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   30218篇
  免费   1429篇
  国内免费   111篇
电工技术   401篇
综合类   228篇
化学工业   5309篇
金属工艺   678篇
机械仪表   678篇
建筑科学   1028篇
矿业工程   95篇
能源动力   996篇
轻工业   4273篇
水利工程   271篇
石油天然气   162篇
武器工业   6篇
无线电   2429篇
一般工业技术   4454篇
冶金工业   6468篇
原子能技术   253篇
自动化技术   4029篇
  2023年   160篇
  2022年   248篇
  2021年   886篇
  2020年   617篇
  2019年   682篇
  2018年   810篇
  2017年   859篇
  2016年   846篇
  2015年   641篇
  2014年   963篇
  2013年   1592篇
  2012年   1425篇
  2011年   1731篇
  2010年   1274篇
  2009年   1309篇
  2008年   1198篇
  2007年   1031篇
  2006年   841篇
  2005年   891篇
  2004年   947篇
  2003年   849篇
  2002年   812篇
  2001年   721篇
  2000年   569篇
  1999年   553篇
  1998年   2118篇
  1997年   1367篇
  1996年   937篇
  1995年   631篇
  1994年   492篇
  1993年   543篇
  1992年   220篇
  1991年   287篇
  1990年   234篇
  1989年   197篇
  1988年   212篇
  1987年   167篇
  1986年   170篇
  1985年   185篇
  1984年   130篇
  1983年   92篇
  1982年   118篇
  1981年   128篇
  1980年   117篇
  1979年   92篇
  1978年   73篇
  1977年   143篇
  1976年   233篇
  1975年   81篇
  1973年   50篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
11.
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   
12.
13.
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   
14.
15.
Debittered trub (brewing waste) is an important source of protein source (70.26%). Trub and whey protein were used for 5% protein enrichment of ice cream frozen by liquid nitrogen. Three formulations were elaborated: ice cream standard (ICS), ice cream with whey protein (ICW) and ice cream with trub (ICT). Chemical composition, rheological properties, texture, overrun, melting rate, scanning electron microscopy and a sensorial test were performed. Results showed that ICT presented a higher viscosity, obtained on the upward curve up to 6.76 Pa s−1, consistency index (22.96 (Pa s−1)n), hysteresis area (140.40 mPa s−1) and hardness (31113.33 g) but a lower melting rate (0.38 g min−1), overrun (13.92%) and sensorial acceptability than the other formulations. The addition of trub debittered for protein enrichment improved ice cream properties and demonstrated that it could be used as a food ingredient.  相似文献   
16.
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   
17.
18.
19.
20.
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