全文获取类型
收费全文 | 604篇 |
免费 | 73篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 1篇 |
综合类 | 27篇 |
化学工业 | 337篇 |
金属工艺 | 4篇 |
机械仪表 | 12篇 |
建筑科学 | 7篇 |
能源动力 | 2篇 |
轻工业 | 148篇 |
水利工程 | 1篇 |
石油天然气 | 10篇 |
无线电 | 18篇 |
一般工业技术 | 92篇 |
冶金工业 | 7篇 |
原子能技术 | 1篇 |
自动化技术 | 20篇 |
出版年
2024年 | 2篇 |
2023年 | 11篇 |
2022年 | 32篇 |
2021年 | 25篇 |
2020年 | 27篇 |
2019年 | 28篇 |
2018年 | 23篇 |
2017年 | 36篇 |
2016年 | 30篇 |
2015年 | 37篇 |
2014年 | 57篇 |
2013年 | 54篇 |
2012年 | 71篇 |
2011年 | 74篇 |
2010年 | 35篇 |
2009年 | 29篇 |
2008年 | 25篇 |
2007年 | 32篇 |
2006年 | 16篇 |
2005年 | 10篇 |
2004年 | 11篇 |
2003年 | 7篇 |
2002年 | 8篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1997年 | 1篇 |
1951年 | 1篇 |
排序方式: 共有687条查询结果,搜索用时 78 毫秒
81.
82.
Fuqiang An 《Desalination》2009,249(3):1390-273
In this paper, a kind of ionic imprinting polyamine (IIP) was prepared through an advanced approach. Firstly, functional macromolecule polyethyleneimine (PEI) was grafted onto the surfaces of silica gel particles, and the PEI/SiO2 was formed. Secondly, the ionic imprinting process was carried out using Cr3+ ion as a template, and epichlorohydrin (ECH) as a crosslinking agent, and Cr3+ ionic imprinting polyamine IIP-PEI/SiO2 was prepared. The adsorption properties of IIP-PEI/SiO2 for Cr3+ ion were studied in details by adopting both static and dynamic methods, and the effects of main imprinting conditions, such as the concentrations of Cr(III) ion and the amount of ECH, on the adsorption property of the imprinted material IIP-PEI/SiO2 were examined. The experimental results show that the IIP-PEI/SiO2 has high affinity and excellent selectivity for the template ion. Its adsorption amounts for template ion enhances nearly two times compared to PEI/SiO2, and its relative selectivity coefficients relative to Zn2+ and Pb2+ are 24.63 and 59.32 respectively. Besides, the IIP-PEI/SiO2 has a fine elution property using HCl solution as eluent. 相似文献
83.
分子印迹电化学传感器检测链霉素 总被引:1,自引:0,他引:1
为实现链霉素的快速、灵敏测定,将特异性强的分子印迹技术与检测灵敏度高的电化学检测方法结合,构建链霉素分子印迹电化学传感器。以链霉素为模板分子,吡咯为功能单体,利用电化学聚合方法制备分子印迹聚合物(MIP)膜。在最优化实验条件下,以铁氰化钾为探针,利用循环伏安法(CV)对链霉素进行定量测定及传感器性能研究。结果表明:传感器线性范围为5.00×10~(-8)~8.00×10~(-5)mol/L,最低检出限(LOD)为3.45×10~(-8)mol/L,为链霉素的测定提供了高效的方法。 相似文献
84.
A molecularly imprinted polymer (MIP) was synthesized via a two-step swelling polymerization method for the purification of lincomycin. Polystyrene microspheres were prepared by the dispersion-polymerization process and used as the substrate. Methacrylic acid was used as the functional monomer, whereas ethylene glycol dimethacrylate was the cross-linker. The MIP was structurally characterized and examined for its separation performance at different conditions (temperature, solvents, etc.). It was found that the MIP possesses the good sphericity, porosity, monodispersity, and a high adsorption capacity of (180 μmol/g) in chloroform solution. Comparison studies showed that the MIP presents a higher capacity than the NIP (non-imprinted polymer) in chloroform solution and a much higher capacity in the practical lincomycin fermentation solution extracts, confirming the underlining mechanisms of the MIP. Scatchard plot revealed two adsorption mechanisms on the MIP, whereas the isotherm is better described by Freundlich equation. The adsorption/elution kinetics demonstrated that the MIP possesses good elution/regeneration capabilities with the elution ratio > 93%. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47938. 相似文献
85.
Hai Chi Yujie Li Guoqin Liu 《International Journal of Food Science & Technology》2022,57(8):5376-5387
In this study, a new electrochemical strategy based on the fabrication of a molecularly imprinted sensor onto a MoS2-loaded peanut shell carbon complex with gold nanoparticles (AuNPs) and nitrogen-doped carbon dots (N-CDs) was proposed for the detection of benzo(a)pyrene (BaP). Molecularly imprinted polymer (MIP) films were prepared by cyclic voltammetry (CV) using 2-mercaptobenzimidazole (2-MBI) as a functional monomer in the presence of BaP. The surface morphologies, structural characteristics and electrochemical properties of the obtained MIP/AuNPs/N-CDs/PSBC/MoS2/GCE were investigated via scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive spectrometry (EDS), Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD), UV–Vis spectrometry, fluorescence spectrometry, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under the optimised conditions, the detection range of the electrode towards BaP varied from 5 nM to 20 μM with a detection limit of 1.5 nM. The prepared electrochemical sensor also exhibited good stability, relevant reproducibility and high selectivity. The application of the sensor in the actual analysis of edible oil samples showed promising results, thereby being relevant as a biomimetic sensing platform for the detection of chemical hazards in food and environment. 相似文献
86.
Yu Cao Jiayu Li Jun Liu Hongbo Liu Yan Jiang Hongwen Zhang 《Polymer International》2019,68(4):694-699
A novel ion‐imprinted polymer (IIP) using (6‐O‐butene diacid ester)‐β‐cyclodextrin (β‐CD‐MAH) as the functional monomer and copper ions as the template was developed for Cu2+ sensing. First, reactive β‐cyclodextrin (β‐CD) monomers with vinyl carboxylic acid functional groups were synthesised and were co‐polymerised with styrene via radical polymerisation. Then, the β‐CD copolymers were complexed with Cu2+ in order to obtain the IIP. The imprinting effect was realised by removing the template ions from the imprinted polymer. The structure, composition and morphology of the IIP were characterised by Fourier transform IR spectroscopy, energy‐dispersive spectroscopy and field‐emission SEM. The adsorption capacity was investigated by UV–visible spectroscopy in batch operation mode. The maximum adsorption capacity for the Cu2+ template ions was 28.91 mg g?1, and the adsorption selectivity was clearly illustrated from the increased sorption affinity towards Cu2+ ions over other competing ions. The adsorption was affected by the pH of the aqueous medium, and enhanced adsorption capacity was observed at pH 5. The prepared IIP could be used 10 times after its regeneration without significant loss of the adsorption capacity. © 2018 Society of Chemical Industry 相似文献
87.
Recent progress in derivatized polythiophenes (PTs) and polymerized thiophene derivatives is reviewed, with emphasis on applications that involve devising and fabricating selective and sensitive chemo- and biosensors. The literature results summarized show that appreciable selectivity is attained if derivatized polythiophene films are used as recognition units. Illustrative examples include determination of polyatomic anions and metal cations, volatile organic compounds, and biocompounds including glucose and nucleic acids. Moreover, progress is presented in the use of derivatized thiophenes as functional monomers for preparation of molecularly imprinted polymers (MIPs) for chemosensing. Thanks to the range of synthetic procedures developed for preparation of derivatized PTs, these electronically conducting polymers have served as excellent recognition units for fabricating highly sensitive and selective chemosensors for target analytes. 相似文献
88.
Vanessa H. Fragal Elizngela H. Fragal Tao Zhang Xiaoxi Huang Thelma Sley P. Cellet Guilherme M. Pereira Andrei Jitianu Adley F. Rubira Rafael Silva Tewodros Asefa 《Advanced functional materials》2019,29(8)
In this work, the synthesis of high‐performance, metal ion‐imprinted, mesoporous carbon electrocatalysts for hydrazine oxidation reaction (HzOR) using casein or a family of phosphoproteins derived from cow's milk as a precursor is shown. The synthesis is made possible by mixing trace amounts of non‐noble metal ions (Fe3+ or Co2+) with casein and then producing different metal ions‐functionalized casein intermediates, which upon carbonization, followed by acid treatment, lead to metal ion‐imprinted catalytically active sites on the materials. The materials effectively electrocatalyze HzOR with low overpotentials at neutral pH and exhibit among the highest electrocatalytic performances ever reported for carbon catalysts. Their catalytic activities are also better than the corresponding control material, synthesized by carbonization of pure casein and other materials previously reported for HzOR. This work demonstrates a novel synthetic route that transforms an inexpensive protein to highly active carbon‐based electrocatalysts by modifying its surfaces with trace amounts of non‐noble metals. The types of metal ions employed in the synthesis are found to dictate the electrocatalytic activities of the materials. Notably, Fe3+ is found to be more effective than Co2+ in helping the conversion of casein into more electrocatalytically active carbon materials for HzOR. 相似文献
89.
Lukuan Liu Chengyong Dong Xinwei Li Senwu Li Baofu Ma Baofeng Zhao Xiao Li Zhen Liang Kaiguang Yang Lihua Zhang Yukui Zhang 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(7)
The selective and highly efficient capture of circulating tumor cells (CTCs) from blood and their subsequent release without damage are very important for the early diagnosis of tumors and for understanding the mechanism of metastasis. Herein, a universal strategy is proposed for the fabrication of an antibody‐free hydrogel that has a synergistic effect by featuring microinterfaces obtained by cell imprinting and molecular recognition conferred by boronate affinity. With this artificial antibody, highly efficient capture of human hepatocarcinoma SMMC‐7721 cells is achieved: as many as 90.3 ± 1.4% (n = 3) cells are captured when 1 × 105 SMMC‐7721 cells are incubated on a 4.5 cm2 hydrogel, and 99% of these captured cells are subsequently released without any loss of proliferation ability. In the presence of 1000 times as many nontarget cells, namely, leukaemia Jurkat cells, the SMMC‐7721 cells can be captured with an enrichment factor as high as 13.5 ± 3.2 (n = 3), demonstrating the superior selectivity of the artificial antibody for the capture of the targeted CTCs. Most importantly, the SMMC‐7721 cells can be successfully captured even when spiked into whole blood, indicating the great promise of this approach for the further molecular characterization of CTCs. 相似文献
90.
Molecularly imprinting of polymeric nucleophilic catalysts containing 4-alkylaminopyridine functions
Imidazole group of histidine residue is the essential catalytic group in the active site of a hydrolase protein. However, the imidazole is usually replaced with more nucleophilic 4-(N,N-dimethylamino)pyridines in organic syntheses. In order to introduce the supernucleophilic 4-dialkylaminopyridines into a catalytic site, a polymeric catalyst containing pyrrolidinopyridine moiety, is synthesized by imprinting of the bulk polymer with the transition state analogue of a substrate, accelerates the substrate-specific hydrolysis of p-nitrophenyl acetate. The results show that TSA-imprinted polymer containing 4-alkylaminopyridine groups is better than imidazole-appended polymer in artificial enzyme activity. 相似文献