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   199篇
  免费   11篇
  国内免费   2篇
电工技术   25篇
化学工业   43篇
金属工艺   6篇
机械仪表   10篇
建筑科学   7篇
能源动力   7篇
轻工业   20篇
水利工程   1篇
无线电   12篇
一般工业技术   45篇
冶金工业   11篇
原子能技术   7篇
自动化技术   18篇
  2023年   2篇
  2022年   4篇
  2021年   4篇
  2020年   3篇
  2019年   3篇
  2018年   6篇
  2017年   6篇
  2016年   3篇
  2015年   2篇
  2014年   3篇
  2013年   13篇
  2012年   11篇
  2011年   13篇
  2010年   6篇
  2009年   8篇
  2008年   16篇
  2007年   9篇
  2006年   9篇
  2005年   13篇
  2004年   9篇
  2003年   12篇
  2002年   4篇
  2001年   8篇
  2000年   4篇
  1999年   6篇
  1998年   5篇
  1997年   6篇
  1996年   3篇
  1995年   1篇
  1994年   2篇
  1993年   1篇
  1992年   1篇
  1991年   2篇
  1989年   2篇
  1988年   2篇
  1986年   2篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1982年   2篇
  1978年   1篇
  1977年   1篇
  1975年   1篇
排序方式: 共有212条查询结果,搜索用时 234 毫秒
71.
We propose an efficient and exact method for the adaptive sign detection of 4×4 determinants using a standard arithmetic unit. The entities of determinants are variable length integers (integers of arbitrary bit length). The integers are expressed in 16-bit data units, and the sign detection is reduced to the computation of 4×4 determinants of 16-bit integers. To accelerate the computation, the calculation is performed by using a standard arithmetic unit. We have implemented our method and confirmed that it significantly improves the computation time of 4×4 determinants. The method can be applicable to many geometric algorithms that need the exact sign evaluation of 4×4 determinants, especially to construct robust geometric algorithms.  相似文献   
72.
Kojima T  Uesugi T  Toda T  Miura Y  Yagasaki K 《Lipids》2002,37(3):261-265
Effects of genistein and its glycoside genistin were studied in nephritic rats with endogenous hyperlipidemia. Male Wistar rats with glomerulonephritis caused by a single intravenous injection of nephrotoxic serum were orally given 5 mg of genistein or 8 mg of genistin/d/100 g body weight for 12 d. These isoflavones suppressed nephritis-induced severe hypercholesterolemia and hypertriglyceridemia, and their hypolipidemic action was almost identical. Fecal steroid excretion was unchanged by administration of the two isoflavones. Genistein inhibited the incorporation of [1-14C]acetate into cholesterol and FA in liver slices from nephritic rats when added to an incubation buffer, whereas genistin did not. These results suggest that genistin may be hydrolyzed to genistein and that genistein itself and/or its metabolite(s) may be intracorporal entities suppressing hepatic lipid syntheses. They also suggest that the suppression of hepatic lipid synthesis may be one mechanism of the hypolipidemic action of genistein.  相似文献   
73.
We investigated the fundamental characteristics of cell adhesion during cell culture on the Si3N4 surface for using it as the gate insulator in field‐effect devices. The culture medium and the surface condition of Si3N4 were controlled for cell culture on the Si3N4 substrate. When we measure electrical characteristics of cell adhesion and cell function using field‐effect devices, we require a stable measurement of the electrical signals. The serum in the culture medium includes a number of proteins, which cause instability of the potential behavior. In this paper, we show that the cell‐adhesive molecules on the Si3N4 surface used as a gate insulator should be designed and controlled when cell culture is performed in the culture medium without the serum. Copyright © 2007 Institute of Electrical Engineers of Japan© 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.  相似文献   
74.
With the penetration of the IoT and data science, new manufacturing initiatives are accelerating. However, conventional approaches have emphasized the use of machine-based data. A need exists to realize more productive work styles considering the abilities and physical condition of operators. In this paper, we propose a production planning method to allocate machines and operators with different skill level optimally. After formulating a combinatorial auction mechanism, developing a schedule that minimizes the total production cost, we verify that the proposed method can realize human-centered production planning by combining the schedules with different evaluation indices.  相似文献   
75.
The bactericidal activity of copper-deposited titanium dioxide thin film (Cu/TiO2) was investigated under very weak ultraviolet (UV) light illumination. To elucidate the roles of the film photocatalyst and the deposited copper in the bactericidal activity, cells from a copper-resistant Escherichia coli (E. coli) strain were utilized. A decrease in survival rate was not observed with the copper-resistant cells under dark conditions, but when illuminated with a very weak UV intensity of 1 microW/cm2, the survival rate decreased, suggesting photocatalytic bactericidal activity. The decay curve of survival on the Cu/TiO2 film under very weak UV light illumination consisted of two steps, similar to the survival change of normal E. coli on TiO2 films under rather strong UV illumination. The first step is due to the partial decomposition of the outer membrane in the cell envelope by a photocatalytic process, followed by permeation of the copper ions into the cytoplasmic membrane. The second step is due to a disorder of the cytoplasmic membrane caused by the copper ions, which results in a loss of the cell's integrity. These processes explain why the Cu/TiO2 film system shows an effective bactericidal activity even under very weak UV light illumination.  相似文献   
76.
Bellare and Goldwasser showed that if the modulus N is guaranteed to be the product of O(log log ¦N¦) distinct odd primes, then quadratic residuosity has a competitive interactive proof system (with reasonably large communication complexity). In this paper we show that if the modulus N is guaranteed to be the product of O(log ¦N¦) distinct odd primes, then quadratic residuosity has a competitive interactive proof system with low communication complexity.  相似文献   
77.
Bacterial oxygenation of halogenated aromatic compounds yields arene cis-diols of type 2 of high enantiomeric purity. Further oxygenation of these extremely versatile synthetic intermediates provides for stereo- and regioselective introduction of additional functionalities such as hydroxyl groups. Several rational methods of oxygenation (epoxidation, osmylation, singlet oxygen addition, and ozonolysis) are used to produce, in short synthetic routes, cyclitol derivatives of medicinal importance. Proper symmetry considerations lead to the development of enantiodivergent synthetic design of target compounds from a single enantiomer of a starting diol. These principles are illustrated on the short syntheses of (+)- and (-)-pinitol. Stereocontrolled oxidative transformation of diols of type 2 are exemplified in the synthesis of conduritol C and dihydroconduritol C. Full experimental details are provided for all compounds. A guide to the stereorational design of any stereoisomer of cyclohexane (poly)ols or carbohydrates is provided at the end of the paper.  相似文献   
78.
79.
A nine-step synthesis is described for a diastereomeric mixture of 15,19,23-trimethylheptatriacontane, a contact sex pheromone ofGlossina morsitans morsitans Westwood. The compound has been synthesized by means of double alkylation of diethyl 3-oxoglutarate (DEOG) with 3-methyl-2-heptadecenyl methanesulfonate, which was readily prepared from 1-hexadecene, as the key step.This study constitutes Part XII of Selective Alkylation of Diethyl 3-Oxoglutarate. Part XI of this series, see Naoshima et al. (1984).  相似文献   
80.
This article focuses on the multi-attribute multi-item negotiation between multiple manufacturer agents (MAs) and multiple material supplier agents (MSAs). A coalition formation-based negotiation protocol is proposed. The MSAs are allowed to establish coalitions when the orders of the MAs exceed their abilities. Three attributes (price, quantity and lead time) of the items are considered during the negotiation. Both the MAs and the MSAs can give concessions among the attributes in tradeoff relationships according to their own preferences. The non-cooperative game is introduced to find the equilibria of the negotiations. The final allocation scheme is determined to maximise the total profit of the supply chain networks based on the equilibria. Simulations are provided to verify the effectiveness and feasibility of the proposed protocol.  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