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   880篇
  免费   22篇
  国内免费   2篇
电工技术   60篇
综合类   1篇
化学工业   169篇
金属工艺   22篇
机械仪表   16篇
建筑科学   21篇
能源动力   23篇
轻工业   63篇
水利工程   4篇
无线电   117篇
一般工业技术   146篇
冶金工业   201篇
原子能技术   22篇
自动化技术   39篇
  2023年   4篇
  2022年   16篇
  2021年   18篇
  2020年   4篇
  2019年   7篇
  2018年   13篇
  2017年   7篇
  2016年   17篇
  2015年   13篇
  2014年   21篇
  2013年   40篇
  2012年   22篇
  2011年   29篇
  2010年   28篇
  2009年   21篇
  2008年   34篇
  2007年   29篇
  2006年   28篇
  2005年   29篇
  2004年   26篇
  2003年   25篇
  2002年   17篇
  2001年   23篇
  2000年   16篇
  1999年   17篇
  1998年   86篇
  1997年   51篇
  1996年   45篇
  1995年   28篇
  1994年   16篇
  1993年   25篇
  1992年   7篇
  1991年   12篇
  1990年   17篇
  1989年   9篇
  1988年   11篇
  1987年   7篇
  1986年   6篇
  1985年   5篇
  1984年   4篇
  1983年   12篇
  1981年   11篇
  1980年   10篇
  1979年   3篇
  1978年   5篇
  1977年   7篇
  1976年   11篇
  1973年   2篇
  1972年   2篇
  1971年   2篇
排序方式: 共有904条查询结果,搜索用时 15 毫秒
131.
132.
133.
A low-loss narrow band (below 3%) resonant filter has been achieved using twin-turn reflectors and a surface shear wave mode on 36° YX LiTaO3 substrate.  相似文献   
134.
Xylanase production by a XynF1 (33 kDa)-transformant of Aspergillus oryzae RIB40 was compared between submerged cultivation (SmC) and liquid-surface immobilization (LSI) systems. While the accumulation of xylanase in the SmC decreased by prolonged incubation, LSI system enabled the continuation of xylanase production to afford 4.5-fold xylanase production compared with the SmC system.  相似文献   
135.
The effects of fucose-containing sulfated polysaccharides, ascophyllan and fucoidan, isolated from the brown alga Ascophyllum nodosum, on the growth of various cell lines (MDCK, Vero, PtK1, CHO, HeLa, and XC) were investigated. In a colony formation assay, ascophyllan and fucoidan showed potent cytotoxic effects on Vero and XC cells, while other cell lines were relatively resistant to these polysaccharides. Almost no significant effects of these polysaccharides were observed in the cell lines tested using the Alamar blue cytotoxicity assay over 48 h with varying initial cell densities (2500–20,000 cells/well) in growth medium. Interestingly, a significant growth promoting effect of ascophyllan on MDCK cells was observed, whereas treatment with fucoidan showed growth suppressive effects on this cell line under the same experimental conditions. These results suggest that ascophyllan is distinguishable from fucoidan in terms of their bioactivities. This is the first report of the growth promoting effects of a sulfated fucan on a mammalian cell line under normal growth conditions.  相似文献   
136.
If both EVs (Electric Vehicles, includes plug‐in hybrid electric vehicles) and renewable energies spread in large quantities, it is possible to control the supply fluctuation of renewable energies using the storage battery of EVs. This research sought to show the charge load potential of EVs based on the state of the Japanese passenger car using traffic census results, etc. Furthermore, it tried to show the trend of the storage battery capacity according to time. From the estimated results: (1) the charge electricity of low and middle distance gets a majority of the total charge demand, (2) charge load changes according to time several times, and the minimum load is the number of gigawatt‐hours at early morning, (3) if night charge is assumed, the standby charge demand of noon will reach tens of gigawatt‐hours, it may have sufficient scale for supply fluctuation control of PVs. Although the present EV is not suitable for long‐distance running, these are expected to be 30 or less percent of the total charge demand. The estimated storage capacity potential in this research will not change numbers of times. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 182(3): 30–38, 2013; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22352  相似文献   
137.
A direct methanol fuel cell (DMFC) is highly anticipated as a new, high‐density energy source for mobile usage; however, its poor power density presents a problem. As a result, the size of portable electronic equipment using DMFCs is far larger than that of equipment using another type of battery. In addition, steady power supply control is difficult, because the output power of the DMFC is affected by the environment. First, this paper presents a pulse charge control system that is a new control system applied to a mobile device, which uses the DMFC and an electric double layer capacitor (EDLC), then describes the new passive heat control and presents experimental results. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 179(1): 46–53, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21129  相似文献   
138.
Negatively charged gold nanoparticles (AuNPs) and a polyelectrolyte (PE) have been assembled alternately on a polystyrene (PS) colloid by a layer‐by‐layer (LBL) self‐assembly technique to form three‐dimensional (Au/PAH)4/(PSS/PAH)4 multilayer‐coated PS spheres (Au/PE/PS multilayer spheres). The Au/PE/PS multilayer spheres have been used to modify a boron‐doped diamond (BDD) electrode. Cyclic voltammetry is utilized to investigate the properties of the modified electrode in a 1.0 M KCl solution that contains 5.0 × 10?3 M K3Fe(CN)6, and the result shows a dramatically decreased redox activity compared with the bare BDD electrode. The electrochemical behaviors of dopamine (DA) and ascorbic acid (AA) on the bare and modified BDD electrode are studied. The cyclic voltammetric studies indicate that the negatively charged, three‐dimensional Au/PE/PS multilayer sphere‐modified electrodes show high electrocatalytic activity and promote the oxidation of DA, whereas they inhibit the electrochemical reaction of AA, and can effectively be used to determine DA in the presence of AA with good selectivity. The detection limit of DA is 0.8 × 10?6 M in a linear range from 5 × 10?6 to 100 × 10?6 M in the presence of 1 × 10?3 M AA.  相似文献   
139.
Heat shock protein 70 (Hsp70) family members are known as facilitators of immune responses by interacting with receptors on antigen-presenting cells leading to Hsp70-peptide uptake and antigen cross priming. Here, identification of human leukocyte antigen (HLA)-A24-restricted epitopes was achieved using peptide arrays for evaluation of their affinities to Hsp70 and HLA-A24 binding prediction tools. Using Hsp70 as the model antigen, the GYPVTNAVI and VFQHGKVEI peptides were identified as antigens. These peptides actually bound to HLA-A24 in the stabilization assay using T2-A*2402 cells, and induced a strong peptide-reactive cytotoxic T lymphocyte response in HLA-A24 transgenic mice after vaccination.  相似文献   
140.
A new maximum‐power‐point limiting (MPPL) control method for a direct methanol fuel cell (DMFC) was proposed. In regard to achieving MPPL, it was affirmed by experiment that it is possible to control the DMFC by simply ensuring that its voltage does not fall below a certain level regardless of its state. An MPPL control system that accomplishes the DMFC voltage limitation required for MPPL control by using a ‘soft‐start function’ fitted in a ready‐made DC/DC converter was developed. It was confirmed by experimental tests that the circuit board of the developed MPPL control system can perform DMFC voltage limitation control. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.  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