首页 | 官方网站   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   125924篇
  免费   9290篇
  国内免费   4303篇
工业技术   139517篇
  2024年   123篇
  2023年   1344篇
  2022年   1909篇
  2021年   3637篇
  2020年   2846篇
  2019年   2606篇
  2018年   3124篇
  2017年   3322篇
  2016年   3508篇
  2015年   4039篇
  2014年   5530篇
  2013年   7792篇
  2012年   8401篇
  2011年   9502篇
  2010年   7955篇
  2009年   8040篇
  2008年   8039篇
  2007年   7541篇
  2006年   7023篇
  2005年   5868篇
  2004年   4742篇
  2003年   3955篇
  2002年   3793篇
  2001年   3049篇
  2000年   2679篇
  1999年   2391篇
  1998年   3070篇
  1997年   2169篇
  1996年   1868篇
  1995年   1580篇
  1994年   1313篇
  1993年   1045篇
  1992年   773篇
  1991年   694篇
  1990年   562篇
  1989年   540篇
  1988年   412篇
  1987年   339篇
  1986年   294篇
  1985年   243篇
  1984年   221篇
  1983年   165篇
  1982年   172篇
  1981年   144篇
  1980年   141篇
  1979年   106篇
  1978年   100篇
  1977年   126篇
  1976年   163篇
  1975年   82篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Wen  Pushan  He  Rui  Li  Xiang-Dan  Lee  Myong-Hoon 《Journal of Materials Science》2022,57(1):755-765
Journal of Materials Science - Three polyimides (PIs) were prepared from a diamine containing biphenyl ester group as a side chain and a corresponding dianhydride chosen from...  相似文献   
2.
This study was conducted to evaluate the effect of red-wine grape pomaces on the quality and sensory attributes of beef hamburger patties. Both phenolic content and antioxidant activity were assessed using Syrah, Merlot and Cabernet Sauvignon pomaces. Following the assessment, hamburger patties were prepared with Merlot pomace at 0%, 2% and 4% for the patty quality and sensory attributes. Grape seeds possessed significantly higher phenolics and antioxidant activities over the seedless pomace (P < 0.05), whereas no significant difference was found for phenolics and antioxidant activities within the seeds and seedless pomaces. The patty pH decreased as the pomace was added for 2% and 4%. Colour values (L*, a* and b*) of patties lowered as the pomace was added. Allo-Kramer shear force and hardness values increased while cooking yield decreased (P < 0.05) with the addition of pomace. No significant difference between control and Merlot patties was found for flavour, juiciness and colour, whereas lower sensory attributes were observed for texture, taste and overall acceptability. It is observed that the addition of fermented red-wine grape pomace provides hamburger patties with health promoting factors such as antioxidant and other functional components, but it also provided darker, sourer and lower cooking yield.  相似文献   
3.
A high-throughput (105.5 g/h) passive four-stage asymmetric oscillating feedback microreactor using chaotic mixing mechanism was developed to prepare aggregated Barium sulfate (BaSO4) particles of high primary nanoparticle size uniformity. Three-dimensional unsteady simulations showed that chaotic mixing could be induced by three unique secondary flows (i.e., vortex, recirculation, and oscillation), and the fluid oscillation mechanism was examined in detail. Simulations and Villermaux–Dushman experiments indicate that almost complete mixing down to molecular level can be achieved and the prepared BaSO4 nanoparticles were with narrow primary particle size distribution (PSD) having geometric standard deviation, σg, less than 1.43 when the total volumetric flow rate Qtotal was larger than 10 ml/min. By selecting Qtotal and reactant concentrations, average primary particle size can be controlled from 23 to 109 nm as determined by microscopy. An average size of 26 nm with narrow primary PSD (σg = 1.22) could be achieved at Qtotal of 160 ml/min.  相似文献   
4.
5.
Li  Miao  Xiong  Naixue  Zhang  Yin  Hu  Ying 《Mobile Networks and Applications》2022,27(4):1768-1777
Mobile Networks and Applications - With the rapid development of Internet of things, the traditional city model is no longer applicable. Therefore, the emerging concept of smart city meets the...  相似文献   
6.
Food Science and Biotechnology - The objective of this study was to develop a non-fermented probiotic milk that maintains its physicochemical properties, microbial properties, antioxidant activity,...  相似文献   
7.
Multimedia Tools and Applications - Individual tooth segmentation and identification from cone-beam computed tomography images are preoperative prerequisites for orthodontic treatments. Instance...  相似文献   
8.
尹波  周书仁  桂彦 《电子质量》2022,(1):103-106
在实施国家大数据战略和创新型国家建设的引导下,培养跨学科思维与能力是创新型人才培养的核心要求.大数据是一个典型的学科交叉的技术,资源分散是当前高校大数据人才培养存在的主要问题.该文以长沙理工大学"大数据行业应用"虚拟教研室建设为例,打造"大数据"特色跨学科跨专业教学组织,从课程体系、实践环节、师资队伍、质量监督等方面提出建设措施,为培养跨学科创新型复合型人才提供参考.  相似文献   
9.
10.
Park  Jieun  Kim  Junghun  Hyun  Sinjae  Lee  Jongmin 《Magma (New York, N.Y.)》2022,35(5):719-732
Magnetic Resonance Materials in Physics, Biology and Medicine - This study aims to compare an electrocardiogram (ECG)-gated four-dimensional (4D) phase-contrast (PC) magnetic resonance imaging...  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-23

京公网安备 11010802026262号