全文获取类型
收费全文 | 306篇 |
免费 | 30篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 16篇 |
化学工业 | 85篇 |
金属工艺 | 8篇 |
机械仪表 | 3篇 |
建筑科学 | 15篇 |
矿业工程 | 1篇 |
能源动力 | 26篇 |
轻工业 | 31篇 |
水利工程 | 1篇 |
石油天然气 | 4篇 |
无线电 | 41篇 |
一般工业技术 | 65篇 |
冶金工业 | 11篇 |
自动化技术 | 32篇 |
出版年
2023年 | 10篇 |
2022年 | 9篇 |
2021年 | 19篇 |
2020年 | 14篇 |
2019年 | 14篇 |
2018年 | 17篇 |
2017年 | 32篇 |
2016年 | 17篇 |
2015年 | 9篇 |
2014年 | 23篇 |
2013年 | 32篇 |
2012年 | 27篇 |
2011年 | 32篇 |
2010年 | 18篇 |
2009年 | 11篇 |
2008年 | 14篇 |
2007年 | 5篇 |
2006年 | 9篇 |
2005年 | 5篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 5篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1993年 | 1篇 |
1989年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有339条查询结果,搜索用时 15 毫秒
331.
Cheng Shiyu Pahlavan Kaveh Wei Haowen Su Zhuoran Zekavat Seyed Reza Abedi Ali 《International Journal of Wireless Information Networks》2022,29(3):222-231
International Journal of Wireless Information Networks - This paper presents an empirical analysis of the mutual interference between the IEEE 802.11ad communication link and the Texas Instruments... 相似文献
332.
The increasing trend of sustainability (single-use packaging), safety (fresh consumption), and convenience (processing and application) in packaging science has created a high demand for packaging materials with advanced functions. Thus, the challenges involved with conventional active packaging, for example, migration, low efficiency, upscaling difficulty, safety, and regulations should be addressed through an industrial scalable method, such as photografting coating. Photografting coating, which involves a strong surface covalent linkage, can be employed for preparing novel “non-migratory” active packaging systems with strong antimicrobial and self-cleaning, antifouling and self-defensive, metal chelating as antioxidant, free-radical scavenging as antioxidant, biocatalytic, and easy printing properties. Herein, profound insights into the technique of photografting coating are provided, with a focus on its application potential in non-migratory active packaging. The scientific explanation for the photografting coating technique and its application feasibility are illustrated to introduce its potential to confer new functions onto packaging materials. Furthermore, the recent progress, application functions, process, and safety challenges, as well as future directions of photografting coating in the preparation of non-migratory active packaging systems are explored in detail. 相似文献
333.
Engineering with Computers - Simulated annealing (SA) algorithms are capable of solving discrete and continuous problems. However, they are less efficient than other algorithms in solving applied... 相似文献
334.
Rostampour B. Seifzadeh D. Abedi M. Shamkhali A. N. 《Protection of Metals and Physical Chemistry of Surfaces》2020,56(1):233-244
Protection of Metals and Physical Chemistry of Surfaces - In this study, a new N4S2 Schiff base compound based on [2-({2-[(2-aminophenyl)thio]ethyl}thio)phenyl] amine and pyridine-2-carboxaldehyde... 相似文献
335.
Abbasi H Hamedi MM Lotfabad TB Zahiri HS Sharafi H Masoomi F Moosavi-Movahedi AA Ortiz A Amanlou M Noghabi KA 《Journal of Bioscience and Bioengineering》2012,113(2):211-219
An extensive investigation was conducted to isolate indigenous bacterial strains with outstanding performance for biosurfactant production from different types of spoiled fruits, food-related products and food processing industries. An isolate was selected from 800 by the highest biosurfactant yield in soybean oil medium and it was identified by 16S rRNA and the two most relevant hypervariable regions of this gene; V3 and V6 as Pseudomonas aeruginosa MA01. The isolate was able to produce 12 g/l of a glycolipid-type biosurfactant and generally less efficient to emulsify vegetable oils compared to hydrocarbons and could emulsify corn and coconut oils more than 50%. However, emulsification index (E(24)) of different hydrocarbons including hexane, toluene, xylene, brake oil, kerosene and hexadecane was between 55.8% and 100%. The surface tension of pure water decreased gradually with increasing biosurfactant concentration to 32.5 mNm(-1) with critical micelle concentration (CMC) value of 10.1mg/l. Among all carbon substrates examined, vegetable oils were the most effective on biosurfactant production. Two glycolipid fractions were purified from the biosurfactant crude extracts, and FTIR and ES-MS were used to determine the structure of these compounds. The analysis indicated the presence of three major monorhamnolipid species: R(1)C(10)C(10), R(1)C(10)C(12:1), and R(1)C(10)C(12); as well as another three major dirhamnolipid species: R(2)C(10)C(10), R(2)C(10)C(12:1), and R(2)C(10)C(12). The strain sweep experiment for measuring the linear viscoelastic of biosurfactant showed that typical behavior characteristics of a weak viscoelastic gel, with storage modulus greater than loss modulus at all frequencies examined, both showing some frequency dependence. 相似文献
336.
A new insight into the stability of variable viscosity diffusive boundary layers in porous media under gravity field 下载免费PDF全文
Nasser Sabet Hassan Hassanzadeh Jalal Abedi 《American Institute of Chemical Engineers》2018,64(3):1083-1094
We study the stability of gravitationally unstable transient diffusive boundary layers with variable viscosity in porous media. The previous studies characterize the effect of viscosity variation only in terms of viscosity contrast and generalize their findings. However, conclusions of different studies seem contradictory. Our results demonstrate that stability of diffusive fronts is governed by the boundary layer viscosity and not solely by the viscosity contrast. In other words, the use of viscosity contrast to ascertain the stability of the system cannot be generalized. Nonlinear simulations are conducted based on a finite difference scheme to validate the results of linear stability analysis for which the amplification theory is adopted. We also revisit other available scaling approaches used to characterize the effect of viscosity variation on the onset of convective dissolution and explain why previously made conclusions are not inclusive and sometimes appeared to be contradictory. A critical Rayleigh number is found to predict stability of Rayleigh‐Darcy convection in a porous layer with variable viscosity. The results reveal that this critical value can differ highly from the conventional value of 4π2. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1083–1094, 2018 相似文献
337.
338.
Preparation of high surface area activated carbon from corn by chemical activation using potassium hydroxide 总被引:2,自引:0,他引:2
Activated carbons were prepared through chemical activation of corn cob precursor, using potassium hydroxide as the chemical agent. The effect of different parameters, such as particle size, method of mixing, chemical/corn ratio, activation time and activation temperature, on weight loss and BET surface area of the produced activated carbons were discussed. The porosity of the activated carbons was evaluated through nitrogen adsorption. The storage capacity of the activated carbon was evaluated using natural gas. Under the experimental conditions investigated, the optimal conditions for production of high surface area carbons by chemical activation were identified. The results were compared with commercial activated carbons from coal. 相似文献
339.
In holometabolous development, higher insects have two different life forms, the larva and the imago. Both larval and imaginal cells are derived from cells of the blastoderm stage. After the final embryonic wave of mitosis, however, only the imaginal cells remain diploid, proliferate massively and do not differentiate until metamorphosis. The separation of these two pathways was described by many authors as a fundamental process that must take place at a very early stage of development, most probably the blastoderm stage. Mainly by using single cell transplantations at the blastoderm or early gastrula stages, respectively, we found common cell lineages between larval and imaginal structures by clones overlapping in the ectoderm (i.e. larval epidermal cells and imaginal discs within a segment, or larval and imaginal salivary gland cells), the mesoderm (i.e. larval somatic muscles and adepithelial cells), and the endoderm (i.e. larval and imaginal midgut cells). From these findings we conclude that it seems to be a principle in Drosophila embryogenesis that the separation of larval and imaginal pathways is postponed to a later developmental stage. 相似文献