首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   137篇
  免费   10篇
化学工业   12篇
金属工艺   4篇
机械仪表   2篇
建筑科学   1篇
矿业工程   1篇
能源动力   7篇
轻工业   18篇
无线电   34篇
一般工业技术   38篇
冶金工业   17篇
自动化技术   13篇
  2023年   1篇
  2022年   2篇
  2021年   3篇
  2020年   3篇
  2019年   2篇
  2018年   8篇
  2017年   1篇
  2016年   6篇
  2015年   2篇
  2014年   5篇
  2013年   8篇
  2012年   4篇
  2011年   10篇
  2010年   12篇
  2009年   16篇
  2008年   11篇
  2007年   3篇
  2006年   4篇
  2005年   5篇
  2004年   1篇
  2002年   4篇
  2000年   2篇
  1999年   4篇
  1998年   4篇
  1997年   4篇
  1996年   2篇
  1995年   1篇
  1994年   3篇
  1993年   1篇
  1992年   1篇
  1991年   2篇
  1989年   1篇
  1987年   1篇
  1986年   2篇
  1983年   4篇
  1982年   1篇
  1980年   1篇
  1977年   1篇
  1955年   1篇
排序方式: 共有147条查询结果,搜索用时 0 毫秒
41.
42.
43.
The effect of preheat temperature (63 or 77 °C for 30 s; final heat 120 °C for 30 s) and casein to whey protein ratio on the physical characteristics of 3.3%, w/w, dairy protein beverages was investigated. Dispersions preheated at 77 °C had lower viscosity than dispersions preheated at 63 °C. Casein‐containing dispersions had significantly lower levels of α‐lactalbumin denaturation than whey protein‐only dispersions. A higher proportion of casein improved the thermal stability of protein dispersions. Overall, alteration of preheat temperature and casein to whey protein ratio can influence dairy beverage quality, with increasing levels of casein reducing physical changes due to heat treatment.  相似文献   
44.
45.
Hybrid bulk heterojunction solar cells based on nanocrystalline TiO2 (nc‐TiO2) nanorods capped with trioctylphosphine oxide (TOPO) and regioregular poly(3‐hexylthiophene) (P3HT) are processed from solution and characterized in order to relate the device function (optical absorption, charge separation, and transport and photovoltaic properties) to active‐layer properties and device parameters. Annealing the blend films is found to greatly improve the polymer–metal oxide interaction at the nc‐TiO2/P3HT interface, resulting in a six‐fold increase of the charge separation yield and improved photovoltaic device performance under simulated solar illumination. In addition, the influence of the organic ligand at the nc‐TiO2 particle surface is found to be crucial for charge separation. Ligand‐exchange procedures applied on the TOPO‐capped nc‐TiO2 nanorods with an amphiphilic ruthenium‐based dye are found to further improve the charge‐separation yield at the polymer–nanocrystal interface. However, the poor photocurrents generated in the hybrid blend devices, before and after ligand exchange, suggest that transport within or between nanoparticles limits performance. By comparison with other donor–acceptor bulk heterojunction systems, we conclude that charge transport in the nc‐TiO2:P3HT blend films is limited by the presence of an intrinsic trap distribution mainly associated with the nc‐TiO2 particles.  相似文献   
46.
J. Carlopio et al (see record 1983-31564-001) criticized several aspects of the present authors' (see record 1982-12761-001) procedures and conclusions in a study of S roles and contended that the entire "subject role" approach is misguided. In this reply, the merits of the arguments and follow-up study of Carlopio et al are considered along with the "alternative" conception of S behavior they proposed. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
47.
48.
为了发现高效的光动力药物.以焦脱镁叶绿酸a衍生物为母体,通过酰胺反应引入氨基苯并吩噁嗪盐酸盐,制得苯并吩噁嗪叶绿素衍生物(PTM);采用1 H NMR、MS对其结构进行表征;用紫外-可见光谱、荧光发射光谱对其光学性能进行表征;用DPBF法测定了单线态氧生成速率;用MTT法测定了化合物光动力抗肿瘤活性.该化合物的紫外-可...  相似文献   
49.
Efficient ethanol production from lignocellulosic biomass requires highly degradable feedstock; therefore, there is a similarity between forage crop production for ruminant animals and ethanol production from lignocellulosic biomass. Feed value analysis techniques may be used to estimate lignocellulosic biomass quality. Because lignin and its derivatives in cell walls are major compounds interrupting biomass degradation, fiber analysis and in vitro incubation tests were conducted with switchgrass (Panicum virgatum) and energycane (Saccharum spp.) biomass collected at 100 and 120 g lignin (acid detergent lignin) kg?1 DM (dry matter). Mean NDF (neutral detergent fiber) in switchgrass was consistently greater than that of energy cane regardless of lignin levels, while ADF (acid detergent fiber) did not differ. Mean of energycane in vitro true digestibility and digestible neutral detergent fiber were greater than those of switchgrass. The ADF and ruminal fermentation rate averaged by lignin levels differed, while most of the analysis results did not. Based on ADF and NDF concentrations, switchgrass contained a greater concentration of hemicellulose than energycane, while cellulose concentration was similar. Fermentability of energycane was consistently greater than that of switchgrass. Fermentation gas volume was positively correlated with cellulosic biomass degradation for ethanol production. Consequently, fermentation gas kinetic parameters obtained from biomass fermentation with rumen fluid or with yeast indicate that the fermentable pool size is the parameter most closely correlated to ethanol production potential across the species. Results obtained from feed value analyses demonstrate fermentation variability and meaningful relationships between fermentation gas parameters and ethanol production. Thus, the ruminal fermentation process is useful as a screening tool for ethanol production potential of biofuel feedstock. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
50.
Materials in which sub‐wavelength physical structures, rather than variations in chemical composition, are used to modify the nature of their interaction with electromagnetic radiation form the promising new class of metamaterials. For molecular materials one has an intriguing alternative, namely structuring the conformation or physical geometry of the molecule. In order for this to be an effective methodology one needs the change in conformation i) to engender a significant change in electromagnetic properties and ii) to be spatially controllable to allow patterning of practical structures. In this paper the potential of such an approach is demonstrated through spatial patterning, via masked solvent vapor exposure, of the β‐phase conformation in poly(9,9‐dioctylfluorene) (PFO). Significantly the conformation change approach preserves a planar film format and is found not to negatively impact on optical gain properties, both very attractive features for optoelectronic and photonic lightwave circuit applications. As a specific demonstration the ability to spatially control the lasing wavelength for samples in which a β‐phase conformation is selectively patterned in a glassy PFO film spin coated atop a one‐dimensional distributed‐feedback grating etched into a spectrosil substrate is shown.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号