全文获取类型
收费全文 | 187篇 |
免费 | 25篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 83篇 |
金属工艺 | 4篇 |
机械仪表 | 1篇 |
建筑科学 | 5篇 |
能源动力 | 4篇 |
轻工业 | 44篇 |
无线电 | 9篇 |
一般工业技术 | 27篇 |
冶金工业 | 11篇 |
原子能技术 | 1篇 |
自动化技术 | 22篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 5篇 |
2021年 | 11篇 |
2020年 | 11篇 |
2019年 | 8篇 |
2018年 | 10篇 |
2017年 | 12篇 |
2016年 | 14篇 |
2015年 | 8篇 |
2014年 | 9篇 |
2013年 | 22篇 |
2012年 | 8篇 |
2011年 | 8篇 |
2010年 | 7篇 |
2009年 | 6篇 |
2008年 | 7篇 |
2007年 | 12篇 |
2006年 | 13篇 |
2005年 | 7篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 6篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1973年 | 2篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1963年 | 1篇 |
1956年 | 2篇 |
排序方式: 共有212条查询结果,搜索用时 15 毫秒
41.
Emine Acer Emin Çadırlı Harun Erol Hasan Kaya Mehmet Gündüz 《Metallurgical and Materials Transactions A》2017,48(12):5911-5923
Dendritic spacing can affect microsegregation profiles and also the formation of secondary phases within interdendritic regions, which influences the mechanical properties of cast structures. To understand dendritic spacings, it is important to understand the effects of growth rate and composition on primary dendrite arm spacing (λ 1) and secondary dendrite arm spacing (λ 2). In this study, aluminum alloys with concentrations of (1, 3, and 5 wt pct) Zn were directionally solidified upwards using a Bridgman-type directional solidification apparatus under a constant temperature gradient (10.3 K/mm), resulting in a wide range of growth rates (8.3–165.0 μm/s). Microstructural parameters, λ 1 and λ 2 were measured and expressed as functions of growth rate and composition using a linear regression analysis method. The values of λ 1 and λ 2 decreased with increasing growth rates. However, the values of λ 1 increased with increasing concentration of Zn in the Al-Zn alloy, but the values of λ 2 decreased systematically with an increased Zn concentration. In addition, a transition from a cellular to a dendritic structure was observed at a relatively low growth rate (16.5 μm/s) in this study of binary alloys. The experimental results were compared with predictive theoretical models as well as experimental works for dendritic spacing. 相似文献
42.
In this study, wool fibre samples were mordanted by means of 25% alum mordant solution. The mordanted wool samples were dyed in 50%Reseda luteola L. (weld), 20%Rhamnus petiolaris Boiss (buckthorn) and 50%Datisca cannabina L. (bastard hemp) dyebaths. A reverse‐phase high‐performance liquid chromatography with diode‐array detection method was utilised for the identification of dyes in the dyed wool samples and the plant extracts. The extraction of dyes was carried out with a hydrogen chloride/methanol/water (2:1:1; v/v/v) mixture. 相似文献
43.
Ari E Kaya Y Demir H Cebi A Alp HH Bakan E Odabasi D Keskin S 《Hemodialysis international. International Symposium on Home Hemodialysis》2011,15(4):453-459
Oxidative stress is accepted as a nonclassical cardiovascular risk factor in chronic renal failure patients. The aim of this study was to evaluate the relation between oxidative DNA damage (8‐hydroxy‐2′‐deoxyguanosine/deoxyguanosine [8‐OHdG/dG] ratio), oxidative stress biomarkers, antioxidant enzymes, and carotid artery intima‐media thickness (CIMT) in hemodialysis (HD) patients. Forty chronic HD patients without known atherosclerotic disease and 48 age‐ and sex‐matched healthy individuals were included in the study. Plasma malondialdehyde (MDA) levels and 8‐OHdG/dG ratio were determined as oxidative stress markers. Superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities were measured as antioxidants. CIMT was assessed by carotid artery ultrasonography. 8‐OHdG/dG ratios and MDA levels were higher; SOD and GPx activities were lower in HD patients compared to controls. HD patients had significantly higher CIMT compared to controls (0.61 ± 0.08 vs. 0.42 ± 0.05, p < 0.001). There was a significant positive correlation between CIMT and 8‐OHdG/dG ratio (r = 0.57, p < 0.01) and MDA levels (r = 0.41, p < 0.01), while there was a significant negative correlation between CIMT and SOD (r = ?0.47, p < 0.01) and GPx levels (r = ?0.62, p < 0.01). It is firstly demonstrated that CIMT is positively correlated with oxidative DNA damage in HD patients without known atherosclerotic disease. 相似文献
44.
The purpose of this study is to show the capability of recurrent neural nets (RNN) for condition monitoring and diagnosis in nuclear power plant systems and rotating machinery. In the first application, the study addresses the use of RNN for detecting anomalies introduced from the simulated power operation of a high-temperature gas cooled nuclear reactor. In the second, it is used to detect the motor bearing damage using a coherence function approach, which is defined between the motor current and vibration signals, for induction motors. Hence, the high performance of Elman's RNN was shown by means of two different applications. 相似文献
45.
Ali Celik Emine Nur Herken Ahmet Ermis 《International Journal of Food Properties》2013,16(8):1655-1662
Chemical constituents, total phenolic content, total oxidant status, total antioxidant status, lipid hydroperoxides, total free –SH levels, and antimicrobial activity of essential oil obtained from the Ferulago sandrasica (Umbelliferae) were investigated. The essential oil was obtained by hydrodistillation using a Clevenger-type apparatus. The chemical constituents were analyzed by gas chromatography‐mass spectrometry. The main components of the essential oil were ocimene (30.5%), carene-δ-3 (27.4%), and α-pinene (17.8). The antimicrobial activity was tested by a disc diffusion method against E. coli MC 400, E. coli ATCC 25922, E. coli 0157 H7, E. colaecea ATCC 23355, E. feacalis ATCC 19433, P. aeruginosa NRRL B-2679, S. aureus ATCC 25923, B. nischenoformis NRRL B-1001, S. aureus ATCC 33862, B. cereus NRRL B-3711, B. subtilis NRRL B-209, M. luteus NRRL B-1013, L. monocytogenes ATCC 7644, B. subtulis ATCC 6633. 相似文献
46.
Emine Sirin Karaarslan Fatma Aytaç Bilge Hilal Çadirci Merve Ağaccioğlu Emine Taştan Gülesme Yilmaz 《Journal of Adhesion Science and Technology》2013,27(23):2617-2630
The aim of the study was to compare the effects of different remineralization methods that are well established in clinical and daily use on S. mutans biofilm adhesion. In this study 72 human third molars were used. From each tooth two pieces of 4?mm x 7?mm enamel blocks were acquired. The samples were divided into 6 groups in which include 10 samples per time period (24h and 48?h) and for each remineralization method; control, flouride, ozone, CPP-ACP, arginine, novamin. After remineralization procedures, enamel surfaces were covered with saliva. 105 CFU/mL of active S. mutans culture were inoculated onto the samples. S. mutans colonies were counted with Plate Count Agar (PCA) decimal dilution method. Micromorphologic effects of different remineralization methods were observed by Scanning Electron Microscopy (SEM). The most S. mutans biofilm formation for both time periods was observed in the control group whereas the less biofilm adhesion was showed in the arginine group. There were no statistically significant differences among remineralization agents (p?>?0.05). In the control group there was statistical difference between 24?h and 48?h (p?<?0.005) but in the other study groups there were no significant difference between the time periods (p?>?0.05). Remineralization agents did not significant differ on S. mutans biofilm adhesion. 相似文献
47.
Wind loads for the ultimate limit state design of the roof structures of stadiums. Wind effects are usually the dominant loading on roofs of stadia, however, on the basis of actual wind loading codes they cannot be determined with the required accuracy in each case. Often, wind tunnel investigations provide more precise wind loads. Herewith, the aerodynamic coefficients are determined individually for each particular case and they are transferred to wind loads for the design. Load assumption are focused on an optimum modelling of the aerodynamic effects on the structures under consideration. By means of wind loads for realized stadia the potential of improved load investigations are introduced. The size effect of the loading area, which significantly reduces the load magnitude is pointed out. On the other hand, buffeting resonance effects may set particular requirements. Wind loads on stadia during erection are addressed. 相似文献
48.
Ongen Atakan Ozcan Hüseyin Kurtulus Elmaslar Ozbas Emine Pangaliyev Yerbol 《Clean Technologies and Environmental Policy》2019,21(6):1281-1291
Clean Technologies and Environmental Policy - Thermochemical decomposition of waste tires was evaluated in order to produce solid and gaseous products within the aim of waste-to-energy concept.... 相似文献
49.
Ayşegül Yücel Selda Sezer Emre Birhanlı Tuba Ekinci Emine Yalman Tolga Depci 《Ceramics International》2021,47(1):626-633
In the present study, undoped whitlockite and ZnO doped-Whitlockite, which is the second most abundant inorganic material in bone structure, were synthesized from sea urchin skeleton. The obtained bioceramic materials were characterized by XRD, FT-IR, and SEM and their antibacterial activities were determined using the inhibition zone diameters of Escherichia coli and Pseudomonas aeruginosa as gram negative bacteria and Staphylococcus aureus as gram positive bacterium after 24 h incubation. The characterization studies showed that nano size homogenous biocereamic whitlockite (Ca2.86Mg0.14(PO4)2) was synthesized from the sea urchin skeleton. After dopping process, the main structure of the whitlockite keeps stable, showing a dopping concentration-independent character. On the other hand, the peaks belonging to ZnO were started to seen in the XRD pattern with increasing the level of ZnO-concentration (after 7 %). All experimental results point out that the obtained whitlockites are viable nominate candidates for bioceramic materials and the results of antibacterial sensitivity prove the inhibitory effect towards Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus for ZnO-doped-whitlockite. 相似文献
50.
In this study an amperometric biosensor based on pyruvate oxidase was developed for the determination of pyruvate and phosphate. For construction of the biosensor pyruvate oxidase was immobilized with gelatin and insolubilized in film by forming cross-linked bonds with glutaraldehyde. The film was fixed on a YSI type dissolved oxygen (DO) probe, covered with a teflon membrane which is high-sensitive for oxygen. The working principle of the biosensor depends on detection of consumed DO concentration related to pyruvate concentration which is used in enzymatic reaction catalyzed by pyruvate oxidase. The biosensor response shows a linearity with pyruvate concentration between 0.0025 and 0.05 μM and also response time of the biosensor is 3 min. In the optimization studies of the biosensor the most suitable enzyme activity was found as 2.5 U/cm2 for pyruvate oxidase, and also phosphate buffer (pH 7.0; 50 mM) and 35 °C were established as providing the optimum working conditions. In the characterization studies of the biosensor some parameters such as reproducibility, substrate specificity, operational stability, determination of phosphate, and interference effects of some compounds on the pyruvate determination were investigated. Finally, the concentration of pyruvate was determined by using spectrophotometric method and the results obtained were compared to results obtained by the biosensor. 相似文献