全文获取类型
收费全文 | 210篇 |
免费 | 17篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 63篇 |
金属工艺 | 5篇 |
机械仪表 | 8篇 |
建筑科学 | 13篇 |
能源动力 | 23篇 |
轻工业 | 22篇 |
水利工程 | 1篇 |
无线电 | 20篇 |
一般工业技术 | 34篇 |
冶金工业 | 9篇 |
自动化技术 | 28篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 7篇 |
2020年 | 6篇 |
2019年 | 6篇 |
2018年 | 16篇 |
2017年 | 9篇 |
2016年 | 10篇 |
2015年 | 9篇 |
2014年 | 7篇 |
2013年 | 25篇 |
2012年 | 7篇 |
2011年 | 19篇 |
2010年 | 13篇 |
2009年 | 19篇 |
2008年 | 14篇 |
2007年 | 11篇 |
2006年 | 10篇 |
2005年 | 9篇 |
2004年 | 6篇 |
2002年 | 3篇 |
2001年 | 4篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1988年 | 1篇 |
1979年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有227条查询结果,搜索用时 418 毫秒
31.
Zeliha Uur Aydn Neslihan Büra Keskin Taha
zyürek 《Microscopy research and technique》2019,82(6):856-860
The purpose of this study was to evaluate and compare the effect of Reciproc Blue (RPCB), XP‐endo Shaper (XPS), and WaveOne Gold (WOG) single‐files on dentinal microcrack formation using micro‐computed tomography (micro‐CT). Twenty‐four mesial roots (24 mesio‐buccal and 24 mesio‐lingual canals) of mandibular molar teeth were prepared using RPCB, XPS, and WOG files (n = 8/each group). The samples were scanned with micro‐CT in the pre‐ and post‐preparation. Then, before preparation and after preparation cross‐sectional images of the teeth were evaluated to detect the presence of microcracks. For each group, the number of microcracks was calculated as a percentage rate. The data were statistically analyzed using McNemar at 5% significance level (p < .05). Dentinal microcracks were observed in 25.99% (2,103 of 7,813), 31.99% (2,482 of 7,758), and 36.66% (2,836 of 7,731) of cross‐sectional images of the XPS, WOG, and RPCB groups, respectively. In all the groups, all the dentinal microcracks seen in the post‐treatment cross‐sectional images were present in the corresponding pre‐treatment images. Within the limitations of this study, the XPS, WOG, and RPCB files did not cause new dentinal microcrack formation or propagation of existing dentinal microcracks. 相似文献
32.
33.
34.
Yusuf Keskin H. Selçuk Halkacı Mevlüt Kizil 《The International Journal of Advanced Manufacturing Technology》2006,28(11-12):1118-1121
Electrical discharge machining (EDM) is a non-traditional production method that has been widely used in the production of dies throughout the world in recent years. The most important performance measure in EDM is the surface roughness; among other measures material removal and tool wear rates could be listed. In this study, experiments were performed to determine parameters effecting surface roughness. The data obtained for performance measures have been analyzed using the design of experiments methods. A considerably profound equation is obtained for the surface roughness using power, pulse time, and spark time parameters. The results are discussed. 相似文献
35.
The impact of impregnation and bleaching on the hardness of varnish layers on oak (Quercus petraea L.) wood was investigated. A number of solutions [sodium hydroxide (NaOH) and hydrogen peroxide (H2O2); NaOH, calcium hydroxide, and H2O2; NaOH, magnesium sulfate, and H2O2; sodium bisulfate and H2C2O4 · 2H2; sodium silicate and H2O2; and potassium permanganate, sodium bisulfate, and H2O2] were applied at a concentration of 18% to bleach both impregnated [Tanalith‐CBC (T‐CBC) or Imersol‐WR 2000 (I‐WR 2000)] and unimpregnated (natural) wood panels. Subsequently, a water‐based varnish (WB) was coated over the samples, and the hardness of the varnished layers was determined in accordance with ASTM D 4366. Among the samples that were varnish‐coated without bleaching, T‐CBC/WB yielded the highest hardness (59.50), whereas I‐WR 2000/WB exhibited the lowest (49.17). However, among the samples varnish‐coated after bleaching, the highest (56.50) and lowest (40.83) varnish hardness values were obtained with T‐CBC/solution 2/WB and I‐WR 2000/solution 4/WB, respectively. All the chemicals used for the bleaching process reduced the surface hardness. However, after the varnish coating, except for solutions 4 and 6, all the solutions showed hardness values similar to those of varnish‐coated natural (control) samples. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 498–504, 2004 相似文献
36.
Calder Phillips-Grafflin Nicholas Alunni Halit Bener Suay Jim Mainprice Daniel Lofaro Dmitry Berenson Sonia Chernova Robert W. Lindeman Paul Oh 《Intelligent Service Robotics》2014,7(3):121-131
This paper presents our progress toward a user-guided manipulation framework for high degree-of-freedom robots operating in environments with limited communication. The system we propose consists of three components: (1) a user-guided perception interface that assists the user in providing task-level commands to the robot, (2) planning algorithms that autonomously generate robot motion while obeying relevant constraints, and (3) a trajectory execution and monitoring system which detects errors in execution. We report quantitative experiments performed on these three components and qualitative experiments of the entire pipeline with the PR2 robot turning a valve for the DARPA robotics challenge. We also describe how the framework was ported to the Hubo2+ robot with minimal changes which demonstrates its applicability to different types of robots. 相似文献
37.
Spectroscopic and conductometric studies on the interactions of thionine with anionic and nonionic surfactants
下载免费PDF全文
![点击此处可从《Coloration Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Sinem Göktürk Güneş Keskin Remziye Yeşim Cantürk Talman Neşe Çakır 《Coloration Technology》2017,133(5):362-368
In this study, the interaction of thionine, a cationic dye, with anionic [sodium dodecyl sulphate (SDS), lithium dodecyl sulphate (LiDS), and sodium dodecylbenzene sulphonate (SDBS)], nonionic (Tween 20 and Triton X‐100), and binary mixtures of anionic and nonionic surfactants was studied by conductometric and spectrophotometric measurements. The degree of ionisation, the counterion binding parameters, and the equilibrium constants in the premicellar region were obtained from conductivity data. Binding constants of thionine to anionic, nonionic, and mixtures of anionic and nonionic micelles were determined by spectrophotometric measurements. The binding tendency of thionine to anionic micelles followed the order SDBS > SDS > LiDS. The presence of nonionic surfactants increased significantly the binding affinity of thionine to anionic micelles, and the highest binding constant was calculated in the presence of Tween 20. The results obtained from conductometric studies correlated with those obtained from spectroscopic studies. Data concerning dye–surfactant interaction are important for a fundamental understanding of the performance of single and mixed surfactants and for their industrial application. 相似文献
38.
Doğan OM Bolayir G Keskin S Doğan A Bek B 《Journal of materials science. Materials in medicine》2008,19(6):2343-2349
This study was performed to determine whether some flexural properties of a denture base resin material could be improved
through reinforcement with five types of aesthetic fibers at 3% concentration by weight and in 2, 4, and 6 mm length. Five
specimens of similar dimensions were prepared for each of the test groups; base resin and the same resin with glass, rayon,
polyester, nylon 6 and nylon 6,6 fibers in three different lengths. Flexural properties were evaluated by using a 3-point
bending test. A visual examination was also made to determine mode of fracture of the specimens. The incorporation of different
fibers in varying lengths had no significant effect on flexural strength of the resin. The specimens reinforced with nylon
6,6 fibers of 6 mm length showed the highest flexural strength. Young’s modulus and maximum load suggests that such reinforcement
makes resin resistant to fracture. 相似文献
39.
Metal Organic Framework Crystals in Mixed‐Matrix Membranes: Impact of the Filler Morphology on the Gas Separation Performance
下载免费PDF全文
![点击此处可从《Advanced functional materials》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Anahid Sabetghadam Beatriz Seoane Damla Keskin Nicole Duim Tania Rodenas Salman Shahid Sara Sorribas Clément Le Guillouzer Guillaume Clet Carlos Tellez Marco Daturi Joaquin Coronas Freek Kapteijn Jorge Gascon 《Advanced functional materials》2016,26(18):3154-3163
Mixed‐matrix membranes comprising NH2‐MIL‐53(Al) and Matrimid or 6FDA‐DAM have been investigated. The metal organic framework (MOF) loading has been varied between 5 and 20 wt%, while NH2‐MIL‐53(Al) with three different morphologies, nanoparticles, nanorods, and microneedles has been dispersed in Matrimid. The synthesized membranes have been tested in the separation of CO2 from CH4 in an equimolar mixture. At 3 bar and 298 K for 8 wt% MOF loading, incorporation of NH2‐MIL‐53(Al) nanoparticles leads to the largest improvement compared to nanorods and microneedles. The incorporation of the best performing filler, i.e., NH2‐MIL‐53(Al) nanoparticles, into the highly permeable 6FDA‐DAM has a larger effect, and the CO2 permeability increases up to 85% with slightly lower selectivities for 20 wt% MOF loading. Specifically, these membranes have a permeability of 660 Barrer with a CO2/CH4 separation factor of 28, leading to a performance very close to the Robeson limit of 2008. Furthermore, a new non‐destructive technique based on Raman spectroscopy mapping is introduced to assess the homogeneity of the filler dispersion in the polymer matrix. The MOF contribution can be calculated by modeling the spectra. The determined homogeneity of the MOF filler distribution in the polymer is confirmed by focused ion beam scanning electron microscopy analysis. 相似文献
40.
In this study, the performance of a new cell immobilization material, namely ceramic ball, was examined for continuous biohydrogen production in comparison to suspended cell culture system (CSTR). Production of biohydrogen in both systems was assessed under thermophilic conditions. Both systems were operated at varying hydraulic retention times (HRT) by shortening HRT values from 24 to 1.5 h at an influent sucrose concentration of 10 g/l. The immobilized bioreactor configuration outcompeted the CSTR bioreactor in terms of both volumetric hydrogen production (2.7 l H2/l/day for immobilized system @ HRT = 3 h and 0.5 l H2/l/day for CSTR @ HRT = 24 h) and resistance to cell-washout (CSTR reactor lost significant amount of biomass at short HRT values). It was concluded that immobilized bioreactor configuration is much more robust than CSTR against high organic loading rates and 5 fold more volumetric hydrogen production was achieved in 8 fold smaller immobilized bioreactor. 相似文献