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   2555篇
  免费   163篇
  国内免费   1篇
工业技术   2719篇
  2024年   5篇
  2023年   18篇
  2022年   33篇
  2021年   93篇
  2020年   66篇
  2019年   85篇
  2018年   96篇
  2017年   88篇
  2016年   84篇
  2015年   82篇
  2014年   88篇
  2013年   236篇
  2012年   139篇
  2011年   155篇
  2010年   145篇
  2009年   97篇
  2008年   68篇
  2007年   39篇
  2006年   37篇
  2005年   16篇
  2004年   12篇
  2003年   13篇
  2002年   19篇
  2001年   5篇
  2000年   7篇
  1999年   30篇
  1998年   268篇
  1997年   178篇
  1996年   108篇
  1995年   66篇
  1994年   49篇
  1993年   69篇
  1992年   9篇
  1991年   7篇
  1990年   6篇
  1989年   13篇
  1988年   8篇
  1987年   6篇
  1986年   7篇
  1985年   7篇
  1983年   4篇
  1982年   4篇
  1981年   9篇
  1980年   7篇
  1978年   6篇
  1977年   44篇
  1976年   76篇
  1963年   2篇
  1955年   2篇
  1938年   2篇
排序方式: 共有2719条查询结果,搜索用时 15 毫秒
1.
Anzaldo  Alexis  Andrade  Ángel G. 《Wireless Networks》2022,28(8):3613-3620
Wireless Networks - Beyond five generation (B5G) systems will demand strict and heterogeneous service requirements for the emerging applications. One solution to meet these demands is the dense...  相似文献   
2.
Scientometrics - Consolidation of the scientific activity in Latin American research centers has been a matter of serious concern in recent years. In the present study we use a data set of the WoS...  相似文献   
3.
Thin multilayer coatings of ZrO2–Y2O3–Al2O3 were prepared using the sol-gel method and dip-coating technique in order to advance in the study of what influence the incorporation of Al2O3 has on films of Y2O3-doped ZrO2, investigating its role in the synthesis of the solutions and in the characteristics and properties of the coatings. After the characterization of the solutions used in the process, the microstructure of the films was studied and their mechanical behaviour and resistance to thermal shock were determined so as to optimize the characteristics and functionality of these coatings. With increased alumina content, 3YSZ-Al2O3 (20 mol%), the cubic phase of the zirconia disappeared completely at the sintering temperature used (700 °C), resulting in the tetragonal phase with Al in solution. There was also a decrease in the coatings' hardness and Young's modulus, and an increase in toughness and resistance to thermal shock. These results allow guidelines to be established for the design of multilayer structures that are, tougher, more resistant, and have improved surface properties.  相似文献   
4.
5.
Solid oxide fuel cell (SOFC) systems with anode off-gas recirculation (AGR) and diesel pre-reforming are advantageous because they can operate with the current fuel infrastructure. In the SchIBZ-project, the prototype of such a SOFC system for maritime applications has already been commissioned. In this first paper, we model the system devices to conduct an exergy analysis of this real SOFC plant and validate them with experimental values from experiments in laboratory scale. The results of our simulation agree well with the experimental values. The calculations with the validated results may be closer to the real thermodynamic behavior of such system components than previous literature.  相似文献   
6.
7.
Edible mushrooms production presents a potential problem for the environment, due to the large amount of waste generated. These wastes contain nitrogenous matter, which could be used as biostimulant in plants. The aim of this work was to study the effect of waste waters, from the mushroom production process, applied at veraison and 1 week later to grapevine leaves, on grape volatile compounds over two vintages. The results evidenced that mushroom water treatment decreased the grape content of certain terpenoids, C13 norisoprenoids, benzenoid compounds and esters, increasing C6 compounds content during the first season. Treated mushroom water application slightly affected grape volatile composition. This was the treatment that least affected the content of grape volatile composition. Few differences were found after the biostimulation during the second vintage. The season was the dominant factor of grape volatile content variation compared to the treatment and their interaction.  相似文献   
8.
How do nuclear technologies become commonplace? How have the borders between the exceptional and the banal been drawn and redrawn over the last 70 years in order to make nuclear energy part of everyday life? This special issue analyzes the role of fun and display, broadly construed, in shaping the cultural representation and the material circulation (or non‐circulation) of nuclear technologies. Four case studies, covering the United States, Great Britain, Portugal, Spain, and Ukraine from the 1950s to the 2000s, explore how specific forms of public display and playful practices of cultural production were used as means to banalize (or de‐banalize) nuclear energy. This introduction addresses the main theoretical and historiographical signposts of the special issue and outlines the different ways in which the articles explore them.  相似文献   
9.
Pattern Analysis and Applications - As is widely acknowledged, the transportation of goods by road can, in one way or another, be linked to a range of macroeconomic indicators. A hybrid artificial...  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-23

京公网安备 11010802026262号