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   558620篇
  免费   7131篇
  国内免费   987篇
电工技术   10385篇
综合类   463篇
化学工业   85743篇
金属工艺   23221篇
机械仪表   18293篇
建筑科学   12264篇
矿业工程   4307篇
能源动力   14352篇
轻工业   44923篇
水利工程   6931篇
石油天然气   14897篇
武器工业   39篇
无线电   59969篇
一般工业技术   115375篇
冶金工业   95570篇
原子能技术   14687篇
自动化技术   45319篇
  2021年   5258篇
  2020年   4057篇
  2019年   5324篇
  2018年   9265篇
  2017年   9471篇
  2016年   9892篇
  2015年   6076篇
  2014年   10315篇
  2013年   26212篇
  2012年   15845篇
  2011年   21143篇
  2010年   17024篇
  2009年   18861篇
  2008年   19089篇
  2007年   18790篇
  2006年   16301篇
  2005年   14764篇
  2004年   13997篇
  2003年   13572篇
  2002年   12680篇
  2001年   12220篇
  2000年   11479篇
  1999年   11285篇
  1998年   26985篇
  1997年   19469篇
  1996年   14983篇
  1995年   11912篇
  1994年   10754篇
  1993年   10512篇
  1992年   8238篇
  1991年   8018篇
  1990年   7938篇
  1989年   7672篇
  1988年   7387篇
  1987年   6659篇
  1986年   6458篇
  1985年   7328篇
  1984年   6640篇
  1983年   6358篇
  1982年   5717篇
  1981年   5845篇
  1980年   5586篇
  1979年   5689篇
  1978年   5634篇
  1977年   6149篇
  1976年   7654篇
  1975年   5070篇
  1974年   4867篇
  1973年   4943篇
  1972年   4256篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Multimedia Tools and Applications - The design of robots capable of operating autonomously in changing and unstructured environments, requires using complex software architectures in which,...  相似文献   
92.
Journal of Computer and Systems Sciences International - It is shown that the Lyapunov theorem on the distribution properties of the sum of random variables with different distribution densities...  相似文献   
93.
Cybernetics and Systems Analysis - The authors propose a new method for finding the sum of two or more multidigit values in a parallel computational model. The method reduces finding the sum of a...  相似文献   
94.
Programming and Computer Software - In this paper, we propose an algorithm for solving the Cauchy problem for a two-dimensional difference equation with constant coefficients at a point, based on...  相似文献   
95.
96.
Russian Engineering Research - The stability of robot-mower motion in a specific direction is considered. The direction is regulated by means of an angular sensor and a programmable controller...  相似文献   
97.
Cybernetics and Systems Analysis - The authors propose a method for solving the problem of approach of controlled objects in dynamic game problems with a terminal payoff function. The method is...  相似文献   
98.
Grachev  A. I. 《Semiconductors》2022,56(2):67-70
Semiconductors - In this work, we discuss for the first time the principle of rotation in the constant electric field of a conducting particle with participation of the Lorentz force, which ensures...  相似文献   
99.
Gelatin is one of the most important multifunctional biopolymers and is widely used as an essential ingredient in food, pharmaceutical, and cosmetics. Porcine gelatin is regarded as the leading source of gelatin globally then followed by bovine gelatin. Porcine sources are favored over other sources since they are less expensive. However, porcine gelatin is religiously prohibited to be consumed by Muslims and the Jewish community. It is predicted that the global demand for gelatin will increase significantly in the future. Therefore, a sustainable source of gelatin with efficient production and free of disease transmission must be developed. The highest quality of Bovidae-based gelatin (BG) was acquired through alkaline pretreatment, which displayed excellent physicochemical and rheological properties. The utilization of mammalian- and plant-based enzyme significantly increased the gelatin yield. The emulsifying and foaming properties of BG also showed good stability when incorporated into food and pharmaceutical products. Manipulation of extraction conditions has enabled the development of custom-made gelatin with desired properties. This review highlighted the various modifications of extraction and processing methods to improve the physicochemical and functional properties of Bovidae-based gelatin. An in-depth analysis of the crucial stage of collagen breakdown is also discussed, which involved acid, alkaline, and enzyme pretreatment, respectively. In addition, the unique characteristics and primary qualities of BG including protein content, amphoteric property, gel strength, emulsifying and viscosity properties, and foaming ability were presented. Finally, the applications and prospects of BG as the preferred gelatin source globally were outlined.  相似文献   
100.
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