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   184篇
  免费   3篇
化学工业   30篇
机械仪表   8篇
建筑科学   10篇
轻工业   91篇
水利工程   1篇
无线电   4篇
一般工业技术   25篇
冶金工业   5篇
自动化技术   13篇
  2019年   1篇
  2015年   1篇
  2014年   1篇
  2013年   34篇
  2011年   2篇
  2010年   1篇
  2009年   1篇
  2008年   1篇
  2007年   4篇
  2006年   4篇
  2005年   3篇
  2004年   5篇
  2003年   1篇
  2001年   3篇
  2000年   4篇
  1999年   4篇
  1998年   2篇
  1997年   8篇
  1996年   5篇
  1995年   4篇
  1994年   5篇
  1993年   3篇
  1991年   5篇
  1990年   4篇
  1989年   1篇
  1988年   3篇
  1987年   3篇
  1986年   4篇
  1985年   4篇
  1984年   5篇
  1983年   6篇
  1982年   4篇
  1981年   3篇
  1980年   4篇
  1979年   2篇
  1978年   6篇
  1977年   6篇
  1976年   3篇
  1975年   1篇
  1974年   2篇
  1973年   5篇
  1972年   1篇
  1971年   4篇
  1970年   3篇
  1968年   3篇
  1967年   2篇
  1966年   2篇
  1963年   1篇
  1958年   1篇
  1955年   1篇
排序方式: 共有187条查询结果,搜索用时 15 毫秒
61.
62.
63.
64.
Sensory quality and storage stability of blueberry juice blends were investigated with the goal of maintaining dominant blueberry flavor, aroma and color. Apple juice, Concord and Venus grape juices and cranberry juice cocktail were blended at 75, 50 and 25% with blueberry juice. As the percent of blueberry juice decreased, the intensity of blueberry‐related sensory attributes decreased. The 25% Concord and Venus blends were the only blends that resulted in blueberry flavor similar to the reference. Apple and cranberry juice cocktail blended with blueberry juice produced several blends with good flavor and aroma, but they were not readily characterized as blueberry juice. All blends at the 25% level produced blueberry color equal to or greater than the reference. The juice samples were evaluated initially and after three months of storage at 37C. After storage, all blends had decreased red color.  相似文献   
65.
采用Serirez AP-ZF水溶性低分子改性聚合物进行全棉织物免烫整理,既能提高织物的抗皱性,又能保证整理织物强力和降低缩水率,且不会释放出游离甲醛。通过分析焙烘温度、树脂用量等因素对织物强力和平整度的影响,确定了最优化的免烫整理工艺,即:Serirez AP-ZF140-160g/L;催化剂MC35-40g/L;有机硅柔软剂20g/L;整理液pH值5左右;100℃预烘3min;160°-170°焙烘1min。  相似文献   
66.
Juices from grape samples subjected to two storage methods (fresh and frozen) and two post-homogenisation treatments (21oC and 71oC) were examined for extraction of grape berry components and compared to a microvinified wine made from the same lot of fresh grapes. Cabernet Franc ( Vitis vinifera ) and Cynthiana ( Vitis aestivalis ) grapes were evaluated in 2003. Cabernet Franc, Cabernet Sauvignon ( Vitis vinifera ), Chambourcin (interspecific hybrid) and Cynthiana grapes were evaluated in 2004. Fresh grapes from each variety were sampled, analysed and prepared for microvinification. Frozen grapes of all varieties were thawed and analysed at the same time. For all varieties in both years, heating the must of fresh or frozen grapes increased the titratable acidity (11–58%), tartaric acid levels (12–110%), potassium content (15–62%), darkness (31–97%), red colour (54–1517%) and total red pigment values (36–1171%) of juice as compared to the juice from unheated must. For all varieties in 2004, heating the must from fresh or frozen grapes increased total phenolics (43–619%) of juice as compared to the juice from unheated must. Compared to fresh grape processing, freezing the grapes and then processing at 21oC or 71oC had varying results (increases and decreases) regarding the extraction of components in all varieties and both years but usually provided juice with composition most similar to that of the red wine produced by microvinification. Although the degree of extraction of individual components in the juice is influenced by selection of grape storage and must processing procedures, consistency of handling and procedure provided consistent results with low variability.  相似文献   
67.
Methods for the study of the stratum corneum in situ are described and their application to clinical problems and cosmetic science are discussed. In vivo measurements of the thickness of skin and the components of skin can be made using high frequency pulsed ultrasound. Improved resolution of the device should allow measurement of epidermal thickness, and even that of the stratum corneum, which may vary with hydration. The protective ability of the stratum corneum can be estimated in a number of ways, the most familiar technique being transepidermal water loss measurements. Mechanical properties of the stratum corneum have been widely investigated in vivo by numerous researchers. A recent technique devised by us to deform the stratum corneum using an extendable metal frame has been used on patients with ichthyotic disorders. The deformation or compliance of the skin surface has been measured using profilometric methods, and compared to normal individuals. The results appear to be in agreement with the loss of flexural ability experienced by ichthyotic patients. Other mechanical methods more usually involve the measurement of the forces generated by skin while undergoing extension. Three techniques are described which have been used to investigate hydrational change with emollient application. Finally, the phenomenon of desquamation is discussed and methods presented for its evaluation. Passive collection of corneocytes using chambers is useful for estimation of the rates of desquamation, but are laborious and inconvenient. Forced desquamation using the desquamator enables rapid controlled harvesting of corneocytes. In addition to this, the dansyl chloride fluorescence technique has been adopted for estimation of stratum corneum kinetics using visual comparison and fluorimetric techniques. These techniques require further refinement and validation, but the tests available now are nonetheless important in understanding the biology and pharmacology of the stratum corneum.  相似文献   
68.
A modified headspace solid phase microextraction (HS‐SPME) method was compared with Amberlite® XAD‐2 resin for the extraction of volatile compounds. In the HS‐SPME method, volatiles were extracted using an 85 μm polyacrylate fiber from wines that contained a standardized amount of ethanol (10% v/v), NaCl (0.325 g/mL) and internal standards (dodecanol and nonanoic acid). Both extraction procedures yielded high relative recoveries (>92%) and reproducibilities (coefficient of variations11%) for the different higher alcohols, esters and medium‐chain fatty acids. Overall, limits of detection for the HS‐SPME and XAD‐2 methods were below sensory threshold concentrations. HS‐SPME and XAD‐2 performed similarly in the analysis of a Riesling wine; however, the HS‐SPME method did not require organic solvents and was generally quicker to perform. In applying the HS‐SPME method, differences in concentrations of volatile compounds produced in Riesling and Chenin blanc wines by 11 different yeast strains were noted.  相似文献   
69.
The detailed analysis of highway locations that have been identified as hazardous within the framework of a state Highway Safety Improvement Program (HSIP) requires a great deal of time and money to perform. Given the limited resources available to state highway agencies, whose task it is to perform such analyses, it seems a worthwhile effort to automate this "location analysis." And, given the nature of location analysis problems, which are based on judgement rather than mathematical models, it was known a prior; that conventional automation techniques were not appropriate for this application. A prototype microcomputer-based expert system, which performs location analysis, was developed to assess the feasibility of applying this new technology to location analysis problems. This paper describes the prototype system, and presents a brief discussion of some of the issues that were addressed when building the system.  相似文献   
70.
The nature of film stresses in hot-filament chemical vapour deposited (HFCVD) diamond thin films on tungsten carbide substrates, is reported. Commercial WC substrates were subjected to various surface treatments. Subsequently, they were coated with a diamond film and examined for stresses using X-ray diffraction. All but one of the stress measurements indicated various levels of compressive stresses in the film and at the film–substrate interface. These stresses are compared with those obtained by other researchers. Intrinsic film stresses were also computed for diamond films and found to be tensile. WC drills, of 0.125 in. diameter, were also diamond coated and the stress levels measured along drill flanks and flutes. Significant variations were found in these stresses, and the results were analysed from a film–substrate adhesion perspective.  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