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   1605507篇
  免费   27926篇
  国内免费   7150篇
电工技术   35431篇
综合类   6648篇
化学工业   277500篇
金属工艺   66536篇
机械仪表   47307篇
建筑科学   48385篇
矿业工程   11980篇
能源动力   50539篇
轻工业   125000篇
水利工程   16407篇
石油天然气   38450篇
武器工业   202篇
无线电   200808篇
一般工业技术   303088篇
冶金工业   202500篇
原子能技术   34705篇
自动化技术   175097篇
  2021年   15670篇
  2020年   11994篇
  2019年   14768篇
  2018年   19261篇
  2017年   19080篇
  2016年   23118篇
  2015年   17683篇
  2014年   28827篇
  2013年   88207篇
  2012年   38590篇
  2011年   54088篇
  2010年   46310篇
  2009年   54030篇
  2008年   49437篇
  2007年   47601篇
  2006年   47101篇
  2005年   43032篇
  2004年   44090篇
  2003年   43741篇
  2002年   42348篇
  2001年   39204篇
  2000年   37307篇
  1999年   36904篇
  1998年   56831篇
  1997年   46472篇
  1996年   40066篇
  1995年   33605篇
  1994年   31044篇
  1993年   30867篇
  1992年   27034篇
  1991年   24265篇
  1990年   24530篇
  1989年   23576篇
  1988年   22124篇
  1987年   20356篇
  1986年   19765篇
  1985年   23057篇
  1984年   22827篇
  1983年   20797篇
  1982年   19597篇
  1981年   19697篇
  1980年   18341篇
  1979年   18834篇
  1978年   18046篇
  1977年   18355篇
  1976年   20165篇
  1975年   16246篇
  1974年   15749篇
  1973年   15868篇
  1972年   13284篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
191.
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   
192.
193.
To overcome the drawbacks of solid microporous materials for CO2 capture, this proof‐of‐concept study demonstrates a low‐cost and rapid method for producing composites consisting of hypercrosslinked polymers (HCP) with a polyethyleneimine (PEI) binder. The resulting materials capture CO2 through physical and chemical absorption simultaneously. Compared with HCP, the composites exhibit higher CO2 uptake, higher volumetric density, and improved tolerance to water which is attributed to the PEI binder.  相似文献   
194.
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   
195.
Potato processing industry has a high degree of discarding, which currently has low added value being used primarily for animal feed. However, potato wastes offer a broad range of interesting components such as antioxidants, starch, protein or fibre with potential applications in the food and non-food industries. The recovery of these high valuable fractions using efficient multistage and multiproduct processes could be of great interest. This short review provides a general overview on the integral valorisation of potato wastes, offering an updated vision of the main residual parts generated during potato harvesting and processing, the high valuable obtained components focusing on the bioactive ones and the potential of the emerging extraction techniques over conventional ones. In addition, innovative applications are discussed to highlight the scientific and applied interest of these underutilised and undervalued fractions and to emphasise the integral valorisation of raw materials.  相似文献   
196.
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   
197.
198.
The objective of this study was to determine the effect of temperature on whole milk density measured at four different temperatures: 5, 10, 15, and 20 °C. A total of ninety-three individual milk samples were collected from morning milking of thirty-two Holstein Friesian dairy cows, of national average genetic merit, once every two weeks over a period of 4 weeks and were assessed by Fourier transform infrared spectroscopy for milk composition analysis. Density of the milk was evaluated using two different analytical methods: a portable density meter DMA35 and a standard desktop model DMA4500M (Anton Paar GmbH, UK). Milk density was analysed with a linear mixed model with the fixed effects of sampling period, temperature and analysis method; triple interaction of sampling period x analysis method x temperature; and the random effect of cow to account for repeated measures. The effect of temperature on milk density (ρ) was also evaluated including temperature (t) as covariate with linear and quadratic effects within each analytic method. The regression equation describing the curvature and density–temperature relationship for the DMA35 instrument was ρ = 1.0338−0.00017T−0.0000122T2 (R2 = 0.64), while it was ρ = 1.0334 + 0.000057T−0.00001T2 (R2 = 0.61) for DMA4500 instrument. The mean density determined with DMA4500 at 5 °C was 1.0334 g cm−3, with corresponding figures of 1.0330, 1.0320 and 1.0305 g cm−3 at 10, 15 and 20 °C, respectively. The milk density values obtained in this study at specific temperatures will help to address any bias in weight–volume calculations and thus may also improve the financial and operational control for the dairy processors in Ireland and internationally.  相似文献   
199.
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   
200.
A method is proposed to generate categorical colour observer functions (individual colour matching functions) for any field size based on the CIE 2006 system of physiological observer functions. The method combines proposed categorical observer techniques of Sarkar et al with a physiologically-based individual observer model of Asano et al and a clustering technique to produce the optimal set of categorical observers. The number of required categorical observers varies depending on an application with as many as 50 required to predict individual observers' matches when a laser projector is viewed. However, 10 categorical observers are sufficient to represent colour-normal populations for personalized colour imaging. The proposed and recommended categorical observers represent a robust and inclusive technique to examine and quantify observer metamerism in any application of colorimetry.  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