全文获取类型
收费全文 | 199篇 |
免费 | 14篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 60篇 |
金属工艺 | 6篇 |
机械仪表 | 2篇 |
建筑科学 | 5篇 |
能源动力 | 9篇 |
轻工业 | 10篇 |
水利工程 | 2篇 |
石油天然气 | 3篇 |
无线电 | 18篇 |
一般工业技术 | 53篇 |
冶金工业 | 8篇 |
自动化技术 | 39篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 10篇 |
2020年 | 9篇 |
2019年 | 8篇 |
2018年 | 16篇 |
2017年 | 8篇 |
2016年 | 6篇 |
2015年 | 9篇 |
2014年 | 12篇 |
2013年 | 21篇 |
2012年 | 16篇 |
2011年 | 12篇 |
2010年 | 7篇 |
2009年 | 13篇 |
2008年 | 11篇 |
2007年 | 13篇 |
2006年 | 9篇 |
2005年 | 7篇 |
2004年 | 5篇 |
2003年 | 2篇 |
2002年 | 5篇 |
1998年 | 3篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1990年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有216条查询结果,搜索用时 15 毫秒
211.
In this contribution, 2‐(9H‐carbazol‐9‐yl) ethyl methacrylate (CzEMA) monomer was chemically synthesized. The monomer characterization was performed by FT‐IR, 1H‐NMR, 13C‐NMR, and melting point analysis. The electropolymerization of CzEMA was studied onto carbon fiber microelectrodes (CFMEs) as an active electrode material in 0.1M sodium perchlorate (NaClO4)/acetonitrile (ACN) solution. The electropolymerization experiments were done from 1 mM to 10 mM. The detailed characterization of the resulting electrocoated Poly (CzEMA)/CFME thin films was studied by various techniques, i.e., cyclic voltammetry (CV), Scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The effects of initial monomer concentrations (1, 3, 5, and 10 mM) during the preparation of modified electrodes were examined by EIS. Capacitive behaviors of modified CFMEs were defined via Nyquist, Bode‐magnitude, and Bode‐phase plots. Variation of capacitance values by initial monomer concentration and specific capacitance values are presented. The highest specific capacitance value electrocoated polymer thin film by CV method in the initial monomer concentration of 5 mM with a charge of 52.74 mC was obtained about 424.1 μF cm?2. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
212.
A. Sezai Sarac S. Esra Ozgul Asli Gencturk Burkhard Schulz Hans-Detlev Gilsing Heike Faltz 《Progress in Organic Coatings》2010
Micron sized single carbon fibers were cyclovoltammetrically coated with poly[3,4-(2,2-dibenzylpropylenedioxy)thiophene] resulting in a nanofiber network at the surface. The method provides conjugated polymer nanostructures covalently and uniformly bound to micron sized substrates. When the electropolymerization is carried out with different electrolytes in acetonitrile the dopant influences the structure of the coating layer what is proved by electrochemical impedance spectroscopy and electron microscopy. Electrodes based on poly[3,4-(2,2-dibenzylpropylenedioxy)thiophene] on single carbon fiber microelectrodes (SCFMEs) prepared in Bu4NPF6/ACN show the best capacitance performance due to their higher surface area. The improvement is attributed to the formed nanofiber network structure which results in a more efficient charge transport and collection. 相似文献
213.
Well-defined mid-chain functional macrophotoinitiator of poly(ε-caprolactone) (PCL-PI-PCL) was synthesized by combination of ring-opening polymerization (ROP) and click chemistry strategy. Dibromo functional photoinitiator (Br–PI–Br) was prepared by the condensation of 2-bromopropanoyl bromide with 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl propan-1-one (PI). Subsequently, terminal bromo groups in Br–PI–Br were converted to azido groups to form diazido functional photoinitiator (N3–PI–N3) using NaN3. Well-defined precursor alkyne-functionalized PCL (alkyne-PCL) was prepared by ROP of ε-CL in the presence of propargyl alcohol as the initiator and stannous-2-ethylhexanoate (Sn(Oct)2) as the catalyst. Finally, the alkyne-functionalized PCL was coupled with N3–PI–N3 with high efficiency by click chemistry. The spectroscopic studies showed that low-polydispersity PCL with desired photoinitiator functionality in the middle of the chain was obtained. 相似文献
214.
In this study, PVA-CaB6O10·5H2O precursor mixtures were prepared by coating the ceramic powders with PVA to synthesize CaB6 via carbothermal reduction. Boron loss, the main problem in the synthesis of borides, was reduced by the use of metastable CaB6O10 as a transitional phase which is stable until the critical temperature ranges where the boron sub-oxides have higher volatilities. To minimize boron loss, due to the high hydrophilicity and ability to form cross-linked PVA-borate gels, PVA was used as a carbon source and carbon coating process was carried out via pyrolysis of the PVA - CaB6O10·5H2O mixed gels. The effect of the molecular weight of PVA on the CaB6 synthesis was also studied. Because of highly efficient interaction of CaB6O10·5H2O with the PVA60-water solution, PVA60 was found to be the optimal carbon source. The CaB6O10·5H2O-PVA60 composite powder was characterized by using Fourier transform infrared spectroscopy (FTIR) and the effect of molecular weight of the PVA’s on the thermal characteristics of mixed powders were analyzed by using simultaneous thermal analysis (STA). The effect of carbothermic reduction temperature and dwell time on the phase formation were examined via x-ray diffractometer (XRD) and scanning and transmission electron microscopy (SEM and TEM) techniques. The optimum synthesis conditions were determined for the formation of CaB6 as 1450ºC for 12 h under an Argon flow by using the CaB6O10·5H2O-PVA60 mixed precursor. 相似文献
215.
Bodo Böhme Umut Aydemir Alim Ormeci Walter Schnelle Michael Baitinger Yuri Grin 《Science and Technology of Advanced Materials》2007,8(5):410-415
A new preparation route to the intermetallic clathrate-I compound Na2Ba6Si46 is introduced, which allows one to make large amounts of product with standard laboratory equipment. The precursor Na2BaSi4 is oxidized with gaseous HCl at 673 K to Na2Ba6Si46, NaCl and BaCl2. Full-profile refinement of the crystal structure from the X-ray powder diffraction data revealed a composition close to Na2Ba6Si46 (Na1.94(1)Ba6.06(1)Si46, space group , a=10.281(1) Å). Differential scanning calorimetry showed an exothermic effect at 874 K, indicating that Na2Ba6Si46 is metastable. The product was additionally characterized by scanning electron microscopy. The electronic structure of Na2Ba6Si46 was investigated by a first-principles, all-electron full-potential method, predicting metallic conductivity. Na2Ba6Si46 obtained by oxidation with HCl shows Pauli paramagnetism; no bulk superconductivity was found down to 1.8 K in a magnetic field of 20 Oe. 相似文献
216.
Mostafa Taghvaei Bade Tonyali Christopher Sommers Olgica Ceric Ziyi Linghu Joseph Scott Smith Umut Yucel 《Journal of the American Oil Chemists' Society》2021,98(7):737-746
Irradiation processes can change the lipid composition of foods. The major lipid radiolysis products are known to be 2-alkylcyclobutanones and hydrocarbons, the formation kinetics of which is determined by the chemical nature of the inherent lipids. This information can be used to evaluate the irradiation history of lipid-rich foods. A solid-phase microextraction (SPME)-assisted gas chromatography–mass spectrometry (GC–MS) technique was used to study the formation of volatile hydrocarbons and 2-dodecylcyclobutanone (2-DCB), a cyclobutanone formed from the esters of palmitic acid, in irradiated (0–50 kGy) tripalmitin and chicken fat. Thirty-three volatile compounds (hydrocarbons, aldehydes, ketones) increased with irradiation dose to varying extents. Six major lipid radiolysis products were selected to analyze their formation kinetics: tridecane, 1-tetradecene, tetradecane, 1-pentadecene, pentadecane, and 2-DCB. The concentration of the selected compounds increased linearly with irradiation dose following zeroth-order kinetics, except for tridecane and tetradecane in tripalmitin, formation of which followed first-order kinetics. The formation rate of hydrocarbons was higher in tripalmitin than in chicken fat (5× higher for pentadecane), while 2-DCB formed faster (3.5×) in chicken fat than in tripalmitin. This difference was related to the diversity in the natural fatty acid composition of chicken fat as compared to the homogeneous structure of tripalmitin. The results of this study indicate that the concentrations of palmitic acid radiolysis products linearly increase with irradiation dose in general to offer potential to back-trace irradiation dose in lipid-rich foods. 相似文献