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   73951篇
  免费   7157篇
  国内免费   3623篇
电工技术   4678篇
技术理论   9篇
综合类   5377篇
化学工业   12201篇
金属工艺   4034篇
机械仪表   4768篇
建筑科学   6027篇
矿业工程   2443篇
能源动力   2450篇
轻工业   5446篇
水利工程   1514篇
石油天然气   3849篇
武器工业   693篇
无线电   8476篇
一般工业技术   8740篇
冶金工业   3390篇
原子能技术   829篇
自动化技术   9807篇
  2024年   160篇
  2023年   1344篇
  2022年   2161篇
  2021年   3265篇
  2020年   2488篇
  2019年   2103篇
  2018年   2383篇
  2017年   2573篇
  2016年   2308篇
  2015年   3115篇
  2014年   3884篇
  2013年   4653篇
  2012年   5114篇
  2011年   5236篇
  2010年   4912篇
  2009年   4604篇
  2008年   4477篇
  2007年   4015篇
  2006年   3959篇
  2005年   3251篇
  2004年   2313篇
  2003年   1998篇
  2002年   2113篇
  2001年   1816篇
  2000年   1590篇
  1999年   1682篇
  1998年   1288篇
  1997年   1095篇
  1996年   1026篇
  1995年   816篇
  1994年   746篇
  1993年   524篇
  1992年   438篇
  1991年   304篇
  1990年   207篇
  1989年   189篇
  1988年   151篇
  1987年   95篇
  1986年   72篇
  1985年   49篇
  1984年   31篇
  1983年   21篇
  1982年   31篇
  1981年   20篇
  1980年   22篇
  1979年   16篇
  1977年   6篇
  1976年   6篇
  1975年   6篇
  1951年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Niu  Hao  Yang  Dan-Lei  Pu  Yuan  Wang  Dan  Wang  Jie-Xin 《Journal of Materials Science》2022,57(10):5788-5804
Journal of Materials Science - Nanocomposites have been used in various industries due to their excellent properties. For some of them, high filler content (over 50 wt%) is beneficial to improving...  相似文献   
2.
3.
Zhang  Qi  Wang  Yujing  Zhang  Xueling  Song  Jun  Li  Yinlei  Wu  Xuehong  Yuan  Kunjie 《Journal of Materials Science》2022,57(14):7208-7224
Journal of Materials Science - Form-stable composite phase change materials (C-PCMs) prepared by microencapsulation method and porous matrix adsorption method need for compression molding after...  相似文献   
4.
5.
The effects of non-thermal plasma (NTP) on the physicochemical properties of wheat flour and the quality of fresh wet noodles ( FWN) were investigated. The results showed that NTP effectively decreased the total plate count (TPC), yeast and mould count (YMC) and Bacillus spp. in wheat flour. Wet gluten contents and the stability time reached the maximum when treated for 20 s. The viscosity of starch increased significantly after treatment due to the increased of damaged starch. The contents of secondary structure were altered to some extent, which was because that the ordered network structure of gluten protein broken. Furthermore, compared with the control, texture properties of FWN were enhanced significantly at 20 s, and the darkening rate of FWN was greatly inhibited due to the low polyphenol oxidase (PPO) activity. Consequently, the most suitable treatment was 500 W for 20 s, providing a basis for the application of NTP in flour products.  相似文献   
6.
The aim of this study was to determine the effects of tumbling at different post-mortem times on the proteolytic features and quality attributes of beef loins (M. longissimus lumborum). Loins (n = 12) were cut into 4 sections and assigned to tumbling at 1, 6 or 11 days post-mortem or non-tumbled control. Upon tumbling, additional ageing was applied to a common post-mortem time of 16 days. In general, tumbling had no considerable impacts on water-holding ability of samples. Tumbling resulted in an immediate decrease in shear force values (WBSF) of beef samples. Tumbling at 1 day post-mortem with no ageing had similar WBSF compared to the non-tumbled controls at 16 days (P > 0.05). With ageing, tumbling increased amounts of protein degradation, myofibrillar fragmentation and calpain-1 autolysis of samples. These results suggest that early post-mortem tumbling coupled with ageing can synergistically impact the tenderness development of beef loins and shorten the necessary ageing period.  相似文献   
7.
The present study aimed to evaluate the effect of fermentation and gastrointestinal digestion of three kinds of fermented kiwifruit pulps with different Lactobacillus (Lactobacillus plantarum, Lactobacillus acidophilus and Lactobacillus casei). The changes in bioactive substances (total phenolic acid, total flavonoid, vitamin C and the viable count), antioxidant capacity (DPPH, ABTS, hydroxyl radical and superoxide anion radical scavenging activity) and phenolic profiles (protocatechuic acid, protocatechualdehyde, chlorogenic acid, caffeic acid and p-coumaric acid) were detected. The result showed, compared to non-fermented kiwifruit pulp, fermentation with LP and LA had higher content of TPA, TF and VC, as well as antioxidant capacity. Fermentation with LP and the content of protocatechualdehyde, p-coumaric acid and chlorogenic acid were increased. However, after digestion, LP showed more effect in maintaining the content of antioxidants, antioxidant capacity and the viable count rather than LA. During digestion, the content of protocatechualdehyde and p-coumaric acid was increased in fermented samples compared with non-fermented samples. Overall, compared with LA and LC, LP is more suitable for the fermentation of kiwifruit pulp.  相似文献   
8.
Solar steam generation has attracted considerable interest due to its easy accessibility and sustainability. However, dye molecules were gradually concentrated on bulk water or the surface of solar absorbers during the disposal of dye wastewater. Herein, LaB6/g-C3N4 composites were immobilized on porous cotton cloth, served as a solar absorber resistant to dye clogging. The optimal solar absorber possessed solar harvesting of 92.3% and showed great application potential in the field of the treatment of dye wastewater. This study presented a new approach for the treatment of dye wastewater.  相似文献   
9.
本文通过对国内外石油及石化产品分析检测相关标准技术的调研与收集,以及相关检测仪器特点的分析,对目前包括润滑油、汽油、柴油、煤油、石蜡、石化聚合物、原油等样品类型,共计80个样品在现有仪器上进行测试,使用标准方法对样品中碳、氢、氮、硫元素进行检测,获取样品的检测时间、含量结果、仪器条件等参数,为相关仪器检测提供数据基础.  相似文献   
10.
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