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   989110篇
  免费   14271篇
  国内免费   2478篇
电工技术   17242篇
综合类   3098篇
化学工业   149469篇
金属工艺   39652篇
机械仪表   30538篇
建筑科学   23786篇
矿业工程   6090篇
能源动力   24889篇
轻工业   80723篇
水利工程   11286篇
石油天然气   19455篇
武器工业   64篇
无线电   108235篇
一般工业技术   193888篇
冶金工业   175475篇
原子能技术   20238篇
自动化技术   101731篇
  2021年   8574篇
  2020年   6410篇
  2019年   8144篇
  2018年   26749篇
  2017年   25717篇
  2016年   23588篇
  2015年   10239篇
  2014年   16180篇
  2013年   42455篇
  2012年   27674篇
  2011年   42073篇
  2010年   34252篇
  2009年   34973篇
  2008年   36647篇
  2007年   37058篇
  2006年   26376篇
  2005年   24935篇
  2004年   23858篇
  2003年   23565篇
  2002年   22045篇
  2001年   21308篇
  2000年   20182篇
  1999年   20701篇
  1998年   51756篇
  1997年   36824篇
  1996年   28424篇
  1995年   21431篇
  1994年   18974篇
  1993年   18604篇
  1992年   13755篇
  1991年   13041篇
  1990年   12898篇
  1989年   12495篇
  1988年   11873篇
  1987年   10653篇
  1986年   10413篇
  1985年   11721篇
  1984年   10701篇
  1983年   9931篇
  1982年   9167篇
  1981年   9312篇
  1980年   8869篇
  1979年   8793篇
  1978年   8606篇
  1977年   9954篇
  1976年   12940篇
  1975年   7593篇
  1974年   7225篇
  1973年   7376篇
  1972年   6175篇
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
91.
Golubev  N. V.  Ignat’eva  E. S.  Maurus  A. A.  Ziyatdinova  M. Z.  Lopatina  E. V.  Lorenzi  R.  Paleari  A.  Sigaev  V. N. 《Glass and Ceramics》2021,77(11-12):415-418
Glass and Ceramics - The influence of Al2O3 as an additive and the heat-treatment regime on the luminescence spectra of gallate glass-ceramics was investigated. It is shown that its luminescence...  相似文献   
92.
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   
93.
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   
94.
95.
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   
96.
97.
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   
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