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   219篇
  免费   8篇
电工技术   18篇
化学工业   47篇
金属工艺   11篇
机械仪表   3篇
建筑科学   11篇
能源动力   19篇
轻工业   26篇
水利工程   1篇
无线电   8篇
一般工业技术   42篇
冶金工业   5篇
原子能技术   4篇
自动化技术   32篇
  2023年   3篇
  2022年   4篇
  2021年   10篇
  2020年   4篇
  2019年   8篇
  2018年   7篇
  2017年   5篇
  2016年   5篇
  2015年   4篇
  2014年   10篇
  2013年   23篇
  2012年   13篇
  2011年   17篇
  2010年   17篇
  2009年   17篇
  2008年   15篇
  2007年   14篇
  2006年   5篇
  2005年   7篇
  2004年   6篇
  2003年   4篇
  2002年   4篇
  2001年   1篇
  2000年   3篇
  1999年   4篇
  1998年   3篇
  1997年   7篇
  1996年   3篇
  1994年   1篇
  1993年   1篇
  1989年   1篇
  1983年   1篇
排序方式: 共有227条查询结果,搜索用时 13 毫秒
51.
52.
The solubility of butane and isobutane in molten polypropylene (PP) and polystyrene (PS) was measured at pressures up to 3 MPa and along four isotherms from 438 to 483 K for PP and from 348 to 473 K for PS. The solubility increased with increasing pressure and decreasing temperature. At 438 K and 2 MPa, the solubilities of butane and isobutane in PP were 0.15 and 0.11 g‐gas/g‐polym, respectively. At 423 K and 2 MPa, the solubilities of butane and isobutane in PS were 0.08 and 0.05 g‐gas/g‐polym, respectively. Solubility could be correlated with the Sanchez‐Lacombe equation of state with temperature‐dependent binary interaction parameters to within 4.4% average relative deviation. Henry's constant for these gases in the PP and PS obtained in this work were used to determine correlation equations along with literature data. Polym. Eng. Sci. 44:2083–2089, 2004. © 2004 Society of Plastics Engineers.  相似文献   
53.
Service-oriented architecture is an architecture style to build up a large-scale networked system composed of a set of components or functions, each of which is called a service. A problem to construct behavioral models of services from given global interaction specifications, called choreography, is known as the choreography realization problem. The constructed model is still an intermediate model in the process of system developments; the model will be corrected, modified, and enhanced further by designers. Therefore, we also have to consider readability of the constructed model. In this paper, we proposed a method to construct state machine models from choreographies described by a set of communication diagrams using Petri nets. The proposed method will try to use the composite states and the orthogonal regions of UML state machines for the readability.  相似文献   
54.
To identify proteins associated with esophageal carcinogenesis, we performed protein profiling of 16 esophageal squamous cell carcinomas (ESCCs) and paired noncancerous tissues by 2-DE and MS/MS. In cancerous tissues, three spots showed significant up-regulation in the amount of protein, while eight spots were significantly down-regulated. The identities of the spots were determined by PMF with LC-MS/MS and were confirmed by immunoblotting. The up-regulated proteins were tropomyosin alpha 4 chain, transgelin, and pyruvate kinase. The down-regulated proteins were serum albumin precursor, isoforms of annexin A1, tropomyosin beta chain, 14-3-3 protein sigma, and isoforms of serotransferrin precursor. In all 16 cases, up-regulation of the tropomyosin alpha 4 chain was confirmed by immunoblotting. Localization of the tropomyosin alpha 4 chain in ESCC cells and adjacent fibroblasts was confirmed by immunohistochemistry.  相似文献   
55.
56.
The hydrogenation capacities of CeNi5?xAlx (x = 0, 0.75, 1.0, 1.25, 1.5 and 1.75) alloys were assessed. In contrast to LaNi5-based alloys, the addition of Al to CeNi5 enables hydrogen absorption by creating larger interstitial sites as the result of an expanded lattice. Structure analyses indicate that each of these alloys maintained a CeNi5 (CaCu5-type) structure in which Al atoms exclusively occupied Ni 3g sites. Among these specimens, CeNi4Al absorbed the greatest proportion of hydrogen atoms, decreasing its c/a ratio from 0.826 to 0.802 upon the formation of CeNi4AlH4.3. This drastic decrease in the c/a ratio is attributed to an anisotropic lattice expansion along the a-axis, as verified by in situ X-ray diffraction under H2. The enhanced hydrogen absorption of these alloys is thought to be associated with the preferential situation of hydrogen atoms at interstitial sites located at the centers of octagons as well as a charge transition of Ce ions upon hydrogenation. It is verified that CeNi4Al after hydrogenation shows high catalytic activity toward propyne hydrogenation: 100% conversion of propyne even at room temperature.  相似文献   
57.
Recently, solubilizing tag methods (Trt-K and Trt-R method) were developed for the challenging synthesis of peptides/proteins by means of native chemical ligation. In this system, the solubilizing tag can be attached to the Cys side chain by simply mixing the tag-introducing reagent under acidic conditions. The tagged peptides/proteins exhibited high water solubility thanks to the introduction of redundant oligo-Lys/Arg. In the final reaction, the tag can be quickly and cleanly detached by a standard deprotection reaction with trifluoroacetic acid. Herein, the development and application of these methods are described.  相似文献   
58.
This paper reports the on-site performance evaluation of conventional and improved gas engine-driven VRF (variable refrigerant flow) units and (abbreviated as GHP) units. The study aims to elucidate two actual GHP units by using the probe insertion method. There is a tendency to decrease energy efficiency compared to a high loading factor. GHP operation was almost all part load operation. This on-site evaluation indicates a clear difference between conventional and improved GHP.  相似文献   
59.
A hydrogen fueled internal combustion engine has great advantages on exhaust emissions including carbon dioxide (CO2) emission in comparison with a conventional engine fueling fossil fuel. In addition, if it is compared with a hydrogen fuel cell, the hydrogen engine has some advantages on price, power density, and required purity of hydrogen. Therefore, they expect that hydrogen will be utilized for several applications, especially for a combined heat and power (CHP) system which currently uses diesel or natural gas as a fuel.A final goal of this study is to develop combustion technologies of hydrogen in an internal combustion engine with high efficiency and clean emission. This study especially focuses on a diesel dual fuel (DDF) combustion technology. The DDF combustion technology uses two different fuels. One of them is diesel fuel, and the other one is hydrogen in this study. Because the DDF engine is not customized for hydrogen which has significant flammability, it is concerned that serious problems occur in the hydrogen DDF engine such as abnormal combustion, worse emission and thermal efficiency.In this study, a single cylinder diesel engine is used with gas injectors at an intake port to evaluate performance swung the hydrogen DDF engine with changing conditions of amount of hydrogen injected, engine speed, and engine loads. The engine experiments show that the hydrogen DDF operation could achieve higher thermal efficiency than a conventional diesel operation at relatively high engine load conditions. However, it is also shown that pre-ignition with relatively high input energy fraction of hydrogen occurred before diesel fuel injection and its ignition. Therefore, such abnormal combustion limited amount of hydrogen injected. Fire-deck temperature was measured to investigate causal relationship between fire-deck temperature and occurrence of pre-ignition with changing operative conditions of the hydrogen DDF engine.  相似文献   
60.
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