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   846篇
  免费   52篇
  国内免费   16篇
电工技术   13篇
综合类   1篇
化学工业   227篇
金属工艺   27篇
机械仪表   31篇
建筑科学   41篇
矿业工程   3篇
能源动力   54篇
轻工业   63篇
水利工程   19篇
石油天然气   27篇
无线电   67篇
一般工业技术   185篇
冶金工业   26篇
原子能技术   12篇
自动化技术   118篇
  2023年   9篇
  2022年   21篇
  2021年   49篇
  2020年   36篇
  2019年   51篇
  2018年   81篇
  2017年   52篇
  2016年   66篇
  2015年   37篇
  2014年   47篇
  2013年   101篇
  2012年   56篇
  2011年   53篇
  2010年   54篇
  2009年   36篇
  2008年   23篇
  2007年   17篇
  2006年   18篇
  2005年   6篇
  2004年   8篇
  2003年   2篇
  2002年   11篇
  2001年   3篇
  2000年   3篇
  1999年   1篇
  1998年   4篇
  1997年   5篇
  1996年   1篇
  1995年   5篇
  1994年   4篇
  1993年   4篇
  1992年   4篇
  1991年   3篇
  1990年   4篇
  1989年   2篇
  1988年   2篇
  1987年   1篇
  1986年   1篇
  1985年   3篇
  1983年   4篇
  1982年   2篇
  1981年   3篇
  1980年   2篇
  1979年   5篇
  1978年   2篇
  1977年   2篇
  1976年   2篇
  1975年   3篇
  1974年   2篇
  1973年   2篇
排序方式: 共有914条查询结果,搜索用时 15 毫秒
1.
Journal of Inorganic and Organometallic Polymers and Materials - 3-Chloropropyltrimethoxysilane (CPTMS) was grafted on the surface of silica coated Fe3O4 core (Fe3O4@MCM-41) and then condensed with...  相似文献   
2.
Taguchi design of experiments methodology was used to determine the most influential spark plasma sintering (SPS) parameters on densification of TiB2–SiC ceramic composites. In this case, four processing factors (SPS temperature, soaking time, applied external pressure and SiC particle size) at three levels were examined in order to acquire the optimum conditions. The statistical analysis identified the sintering temperature as the most effective factor influencing the relative density of TiB2–SiC ceramics. A relative density of 99.5% was achieved at the optimal SPS conditions; i.e. temperature of 1800?°C, soaking time of 15?min and pressure of 30?MPa by adding 200-nm SiC particulates to the TiB2 matrix. The experimental measurements and predicted values for the relative density of composite fabricated at the optimum SPS conditions and reinforced with the proper SiC particle size were almost similar. The mechanisms of sintering and densification of spark plasma sintered TiB2–SiC composites were discussed in details.  相似文献   
3.
4.
5.
Universal Access in the Information Society - The Internet of Things (IoT) is an ecosystem that integrates physical objects, software and hardware to interact with each other. Aging of population,...  相似文献   
6.
International Journal of Control, Automation and Systems - In this paper, observer-based reliable control problem for nonlinear networked control systems (NCSs) with quadratic protocol (QP) in...  相似文献   
7.
There are many optimization problems in different branches of science that should be solved using an appropriate methodology. Population-based optimization algorithms are one of the most efficient approaches to solve this type of problems. In this paper, a new optimization algorithm called All Members-Based Optimizer (AMBO) is introduced to solve various optimization problems. The main idea in designing the proposed AMBO algorithm is to use more information from the population members of the algorithm instead of just a few specific members (such as best member and worst member) to update the population matrix. Therefore, in AMBO, any member of the population can play a role in updating the population matrix. The theory of AMBO is described and then mathematically modeled for implementation on optimization problems. The performance of the proposed algorithm is evaluated on a set of twenty-three standard objective functions, which belong to three different categories: unimodal, high-dimensional multimodal, and fixed-dimensional multimodal functions. In order to analyze and compare the optimization results for the mentioned objective functions obtained by AMBO, eight other well-known algorithms have been also implemented. The optimization results demonstrate the ability of AMBO to solve various optimization problems. Also, comparison and analysis of the results show that AMBO is superior and more competitive than the other mentioned algorithms in providing suitable solution.  相似文献   
8.
Bulletin of Engineering Geology and the Environment - In recent years, anumber of models and formulas have been proposed to estimate the penetration rate of hard rock tunnel boring machines (TBMs)....  相似文献   
9.
We inspected the possibility of using a synthesized boron nitride nanocluster (B12N12) as a potential chemical sensor for anticancer α-cyano-4-hydroxycinnamic acid (CHC) drug by performing density functional theory calculations. It was found that CHC drug is mainly adsorbed via its acidic group on the BN nanocluster with adsorption energy about ??23.7 kcal/mol. In view of the high decrease of HOMO–LUMO energy gap (Eg) of the BN nanocluster after the adsorption process, it is expected that this process induces a significant increase in its electrical conductivity. Thus, the BN nanocluster is suggested as a potential sensor for CHC drug detection. We predicted that the BN cluster benefits from a short recovery time (~?22.7 s) and high sensitivity (55.2% decrease in the Eg). Also, it is interesting that the BN nanocluster can be used as a sensor in the pristine form without needing to the functionalization, doping, decoration, etc. Finally, we showed that by increasing the percentage of Hartree–Fock exchange of the functional, the adsorption energy, and sensitivity are increased and decreased, respectively. Also, the sensitivity of the BN nanocluster is predicted to decrease in water solution.  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