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   390433篇
  免费   6039篇
  国内免费   1731篇
电工技术   5746篇
综合类   2855篇
化学工业   57529篇
金属工艺   16262篇
机械仪表   12000篇
建筑科学   9585篇
矿业工程   2177篇
能源动力   8764篇
轻工业   30451篇
水利工程   4475篇
石油天然气   6251篇
武器工业   47篇
无线电   44274篇
一般工业技术   77372篇
冶金工业   60959篇
原子能技术   7856篇
自动化技术   51600篇
  2021年   3006篇
  2020年   2313篇
  2019年   2700篇
  2018年   18508篇
  2017年   17496篇
  2016年   14572篇
  2015年   4005篇
  2014年   5796篇
  2013年   14489篇
  2012年   12018篇
  2011年   20462篇
  2010年   16799篇
  2009年   15262篇
  2008年   17011篇
  2007年   17758篇
  2006年   8994篇
  2005年   9268篇
  2004年   9086篇
  2003年   8799篇
  2002年   7853篇
  2001年   7295篇
  2000年   7032篇
  1999年   7288篇
  1998年   18661篇
  1997年   13038篇
  1996年   9903篇
  1995年   7406篇
  1994年   6495篇
  1993年   6532篇
  1992年   4575篇
  1991年   4387篇
  1990年   4265篇
  1989年   4224篇
  1988年   3926篇
  1987年   3521篇
  1986年   3526篇
  1985年   3904篇
  1984年   3612篇
  1983年   3323篇
  1982年   3154篇
  1981年   3192篇
  1980年   3157篇
  1979年   2932篇
  1978年   2964篇
  1977年   3301篇
  1976年   4430篇
  1975年   2485篇
  1974年   2439篇
  1973年   2459篇
  1972年   2054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.
3.
The use of field robots can greatly decrease the amount of time, effort, and associated risk compared to if human workers were to carryout certain tasks such as disaster response. However, transportability and reliability remain two main issues for most current robot systems. To address the issue of transportability, we have developed a lightweight modularizable platform named AeroArm. To address the issue of reliability, we utilize a multimodal sensing approach, combining the use of multiple sensors and sensor types, and the use of different detection algorithms, as well as active continuous closed‐loop feedback to accurately estimate the state of the robot with respect to the environment. We used Challenge 2 of the 2017 Mohammed Bin Zayed International Robotics Competition as an example outdoor manipulation task, demonstrating the capabilities of our robot system and approach in achieving reliable performance in the fields, and ranked fifth place internationally in the competition.  相似文献   
4.

Stability constants and formation enthalpies of supramolecular complexes of crown ethers and their cyclic and acyclic analogues are determined on the basis of experimental data obtained by different physicochemical methods in the terms of a general approach developed and implemented in the ChemEqui software package. The established regularities of variation of stability of complexes are discussed as dependent on the ligand structure, nature of the cation, solvent, and anion. The applicability of the suggested method of determining complexation selectivity is shown for multicomponent equilibria in solutions.

  相似文献   
5.
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   
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