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   830530篇
  免费   10801篇
  国内免费   2086篇
电工技术   15381篇
综合类   705篇
化学工业   127681篇
金属工艺   33277篇
机械仪表   26505篇
建筑科学   18564篇
矿业工程   5417篇
能源动力   22470篇
轻工业   64549篇
水利工程   9566篇
石油天然气   18188篇
武器工业   46篇
无线电   93124篇
一般工业技术   168033篇
冶金工业   150307篇
原子能技术   19132篇
自动化技术   70472篇
  2021年   7672篇
  2020年   5780篇
  2019年   7377篇
  2018年   12569篇
  2017年   12684篇
  2016年   13375篇
  2015年   8574篇
  2014年   14317篇
  2013年   39203篇
  2012年   22543篇
  2011年   30732篇
  2010年   24543篇
  2009年   27560篇
  2008年   28073篇
  2007年   27679篇
  2006年   24257篇
  2005年   21929篇
  2004年   20932篇
  2003年   20695篇
  2002年   19678篇
  2001年   19287篇
  2000年   18306篇
  1999年   18597篇
  1998年   45499篇
  1997年   32256篇
  1996年   25022篇
  1995年   18920篇
  1994年   16922篇
  1993年   16725篇
  1992年   12506篇
  1991年   11900篇
  1990年   11765篇
  1989年   11353篇
  1988年   10788篇
  1987年   9737篇
  1986年   9380篇
  1985年   10706篇
  1984年   9739篇
  1983年   9106篇
  1982年   8278篇
  1981年   8451篇
  1980年   7896篇
  1979年   7956篇
  1978年   7797篇
  1977年   8803篇
  1976年   11191篇
  1975年   6901篇
  1974年   6622篇
  1973年   6727篇
  1972年   5687篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
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   
92.
93.
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   
94.
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.
Topics in Catalysis - In this work, a simple thermal-catalytic system was used to valorize peanut shells (Arachis hypogaea), the residual biomass from the peanut industry. To accomplish this...  相似文献   
99.
100.
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