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   245篇
  免费   24篇
  国内免费   1篇
化学工业   13篇
金属工艺   3篇
机械仪表   6篇
建筑科学   16篇
矿业工程   1篇
能源动力   14篇
轻工业   69篇
水利工程   7篇
石油天然气   1篇
无线电   25篇
一般工业技术   46篇
冶金工业   10篇
原子能技术   2篇
自动化技术   57篇
  2023年   6篇
  2022年   10篇
  2021年   18篇
  2020年   14篇
  2019年   22篇
  2018年   18篇
  2017年   19篇
  2016年   21篇
  2015年   10篇
  2014年   15篇
  2013年   25篇
  2012年   10篇
  2011年   21篇
  2010年   8篇
  2009年   11篇
  2008年   5篇
  2007年   6篇
  2006年   1篇
  2005年   1篇
  2004年   3篇
  2003年   1篇
  2002年   2篇
  2001年   2篇
  1998年   4篇
  1997年   2篇
  1996年   3篇
  1995年   1篇
  1994年   2篇
  1991年   1篇
  1990年   1篇
  1989年   2篇
  1982年   2篇
  1981年   1篇
  1979年   1篇
  1977年   1篇
排序方式: 共有270条查询结果,搜索用时 15 毫秒
71.
The effects of osmotic (OP), ultrasound-assisted osmotic pretreatment (UAOP) and frying conditions on quality and storage stability of vacuum fried pumpkin chips were investigated. The pumpkin samples were pretreated in maltodextrin solution and subsequently fried at different temperatures (90–110 °C) and time periods (10–30 min). The results demonstrated that the moisture content, water activity, lightness, yellowness and carotenoid content of the fried chips decreased, while oil content, hardness and a* (dark brown colour) value increased with increasing frying temperature and time. UAOP reduced about 16.0% of oil absorption and enhanced approximately 70% of carotenoid retention in the fried chips. UAOP samples were also more stable during storage than the untreated ones, indicated by lower degradation kinetics constants of key quality parameters. The proposed pretreatment could be an effective method for food industries to develop vacuum fried pumpkin chips with improved quality and stability.  相似文献   
72.
73.
Spring wheat varieties were subjected to physico-chemical, mixographic and amino acid analysis. The data obtained was subjected statistically analyzed. The cluster analysis classification based on centroid method indicated that for lysine and overall cookie scores, generally most wheat varieties fell in one group, while for total chapati score most of the wheat varieties were classified into two groups. The wheat varieties falling in same cluster group have similarities in respect of lysine, chapati and cookie quality. This indicated that wheat varieties in Pakistan have narrow ranges of spectrum in their genetic make up for their quality attributes. However, some wheat varieties were distinguished into different groups having a wide distance range especially Shahkar 95 for lysine content, LU 26 and Punjab 96 for cookie quality and Punjnad 88 in case of chapati quality. The present grouping suggests that wheat varieties in cluster group with wider range for lysine content may be used further in a hybridization program to improve the nutritional quality of wheat.  相似文献   
74.
Magnetorheological Abrasive Honing (MRAH) is a recently developed process to finish engineering surfaces. The process makes use of a magnetically stiffened abrasive-mixed magnetorheological fluid as the flexible tool and rotation-cum-reciprocation movements between the finishing medium and the workpiece surface for providing finishing action. In the present work, a finite element analysis with Mechanical/Emag module of ANSYS is performed to understand the nature of magnetic field developed in the process and verification is done with actual measurements. Considering the simulated magnetic field, a model to predict final roughness value (R a ) is developed. The model, when applied for different work materials and various process parameters, such as magnetic flux density, process duration and workpiece rotation, yields results that are in good agreement with experimental results.  相似文献   
75.
Food contagion with aflatoxins is the modern concern and has received a great awareness during the last few decades. The intermittent incidence of these toxins in agricultural commodities has negative role on the economy of the affected regions where harvest and postharvest techniques for the prevention of mold growth, are seldom practiced. Aflatoxins are difuranocoumarin derivatives produced by a polyketide pathway by the fungus Aspergillus flavus and Aspergillus parasiticus via polyketide pathway which are highly hepatotoxic, hepatocarcinogenic, teratogenic, and mutagenic in nature and contaminate a wide variety of important agricultural commodities before, during, and after harvest in various environmental conditions. The production of aflatoxins in innate substrates depends upon the various factors, that is, type of substrate, fungal species, moisture contents of the substrate, minerals, humidity, temperature, and physical damage of the kernels. These toxins cause several ailments such as cancer, hepatitis, mutation abnormalities, and reproduction disorders. Minimization and inactivation of aflatoxins contaminants through proper crop management at farm level and with physical, chemical, and biological techniques are the limelight of the article.  相似文献   
76.
Soil corrosivity is considered to be a major factor for the deterioration of metallic water mains. Using a 10-point scoring method as suggested by the American Water Works Association, soil corrosivity potential can be estimated by five soil properties: (1) resistivity; (2) pH value; (3) redox potential; (4) sulfide; and (5) percentage of clay fines. However, the relationship between soil corrosivity and pipe deterioration is often ambiguous and not well-defined. In order to identify the direct relationship between soil properties and pipe deterioration, which is defined as the ratio of the maximum pit depth to pipe age, predictive data mining approaches are investigated in this study. Both single- and multipredictor based approaches are employed to model such relationship. The advantage of combining multiple predictors is also demonstrated. Among all approaches, rotation forest achieves the best result in terms of the prediction error to estimate pipe deterioration rate. Compared to the random forest method, which is next to the best, the normalized mean square error decreased 50%. With the proposed approaches, the assessment of pipe condition can be achieved by analyzing soil properties. This study also highlights the importance for collecting more reliable soil properties data.  相似文献   
77.
78.
Evaluation of wheat cultivars from different eras allows scientists to determine changes in agronomic and end-use quality characteristics associated with grain yield and end-use quality improvement over time. Forty-four spring wheat cultivars introduced or released since 1933 were evaluated for quality improvement using canonical variant analysis. It was observed that there was a considerable improvement in protein content from 1933 to 1964 whereas the genetic potential for straight grade flour protein from 11.34% in 1933–1964 to 12.13% in 1991–1996. Crude protein increased by 6.95% from 1933 to 1996. Ash content and flour yield declined by 9.55% and 5.51%, respectively. Total chapati scores of modern cultivars were 8.97% higher than those of cultivars grown earlier. The average spread ratio and overall cookie scores increased almost 5.53% and 4.44%, respectively from 1933 to 1996. It was also observed that overall cookie scores were highest during the period 1981–1990. The average dry gluten and total chapati scores of varieties grown since 1991 were approximately 10.20% and 74.72% respectively, which were 4.72% and 8.97% higher than those of cultivars grown since 1933. Average spread ratio and overall cookie scores increased almost 5.53% and 4.44% from 1933 to 1996, respectively. The era (1991–1996) containing the modern varieties showed a substantial improvement in lysine content than the era containing the oldest wheat varieties. Similarly amino acid score was also found to be 4.26% higher than the varieties released during the period 1933–1964.  相似文献   
79.
We present the design analysis of a point focused electron beam emitter using numerical techniques. Simulation and modeling were performed followed by the calculation of emission parameters using programming codes EGUN and CST-PS. Beam emittance, average current density and perveance were calculated and are in agreement with the experimental values obtained at 10 kV acceleration potential. The emission parameters were evaluated up to 110 kV. This confirms possibilities of potential application of emitter for a linear accelerator.  相似文献   
80.
Clean Technologies and Environmental Policy - Modular construction has become exceedingly relevant against the current scenario of increasing housing demand and can respond to this need in Canada...  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