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   1001篇
  免费   19篇
  国内免费   1篇
电工技术   80篇
综合类   3篇
化学工业   313篇
金属工艺   24篇
机械仪表   41篇
建筑科学   14篇
能源动力   172篇
轻工业   82篇
水利工程   2篇
石油天然气   1篇
无线电   47篇
一般工业技术   139篇
冶金工业   34篇
原子能技术   19篇
自动化技术   50篇
  2023年   3篇
  2022年   10篇
  2021年   13篇
  2020年   4篇
  2019年   11篇
  2018年   14篇
  2017年   14篇
  2016年   21篇
  2015年   13篇
  2014年   28篇
  2013年   59篇
  2012年   36篇
  2011年   68篇
  2010年   48篇
  2009年   43篇
  2008年   58篇
  2007年   52篇
  2006年   39篇
  2005年   39篇
  2004年   46篇
  2003年   46篇
  2002年   39篇
  2001年   16篇
  2000年   25篇
  1999年   19篇
  1998年   34篇
  1997年   25篇
  1996年   25篇
  1995年   15篇
  1994年   15篇
  1993年   15篇
  1992年   10篇
  1991年   10篇
  1990年   13篇
  1989年   5篇
  1988年   6篇
  1987年   2篇
  1986年   9篇
  1985年   13篇
  1984年   3篇
  1983年   6篇
  1982年   9篇
  1981年   7篇
  1980年   7篇
  1979年   6篇
  1978年   9篇
  1977年   4篇
  1976年   4篇
  1975年   3篇
  1971年   2篇
排序方式: 共有1021条查询结果,搜索用时 15 毫秒
81.
We propose a new geometric method of IR factorization in sector decomposition. The problem is converted into a set of problems in convex geometry. The latter problems are solved using algorithms in combinatorial geometry. This method provides a deterministic algorithm and never falls into an infinite loop. The number of resulting sectors depends on the algorithm of triangulation. Our test implementation shows smaller number of sectors comparing with other existing methods with iterations.  相似文献   
82.
This paper proposes a whole‐body haptic sensing system that has multiple supporting points between the body frame and the end‐effector. The system consists of an end‐effector and multiple force sensors. Using this mechanism, the position of a contact force on the surface can be calculated without any sensor array. A haptic sensing system with a single supporting point structure has previously been developed by the present authors. However, the system has drawbacks such as low stiffness and low strength. Therefore, in this study, a mechanism with multiple supporting points was proposed and its performance was verified. In this paper, the basic concept of the mechanism is first introduced. Next, an evaluation of the proposed method, performed by conducting some experiments, is presented. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 182(1): 48‐56, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22310  相似文献   
83.
In this paper, we present a new view synthesis method in multiview camera configurations of Free viewpoint TV (FTV) where potential depth errors are considered. The emphasis is on the artifacts eliminating for photorealistic synthesis especially near object boundaries. In contrast to conventional techniques which ignore geometry errors, we first categorize the artifact cases and depth modes. Furthermore, this paper infers the complementarity principle of the artifacts from left and right references. This complementarity guarantees the effectiveness of our reliability-based synthesis. The reliability reasoning is crucial for artifacts reduction. The reliable and unreliable areas from different views can be correctly labeled. Then artifacts caused by unreliable pixels from one reference can be replaced by the reliable pixels from the other reference. As a final result, artifacts of novel view are demonstrated to be significantly reduced on different multiview sequences.  相似文献   
84.
Preparation of CuO-BaTiO3 mixed oxide thin film by the decomposition of a self-assembled multibilayer film as a molecular template was investigated in this study. Furthermore, CO2 sensing property of the resultant thin film was investigated as a capacitive type sensor. The self-assembled bilayer film of few 1000 layers thickness can be obtained easily by casting an aqueous suspension consisting of dimethyldihexadecylammoiun bromide (DC1-16), Cu(ClO4)2, Ba(TiO(C2H4)2), 2,6-dimetyle-3,5heptadione (DHP), and polyvinyl alcohol. Divalent copper ion (Cu2+)) which is associated with 2 DHP molecules was incorporated into the molecular bilayer film and BaTiO3 precursor exists at the interspace of molecular bilayer film by coordinating with polyvinyl alcohol. Upquenching the organic-inorganic film at 1173 K leads to the uniform film of CuO-BaTiO3 oxide mixture. Although operating temperature shifted to higher temperature, the resultant film exhibits the capacitance change upon exposure to CO2. Consequently, it is concluded that the mixed oxide film of CuO-BaTiO3 prepared by the decomposition of multibilayer film was also an appropriate capacitive type CO2 sensor.  相似文献   
85.
Aroma active compounds in commercial fermented fish meat paste product (fish miso), fermented soy paste (soy miso), fish sauce and soy sauces were characterized by using a dynamic headspace method for volatile isolation and GC olfactometry for odor perception. A total of 123 volatile compounds consisting mainly of aldehydes, alcohols, esters, ketones, furans, sulfur and nitrogen-containing compounds, aromatics and acids were consistently identified. A major 16 odor-active compounds were distinguished to contribute as key aroma compounds for the miso and sauce products. Olfactometric and sensory findings clearly differentiated miso products with caramelic, fruity aroma notes, whereas fish sauce products were characterized by ammoniacal, fishy, nutty and cheesy odor note. Soy sauce products, however, were dominated by nutty and cheese aroma. Use of koji for fish miso production was found effective to enhance sweet aroma to the product with a reduction of nutty, meaty and rancid nuance. Principal component analysis employed for statistical interpretations clearly elucidated the relationship among different types of fermented products.  相似文献   
86.
The concept of ‘recycling’ was adopted to solve the overuse of resources by mass production and mass consumption of products in the 20th century. In the latter half of the 20th century, all companies started recycling activities slowly but positively, and some of them established their own recycling plants. This article introduces the processes through which used home appliances are made into materials (for reuse), and the machines, facilities, and methods for such reuse, as well as the results of their actual application by the study of a recycling plant. It is expected that this article would motivate the readers for recycling and to consider and feel what we, consumers, should do. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.  相似文献   
87.
The recent years have seen an increasing trend in the cumulative installed capacity of distributed generators. As a result, voltage management may become difficult in existing power distribution systems in the future. A STATCOM (STAtic synchronous COMpensator) is a promising option for solving this problem because it can control reactive power rapidly and continuously. For a distribution system, STATCOM needs to be pole‐mounted to realize its low cost. However, a transformer for a STATCOM is large and heavy, and hence it is difficult to install a STATCOM on a distribution pole. We adopt a transformerless STATCOM to reduce STATCOM size and use SiC devices with low‐loss performance to obtain a more compact and efficient STATCOM. There are a large number of circuits available for a STATCOM, and there has been considerable research on performance comparisons among these circuits. However, these comparisons were drawn under different conditions, including switching frequency and level number for the circuits. In addition, these comparisons do not include the use of SiC devices. We made an equitable comparison for a 100 kVa pole‐mounted STATCOM using SiC devices. We discuss the performance and characteristics of each circuit in terms of efficiency and volume.  相似文献   
88.
A BaCO3 phase is found on the surfaces of hydrothermally synthesized BaTiO3 particles; it occurs as aggregates or small protuberances. A small proportion of the phase decomposes to BaO crystallites when heated by a convergent electron beam in a transmission electron microscope. The BaO and BaCO3 crystallites disappear when they are irradiated successively by the convergent electron beam. The BaO crystallites and the BaCO3 phase sublimate and/or react with BaTiO3 crystals whose surface layers are deficient in Ba2+ ions.  相似文献   
89.
Supported Co3O4 catalysts were prepared via the calcination of Co-containing hydrogarnet, (Ca3-x Co x )Al2(SiO4)3- y (OH)4y , at 400 °C. Such precursors with various extents of substitution were synthesized from the hydrothermal reaction of a stoichiometric mixture of calcium oxide, amorphous silica, alumina sol, and cobalt hydroxide at 200 °C. It was found that the catalyst consisted of Co3O4, CaO, and mayenite and exhibited a high activity for the combustion of propylene, benzene, and toluene at temperatures below 300 °C.  相似文献   
90.
The miscibility of poly(methyl methacrylate) (PMMA) and styrene-acrylonitrile random copolymers (SAN) blends was investigated on the basis of the Flory—Orwoll—Vrij equation of state theory. To obtain the equation of state parameters (P*, V*sp, T*: characteristic parameters), the pressure—volume—temperature (PVT) behaviour was measured for PMMA and a series of SANs with various acrylonitrile contents. The exchange energy parameter Xij was also calculated by fitting the theory to some phase diagrams of PMMA/SAN blends. The Flory—Huggins interaction parameter χ was separated into two contributions based on the equation of state theory for mixtures: the exchange energy term χinter and the free volume term χfree. Both the temperature and copolymer composition dependences of χinter and χfree were estimated by calculations using the equation of state parameters. There exists a region in which χinter is negative, leading to a miscibility window in PMMA/SAN blends. However, the immiscibility at high temperatures in the blends cannot be explained only by χinter; it is caused by the free volume contribution, χfree. The miscibility window behaviour in PMMA/SAN blends may be explained within the framework of the equation of state theory.  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