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   3011篇
  免费   108篇
  国内免费   18篇
工业技术   3137篇
  2023年   31篇
  2022年   46篇
  2021年   107篇
  2020年   78篇
  2019年   81篇
  2018年   99篇
  2017年   84篇
  2016年   101篇
  2015年   53篇
  2014年   97篇
  2013年   169篇
  2012年   132篇
  2011年   163篇
  2010年   122篇
  2009年   103篇
  2008年   119篇
  2007年   114篇
  2006年   97篇
  2005年   92篇
  2004年   60篇
  2003年   56篇
  2002年   46篇
  2001年   27篇
  2000年   40篇
  1999年   38篇
  1998年   159篇
  1997年   103篇
  1996年   84篇
  1995年   57篇
  1994年   62篇
  1993年   53篇
  1992年   37篇
  1991年   32篇
  1990年   23篇
  1989年   24篇
  1988年   25篇
  1987年   16篇
  1986年   21篇
  1985年   26篇
  1984年   32篇
  1983年   14篇
  1982年   18篇
  1981年   17篇
  1980年   19篇
  1978年   17篇
  1977年   17篇
  1976年   31篇
  1975年   15篇
  1974年   20篇
  1972年   12篇
排序方式: 共有3137条查询结果,搜索用时 15 毫秒
1.
2.
Shah  Dawood  Shah  Tariq 《Multimedia Tools and Applications》2020,79(37-38):28023-28042
Multimedia Tools and Applications - The arithmetic properties of a finite field have a remarkable impact on the security features of symmetric and asymmetric cryptosystems. Conventionally, in...  相似文献   
3.
4.
3D Numerical study of temperature variation for subsonic rarefied gas flow in a microchannel is carried out using an in-house MPI-based parallelized DSMC code. The temperature drop in the microchannel decreases with an increase in the aspect ratio whereas it increases with an increase in the pressure ratio, the cross-aspect ratio (CAR), and the Knudsen number. 3D and 2D simulations results are compared and effect of the CAR and Knudsen number are brought out. Finally, a correlation that predicts the temperature drop is formulated along with a list of conditions that ensures a near isothermal flow.  相似文献   
5.
Wireless Personal Communications - Grid based sensor networks are significant for applications such as monitoring goods in a warehouse, studying traffic level of city streets, monitoring energy...  相似文献   
6.
Shah  Raj  Dhavse  Rasika 《SILICON》2021,13(2):587-597
Silicon - A novel hybrid silicon Single Electron Transistor Metal Oxide Semiconductor (SETMOS) logic is evaluated for its functionality and usability. Emphasis is given on obtaining functionality...  相似文献   
7.
This white paper is the result of discussions during the FIPSE-4 conference ( http://fi-in-pse.org ) in June 2018. It aims to highlight open problems and provide directions for future research in the area of water with emphasis on its agricultural usages. Some of the open problems discussed are: (a) the use of ecosystems as unit operations to understand their role in providing freshwater and in cleaning polluted water; (b) consideration of interactions and independencies between flows of water and other resources, such as food, energy, materials, ecosystem services, and environmental emissions; (c) challenges in modeling, sensing, and closed-loop control in precision irrigation. In particular, the development of agro-hydrological models that balance computing speed versus solution details and accuracy: (d) The use of state and parameter estimation approaches, through field measurements, to obtain soil moisture levels accurately; and (e) decision support systems to administer water and nutrient needs for optimum yields of agricultural products.  相似文献   
8.
Magnetic induction applications mostly rely on resonance for inducing maximum magnetic fields to system loads and hence for each resonant frequency dedicated circuits are required. Unfortunately, the frequency responses of such inductive systems manifest several peaks (frequency splitting) when their coupling coefficients are equal to or larger than critical coupling. Such frequency responses with several peaks are detrimental when the objective is to transfer maximum energy. Frequency splitting between inductive coils have been seen to date as detrimental to wireless power transfer and inductive communication systems. In this paper it is demonstrated that frequency splitting is a welcome phenomenon with advantage in the design of inductive filter banks and multi-frequency inductive systems. The centre frequencies of the filter banks result from split bands of inductive systems. This phenomenon is applied in conjunction with an innovative recursive algorithm to design inductive filter banks. The filters straddle both sides of the resonant frequency position and can be resolved individually.  相似文献   
9.
Silicon - Feeling prone to stress differs with plant production stage, water scarcity near commencement of grain filling phase has a significant reduced grain yield through fewer endosperm and sink...  相似文献   
10.
It is eminent that partial differential equations are extensively meaningful in physics, mathematics and engineering. Natural phenomena are formulated with partial differential equations and are solved analytically or numerically to interrogate the system’s dynamical behavior. In the present research, mathematical modeling is extended and the modeling solutions Helmholtz equations are discussed in the fractional view of derivatives. First, the Helmholtz equations are presented in Caputo’s fractional derivative. Then Natural transformation, along with the decomposition method, is used to attain the series form solutions of the suggested problems. For justification of the proposed technique, it is applied to several numerical examples. The graphical representation of the solutions shows that the suggested technique is an accurate and effective technique with a high convergence rate than other methods. The less calculation and higher rate of convergence have confirmed the present technique’s reliability and applicability to solve partial differential equations and their systems in a fractional framework.  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