全文获取类型
收费全文 | 132篇 |
免费 | 6篇 |
专业分类
电工技术 | 1篇 |
综合类 | 3篇 |
化学工业 | 33篇 |
金属工艺 | 3篇 |
建筑科学 | 7篇 |
能源动力 | 4篇 |
轻工业 | 20篇 |
石油天然气 | 2篇 |
无线电 | 3篇 |
一般工业技术 | 19篇 |
冶金工业 | 17篇 |
自动化技术 | 26篇 |
出版年
2023年 | 1篇 |
2021年 | 11篇 |
2020年 | 7篇 |
2019年 | 9篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 2篇 |
2014年 | 3篇 |
2013年 | 8篇 |
2012年 | 6篇 |
2011年 | 11篇 |
2010年 | 5篇 |
2009年 | 8篇 |
2008年 | 9篇 |
2007年 | 8篇 |
2006年 | 9篇 |
2005年 | 4篇 |
2004年 | 5篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2001年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1989年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有138条查询结果,搜索用时 15 毫秒
71.
The application of computational fluid dynamics (CFD) in the design of water turbines and pumps started about 30 years ago. This paper reviews the main steps and breakthroughs in the methods that were made during this period, through the eyes of one particular water turbine company which spear-headed some of the first developments for practical applications. Practical examples are used to illustrate the developments of the tools from 1978 to 2008 and to give an overview of the complete revolution in hydraulic turbine design that has occurred over this time. Several periods with distinct levels of complexity, and hence accuracy of the physical models and of the simulation methods can be distinguished. The first steps coincided with the introduction of the Finite Element Method into CFD, and were characterized by simplified Quasi-3D Euler solutions and Fully 3D potential flow solutions. Over the years the complexity continuously increased in stages: via 3D Euler solutions, to steady RANS simulations of single blade passages using finite volume methods, extending to steady simulations of whole machines, until today unsteady RANS equations are solved with advanced turbulence models. The most active areas of research and development are now concerned with including the effects of 2-phase flows (free surface flow in Pelton turbines and cavitation) and fluid–structure interaction. 相似文献
72.
Jochen Jung Tatjana Jaufmann Uwe Hener Andreas Münch Mirjam Kreck Helmut Dietrich Armin Mosandl 《European Food Research and Technology》2006,223(6):811-820
The determination of glycerol and 2,3-butanediol by photometric or enzymatic methods is well established. This paper reports on the direct assessment of glycerol and stereoselective analysis of 2,3-butanediol isomers in wine using capillary GC without any derivatisation. A “model wine” and commercially available wines, as well as wines of definite origin were investigated. The contents of glycerol and 2,3-butanediol and the ratio of (R,R)- and meso-2,3-butanediol were determined. Capillary GC has proved to be a reliable alternative in glycerol assessment from wine, thus a GC-IRMS method for authenticity assessment of glycerol was developed.δ13CV‐PDB and δ18OV‐SMOW multi-element IRMS-analysis of glycerol, an important by-product of wine fermentation, is reported. For that reason glycerol, extracted from a self-prepared “model wine”, from wines of definite origin, as well as commercially available wines, was investigated. Furthermore, the 18O/16O and 13C/12C isotope ratios of commercial glycerols from different origins were determined. In addition fermentation experiments with beet and cane sugar, and with grape juices were carried out. In order to check the influence of water on the oxygen isotope ratios, water from different places in Germany was used in the fermentation experiments with cane and beet sugar. 相似文献
73.
R de Jong F Altare IA Haagen DG Elferink T Boer PJ van Breda Vriesman PJ Kabel JM Draaisma JT van Dissel FP Kroon JL Casanova TH Ottenhoff 《Canadian Metallurgical Quarterly》1998,280(5368):1435-1438
Interleukin-12 (IL-12) is a cytokine that promotes cell-mediated immunity to intracellular pathogens by inducing type 1 helper T cell (TH1) responses and interferon-gamma (IFN-gamma) production. IL-12 binds to high-affinity beta1/beta2 heterodimeric IL-12 receptor (IL-12R) complexes on T cell and natural killer cells. Three unrelated individuals with severe, idiopathic mycobacterial and Salmonella infections were found to lack IL-12Rbeta1 chain expression. Their cells were deficient in IL-12R signaling and IFN-gamma production, and their remaining T cell responses were independent of endogenous IL-12. IL-12Rbeta1 sequence analysis revealed genetic mutations that resulted in premature stop codons in the extracellular domain. The lack of IL-12Rbeta1 expression results in a human immunodeficiency and shows the essential role of IL-12 in resistance to infections due to intracellular bacteria. 相似文献
74.
75.
Articulatory feature recognition using dynamic Bayesian networks 总被引:2,自引:0,他引:2
We describe a dynamic Bayesian network for articulatory feature recognition. The model is intended to be a component of a speech recognizer that avoids the problems of conventional “beads-on-a-string” phoneme-based models. We demonstrate that the model gives superior recognition of articulatory features from the speech signal compared with a state-of-the-art neural network system. We also introduce a training algorithm that offers two major advances: it does not require time-aligned feature labels and it allows the model to learn a set of asynchronous feature changes in a data-driven manner. 相似文献
76.
77.
SUNtool – A new modelling paradigm for simulating and optimising urban sustainability 总被引:1,自引:0,他引:1
D. Robinson N. Campbell W. Gaiser K. Kabel A. Le-Mouel N. Morel J. Page S. Stankovic A. Stone 《Solar Energy》2007,81(9):1196-1211
This paper describes the development and application of a new unique tool to support designers to optimise the sustainability of urban neighbourhoods (SUNtool). In this the paper introduces (i) the software architecture, (ii) the integrated solver and related innovations in the modelling of radiation exchange, reduced thermal modelling, stochastic modelling of occupant presence and behaviour, and urban plant modelling, (iii) interface design and innovations in building attribution, (iv) results analysis methods. Finally the software is applied to demonstrate its application to the development of urban planning guidelines and also to the design of a masterplan. 相似文献
78.
79.
Marcia Bodero Si Wang Ron L. A. P. Hoogenboom Mirjam D. Klijnstra Liza Portier 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2018,35(2):351-365
The neuro-2a bioassay is considered as one of the most promising cell-based in vitro bioassays for the broad screening of seafood products for the presence of marine biotoxins. The neuro-2a assay has been shown to detect a wide array of toxins like paralytic shellfish poisons (PSPs), ciguatoxins, and also lipophilic marine biotoxins (LMBs). However, the neuro-2a assay is rarely used for routine testing of samples due to matrix effects that, for example, lead to false positives when testing for LMBs. As a result there are only limited data on validation and evaluation of its performance on real samples. In the present study, the standard extraction procedure for LMBs was adjusted by introducing an additional clean-up step with n-hexane. Recovery losses due to this extra step were less than 10%. This wash step was a crucial addition in order to eliminate false-positive outcomes due to matrix effects. Next, the applicability of this assay was assessed by testing a broad range of shellfish samples contaminated with various LMBs, including diarrhetic shellfish toxins/poisons (DSPs). For comparison, the samples were also analysed by LC-MS/MS. Standards of all regulated LMBs were tested, including analogues of some of these toxins. The neuro-2a cells showed good sensitivity towards all compounds. Extracts of 87 samples, both blank and contaminated with various toxins, were tested. The neuro-2a outcomes were in line with those of LC-MS/MS analysis and support the applicability of this assay for the screening of samples for LMBs. However, for use in a daily routine setting, the test might be further improved and we discuss several recommended modifications which should be considered before a full validation is carried out. 相似文献
80.
Mirjam Seckler Alexandre N. Tuch Klaus Opwis Javier A. Bargas-Avila 《Interacting with computers》2012,24(3):107-118
There are many ways of placing error messages in web forms. A study of web conventions shows that the most common approach is to display error messages embedded in the form at the top of the entire form. Six frequent locations (right, left, above and below the erroneous input field, as well as on the top and at the bottom of the form) were tested in an online study with n = 303 participants. Results of efficiency, effectiveness and satisfaction show that the locations near the erroneous input field lead to a significantly better performance than the error messages on the top and at the bottom of the form; in addition error messages on the right side of the erroneous input field were subjectively evaluated as the most satisfying and intuitive by participants. The results indicate possible improvements for online shops, where error messages are currently mostly placed on the top of the form. 相似文献