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   200809篇
  免费   3425篇
  国内免费   222篇
电工技术   2786篇
综合类   138篇
化学工业   33603篇
金属工艺   10089篇
机械仪表   6436篇
建筑科学   3945篇
矿业工程   1964篇
能源动力   3308篇
轻工业   14068篇
水利工程   3026篇
石油天然气   8816篇
武器工业   17篇
无线电   15724篇
一般工业技术   43819篇
冶金工业   34920篇
原子能技术   7061篇
自动化技术   14736篇
  2021年   2364篇
  2019年   2325篇
  2018年   4320篇
  2017年   4376篇
  2016年   4705篇
  2015年   2695篇
  2014年   4267篇
  2013年   8899篇
  2012年   6215篇
  2011年   7157篇
  2010年   5847篇
  2009年   6219篇
  2008年   6201篇
  2007年   6033篇
  2006年   4956篇
  2005年   4506篇
  2004年   4283篇
  2003年   4096篇
  2002年   3995篇
  2001年   3863篇
  2000年   3750篇
  1999年   3624篇
  1998年   9095篇
  1997年   6601篇
  1996年   4750篇
  1995年   3491篇
  1994年   3038篇
  1993年   3226篇
  1992年   2448篇
  1991年   2512篇
  1990年   2557篇
  1989年   2476篇
  1988年   2468篇
  1987年   2327篇
  1986年   2368篇
  1985年   2435篇
  1984年   2326篇
  1983年   2244篇
  1982年   2120篇
  1981年   2334篇
  1980年   2205篇
  1979年   2355篇
  1978年   2513篇
  1977年   2694篇
  1976年   3692篇
  1975年   2306篇
  1974年   2360篇
  1973年   2417篇
  1972年   2185篇
  1971年   1954篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Journal of Low Temperature Physics - This study modeled and investigated the magnetocaloric effect in Ni2MnGa Heusler alloy characterized by its magnetic entropy change (ΔSm) and its...  相似文献   
32.
Mobile Networks and Applications - 5G/6G communication are first generation high speed wireless communication network which integrates the aerial data, terrestrial data and maritime data via...  相似文献   
33.
Theoretical Foundations of Chemical Engineering - The effect of the electrolyte composition, mass-transfer conditions, pore diameter, interpore distance, and electric parameters on the formation of...  相似文献   
34.
Chronic stress is a combination of nonspecific adaptive reactions of the body to the influence of various adverse stress factors which disrupt its homeostasis, and it is also a corresponding state of the organism’s nervous system (or the body in general). We hypothesized that chronic stress may be one of the causes occurence of several molecular and cellular types of stress. We analyzed literary sources and considered most of these types of stress in our review article. We examined genes and mutations of nuclear and mitochondrial genomes and also molecular variants which lead to various types of stress. The end result of chronic stress can be metabolic disturbance in humans and animals, leading to accumulation of reactive oxygen species (ROS), oxidative stress, energy deficiency in cells (due to a decrease in ATP synthesis) and mitochondrial dysfunction. These changes can last for the lifetime and lead to severe pathologies, including neurodegenerative diseases and atherosclerosis. The analysis of literature allowed us to conclude that under the influence of chronic stress, metabolism in the human body can be disrupted, mutations of the mitochondrial and nuclear genome and dysfunction of cells and their compartments can occur. As a result of these processes, oxidative, genotoxic, and cellular stress can occur. Therefore, chronic stress can be one of the causes forthe occurrence and development of neurodegenerative diseases and atherosclerosis. In particular, chronic stress can play a large role in the occurrence and development of oxidative, genotoxic, and cellular types of stress.  相似文献   
35.
Kirovskaya  I. A.  Filatova  T. N.  Nor  P. E. 《Semiconductors》2021,55(2):228-233
Semiconductors - According to developed methods, in the fields of the mutual solubility of initial binary compounds (InP, InSb, and CdS), solid solutions of the InP–CdS and InSb–CdS...  相似文献   
36.
Trofimova  Elena G.  Lomovsky  Oleg I. 《SILICON》2021,13(2):433-439
Silicon - The products of solid-phase mechanochemical interaction between pyrocatechol and silicon dioxide yielding a powdered composite were studied using a number of physicochemical methods. This...  相似文献   
37.
Russian Engineering Research - Models based on regression analysis for predicting the operational efficiency of high-pressure roller crushers are considered. A systematized and structured...  相似文献   
38.
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   
39.
40.
Theoretical Foundations of Chemical Engineering - New research results, as well as those published earlier by the authors, on the synthesis of azo compounds based on nitroanilines obtained by the...  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