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   493篇
  免费   17篇
  国内免费   5篇
电工技术   76篇
化学工业   113篇
金属工艺   12篇
机械仪表   10篇
建筑科学   22篇
能源动力   15篇
轻工业   48篇
水利工程   3篇
无线电   42篇
一般工业技术   44篇
冶金工业   42篇
原子能技术   19篇
自动化技术   69篇
  2023年   2篇
  2022年   12篇
  2021年   14篇
  2020年   7篇
  2019年   10篇
  2018年   15篇
  2017年   4篇
  2016年   18篇
  2015年   6篇
  2014年   12篇
  2013年   34篇
  2012年   29篇
  2011年   32篇
  2010年   25篇
  2009年   23篇
  2008年   25篇
  2007年   15篇
  2006年   16篇
  2005年   14篇
  2004年   13篇
  2003年   9篇
  2002年   6篇
  2001年   10篇
  2000年   11篇
  1999年   7篇
  1998年   22篇
  1997年   19篇
  1996年   9篇
  1995年   3篇
  1994年   6篇
  1993年   3篇
  1991年   9篇
  1990年   5篇
  1988年   7篇
  1987年   6篇
  1986年   10篇
  1985年   4篇
  1984年   3篇
  1982年   3篇
  1981年   6篇
  1980年   13篇
  1976年   1篇
  1975年   1篇
  1974年   2篇
  1973年   3篇
  1972年   2篇
  1971年   1篇
  1970年   1篇
  1969年   2篇
  1957年   1篇
排序方式: 共有515条查询结果,搜索用时 15 毫秒
101.
Classical estimation of distribution algorithms (EDAs) generally use truncation selection to estimate the distribution of the good individuals while ignoring the bad ones. However, various researches in evolutionary algorithms (EAs) have reported that the bad individuals may affect and help solving the problem. This paper proposes a new method to use the bad individuals by studying the substructures rather than the entire individual structures to solve reinforcement learning (RL) problems, which generally factorize their entire solutions to the sequences of state–action pairs. This work was studied in a recent graph‐based EDA named probabilistic model building genetic network programming (PMBGNP), which could solve RL problems successfully, to propose an extended PMBGNP. The effectiveness of this work is verified in an RL problem, namely robot control. Compared to other related work, results show that the proposed method can significantly speed up the evolution efficiency. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.  相似文献   
102.
In this study, the specific heat of water included in an adsorbent was analyzed by a differential scanning calorimeter in the temperature range from ?50 °C to 50 °C. Zeolites with pore sizes of 3 Å and 9 Å were employed as adsorbents, and the measurement was performed with various water mass fractions in zeolites. In this article, the water was defined as being composed of adsorbed water and free water that is not adsorbed in zeolite. As a result, the specific heat of the dry zeolite increased with temperature. The specific heat of the adsorbed water was measured by a special experimental procedure to establish the experimental accuracy. It was found that the specific heat of the adsorbed water had values in the range from (3 to 5) J · g?1 · K?1.  相似文献   
103.
Improvements in defect detection and sizing capabilities for non-destructive inspection techniques have been required in order to ensure the reliable operation and life extension of nuclear power plants. For the volumetric inspection, the phased array UT technique has superior capabilities for beam steering and focusing to objective regions, and real-time B-scan imaging without mechanical scanning. In contrast to the conventional UT method, high-speed inspection is realized by the unique feature of the phased array technique. A 256-channel array system has developed for the inspection of weldment of BWR internal components such as core shrouds. The TOFD crack sizing technique also can be applied using this system. For the surface inspection, potential drop techniques and eddy current techniques have been improved, which combined the theoretical analysis. These techniques have the crack sizing capability for surface breaking cracks to which UT method is difficult to apply. This paper provides the recent progress of these phased array and electromagnetic inspection techniques.  相似文献   
104.
All solid-state sheet lithium battery was developed using inorganic solid electrolyte, thio-LISICON (Li3.25Ge0.25P0.75S4), Li–Al anode, and Mo6S8 cathode materials, and the sheet manufacturing process was established. The new sheet-configuration was consisted of the cathode with the grid of current collector, electrolyte sheet with or without mechanical support, and aluminum/lithium composite sheet anode. A sheet battery with a dimension of 30 mm × 30 mm showed good charge–discharge characteristics without any capacity fading at a current of 0.1 mA.  相似文献   
105.
We have developed a public key certificate validation system considering the restrictions peculiar to the mobile environment, such as processing the speed and memory capacity of a cellular‐phone terminal, and the network transmission speed. In this paper we derive a theoretical formula showing the performance of a validity check of the public key certificate of the conventional system and of the proposed system, and compare and examine a theoretical value in a mobile environment. Moreover, we evaluate the actual measurement that uses the server and cellular‐phone terminal that we developed. We show that our proposed system based on the certificate validation server (CVS) system is better than the conventional system from the viewpoint of processing speed and transmission speed. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.  相似文献   
106.
DNA methylation of both viral and host DNA is one of the major mechanisms involved in the development of Epstein–Barr virus-associated gastric carcinoma (EBVaGC); thus, epigenetic treatment using demethylating agents would seem to be promising. We have verified the effect of MC180295, which was discovered by screening for demethylating agents. MC180295 inhibited cell growth of the EBVaGC cell lines YCCEL1 and SNU719 in a dose-dependent manner. In a cell cycle analysis, growth arrest and apoptosis were observed in both YCCEL1 and SNU719 cells treated with MC180295. MKN28 cells infected with EBV were sensitive to MC180295 and showed more significant inhibition of cell growth compared to controls without EBV infection. Serial analysis of gene expression analysis showed the expression of genes belonging to the role of BRCA1 in DNA damage response and cell cycle control chromosomal replication to be significantly reduced after MC180295 treatment. We confirmed with quantitative PCR that the expression levels of BRCA2, FANCM, RAD51, TOP2A, and CDC45 were significantly decreased by MC180295. LMP1 and BZLF1 are EBV genes with expression that is epigenetically regulated, and MC180295 could up-regulate their expression. In conclusion, MC180295 inhibited the growth of EBVaGC cells by suppressing DNA repair and the cell cycle.  相似文献   
107.
108.
A snake, which has a simple shape without limbs, can move over rough terrain, climb a wall or tree, swim, and glide through the air. It is difficult to understand the gliding flight of a snake in aerodynamics assuming a static model, because a snake undulates its body trunk and turns in air. This paper presents an experimental system for investigation of the relationship between the shape of the gliding snake model and gliding characteristics. Results of a gliding experiment confirm a sufficiently high reproducibility of the experiment.  相似文献   
109.
ABSTRACT

Accurate data of gamma-ray emission probabilities are frequently needed when one quantitatively determines the amount of isotope by gamma-ray measurements or obtains neutron capture cross-sections using them. Americium-243, one of the most important minor actinides, produces 244Am after neutron capture. The 744-keV gamma-ray decaying from the ground state of 244Am has a relatively large gamma-ray emission probability about 66%; however, its uncertainty is as large as 29%. The uncertainty of the gamma-ray emission probability leads to a major factor of the systematic uncertainty on determining an amount of isotope, and therefore the gamma-ray emission probability was measured by using an activation method and an examined level structure of 244Cm. In this study, the emission probability of 744-keV gamma-ray was derived as 66.5 ± 1.1%, and its uncertainty was improved from 29% to 2%.  相似文献   
110.
A pulsed electric field(PEF) was applied to unpasteurized sake at constant temperatures, at which α-amylase was not inactivated. We adjusted the input energy to be identical for the temperatures by changing the number of PEF application, because the current significantly increased with the temperature, even the amplitude of the applied voltage was identical. As a result, the α-amylase was seemed to be inactivated by PEF application, not due to thermal effect.The glucoamylase was significantly inactivated by PEF. Moreover, the acid carboxypeptidase was inactivated by PEF at 4 °C but significantly activated at 25 °C. These results show that the sensitivity of enzyme to PEF application differs depending on the types of enzyme and treatment temperature. On the other hand, the colony number of bacteria was remarkably decreased, but the amount of the volatile flavor compounds was not decreased by PEF application.  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