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   104769篇
  免费   7937篇
  国内免费   3014篇
电工技术   4163篇
技术理论   10篇
综合类   4551篇
化学工业   19658篇
金属工艺   4227篇
机械仪表   4583篇
建筑科学   6524篇
矿业工程   1883篇
能源动力   2805篇
轻工业   12136篇
水利工程   1664篇
石油天然气   3810篇
武器工业   527篇
无线电   9735篇
一般工业技术   14287篇
冶金工业   10050篇
原子能技术   866篇
自动化技术   14241篇
  2024年   395篇
  2023年   1507篇
  2022年   2763篇
  2021年   3978篇
  2020年   3068篇
  2019年   2685篇
  2018年   3591篇
  2017年   3601篇
  2016年   3623篇
  2015年   3810篇
  2014年   4779篇
  2013年   6703篇
  2012年   6563篇
  2011年   6931篇
  2010年   5634篇
  2009年   5291篇
  2008年   5260篇
  2007年   4884篇
  2006年   4319篇
  2005年   3718篇
  2004年   2909篇
  2003年   2614篇
  2002年   2375篇
  2001年   2030篇
  2000年   2109篇
  1999年   2465篇
  1998年   4073篇
  1997年   2892篇
  1996年   2333篇
  1995年   1686篇
  1994年   1423篇
  1993年   1124篇
  1992年   681篇
  1991年   526篇
  1990年   453篇
  1989年   411篇
  1988年   340篇
  1987年   264篇
  1986年   210篇
  1985年   193篇
  1984年   154篇
  1983年   108篇
  1982年   125篇
  1981年   137篇
  1980年   128篇
  1979年   56篇
  1978年   56篇
  1977年   150篇
  1976年   275篇
  1973年   65篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
In this study, amaranth flour was used as an ingredient to prepare gluten-free cookies. The production process and attributes of amaranth cookies were characterised, and the potential use of amaranth flour as a functional ingredient was analysed. Cookies exhibited a non-uniform reddish brown colour and a cookie factor ratio of 4.5 ± 0.6. Storage studies indicated that after 3 weeks at room temperature cookies presented slight variations in the texture. Simulated gastrointestinal digestion of this product was able to release peptides capable of exerting potential antithrombotic and antihypertensive activities, IC50 values of 0.22 ± 0.04 and 0.23 ± 0.03 mg mL−1 protein, respectively. This work demonstrates for the first time that food made with amaranth flour exerts potential antithrombotic and antihypertensive activity. In conclusion, these amaranth cookies could be an alternative way of incorporating potentially health beneficial products for people who choose a conscious diet, including coeliac or vegan consumers.  相似文献   
2.
Lobster krill (Munida genus) represents an under‐valued crustacean frequently caught on European fishing banks. In this work, its sensory, microbiological and biochemical qualities were evaluated during chilled storage. Additionally, the effects of a prestorage antimelanosic treatment consisting of soaking in sodium metabisulphite (SMB) solutions at two different concentrations (0.25% and 0.75%) were also studied. SMB prestorage treatment provided lobster specimens that still exhibited acceptable sensory quality after 10 days of storage, while control specimens were unacceptable at that time. SMB treatment also resulted in a significant (P < 0.05) inhibition of microbial growth, mainly of Enterobacteriaceae, psychrotrophes and proteolytic bacteria. Low lipid oxidation levels were observed for all batches; however, a significantly higher (P < 0.05) retention of polyunsaturated fatty acids was found in SMB‐treated lobster, especially in the 0.75% SMB batch. The results presented here open the way to the potential commercialisation of currently under‐utilised lobster krill as a chilled product.  相似文献   
3.
大型综合室内亲子乐园属于高大空间,设有游乐设施和游戏的特殊性使得对空间的舒适性要求一致,但是送风气流遇阻严重,室内存在较多气流死角,影响室内空气质量和儿童健康。因此其空调设计不仅需要考虑温度、风速的空间均匀度,还要考虑各点的空气龄和PMV-PPD指标。以天津某亲子乐园为研究对象,利用scSTREAM软件对适用于该房间的辐射供冷加新风、置换通风、混合通风三种空调方式的送风效果进行数值模拟分析,从流场的均匀性、人员的热舒适性等方面对模拟结果进行探讨,研究结果表明辐射供冷加新风方式的空间均匀性和PMV指标最佳,混合通风方式的空气龄最小。  相似文献   
4.
5.
Removal of imidacloprid and acetamiprid in tea infusions by microfiltration membrane using dead‐end model was investigated in the present study. The results showed that microfiltration significantly promoted the removal of both pesticides (P < 0.05) in tea infusions. Furthermore, the extent of removal was strongly influenced by the pore size of membrane, operational pressure and the concentrations of tea infusions. The initial concentration of imidacloprid and acetamiprid showed no significant effect on their removal rates. The maximum removal rates were 79.7% for imidacloprid and 81.9% acetamiprid. The changes in major chemical components of tea infusions after microfiltration were evaluated. The results indicated that microfiltration caused no considerable changes in total polyphenols and total free amino acids, and small but statistically significant losses (6.3–18.0%) of eight catechins and three methylxanthines when filtration volume reached to 200 mL. The present study validated the application of microfiltration as a potentially feasible and promising method for the removal of imidacloprid and acetamiprid residues from tea infusions.  相似文献   
6.
7.
8.
9.
10.
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