emulsified populations of water droplets, one containing Na2CO3, the other 10% HCl and caseinate, were mixed in miglyol oil; the controlled coalescence of Na2CO3 droplets with the HCl ones served as a microreactor for the pH reduction and the subsequent release of CO2 from Na2CO3; these gas microbubbles were arrested by sodium caseinate, stabilizing a microfoam within the water droplets; these droplets expanded under the rising gas pressure, spontaneously transforming the surrounding oil into a foamy oleogel containing water droplets.  相似文献   
835.
Javier de Mesones-Cabello was an influential and active planner of the 1960s and 1970s in Spain, who passed away in December, 2016. His professional career as a self-taught urban planner was extensively linked to his academic and institutional activities. These connections supported the establishment of relationships with prestigious professionals working in urban planning practice. In planning the 1969 masterplan for the city of Valladolid, in Spain, de Mesones-Cabello made several intellectual references to the Greek urban planner Doxiadis. This masterplan covers a relatively unknown example of directional city growth in a European context. My findings elucidate the extent to which de Mesones-Cabello was influenced by Doxiadis, and the circumstances in which these ideas have continued to dominate thinking about Valladolid's urban development.  相似文献   
836.
Thompson Seedless (TS) and Black (BS) grapes sanitised with 2, 4, 6, 8 mg L?1 O3 or NaOCl (100 mg L?1) were stored 21 days at 5 °C. Ozonated water stimulated the respiration rate, especially after 5 days of storage, and increased superoxide dismutase and catalase activity compared to NaOCl‐sanitised grapes. Total polyphenol content (TPC) was 23–50% higher in TS and 18.5–28% higher in BS samples sanitised with ozonated water. Twofold higher total antioxidant capacity (TAC) was registered in TS at all of the evaluated O3 doses while the doses of 6 and 8 mg L?1 increased TAC by 19–30% in BS. The use of ozonated water as a sanitising method, especially at 6 and 8 mg L?1 doses, improved the functional quality and maintained low microbial counts on fresh‐cut grapes being a good alternative for the industry.  相似文献   
837.
This study evaluated the influence of packaging atmosphere (air versus 50% N2/50% CO2) on microbiological (mesophiles, psychrotrophs), physical (gas measurement) and chemical (pH, total volatile basic nitrogen [TVB‐N], NH3, H2S and biogenic amines) parameters in freshwater prawns during storage at 0 ± 1 °C for 240 h. To select the most appropriate packaging, 21 batches of each treatment were analysed. Both the packaging permeability and the combination of gases affected the shelf life, but the modified‐atmosphere packaging (MAP) was more efficient than air packaging, increasing the shelf life by 40 h. The parameters of pH and TVB‐N showed no statistical difference between the two atmosphere conditions all along the storage period. The biogenic amine agmatine showed potential for use as a quality indicator due to the increased concentration during storage. In further studies, this amine can be applied as an indicator for public health issue.  相似文献   
838.
To ensure the marketing of fresh fish‐based products, it is necessary to develop fast methods that assess its freshness in real time. This study therefore evaluated the applicability of a photochromic time–temperature indicator (TTI) to monitor the time and temperature history during the period of validity of the whole fish of the cobia specimen stored in ice. The TTI response was both visibly interpreted as well as adaptable to measurement using suitable equipment. The results showed that the smart indicator activated during 6 s of ultraviolet light showed a similar rate of deterioration of the analysed product visual response, proving to be a dynamic shelf life indicator that can assure consumers the ultimate quality point of the entire cobia easily, cheaply and accurately.  相似文献   
839.
840.
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