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   393409篇
  免费   31714篇
  国内免费   16825篇
电工技术   23766篇
技术理论   58篇
综合类   26105篇
化学工业   62769篇
金属工艺   22469篇
机械仪表   26036篇
建筑科学   31601篇
矿业工程   12871篇
能源动力   11738篇
轻工业   24215篇
水利工程   7067篇
石油天然气   25320篇
武器工业   3486篇
无线电   43988篇
一般工业技术   44811篇
冶金工业   20185篇
原子能技术   4095篇
自动化技术   51368篇
  2024年   635篇
  2023年   5719篇
  2022年   9048篇
  2021年   14213篇
  2020年   11485篇
  2019年   9179篇
  2018年   10702篇
  2017年   12117篇
  2016年   10901篇
  2015年   14828篇
  2014年   19385篇
  2013年   23079篇
  2012年   25048篇
  2011年   27490篇
  2010年   24057篇
  2009年   23124篇
  2008年   22929篇
  2007年   21879篇
  2006年   22640篇
  2005年   19603篇
  2004年   13197篇
  2003年   11837篇
  2002年   11593篇
  2001年   10324篇
  2000年   9525篇
  1999年   10540篇
  1998年   8533篇
  1997年   7087篇
  1996年   6591篇
  1995年   5588篇
  1994年   4578篇
  1993年   3217篇
  1992年   2593篇
  1991年   2043篇
  1990年   1558篇
  1989年   1285篇
  1988年   1024篇
  1987年   670篇
  1986年   535篇
  1985年   330篇
  1984年   233篇
  1983年   193篇
  1982年   201篇
  1981年   138篇
  1980年   133篇
  1979年   79篇
  1978年   35篇
  1977年   38篇
  1976年   55篇
  1975年   20篇
排序方式: 共有10000条查询结果,搜索用时 19 毫秒
101.
Frozen poultry meat is the most widely consumed animal-based food. However, water loss often leads to quality loss of poultry meat. Therefore, the present study sought to investigate the combined effect of calcium chloride (CaCl2) and pulsed electric fields (PEF) treatment on chicken breast meats and the mechanisms underlying protein degradation. The results showed that the synergistic effect was superior to the single treatment. Compared with the untreated group, the combination of CaCl2 and PEF increased water holding capacity of chicken breast meats by 16.61% and decreased cooking loss by 28.93%. Low-field nuclear magnetic resonance (LF-NMR) results indicated that the synergistic treatment promoted water molecules' binding capacity in myofibrils of poultry meat, which exhibited higher immobilised water. Additionally, the combination of CaCl2 and PEF led to increased degradation of proteins of high-molecular weight and surface hydrophobicity of myofibrillar protein. Furthermore, the extension of the protein molecule and microenvironmental changes promoted interaction between protein and water. In conclusion, the synergistic treatment of CaCl2 and PEF enhanced water retention and improved physicochemical properties of the myofibrillar protein in chicken breast meats.  相似文献   
102.
赫哲族是我国北方人口较少的少数民族之一,分布于黑龙江省东部松花江、黑龙江与乌苏里江流域交汇处及完达山余脉.作为具有悠久历史的东北渔猎民族,其东北寒带地区得天独厚的地理位置,造就了其独特的民族文化与建筑居住形式与居室陈设艺术.陈设用品与生活用品既具有精神与审美层面的艺术装饰,也有易加工的便利取材或因寒冷且潮湿的季节气候而考虑的防潮保暖、夏季通风的选材需求,或学习其他民族的优秀技艺文化而发展起来的具有本民族特色的生活与陈设用品.通过对赫哲族历史起源、生活方式、建筑居室陈设传统纹饰及材质手法的介绍与分析,展现出赫哲族人民勤劳、乐观、豁达、创新的生活面貌与文化.  相似文献   
103.
Li  Yuru  Wang  Fei  Zheng  Zhaowen 《Neural Processing Letters》2022,54(4):3141-3156
Neural Processing Letters - This paper presents an approach to identify the unknown parameters of genetic regulatory network (GRN) in finite-time. The adaptive synchronization-based method is used...  相似文献   
104.
Xian  Yu  Wang  Cuicui  Wang  Ge  Smith  Leemiller  Cheng  Haitao 《Holz als Roh- und Werkstoff》2022,80(2):355-365
European Journal of Wood and Wood Products - To obtain the optimum balance between performance and cost, white mud (lime mud) was incorporated into the shell layer of core–shell structured...  相似文献   
105.
106.
Molecular dynamics simulations are performed to investigate the solid surface-induced microstructure and friction coefficient of glycerol aqueous solutions with different water contents confined in graphene and FeO nanoslits. Results show that the friction coefficient of glycerol aqueous solutions confined in both nanoslits presents similar nonlinear variation tendencies with increasing water content, but their lowest value and the corresponding water contents differ. Distinctive microstructures of the near-surface liquid layer induced by surfaces with different hydrophilicity are responsible for their difference in lubrication. The sliding primarily occurs at the solid–liquid interface for the hydrophobic graphene nanoslit owing to almost the same velocity difference in fluid molecules. By contrast, the sliding mainly occurs at the liquid–liquid interface for the hydrophilic FeO nanoslit because of the large velocity difference in fluid molecules. The weaker the interaction force at the sliding position, the lower the friction coefficient.  相似文献   
107.
Under the circumstance of perceptual consumption, it is still challenging to grasp consumer's emotions and demands due to the large search space, diversified preferences, and easy fatigue of consumers. To reduce user fatigue and enlarge search space, a novel method was presented to design and optimize the pattern of yarn-dyed plaid fabric using the isolation niche genetic algorithm and rough set theory. Each pattern was encoded as a chromosome based on the real number code. The population was initialized and evolved using INGA to maintain the diversity. The rough set theory was adopted as the fitness function of isolation niche genetic algorithm to extract the consumer's demands. After multiple evolutions, a large set of practical patterns of the yarn-dyed plaid fabric are obtained. Experiments were carried out by 24 testers of different ages and genders. The results prove that the proposed method based on the isolation niche genetic algorithm and rough set theory is feasible and effective, supplying references to the designer.  相似文献   
108.
Based on the premise that large bubbles are removed in larger cyclones and small bubbles in smaller cyclones, a combined degassing cyclone with main and subsidiary chambers was designed to enhance liquid degassing. The pressure loss, liquid flow rate at the gas outlet, split ratio, gas flow rate at the liquid outlet, and degassing efficiency of the degassing cyclone were measured and calculated. Pressure loss correlations were established which relates the Euler number to the gas and liquid Reynolds numbers in the main chamber. Most cases exhibit a degassing efficiency greater than 0.998 when the liquid flow rate is more than 0.7 m3h?1. The contours of pressure loss, split ratio, and degassing efficiency provide an effective guidance for designing a degassing cyclone.  相似文献   
109.
110.
International Journal of Control, Automation and Systems - The vibration control problem of offshore jacket platforms is studied. The model of offshore platforms with nonlinear interactions of the...  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