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121.
Didar Sevim Ozlem Tuncay Oya Koseoglu 《Journal of the American Oil Chemists' Society》2013,90(9):1359-1369
In this study, the effects of leaf addition, maturity stage and storage on the antioxidant content and activity of olive oils (cv. Memecik) were investigated in the 2008/09 and 2009/10 crop seasons. Olive fruits were harvested at two different maturity stages (early and late), and the leaves of the same cultivar were added at different rates (0, 1, and 3 %) prior to oil extraction. After extraction, the oil samples were stored for 18 months and total chlorophyll, α-tocopherol, total phenolic content and the antioxidant activity [DPPH· (2,2-diphenyl-1-picrylhydrazyl) and ABTS·+ (2,2-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid) radical scavenging] were determined at 6 month-intervals. Olive leaf addition induced a significant increase in total chlorophyll, α-tocopherol, total phenolic content, and antioxidant activities in both years (P < 0.001). During the storage period antioxidant content and antioxidant activities in the oils significantly decreased in both years (P < 0.001). However, the oils to which leaf material was added had higher antioxidant contents and activities than those without leaf material addition at the end of the 18-month storage period. After storage, the antioxidant content and DPPH· radical scavenging activity of control (0 %) samples were lower than those in the leaf added samples (3 %). The data obtained from this study suggested that the addition of olive leaf to oils allowed more functional olive oils with higher antioxidant contents. 相似文献
122.
Intumescent coating is an insulating material designed to decrease heat transfer to a substrate structure. The coating presented in this research article was based on expandable graphite, ammonium polyphosphate, melamine, and boric acid. Bisphenol A epoxy resin BE‐188 was used as a binder with ACR hardener H‐2310 polyamide amine. Different formulations were developed to study the effect of expansion and heat shielding after fire testing. The coating was tested at 950°C for 1 h. The results show that the coating was stable and well bonded with the substrate. The coating was characterized with thermogravimetric analysis (TGA, Parkin Elmer, Norwalk, CT, 06859, USA), Fourier transform infrared (FTIR, Nicolet 400 D Shimadzu spectrometer) spectroscopy, X‐ray diffraction (XRD, Bruker D8 advance Diffracto meter, Bruker Germany), and scanning electron microscopy (SEM, Carl Zeiss Leo 1430VP, UK). The morphology of char was studied by SEM on the coating after fire testing. XRD and FTIR spectroscopy showed the presence of graphite, boron phosphate, boron oxide, and sassolite in the residual char. TGA (Pyris 1, manufactured by Parkin Elmer, Norwalk, CT, 06859, USA) and differential thermal gravimetric analysis (DTGA) showed that boric acid enhanced the residual weight of the intumescent fire‐retardant coating. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
123.
Taewook Ryu Faiz Ahmed Sabuj Chandra Sutradhar Nasrin Siraj Lopa Hanmo Yang Soojin Yoon Seungchan Lee Inhwan Choi Whangi Kim 《International Journal of Hydrogen Energy》2018,43(26):11862-11871
The grafted block copolymer based polymer electrolyte membrane (PEM) was successfully synthesized by the superacid-catalyzed polyhydroxyalkylation reaction from biphenyl, 2,2′-biphenol and isatin and the performance of the block copolymer were compared in conjunction with the random copolymer. These polymers have all carbon-carbon structure on polymer backbone without ether linkage. The bromoalkylsulfone potassium salt was prepared from 1,3-propane sultone and potassium bromide. Particularly, the attached alkyl sulfone groups were afforded better stability due to less reactivity towards nucleophilic substitution reaction. Moreover, the block copolymer exhibited better proton conductivity (76.84 mS/cm under 90% relative humidity at 80 °C), water resistivity, chemical, and thermal stability compared to the random copolymer, because block copolymer membranes showed good hydrophilic/hydrophobic phase separation and wide ionic channels. The structures of the resultant PEMs were confirmed by 1H NMR spectroscopy and thermogravimetric analysis (TGA). These membranes were studied by proton conductivity, water uptake (WU), and ion exchange capacity (IEC). Fenton test was attended by Fenton's reagent (4 ppm Fe2+, 3% H2O2) for confirmation of the polymer degradation and the surface morphology of membranes was also analyzed by atomic force microscope. 相似文献
124.
In situ synthesis of ultra-fine, porous, tin oxide-carbon nanocomposites via a molten salt method for lithium-ion batteries 总被引:1,自引:0,他引:1
Bin Liu Zai Ping Guo Guodong Du Yanna Nuli Mohd Faiz Hassan Dianzeng Jia 《Journal of power sources》2010,195(16):5382-530
Ultra-fine, porous, tin oxide-carbon (SnO2/C) nanocomposites are fabricated by a molten salt method at 300 °C, and malic acid is decomposed as the carbon source. In situ synthesis is favourable for the combination of carbon and SnO2. The structure and morphology are confirmed by X-ray diffraction analysis, specific surface-area measurements, and transmission electron microscopy (TEM). Examination of TEM images reveals that the SnO2 nanoparticles are embedded in the carbon matrix, with sizes between 2 and 5 nm. The electrochemical measurements show that the nanocomposite delivers a high capacity with good capacity retention as an anode material for lithium-ion batteries, due to the combination of the ultra-fine porous structure and the carbon component. 相似文献
125.
In this study, we used ARIMA, seasonal ARIMA (SARIMA) and alternatively the regression model with seasonal latent variable in forecasting electricity demand by using data that belongs to “Kayseri and Vicinity Electricity Joint-Stock Company” over the 1997:1–2005:12 periods. This study tries to examine the advantages of forecasting with ARIMA, SARIMA methods and with the model has seasonal latent variable to each other. The results support that ARIMA and SARIMA models are unsuccessful in forecasting electricity demand. The regression model with seasonal latent variable used in this study gives more successful results than ARIMA and SARIMA models because also this model can consider seasonal fluctuations and structural breaks. 相似文献
126.
Belgin Sarimehmetoglu Mihriban Hatun Aksoy Naim Deniz Ayaz Yildiz Ayaz Ozlem Kuplulu Yusuf Ziya Kaplan 《Food Control》2009,20(4):357-361
In the study 251 fresh ground beef samples sold in Ankara were analyzed to evaluate the prevalence of Escherichia coli O157:H7 by immunomagnetic separation (IMS) based cultivation technique. Virulence factors of the isolates were determined by multiplex PCR. Nineteen (7.6%) of 251 ground beef samples were found as contaminated with E. coli O157. By PCR analyse in two of the isolates fliCh7 gene was detected and identified as E. coli O157:H7. According to the multiplex PCR one of the isolate has all stx1, stx2, eaeA, hly and fliCh7 genes and the other has stx1, eaeA, hly and fliCh7 genes. 相似文献
127.
Characterisation of esterase activities from the edible mushroom species, Amanita vaginata var. vaginata and Tricholoma terreum, were investigated. Native electrophoresis of the crude extracts prepared from both mushroom samples showed the presence of esterolytic activities. The extracts had the greatest activity in the presence of p-nitrophenyl butyrate (pNPB) as a substrate. pH and temperature optima were found to be 8.0 and 30 °C for both enzymes, respectively. Vmax and Km values were determined as 14.2 U/l and 71 μM for A. vaginata var. vaginata and 34.6 U/l and 9.6 μM for T. terreum, respectively. The pH-stability profile showed a stationary line between 3.0 and 10.0 for both enzymes. The esterolytic activities from the extracts were maintained between 10 and 40 °C for 4 h and started to decrease at 50 °C. The effects of EDTA, NaN3, DTT and PMSF on the enzyme activity were also investigated. 相似文献
128.
129.
130.
Kemal Kocabas Oya Özkan Ozlem Bilgili Yelda Kadıoglu Hatice Yılmaz 《Journal of Superconductivity and Novel Magnetism》2010,23(8):1485-1492
The effects of Mg substitution in Bi-2223 superconductor system has been studied for the Bi1.7Pb0.3Sr2Ca2Cu3−x
Mg
x
O
y
nominal composition (x=0.00, 0.05, 0.10, 0.15 and 0.20) which was prepared by the conventional solid-state reaction. The properties of these compounds
have been investigated by measuring the electrical resistivity, X-ray diffraction (XRD) and density. Also, scanning electron
microscopy (SEM) was employed to investigate the surface microstructure of the samples. It has been found that the effects
of Mg substitution support the development of both the Bi-2212 and Bi-2223 phases. These measurements and analyses enable
us to discuss the effects of Mg dopant on superconducting properties. We found that onset critical temperatures (T
c, onset) decrease with addition x>0.10 in resistivity measurements. The presence of Mg influenced the microstructure of the samples and decreased the mean
grain size of Bi-2223 grains up to x=0.10. 相似文献