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   133篇
  免费   8篇
电工技术   2篇
化学工业   29篇
金属工艺   2篇
机械仪表   1篇
建筑科学   3篇
轻工业   55篇
水利工程   1篇
石油天然气   1篇
一般工业技术   15篇
冶金工业   3篇
自动化技术   29篇
  2024年   1篇
  2023年   1篇
  2022年   7篇
  2021年   11篇
  2020年   5篇
  2019年   2篇
  2018年   5篇
  2017年   6篇
  2016年   3篇
  2015年   3篇
  2014年   6篇
  2013年   9篇
  2012年   6篇
  2011年   12篇
  2010年   11篇
  2009年   9篇
  2008年   11篇
  2007年   7篇
  2006年   4篇
  2005年   3篇
  2004年   2篇
  2003年   1篇
  2002年   4篇
  2001年   4篇
  2000年   1篇
  1999年   1篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1992年   1篇
  1985年   1篇
  1968年   1篇
排序方式: 共有141条查询结果,搜索用时 15 毫秒
81.
82.
Skeletal structure and body composition may be altered permanently in response to aggressions during critical periods of growth. This increases propensity to adverse effects in adulthood. The study explored the association of anthropometric variables of body size and proportions and of body composition with systolic (SBP) and diastolic (DBP) blood pressure (BP) in young adults. We studied 166 men and 246 women age 20-34. SBP, DBP, weight, stature, sitting height, circumferences (waist, hip), breadths (biacromial, biiliac) and skinfolds (bicipital, tricipital, subscapular, suprailiac) were assessed. BMI, waist-hip ratio (WHR), waist-stature ratio, and Sigma skinfolds-stature were calculated. Pearson correlations were determined for anthropometric variables with SBP and DBP and linear regression models for SBP and DBP were developed by sex. Correlation coefficients between indicators and BP were significant, except for stature and SBP and DPB, and WHR with DBP in women; and stature with DBP, biiliac breadth and WHR with SBP, and sitting height with SBP and DPB in men. SBP and DPB were explained by weight, BMI, and biiliac breadth in multivariable analysis in women, where 15.4% and 10.8% of variance of SBP and DPB was explained. In men, SBP was explained by weight, Sigma skinfolds and WHR, and DBP by Sigma skinfolds; models explained almost 20% of SBP and DPB variance. No association was found between BP and past malnutrition indicators. Biiliac breadth, weight and BMI in women, and weight, WHR and Sigma skinfolds in men explained BP. The use of biiliac breadth in the assessment of hypertension risk in women should be explored further.  相似文献   
83.
The content of antioxidant compounds and antioxidant capacity of whole and fresh-cut mango, stored for 10 days at 12 °C and 5 °C, respectively and their influence on serum antioxidant capacity and lipid profile of normolipidemic humans were studied. Whole mango (WM) had a higher content of flavonoids, ??-carotene and antioxidant capacity, determined by oxygen radical scavenging capacity, (ORAC) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays, than the fresh-cut fruit (FCM). FCM presented higher amounts of total phenols. Thirty normolipidemic volunteers, ages 20-50 years, were randomly divided into two groups (WM and FCM) 15 persons each. During 30 consecutive days volunteers from groups 1 and 2, received daily 200 g of WM or FCM, respectively. Lipid levels and antioxidant capacity in plasma were determined at 0, 15 and 30 days of the experiment. Serum triglycerides were significantly reduced after 30 days of supplementation with WM and FCM (37 and 38% respectively); VLDL levels were reduced in a similar proportion. No significant changes in other plasma lipid levels were observed. Both treatments increased plasma antioxidant capacity measured by ORAC and TEAC methods. According to the results obtained in this study, we suggest that addition of mango fruit to generally accepted healthy diets could have a beneficial effect preventing hypertryglyceridemia, and that fresh-cut processing does not affect the beneficial properties of mango.  相似文献   
84.
Scientometrics - In the original publication of the article, the following minor errors had occurred. The corrected text has been provided in Correction.  相似文献   
85.
86.
Pharmaceuticals can exist in many solid forms, which can have different physical and chemical properties. These solid forms include polymorphs, solvates, amorphous, and hydrates. Particularly, hydration process can be quite common since pharmaceutical solids can be in contact with water during manufacturing process and can also be exposed to water during storage. In the present work, it is proved that NQR technique is capable of detecting different hydrated forms not only in the pure raw material but also in the final product (tablets), being in this way a useful technique for quality control. This technique was also used to study the dehydration process from pentahydrate to trihydrate.  相似文献   
87.
Water‐soluble copolymers of N‐acryloyl‐N‐methylpiperazine and N‐acetyl‐α‐aminoacrylic acid were synthesized by radical polymerization. The copolymerization yield ranged between 60 and 97%. The FTIR and NMR spectra demonstrated that the copolymerization occurred. The copolymer composition was determined from 1H‐NMR spectra by comparison of methyl groups from both moieties. The copolymers were richest in AAA units. The metal ion retention properties were investigated by the liquid‐phase polymer‐based retention (LPR) technique at different pH and filtration factors. The affinity for the metal ions depended on the copolymer composition, pH, and filtration factor. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2556–2561, 2002  相似文献   
88.
Honeycomb structured porous materials were formed using four different casting variations of the water droplet templating method. The film quality of the materials generated from these casting techniques (airflow, cold stage, casting on water, and emulsion methods) was investigated by altering the polymer architecture and composition. Linear, star, and comb polystyrene as well as an amphiphilic diblock copolymer comprised of polystyrene-block-poly(dimethylacrylamide) (PS-b-PDMA) were previously synthesized and cast into films via these techniques. While irregular pore distributions were observed for linear polystyrene films generated by every technique screened, increasing the architectural complexity of the polymer yielded more regular films for a broad range of casting conditions for each of the techniques. With the exception of linear polystyrene, the airflow casting technique was shown to be the only technique capable of generating regular porous films for all of the polymeric materials.  相似文献   
89.
90.
This work presents the results of an evaluation of the deterioration of cryogenic toughness by means of an electrochemical method in a N-containing austenitic stainless steel (JK2) aged at temperatures of 700, 800 and 900 °C for times from 10 to 1000 min. The aging process at 700 and 800 °C caused the decrease in the Charpy V-Notch impact energy at ? 196 °C because of the intergranular precipitation of carbides. Scanning electron micrographs of the Charpy V-Notch test specimens showed the presence of intergranular brittle fracture. The degree of sensitization was determined by the ratio of the maximum current density generated by the reactivation scan to that of the anodic scan, Ir/Ia, using the double-loop electrochemical potentiokinetic reactivation test. The Charpy V-Notch impact energy decreased with increase in the Ir/Ia ratio. This relation permits an estimate of the deterioration of cryogenic toughness due to thermal aging in this type of steel.  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