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   908302篇
  免费   12666篇
  国内免费   2106篇
电工技术   16560篇
综合类   809篇
化学工业   139344篇
金属工艺   35307篇
机械仪表   27543篇
建筑科学   21590篇
矿业工程   5559篇
能源动力   23729篇
轻工业   76065篇
水利工程   10122篇
石油天然气   19118篇
武器工业   64篇
无线电   99611篇
一般工业技术   178951篇
冶金工业   171351篇
原子能技术   20010篇
自动化技术   77341篇
  2021年   8379篇
  2020年   6171篇
  2019年   7902篇
  2018年   13476篇
  2017年   13510篇
  2016年   14219篇
  2015年   9396篇
  2014年   15640篇
  2013年   41542篇
  2012年   24421篇
  2011年   33459篇
  2010年   26683篇
  2009年   29768篇
  2008年   30399篇
  2007年   29996篇
  2006年   26059篇
  2005年   23769篇
  2004年   22745篇
  2003年   22397篇
  2002年   21464篇
  2001年   21141篇
  2000年   19974篇
  1999年   20567篇
  1998年   51138篇
  1997年   36434篇
  1996年   28143篇
  1995年   21286篇
  1994年   18856篇
  1993年   18477篇
  1992年   13706篇
  1991年   12986篇
  1990年   12865篇
  1989年   12456篇
  1988年   11825篇
  1987年   10629篇
  1986年   10380篇
  1985年   11682篇
  1984年   10678篇
  1983年   9909篇
  1982年   9137篇
  1981年   9274篇
  1980年   8840篇
  1979年   8781篇
  1978年   8588篇
  1977年   9908篇
  1976年   12841篇
  1975年   7582篇
  1974年   7216篇
  1973年   7371篇
  1972年   6170篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
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   
93.
94.
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   
95.
96.
97.
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   
98.
The role of the following factors in the selection of technological bases for manufacturing is considered: the accessibility of the machined surfaces; their parameters and dimensional relationships; their position relative to the forces acting; and the uniformity of the margin distribution.  相似文献   
99.
100.
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