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   985791篇
  免费   14240篇
  国内免费   3532篇
电工技术   18723篇
技术理论   5篇
综合类   1822篇
化学工业   153347篇
金属工艺   39971篇
机械仪表   30253篇
建筑科学   23912篇
矿业工程   6932篇
能源动力   24990篇
轻工业   82731篇
水利工程   11401篇
石油天然气   22377篇
武器工业   300篇
无线电   106135篇
一般工业技术   195601篇
冶金工业   178944篇
原子能技术   22283篇
自动化技术   83836篇
  2021年   9021篇
  2019年   8267篇
  2018年   13988篇
  2017年   14028篇
  2016年   15002篇
  2015年   10230篇
  2014年   16658篇
  2013年   45126篇
  2012年   26411篇
  2011年   35701篇
  2010年   28643篇
  2009年   31893篇
  2008年   32841篇
  2007年   32637篇
  2006年   28596篇
  2005年   25782篇
  2004年   24066篇
  2003年   23331篇
  2002年   22864篇
  2001年   22431篇
  2000年   21396篇
  1999年   21483篇
  1998年   51587篇
  1997年   37348篇
  1996年   28997篇
  1995年   22026篇
  1994年   19935篇
  1993年   19493篇
  1992年   14822篇
  1991年   14285篇
  1990年   14036篇
  1989年   13864篇
  1988年   13159篇
  1987年   11743篇
  1986年   11591篇
  1985年   13226篇
  1984年   12293篇
  1983年   11658篇
  1982年   10526篇
  1981年   10806篇
  1980年   10290篇
  1979年   10459篇
  1978年   10260篇
  1977年   11573篇
  1976年   14837篇
  1975年   9170篇
  1974年   8767篇
  1973年   8895篇
  1972年   7594篇
  1971年   6986篇
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
101.
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   
102.
103.
Qin  Yi  Tao  Xianping  Huang  Yu    Jian 《World Wide Web》2019,22(1):1-37
World Wide Web - Rule mechanism has been widely used in many areas, such as databases, artificial intelligent and pervasive computing. In a rule mechanism, rule activation decides which rules are...  相似文献   
104.
In this paper, we present an aero‐structural model of a tethered swept wing for airborne wind energy generation. The carbon composite wing has neither fuselage nor actuated aerodynamic control surfaces and is controlled entirely from the ground using three separate tethers. The computational model is efficient enough to be used for weight optimisation at the initial design stage. The main load‐bearing wing component is a nontypical “D”‐shaped wing‐box, which is represented as a slender carbon composite shell and further idealised as a stack of two‐dimensional cross section models arranged along an anisotropic one‐dimensional beam model. This reduced 2+1D finite element model is then combined with a nonlinear vortex step method that determines the aerodynamic load. A bridle model is utilised to calculate the individual forces as a function of the aerodynamic load in the bridle lines that connect the main tether to the wing. The entire computational model is used to explore the influence of the bride on the D‐box structure. Considering a reference D‐box design along with a reference aerodynamic load case, the structural response is analysed for typical bridle configurations. Subsequently, an optimisation of the internal geometry and laminate fibre orientations is carried out using the structural computation models, for a fixed aerodynamic and bridle configuration. Aiming at a minimal weight of the wing structure, we find that for the typical load case of the system, an overall weight savings of approximately 20% can be achieved compared with the initial reference design.  相似文献   
105.
106.
107.
108.
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   
109.
110.
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