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   942428篇
  免费   12982篇
  国内免费   2193篇
电工技术   17205篇
综合类   949篇
化学工业   142469篇
金属工艺   38993篇
机械仪表   29651篇
建筑科学   22379篇
矿业工程   5869篇
能源动力   24063篇
轻工业   76868篇
水利工程   10707篇
石油天然气   19610篇
武器工业   75篇
无线电   102812篇
一般工业技术   187701篇
冶金工业   173773篇
原子能技术   20281篇
自动化技术   84198篇
  2021年   8514篇
  2020年   6318篇
  2019年   8053篇
  2018年   16909篇
  2017年   16994篇
  2016年   16564篇
  2015年   9862篇
  2014年   16020篇
  2013年   42042篇
  2012年   25873篇
  2011年   36987篇
  2010年   30187篇
  2009年   32735篇
  2008年   33410篇
  2007年   33951篇
  2006年   26292篇
  2005年   25235篇
  2004年   23693篇
  2003年   23247篇
  2002年   21825篇
  2001年   21206篇
  2000年   20186篇
  1999年   20658篇
  1998年   51219篇
  1997年   36525篇
  1996年   28177篇
  1995年   21298篇
  1994年   18881篇
  1993年   18498篇
  1992年   13716篇
  1991年   13009篇
  1990年   12877篇
  1989年   12454篇
  1988年   11832篇
  1987年   10629篇
  1986年   10383篇
  1985年   11691篇
  1984年   10680篇
  1983年   9912篇
  1982年   9138篇
  1981年   9280篇
  1980年   8847篇
  1979年   8790篇
  1978年   8592篇
  1977年   9915篇
  1976年   12852篇
  1975年   7584篇
  1974年   7218篇
  1973年   7370篇
  1972年   6174篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Journal of Machinery Manufacture and Reliability - A device based on smart alloys has been designed for use in machine building items, in particular, in nuclear engineering, for preventing...  相似文献   
92.
Journal of Machinery Manufacture and Reliability - The problem of calculating the reliability and fatigue life of machine parts by the fatigue failure under random changes in the actual and limit...  相似文献   
93.
94.
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   
95.
96.
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   
97.
98.
99.
100.
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   
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