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   42114篇
  免费   2337篇
  国内免费   119篇
电工技术   479篇
综合类   235篇
化学工业   10387篇
金属工艺   778篇
机械仪表   917篇
建筑科学   1494篇
矿业工程   112篇
能源动力   1343篇
轻工业   6822篇
水利工程   362篇
石油天然气   225篇
武器工业   6篇
无线电   2849篇
一般工业技术   6058篇
冶金工业   6827篇
原子能技术   281篇
自动化技术   5395篇
  2024年   89篇
  2023年   330篇
  2022年   1396篇
  2021年   1823篇
  2020年   962篇
  2019年   1027篇
  2018年   1177篇
  2017年   1276篇
  2016年   1294篇
  2015年   1025篇
  2014年   1484篇
  2013年   2360篇
  2012年   2118篇
  2011年   2629篇
  2010年   1934篇
  2009年   1975篇
  2008年   1789篇
  2007年   1614篇
  2006年   1270篇
  2005年   1184篇
  2004年   1237篇
  2003年   1127篇
  2002年   1066篇
  2001年   860篇
  2000年   665篇
  1999年   678篇
  1998年   2156篇
  1997年   1450篇
  1996年   1039篇
  1995年   685篇
  1994年   537篇
  1993年   600篇
  1992年   291篇
  1991年   327篇
  1990年   272篇
  1989年   230篇
  1988年   240篇
  1987年   195篇
  1986年   204篇
  1985年   222篇
  1984年   167篇
  1983年   117篇
  1982年   134篇
  1981年   141篇
  1980年   136篇
  1979年   116篇
  1978年   97篇
  1977年   154篇
  1976年   235篇
  1975年   96篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
Alcohol-free beer with isotonic properties is getting more popular and its production can be carried out by different production strategies; however, interrupted fermentation is still a challenge. Therefore, the objective of this study was to develop a low-alcohol isotonic beer (<0.5% v/v) by interrupted fermentation. Moreover, the major objective is to compare the developed product to commercial beverages (sports drinks, ‘Pilsen' regular beer, alcohol-free beers and low-alcohol isotonic beer). The beverages were evaluated based on pH, alcohol content (% v/v), total titratable acidity (mEq L−1), osmolality (mOsmol kg−1), bitterness International Bitterness Units, colour European Brewery Convention, total phenolic compounds (mg L−1 gallic acid), reducing and total sugars (%) and Na and K contents (mg L−1). The developed low-alcohol isotonic beer presented characteristics similar to sports drinks, with the advantage of being richer in phenolic compounds and suitable osmolality. Despite salts were added in its formulation, the grades attributed to all beers employed in the sensory evaluation, as well as the purchase intention did not present significant differences.  相似文献   
22.
23.
This study aimed to evaluate the physicochemical characteristics and sensory attributes of beef burgers with the addition of pea fibre as a partial substitute of meat or fat. Three formulations were prepared: control (CON) – similar to the commercial formulation; fibre/less meat (FLM)—5% meat reduction and addition of 1% pea fibre; fibre/less fat (FLF)—7% fat reduction and addition of 1% pea fibre. Non-significant differences were obtained for pH, colour parameters (L* and b*), texture profile, cooking loss and size reduction among formulations. Moreover, sensory analysis with consumers of beef burgers did not indicate differences among the formulations for all the analysed attributes. Therefore, pea fibre is a promising partial replacer for meat and fat in beef burgers due to the preservation of technological parameters and sensory acceptance.  相似文献   
24.
25.
Here we report some recent biophysical issues on the preparation of solute-filled lipid vesicles and their relevance to the construction of “synthetic cells.” First, we introduce the “semi-synthetic minimal cells” as the liposome-based cell-like systems, which contain a minimal number of biomolecules required to display simple and complex biological functions. Next, we focus on recent aspects related to the construction of synthetic cells. Emphasis is given to the interplay between the methods of synthetic cell preparation and the physics of solute encapsulation. We briefly introduce the notion of structural and compositional “diversity” in synthetic cell populations.  相似文献   
26.
27.
The purpose of this research was to study the capacity of emulsions containing saturated monoglyceride self‐assembly structures to deliver omega‐3 fatty acids in fresh soft cheese. To this aim, fortified emulsions containing different ratios of milk, saturated monoglycerides (MGs) and cod liver oil were added to milk before cheese‐making. These emulsions were characterised by distinct microstructural features observed by polarised light microscopy and apparent viscosity values. The omega‐3 delivery performance of MG emulsions highlighted that this strategy allowed a good retention of the omega‐3‐rich oil in the curd (up to 75%). The fortified cheeses showed yield value and fat content higher than those of control samples. The enriched cheese showed hardness and cohesiveness obtained by texture profile analysis similar to those of the unfortified product. Only a slight decrease in gumminess was detected in fortified cheese.  相似文献   
28.
29.
30.
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