全文获取类型
收费全文 | 383篇 |
免费 | 147篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 2篇 |
综合类 | 5篇 |
化学工业 | 398篇 |
金属工艺 | 1篇 |
机械仪表 | 1篇 |
建筑科学 | 9篇 |
能源动力 | 2篇 |
轻工业 | 5篇 |
石油天然气 | 1篇 |
无线电 | 42篇 |
一般工业技术 | 58篇 |
冶金工业 | 2篇 |
原子能技术 | 6篇 |
自动化技术 | 1篇 |
出版年
2023年 | 6篇 |
2022年 | 10篇 |
2021年 | 37篇 |
2020年 | 30篇 |
2019年 | 20篇 |
2018年 | 27篇 |
2017年 | 28篇 |
2016年 | 27篇 |
2015年 | 24篇 |
2014年 | 40篇 |
2013年 | 50篇 |
2012年 | 21篇 |
2011年 | 22篇 |
2010年 | 19篇 |
2009年 | 33篇 |
2008年 | 20篇 |
2007年 | 21篇 |
2006年 | 17篇 |
2005年 | 15篇 |
2004年 | 15篇 |
2003年 | 8篇 |
2002年 | 7篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1951年 | 1篇 |
排序方式: 共有533条查询结果,搜索用时 15 毫秒
131.
卤代有机污染物(HOCs)在水环境中检出频率高达45%,由于其具有毒性大、持久性强和易累积等特点,该类污染物引发的环境问题已引起越来越多的关注。可见光催化技术具有高效太阳能利用率、强选择性及反应条件温和、处理费用低等优点,对于降解水中HOCs具有独特的处理优势,因此近年来被广泛研究。本文梳理了可见光催化降解水中HOCs的核心脱卤机制,包括氧化脱卤、还原脱卤和水解脱卤,在脱卤机制的基础上汇总了三大类主流催化剂的脱卤贡献率,主要包括金属基光催化剂、碳基光催化剂及其他新型光催化剂三类光催化材料。基于可见光作用下降解水中HOCs的应用案例分析,探讨了光催化反应过程中的主要影响因素是溶液pH、催化剂用量及反应温度等。可见光催化降解去除效率高是本技术的核心优势,但由于催化剂的成本高和选择性差导致了其无法大规模应用,未来可见光催化材料设计应向成本低廉、精准匹配污染物从而实现高选择性的方向改进。 相似文献
132.
Fabian Hogenkamp Fabienne Hilgers Nora Lisa Bitzenhofer Vera Ophoven Mona Haase Dr. Claus Bier Dr. Dennis Binder Prof. Dr. Karl-Erich Jaeger Dr. Thomas Drepper Prof. Dr. Jörg Pietruszka 《Chembiochem : a European journal of chemical biology》2022,23(1):e202100467
Photocaged compounds are applied for implementing precise, optochemical control of gene expression in bacteria. To broaden the scope of UV-light-responsive inducer molecules, six photocaged carbohydrates were synthesized and photochemically characterized, with the absorption exhibiting a red-shift. Their differing linkage through ether, carbonate, and carbamate bonds revealed that carbonate and carbamate bonds are convenient. Subsequently, those compounds were successfully applied in vivo for controlling gene expression in E. coli via blue light illumination. Furthermore, benzoate-based expression systems were subjected to light control by establishing a novel photocaged salicylic acid derivative. Besides its synthesis and in vitro characterization, we demonstrate the challenging choice of a suitable promoter system for light-controlled gene expression in E. coli. We illustrate various bottlenecks during both photocaged inducer synthesis and in vivo application and possibilities to overcome them. These findings pave the way towards novel caged inducer-dependent systems for wavelength-selective gene expression. 相似文献
133.
Production of sulfonated polyetheretherketone/polypropylene fibers for photoactive textiles
下载免费PDF全文
![点击此处可从《应用聚合物科学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ville Mylläri Enrico Fatarella Marco Ruzzante Rebecca Pogni Maria Camilla Baratto Mikael Skrifvars Seppo Syrjälä Pentti Järvelä 《应用聚合物科学杂志》2015,132(39)
New photocatalytic fibers made of sulfonated polyetheretherketone (SPEEK)/polypropylene (PP) are melt compounded and melt spun, first on laboratory scale and then on a semi‐industrial scale. Fiber spinnability is optimized and the fibers are characterized using mechanical testing, electron paramagnetic resonance (EPR) spectroscopy, and scanning electron microscopy (SEM). According to the results, the fiber spinnability remains at a good level up to 10 wt % SPEEK concentration. Optimal processing temperature is 200°C due to the thermal degradation at higher temperatures. EPR measurements show good and long‐lasting photoactivity after the initial irradiation but also decay in the radical intensity during several irradiation cycles. Mechanical tenacity of the SPEEK/PP 5:95 fiber is approximately 20% lower than for otherwise similar PP fiber. The fiber is a potential alternative to compete against TiO2‐based products but more research needs to be done to verify the real‐life performance. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42595. 相似文献
134.
Development of a conjugated polyaniline incorporated electrospun poly(vinylidene fluoride‐co‐hexafluoropropylene) composite membrane electrolyte for high performance dye‐sensitized solar cells
下载免费PDF全文
![点击此处可从《应用聚合物科学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Vijayakumar Elayappan Vignesh Murugadoss Subramania Angaiah Zhaofu Fei Paul J. Dyson 《应用聚合物科学杂志》2015,132(45)
Different weight percentage (2, 3, 4, and 5 wt %) of polyaniline (PANI) were incorporated into electrospun poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVdF‐HFP) composite membranes (esCPMs). The regular morphology, molecular structure, crystallinity, porosity, electrolyte uptake, and leakage of the composite membranes were examined. The esCPMs were activated in liquid electrolyte containing 0.5 M LiI, 0.05 M I2, and 0.5 M 4‐tert‐butylpyridine and 0.5 M 1‐butyl‐3‐methylimidazoliun iodide in acetonitrile to afford electrospun PVdF‐HFP/PANI composite membrane electrolytes (esCPMEs). The influence of different wt % of PANI on the esCPMEs was studied by electrochemical impedance measurements and Tafel polarization studies. The photovoltaic performance of a dye‐sensitized solar cell assembled using 3 wt % PANI incorporated esCPME exhibits a higher power conversion efficiency of 7.20% than that assembled using esPME (η = 6.42%). © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42777. 相似文献
135.
The effect of depth and duration of UV radiation on polypropylene modification via photoinitiation
下载免费PDF全文
![点击此处可从《应用聚合物科学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Linear polypropylene (PP) was modified using UV radiation in the presence of 0.5 wt % of benzophenone photoinitiator to introduce long chain branching (LCB) to the PP backbone. Irradiation was carried out in the solid state and the temperature level was kept below 60°C. The effects of radiation duration and sample thickness on the extent of these branching modification reactions were investigated. Viscoelastic properties, molecular weight, molecular weight distribution, and gel content were determined and compared for runs having different sample thicknesses, irradiated for different times. Comparisons were also conducted with the parent PP and the PP mixed with photoinitiator. It was found that LCB decreased by increasing the thickness of the samples. Conversely, an increase in radiation duration resulted in enhanced LCB but also led to larger gel content in the samples. Based on all these measurements and observations, a mechanism was suggested to explain formation of long chain branches (LCBs) in PP in the solid state via photoinitiation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41021. 相似文献
136.
Xirali Mamtimin Abduwasit Tursun Rukiya Matsidik Sayyare Sidik Kamarnisa Abdulla Hayrulla Mamut Ablikim Obulda Ismayil Nurulla 《应用聚合物科学杂志》2014,131(23)
A new type of low‐molecular‐weight polypyrimidine in a π‐conjugated main chain was prepared by a Grignard reaction between 2‐amino‐4,6‐dichloropyrimidine and 1,4‐dibromo‐2,5‐didodecyloxybenzene in the presence of [1,2‐Bis(diphenylphosphino) ethane]dichloronickel(II). The structure of the copolymer was fully elucidated by Fourier transform infrared spectroscopy, 1H‐NMR, and elemental analysis. The copolymer had good solubility in common organic solvents. The copolymer displayed a bathochromic shift when protonated with an organic or inorganic acid in chloroform or tetrahydrofuran. The copolymer depicted facile p‐doping and good electron‐transporting electrochemical properties in a 1M H2SO4 aqueous solution. The copolymer showed a narrow polydispersity of 1.04. Thermogravimetric analysis showed that the copolymer had a certain thermal stability with no decomposition at a temperature of 250°C under N2. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41174. 相似文献
137.
Composites containing 50% wt fly ash (sourced from the UK and South Africa) in polypropylene homopolymer (manufacturer stabilized for general purpose use) have been prepared by using batch and continuous methods. The effect of the following coupling agents were investigated on the photo‐ and thermal‐decomposition of the composite materials: Lubrizol Solplus C800 (an unsaturated carboxylic acid), γ‐methacryloxypropyl trimethoxy silane (γ‐MPS), 1,3‐phenylene dimaleimide (BMI), and maleic anhydride‐grafted‐polypropylene (m‐PP). High melt, thermal‐, and photo‐stability was favored when the matrix was coupled to the filler surface by monomeric coupling agents that were expected to adsorb in a close packed layer on the fly ash surface. Further improvements were observed in cases where the coupling agent could also self‐polymerize. m‐PP did not lead to increased stability due to its low adsorption density on the fly ash surface. The relatively high water/acid soluble transition metal ion content of the UK sourced fly ash did not appear to affect stability under the test conditions employed in this study. The South African sourced fly ash had a higher level of quartz and mullite together with a high level of group 1 and 2 metals. The latter in particular may have led to debonding of the coupled interfacial region from the filler surface and possible adsorption of stabilizers on the pristine surface. This resulted in the South African fly ash generally possessing poorer resistance to oxidation than the UK fly ash. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39974. 相似文献
138.
Hawn‐Chung Chu Li‐Huei Lin Hsin‐Chi Liu Ho‐Fu Chen Hsin‐Jiant Liu Keng‐Ming Chen 《应用聚合物科学杂志》2009,114(1):413-419
This study uses titanium dioxide treated with calcium phosphate to prepare multilayer structure composites. These products are regarded as photocatalysts. Utilizing polyethylene glycol (PEG)–silicone polyester as an adhesive spread on matrix surfaces, this can provide these products with antifouling properties, good weather resistance, and antibacterial property. It has been observed that UV irradiation has caused changes in the film molecular structure of PEG–silicone polyesters, as well as changes in the surface morphology. These changes in molecular structure have been observed by FTIR and Raman analysis. PEG–silicone polyesters contain silicon atoms with both organic and inorganic characteristics. This makes fixation of photocatalysts possible and retards oxidation of organic materials in the polyesters. The results of FTIR and Raman spectrum analyses indicate films made of these polyesters effectively cover calcium phosphate–titanium dioxide photocatalysts, retard surface cracks, and slow down decomposition, caused by UV light. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
139.
Jianhua Liu Xiaoliang Zhang Mei Yu Songmei Li Jindan Zhang 《Small (Weinheim an der Bergstrasse, Germany)》2012,8(2):310-316
Biological scaffolds are being actively explored for the synthesis of nanomaterials with novel structures and unexpected properties. Toroidal plasmid DNA separated from the Bacillus host is applied as a sacrificial mold for the synthesis of silver nanoparticles and nanorings. The photoirradiation method is applied to reduce AgI on the plasmid. The nanoparticles are obtained by varying the concentration of the AgI ion solution and the exposure time of the plasmid–AgI complex under UV light at 254 nm and room temperature. It is found that the plasmid serves not only as a template but also as a reductant to drive the silver nucleation and deposition. The resulting nanoparticles have a face‐centered cubic (fcc) crystal structure and 20–30 nm average diameter. The detailed mechanism is discussed, and other metals or alloys could also be synthesized with this method. 相似文献
140.