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排序方式: 共有190条查询结果,搜索用时 109 毫秒
81.
Vorkötter C. Hagen S. P. Pintsuk G. Mack D. E. Virtanen S. Guillon O. Vaßen R. 《Oxidation of Metals》2019,92(3-4):167-194
Oxidation of Metals - The oxidation resistance of the bond coat in thermal barrier coating systems has significant influence on thermal cycling performance of the protective coating. In this study,... 相似文献
82.
M.M. Gasik J. Virtanen A. Santasalo-Aarnio 《International Journal of Hydrogen Energy》2017,42(19):13407-13414
In this paper, the performance of a robust SO2 depolarized electrolyser (SDE) stack that involves neither Pt catalyst nor carbon compounds at ambient conditions is demonstrated. In particular, the effect of different anolyte flow configurations to the overall H2 production rate and SO2 carry-over phenomenon is presented. These results indicate that serpentine anolyte flow (U-configuration) provides higher SO2 conversion, however, results in a more severe SO2 carry-over phenomenon due to increased membrane-electrolyte interface. In addition, individual unit cells in the stacks are monitored for further understanding about the different operational environment in each cell and to provide guidelines for future SDE stack design. 相似文献
83.
Ristimäki J Keskinen J Virtanen A Maricq M Aakko P 《Environmental science & technology》2005,39(24):9424-9430
This work examines the methodology to sample and measure the number and size of motor vehicle particulate emissions (PM) at subambient temperatures. The study has two principal objectives. The first is to address the following question: which aspects of the particle sampling, dilution, and size measurement process must be made at the vehicle test temperature to obtain an accurate representation of the PM emissions? The second is to perform a preliminary overview of how subambient temperature operation affects PM emissions from the major classes of current model light duty vehicles. The principal findings are the following: (1) The temperature of the particle size instruments, test cell versus room temperature, has little effect on the measurements. (2) Once the engine has warmed, solid particle (soot) mode emissions in the cold test cell are similar to those at room temperature. The first finding simplifies cold temperature emissionstesting because it allows particle sizing instruments to be placed outside the cold test cell and operated at room temperature. The latter is consistent with the expectation that solid particles are formed in the engine and are therefore relatively unaffected by ambient conditions after engine warm-up. Use of cold dilution air in the room-temperature test cell increases the number and size of nuclei particles; however, the effect of dilution airtemperature was inconclusive in the cold test cell. 相似文献
84.
Ismo?RakkolainenEmail author Tobias?H?llerer Stephen?DiVerdi Alex?Olwal 《Multimedia Tools and Applications》2009,44(3):389-405
Displays are the most visible part of most computer applications. Novel display technologies strongly influence and inspire
new forms of computer use and interaction. We are particularly interested in the interplay of novel displays and interaction
for ubiquitous computing or ambient media environments, as emerging display technologies may become game-changers in how we
define and use computers, possibly changing the context of computing fundamentally.
We present some of our experiments and lessons learnt with a new category of displays, the “immaterial” FogScreen. It can
be described as a novel media platform, exhibiting some fundamental differences to and advantages over other displays. It
also enables novel kinds of user interfaces and experiences. In this paper we give insights about the special properties and
strengths of the FogScreen by looking at a set of successfully demonstrated interfaces and applications. We also discuss its
future potential for user interface design.
相似文献
Ismo RakkolainenEmail: |
85.
Matti Anniko Lars-Eric Thornell Ismo Virtanen Frans C. S. Ramaekers 《Microscopy research and technique》1990,15(2):155-164
Freeze-fracture analysis of adult spiral ganglion cells of CBA/CBA mice revealed two types of membrane specializations. Most cells (type I) had a smooth surface and were surrounded by Schwann cells. Type II spiral ganglion cells showed numerous membrane specializations with well-delineated indentations similar to those previously found on hair cells adjacent to afferent and efferent nerve endings. Immunomorphological analysis (using well-defined monoclonal antibodies directed against different subclasses of intermediate filament proteins) revealed a unique co-expression of neurofilaments, vimentin and cytokeratins in spiral ganglion cells of 8-to 22-week human fetuses. 相似文献
86.
Anna V. Tsiapara Mari Jaakkola Ioanna Chinou Konstadia Graikou Tiina Tolonen Vesa Virtanen Paraskevi Moutsatsou 《Food chemistry》2009
Historically, honey has been important in Greek culture. The chemical composition and the potential of Greek honey extracts (thyme, pine and fir honey) to influence the oestrogenic activity and the cell viability of breast (MCF-7), endometrial (Ishikawa) and prostate (PC-3) cancer cells were investigated. All honeys contained total phenolics, phenolic acids and hydroxymethylfurfural, the levels being highest in thyme honey. Sugars and volatile compounds, but not fatty acids, were detected in all honey extracts. Thyme, pine and fir honey showed both antioestrogenic and a weak oestrogenic effect at low and high concentration, respectively, in MCF-7 cells. Thyme honey reduced the viability of Ishikawa and PC-3 cells, whereas fir honey stimulated the viability of MCF-7 cells. In conclusion, Greek honeys are rich in phenolic compounds, they modulate oestrogenic activity whereas a thyme honey-enriched diet may prevent cancer-related processes in breast, prostate and endometrial cancer cells. 相似文献
87.
Metehan C. Turhan Robert Lynch Manuela S. Killian Sannakaisa Virtanen 《Electrochimica acta》2009,55(1):250-257
Fluoride activation of Mg AZ91D die-cast alloy surfaces by ammonium fluoride pre-treatment is an important procedure in industry. The procedure forms a fluoride rich layer on the surface enabling the formation of coatings in a uniform manner during further treatments. The present study explores the time dependence of the sequential two-step pre-treatment process – acid etching in H2SO4 (first step) and steeping in NH4F (second step) – on the corrosion properties of AZ91D alloy. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) show the α phase to be selectively etched via a “peeling-off” mechanism that eventually leads to the undercutting and undermining of the β-phase network. After ammonium fluoride treatment, variations in structure and chemical composition of the fluoride rich layer were shown to depend on the underlying phase of the alloy surface by SEM and time-of-flight secondary-ion-mass-spectroscopy (ToF-SIMS). After step 1 (acid etching), electrochemical impedance spectroscopy (EIS) in 3.5% NaCl solution indicates greater charge transfer resistance (Rt) for samples of greater exposed β surface area. This greater Rt increases after step 2 (NH4F steeping). Furthermore, the corrosion protection properties of F-coated AZ91D can be significantly enhanced by optimizing the durations of the two pre-treatment steps. Indeed, over extension of the duration of either step 1 or step 2 leads to deterioration of the overall corrosion resistance. 相似文献
88.
Pore formation under anodic polarization of a lightly doped p-type Si wafer previously loaded with Pt, Pd and Ag nanoparticles was investigated in HF solution with and without H2O2. In HF solution without H2O2, a microporous layer was formed in p-Si loaded with Pt or Pd. However, Ag metal nanoparticles yielded pores due to their intrusion in the Si wafer. The addition of H2O2 to the etching solution leads to different pore morphologies depending on the metals. Particles of Ag were found at the bottom of most pores. In the presence of Pt nanoparticles, cone-shaped macropores were produced, and the pore depth and diameter increased with increasing H2O2 content. Current density influenced the pore morphology. For a sample loaded with Pt or Ag, an increase in applied current density widened the pore diameter. The mechanism of the metal-assisted pore formation was discussed by considering a competitive process between the formation of a microporous layer under polarization and metal-assisted chemical oxidation of the microporous layer by a dissolved oxidizing agent. 相似文献
89.
Viitanen AK Saukko E Virtanen A Yli-Pirilää P Smith JN Joutsensaari J Mäkelä JM 《Environmental science & technology》2010,44(23):8917-8923
An ion mobility spectrometer (IMS) was used to study gas phase compounds during nucleation and growth of secondary organic aerosols (SOA). In this study SOA particles were generated by oxidizing α-pinene with O(3) and OH in a 6 m(3) reaction chamber. Positive ion peaks with reduced mobilities of 1.59 cm(2)(Vs)(-1) and 1.05 cm(2)(Vs)(-1) were observed 7 min after α-pinene and ozone were added to the chamber. The detected compounds can be associated with low volatility oxidation products of α-pinene, which have been suggested to participate in new particle formation. This is the first time that IMS has been applied to laboratory studies of SOA formation. IMS was found suitable for continuous online monitoring of the SOA formation process, allowing for highly sensitive detection of gas phase species that are thought to initiate new particle formation. 相似文献
90.