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   108篇
  免费   5篇
化学工业   53篇
金属工艺   2篇
机械仪表   1篇
建筑科学   2篇
能源动力   2篇
轻工业   5篇
水利工程   1篇
无线电   10篇
一般工业技术   20篇
冶金工业   3篇
自动化技术   14篇
  2023年   3篇
  2021年   2篇
  2020年   7篇
  2019年   8篇
  2018年   7篇
  2017年   8篇
  2016年   9篇
  2015年   9篇
  2014年   7篇
  2013年   9篇
  2012年   7篇
  2011年   8篇
  2010年   4篇
  2009年   9篇
  2008年   2篇
  2007年   1篇
  2006年   7篇
  2005年   3篇
  2004年   2篇
  1997年   1篇
排序方式: 共有113条查询结果,搜索用时 15 毫秒
41.
This study investigated the categories of generative and conservative offices by using syntactic theories and conducting a comparativean alysis of two different layout configurations. Generativity depends on several features that include but are not limited to spatial criteria. Generativity is also affected by aspects that extend beyond the physical, such as the symbolic relationship between the social organism of an organization and the internal structure of a workplace. Results show that no consistent relationship exists between spatial variables and behaviors even though the examined layouts satisfy an organization's basi ccultural require-ments, including privacy, territoriality, and hierarchy. Spatial parameters increase the potential for generativity, but such increase is not guaranteed without necessary changes in the attitudes, programs, and policies of organizations. Recognizing the limits of spatial variables requires evidence-based field research on office settings to determine operational and tailor-made solutions.  相似文献   
42.
43.
44.
An adaptive user interface requires identification of user requirements. Interface designers and engineers must understand end-user interaction with the system to improve user interface design. A combination of interviews and observations is applied for user requirement analysis in health information systems (HIS). Then, user preferences are categorized in this paper as either data entry, language and vocabulary, information presentation, or help, warning and feedback. The user preferences in these categories were evaluated using the focus group method. Focus group sessions with different types of HIS users comprising medical staff (with and without computer skills) and system administrators identified each user group’s preference for the initial adaptation of the HIS user interface. User needs and requirements must be identified to adapt the interface to users during data entry into the system. System designers must understand user interactions with the system to identify their needs and preferences. Without this, interface design cannot be adapted to users and users will not be comfortable using the system and eventually abandon its use.  相似文献   
45.
46.
Summary The present paper is an extension of microwave method describing the synthesis of the new optically active poly(amide-imide)s. The main focus of this work is the design of new effective microwave method for preparing optically active poly(amide-imide)s. Imide-acid (3) was synthesized by the reaction of 3,3,4,4-diphenylsulfonetetracarboxylic dianhydride (1) with (s)-(+)-valine (2) in acetic acid. The compound 3 was coverted to diacid chloride 4 by reaction with excess amount of thionyl chloride. Polycondensetion reaction of diacid chloride 4 with several aromatic diamines such as 4,4-sulfonyldianiline (5a), 4,4-diaminodiphenyl methane (5b), 4,4-diaminodiphenylether (5c), p-phenylenediamine (5d), m-phenylenediamine (5e), 2,4-diaminotoluene (5f) and 4,4-diaminobiphenyl (5g) was carried out in the presence of small amount of o-cresol under microwave irradiation as well as conventional heating method. We obtained a series of optically active poly(amide-imide)s with high yield and inherent viscosity ranging from 0.22-0.35 dL/g. These new polymers were characterized by FT IR, 1H NMR, elemental analyses and specific rotation techniques.  相似文献   
47.
3,3′,4,4′‐Diphenylsulfonetetracarboxylic dianhydride ( 1 ) was reacted with L‐leucine ( 2 ) in acetic acid and the resulting imide‐acid ( 3 ) was obtained in high yield. The diacid chloride ( 4 ) was prepared from diacid derivative ( 3 ) by reaction with thionyl chloride. The polycondensation reaction of diacid chloride ( 4 ) with several aromatic diamines such as 4,4′‐sulfonyldianiline ( 5a ), 4,4′‐diaminodiphenyl methane ( 5b ), 4,4′‐diaminodiphenylether ( 5c ), p‐phenylenediamine ( 5d ), m‐phenylenediamine ( 5e ), 2,4‐diaminotoluene ( 5f ), and 1,5‐diaminonaphthalene ( 5g ) was developed by using a domestic microwave oven in the presence of a small amount of a polar organic medium such as o‐cresol. The polymerization reactions were also performed under two conventional methods: low temperature solution polycondensation in the presence of trimethylsilyl chloride, and a short period reflux conditions. A series of optically active poly(amide‐imide)s with inherent viscosity of 0.25–0.42 dL/g were obtained with high yield. All of the above polymers were fully characterized by IR, elemental analyses, and specific rotation techniques. Some structural characterizations and physical properties of these optically active poly (amide‐imide) s are reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2992–3000, 2004  相似文献   
48.
Several new optically active poly(amide‐imide)s have been synthesized by solution polycondensation of readily available aromatic diamines with diacid chloride containing ether‐imide and L ‐methionine moieties. Three polycondensation techniques were used: low temperature solution polycondensation, short period reflux conditions, and microwave‐assisted polycondensation. In all cases, the reactions were carried out using equimolecular amounts of the two monomers, in polar aprotic solvents. The obtained compounds were characterized by elemental analysis, solubility tests, FTIR, and 1H NMR spectrometry. Thermal stability of the polymer was studied by thermogravimetric analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1038–1044, 2006  相似文献   
49.
50.
In this work, a simple equation of state (EoS) has been used to predict some thermodynamic properties of air as a pseudo-pure fluid; as a ternary mixture of nitrogen, oxygen, and argon; and as a binary mixture of nitrogen and oxygen at different temperatures and pressures. A comparison with literature tabulated values has been made. The agreement of calculated densities with corresponding tabulated values is good for which the average absolute deviations are better than 0.06% if we assume air as a pseudo-pure fluid, and 0.9% and 1.2% if we consider air as a ternary mixture and as a binary mixture, respectively. To show the ability of this equation of state to predict density, the calculated densities of air have been compared with those computed by other methods.  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