全文获取类型
收费全文 | 1574764篇 |
免费 | 27924篇 |
国内免费 | 7084篇 |
专业分类
电工技术 | 34793篇 |
综合类 | 6434篇 |
化学工业 | 274806篇 |
金属工艺 | 65596篇 |
机械仪表 | 44988篇 |
建筑科学 | 47307篇 |
矿业工程 | 11592篇 |
能源动力 | 50570篇 |
轻工业 | 118069篇 |
水利工程 | 16068篇 |
石油天然气 | 38003篇 |
武器工业 | 136篇 |
无线电 | 199404篇 |
一般工业技术 | 296020篇 |
冶金工业 | 198932篇 |
原子能技术 | 34350篇 |
自动化技术 | 172704篇 |
出版年
2021年 | 15780篇 |
2020年 | 12049篇 |
2019年 | 14807篇 |
2018年 | 17912篇 |
2017年 | 17485篇 |
2016年 | 22508篇 |
2015年 | 17651篇 |
2014年 | 28936篇 |
2013年 | 88402篇 |
2012年 | 37304篇 |
2011年 | 51382篇 |
2010年 | 44600篇 |
2009年 | 52628篇 |
2008年 | 47255篇 |
2007年 | 44824篇 |
2006年 | 45758篇 |
2005年 | 41098篇 |
2004年 | 42811篇 |
2003年 | 42697篇 |
2002年 | 41294篇 |
2001年 | 38632篇 |
2000年 | 36816篇 |
1999年 | 36671篇 |
1998年 | 56943篇 |
1997年 | 45970篇 |
1996年 | 39762篇 |
1995年 | 33316篇 |
1994年 | 30899篇 |
1993年 | 30761篇 |
1992年 | 26648篇 |
1991年 | 23898篇 |
1990年 | 24187篇 |
1989年 | 23268篇 |
1988年 | 21841篇 |
1987年 | 20021篇 |
1986年 | 19418篇 |
1985年 | 22654篇 |
1984年 | 22584篇 |
1983年 | 20506篇 |
1982年 | 19435篇 |
1981年 | 19620篇 |
1980年 | 18226篇 |
1979年 | 18626篇 |
1978年 | 17877篇 |
1977年 | 18105篇 |
1976年 | 19920篇 |
1975年 | 16122篇 |
1974年 | 15576篇 |
1973年 | 15694篇 |
1972年 | 13092篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
191.
Yana Jorge Polizer-Rocha José M. Lorenzo Daniel Pompeu Isabela Rodrigues Juliana Cristina Baldin Manoela A. Pires Maria Teresa A. Freire Francisco Jose Barba Marco Antonio Trindade 《International Journal of Food Science & Technology》2020,55(3):1018-1024
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.
Fermanelli Carla S. Galarza Emilce D. Pierella Liliana B. Renzini María S. Saux Clara 《Topics in Catalysis》2019,62(12-16):918-930
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.
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
196.
197.
Puneet Parmar Nicolas Lopez-Villalobos John T. Tobin Eoin Murphy Frank Buckley Shane V. Crowley Alan L. Kelly Laurence Shalloo 《International Journal of Food Science & Technology》2021,56(5):2415-2422
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
198.
Kobrakov K. I. Kurnetsov D. N. Ruchkina A. G. Sharpar N. M. 《Theoretical Foundations of Chemical Engineering》2020,54(5):1052-1056
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
199.
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
200.
Zhongkai Zhao Yohanes A. Situmorang Ping An Nichaboon Chaihad Jing Wang Xiaogang Hao Guangwen Xu Abuliti Abudula Guoqing Guan 《化学工程与技术》2020,43(4):625-640
In the future, hydrogen will be an important energy carrier and industrial raw material. Catalytic steam reforming of bio-oils is a promising and economically viable technology for hydrogen production. However, during the reforming process, the catalysts are rapidly deactivated due to coke formation and sintering. Thus, maintaining the activity and stability of catalysts is the key issue in this process. Optimized operation conditions could extend the catalyst lifetime by affecting the coke morphology or promoting coke gasification. This article summarizes the recent developments in the field of catalytic steam reforming of bio-oils, focusing on the operation conditions, the properties of the catalysts, and the effects of the catalyst supports. The expected insights into the catalytic steam reforming of bio-oils will provide further guidance for hydrogen production from bio-oils. 相似文献