全文获取类型
收费全文 | 125篇 |
免费 | 8篇 |
专业分类
化学工业 | 50篇 |
金属工艺 | 5篇 |
机械仪表 | 6篇 |
建筑科学 | 4篇 |
能源动力 | 9篇 |
轻工业 | 18篇 |
水利工程 | 1篇 |
无线电 | 14篇 |
一般工业技术 | 12篇 |
冶金工业 | 5篇 |
自动化技术 | 9篇 |
出版年
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 9篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2017年 | 3篇 |
2016年 | 1篇 |
2015年 | 4篇 |
2014年 | 7篇 |
2013年 | 5篇 |
2012年 | 4篇 |
2011年 | 8篇 |
2010年 | 6篇 |
2009年 | 11篇 |
2008年 | 4篇 |
2007年 | 8篇 |
2006年 | 6篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 2篇 |
2000年 | 6篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1983年 | 2篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1967年 | 4篇 |
1966年 | 1篇 |
排序方式: 共有133条查询结果,搜索用时 15 毫秒
91.
Euler angle transformations 总被引:1,自引:0,他引:1
The definition of sets of Euler angles is discussed and a useful tool for treating the mathematics associated with Euler angles is illustrated. Restricting attention to right-handed coordinate systems and positive rotations, twelve distinct but equivalent sets of Euler angles are partitioned into two subsets. The method of determining a set of orthogonal infinitesimal rotations equivalent to nonorthogonal infinitesimal increments on a set of Euler angles is illustrated. It is shown that the same solution yields expressions for the angular velocities of the final coordinate system relative to the reference coordinate system in terms of derivatives of the Euler angles. The ease with which the infinitesimal increments of one Euler set in terms of the increments of another equivalent Euler set can be determined by the symbolic technique is illustrated. This technique offers a systematic approach to error analysis of sequences of rotations. 相似文献
92.
Pio Conti Fabrizio E. Pregliasco Rosa G. Bellomo Carla E. Gallenga Alessandro Caraffa Spyros K. Kritas Dorina Lauritano Gianpaolo Ronconi 《International journal of molecular sciences》2021,22(15)
Psoriasis (PS) is a skin disease with autoimmune features mediated by immune cells, which typically presents inflammatory erythematous plaques, and is associated with many comorbidities. PS exhibits excessive keratinocyte proliferation, and a high number of immune cells, including macrophages, neutrophils, Th1 and Th17 lymphocytes, and mast cells (MCs). MCs are of hematopoietic origin, derived from bone marrow cells, which migrate, mature, and reside in vascularized tissues. They can be activated by antigen-provoking overexpression of proinflammatory cytokines, and release a number of mediators including interleukin (IL)-1 and IL-33. IL-1, released by activated keratinocytes and MCs, stimulates skin macrophages to release IL-36—a powerful proinflammatory IL-1 family member. IL-36 mediates both innate and adaptive immunity, including chronic proinflammatory diseases such as psoriasis. Suppression of IL-36 could result in a dramatic improvement in the treatment of psoriasis. IL-36 is inhibited by IL-36Ra, which binds to IL-36 receptor ligands, but suppression can also occur by binding IL-38 to the IL-36 receptor (IL-36R). IL-38 specifically binds only to IL-36R, and inhibits human mononuclear cells stimulated with IL-36 in vitro, sharing the effect with IL-36Ra. Here, we report that inflammation in psoriasis is mediated by IL-1 generated by MCs—a process that activates macrophages to secrete proinflammatory IL-36 inhibited by IL-38. IL-37 belongs to the IL-1 family, and broadly suppresses innate inflammation via IL-1 inhibition. IL-37, in murine models of inflammatory arthritis, causes the suppression of joint inflammation through the inhibition of IL-1. Therefore, it is pertinent to think that IL-37 can play an inhibitory role in inflammatory psoriasis. In this article, we confirm that IL-38 and IL-37 cytokines emerge as inhibitors of inflammation in psoriasis, and hold promise as an innovative therapeutic tool. 相似文献
93.
Mário Cerqueira Casimiro Pio Michel Legrand Hans Puxbaum Anne Kasper-Giebl Joana Afonso Susanne Preunkert András Gelencsér Paulo Fialho 《Journal of aerosol science》2010,41(1):51-61
The particulate carbon content of precipitation was investigated in samples collected at five background sites located over a west-east European transect, from the Azores, in the mid-Atlantic Ocean, to the Hungarian plain, in central Europe. Sampling was performed on an event basis and the particulate carbon (elemental carbon, EC, and water insoluble organic carbon, WIOC) content was concentrated on quartz filters for the subsequent analysis by a thermal optical method in order to separate the EC and WIOC fractions. The average EC concentrations range from low values at the Azores (2.8±4.3 μg C L?1) and at the high mountain site of Sonnblick (5.2±3.7 μg C L?1) to high values at the more inland sites of Schauinsland (28±38 μg C L?1) and K-Puszta (24±24 μg C L?1). The average WIOC concentrations range from 98±56 μg C L?1 at the coastal site of Aveiro and 113±78 μg C L?1 at the Azores to 358±194 μg C L?1 at the continental site of K-Puszta. These results are discussed in terms of factors affecting the spatial distribution of particulate carbon, such as emissions from surrounding areas and prevalent meteorological conditions. EC is found to be a minor contributor to total particulate carbon present in rain and snow samples (from 2.5% to 15%). This is particularly true at the remotes sites, where the EC contribution to total particulate carbon is <6.5%, consistent with a negligible impact of anthropogenic combustions locally. The EC and WIOC scavenging ratios were estimated and compared with those of sulfate, also evaluated at the same sampling sites. The results indicated that EC is removed from the atmosphere by wet deposition less efficiently than WIOC, and in turn this species is removed less efficiently than sulfate. 相似文献
94.
Traditional approaches to defect reduction in manufacturing environments rely heavily on the introduction of technology‐based detection techniques that require significant investments in equipment and technical skills. In this article, the authors outline a novel, alternative approach that utilizes the largely untapped abilities of assembly‐line operators. Targeting zero‐defect manufacturing, the SEISMIC (stabilize, evaluate, identify, standardize, monitor, implement, and control) methodology developed herein is a sociotechnical‐based system built on the decentralization of technical knowledge and the transfer of responsibility for product quality from technical staff to manual operators. Along with defect reduction, important secondary goals of the SEISMIC methodology are improved operator performance and job satisfaction. The SEISMIC methodology provides a quantitative approach for classifying assembly environments and determining their required skill sets. Effective methods for transferring the identified skills throughout the production team are also provided. A pilot application of the protocol in an automotive assembly environment has achieved promising results in the target areas of defect reduction and operator performance. © 2007 Wiley Periodicals, Inc. Hum Factors Man 17: 137–148, 2007. 相似文献
95.
Laura Majocchi Gianpiero Groppi Cinzia Cristiani Pio Forzatti Luca Basini Alessandra Guarinoni 《Catalysis Letters》2000,65(1-3):49-56
The partial oxidation of methane to synthesis gas over catalysts consisting of Rh supported on hexaaluminates (BaAl12O19, CaAl12O19 and SrAl12O19) was investigated at atmospheric pressure and high reactant dilution in order to compare their performances within the kinetic-controlling regime. Comparison with the results obtained over a commercial Rh/-Al2O3 system indicates that hexaaluminate catalysts are active and selective in this reaction. Despite of the higher surface area of the support, hexaaluminate-supported catalysts were found less stable, active and selective than an -Al2O3-supported catalyst. 相似文献
96.
Fabrication techniques for mass manufacture of disposable polymer microfluidic chips are important for electrospray application
used in mass spectrometry. Hot embossing offers advantages over traditional MEMS fabrication techniques and is the focus of
this research. The aim of the paper is to evaluate hot embossed open channel polymer chips using two different hot embossing
tools. One tool was fabricated in nickel using the electroforming process, and the other in high carbon bright steel by laser
machining technique using a pulsed Nd:YAG laser that is normally used for conventional applications. Process parameters are
determined and measurement of dimensions and surface roughness of tools and chips are presented. Depending on the fabrication
method, each tool exhibits its own characteristic profile feature and surface roughness. Polystyrene and polycarbonate substrates
embossed with the electroformed tool exhibited lowest surface roughness of 48 nm compared to 450 nm for the laser machined
tool. The embossed microfluidic chips were tested for fluid flow and electrospray and showed good performance. 相似文献
97.
Emir Mutapcic Pio Iovenitti Jason P. Hayes 《The International Journal of Advanced Manufacturing Technology》2006,30(11-12):1076-1083
A CAD/CAM tool for prototyping and small-scale production of micro-electro-mechanical systems (MEMS) devices based on the excimer laser ablation process has been developed. The system’s algorithms use the 3D geometry of a microstructure, defined as an STL file exported from a CAD model, and parameters that influence the process (laser fluence, pulse repetition frequency, number of shots per area, wall angle, stitching errors) to automatically generate a precise NC part program for the excimer laser machine. The performance of the system has been verified by NC part program generation for several 3D microstructures and subsequent machining trials. An initial stitching error of 23.4±2.2-μm wide and 3.4±1.5-μm high was observed when the overlap size between adjacent volumes was zero, when ablating 100×100-μm features in polycarbonate (PC) at a fluence of 0.5 J/cm2 using a workpiece-dragging technique. When the size of the overlap was optimised by a system based on optimal process parameters determined by the Taguchi design of experiment method (DOE), and incorporated in the mask design, the maximum stitching error was reduced to 13.4±2.2-μm wide and 1.4±0.9-μm high under the same conditions. By employing a hexagonal-shaped mask with incorporated size of the image overlap, reduced horizontal-stitching errors of 2.4±0.2-μm wide and 1.4±0.2-μm high were observed. The system simplifies part program creation and is useful for excimer laser operators who currently use a tedious trial and error process to create programs and complex masks to generate microstructure parts. 相似文献
98.
Isabella Nova Lidia Castoldi Luca Lietti Enrico Tronconi Pio Forzatti 《Catalysis Today》2002,75(1-4):431-437
The NOx storage and reduction functions of a Pt–Ba/Al2O3 “NOx storage–reduction” catalyst has been investigated in the present work by applying the transient response and the temperature programmed reaction methods, by using propylene as the reducing agent. It is found that: (i) the storage of NOx occurs first at BaO and then at BaCO3, which are the most abundant sites following regeneration of catalyst with propylene; (ii) the overall storage process at BaCO3 is slower than at BaO; (iii) CO2 inhibits the NOx storage at low temperatures; (iv) the amount of NOx stored up to catalyst saturation at 350 °C corresponds to 17.6% of Ba; (v) the reduction of stored NOx groups is fast and is limited by the concentration of propylene in the investigated T range (250–400 °C); (vi) selectivity to N2 is almost complete at 400 °C but is significantly lower at 300 °C due to the formation of NO which can be tentatively ascribed to the presence of unselective Pt–O species. 相似文献
99.
In general, city trip planning consists of two main steps: knowing Points‐Of‐Interest (POIs), and then planning a tour route from the current point to next preferred POIs. We mainly consider the metro for traveling around touristic cities as the main means of transportation. In this context, existing tools lack a capability to effectively visualize POIs on the metro map for trip planning. To bridge this gap, we propose an interactive framework that holistically combines presentations of POIs and a metro network. Our idea is to identify popular POIs based on visual worth computation, and to introduce POI discovery for effectively identifying POIs within reach of a metro network for users. We use octilinear layouts to highlight the metro network, and show representative POI images in the layout space visualized within a user‐specified viewing window. We have implemented our working prototype showing touristic cities with a metro network. We have factored out various design guidelines that are basis for designing our method, and validated our approach with a user study surveying 70 individuals. 相似文献
100.
Wireless Networks - In this paper, we carry out an experimental analytics to show how much perfectly the conceptual mining framework is operable on re-discovering workflow process patterns and... 相似文献