全文获取类型
收费全文 | 732375篇 |
免费 | 30787篇 |
国内免费 | 13487篇 |
专业分类
电工技术 | 25373篇 |
技术理论 | 56篇 |
综合类 | 19964篇 |
化学工业 | 117164篇 |
金属工艺 | 31865篇 |
机械仪表 | 32733篇 |
建筑科学 | 36906篇 |
矿业工程 | 11685篇 |
能源动力 | 20553篇 |
轻工业 | 61929篇 |
水利工程 | 8464篇 |
石油天然气 | 24465篇 |
武器工业 | 2612篇 |
无线电 | 90143篇 |
一般工业技术 | 113286篇 |
冶金工业 | 91767篇 |
原子能技术 | 8678篇 |
自动化技术 | 79006篇 |
出版年
2023年 | 5545篇 |
2022年 | 9994篇 |
2021年 | 14811篇 |
2020年 | 11212篇 |
2019年 | 10009篇 |
2018年 | 12608篇 |
2017年 | 13883篇 |
2016年 | 13037篇 |
2015年 | 15366篇 |
2014年 | 21242篇 |
2013年 | 37776篇 |
2012年 | 29934篇 |
2011年 | 36523篇 |
2010年 | 30048篇 |
2009年 | 30741篇 |
2008年 | 31388篇 |
2007年 | 31124篇 |
2006年 | 30639篇 |
2005年 | 27709篇 |
2004年 | 21571篇 |
2003年 | 20102篇 |
2002年 | 18822篇 |
2001年 | 18353篇 |
2000年 | 18060篇 |
1999年 | 20135篇 |
1998年 | 31698篇 |
1997年 | 24006篇 |
1996年 | 19922篇 |
1995年 | 16080篇 |
1994年 | 13922篇 |
1993年 | 12254篇 |
1992年 | 9486篇 |
1991年 | 8645篇 |
1990年 | 7785篇 |
1989年 | 7250篇 |
1988年 | 6794篇 |
1987年 | 5495篇 |
1986年 | 5314篇 |
1985年 | 6279篇 |
1984年 | 5805篇 |
1983年 | 5008篇 |
1982年 | 4671篇 |
1981年 | 4561篇 |
1980年 | 4320篇 |
1979年 | 4134篇 |
1978年 | 3798篇 |
1977年 | 4577篇 |
1976年 | 6139篇 |
1975年 | 3132篇 |
1974年 | 3020篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
Wei Shaowei Yu Guoxian Wang Jun Domeniconi Carlotta Zhang Xiangliang 《Machine Learning》2021,110(6):1505-1526
Machine Learning - Traditional clustering algorithms focus on a single clustering result; as such, they cannot explore potential diverse patterns of complex real world data. To deal with this... 相似文献
102.
Fluorescence‐Activated Cell Sorters: Standing Surface Acoustic Wave (SSAW)‐Based Fluorescence‐Activated Cell Sorter (Small 40/2018)
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
103.
104.
105.
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
106.
Gomes A. C. S. A. Costa L. C. Brito D. C. Frana R. J. Marques Mnica R. C. 《Polymer Bulletin》2020,77(4):1969-1981
Polymer Bulletin - In this study, we synthesized a new ion-imprinted polymer (IIP) based on introduction of amidoxime groups in acrylonitrile, complexation with Cd2+ ions and polymerization with... 相似文献
107.
108.
Bianka Rocha Saraiva Lucas Henrique Maldonado da Silva Fernando Antônio Anjo Ana Carolina Pelaes Vital Jéssica Bassi Da Silva Marcos Luciano Bruschi Paula Toshimi Matumoto Pintro 《International Journal of Food Science & Technology》2020,55(5):1962-1970
Debittered trub (brewing waste) is an important source of protein source (70.26%). Trub and whey protein were used for 5% protein enrichment of ice cream frozen by liquid nitrogen. Three formulations were elaborated: ice cream standard (ICS), ice cream with whey protein (ICW) and ice cream with trub (ICT). Chemical composition, rheological properties, texture, overrun, melting rate, scanning electron microscopy and a sensorial test were performed. Results showed that ICT presented a higher viscosity, obtained on the upward curve up to 6.76 Pa s−1, consistency index (22.96 (Pa s−1)n), hysteresis area (140.40 mPa s−1) and hardness (31113.33 g) but a lower melting rate (0.38 g min−1), overrun (13.92%) and sensorial acceptability than the other formulations. The addition of trub debittered for protein enrichment improved ice cream properties and demonstrated that it could be used as a food ingredient. 相似文献
109.
Dan Ye Kaiyu Wang Haijiao Yang Xingang Zhao 《International Journal of Adaptive Control and Signal Processing》2020,34(11):1677-1696
In this article, an adaptive fuzzy output feedback control method is presented for nonlinear time-delay systems with time-varying full state constraints and input saturation. To overcome the problem of time-varying constraints, the integral barrier Lyapunov functions (IBLFs) integrating with dynamic surface control (DSC) are applied for the first time to keep the state from violating constraints. The effects of unknown time delays can be removed by using designed Lyapunov-Krasovskii functions (LKFs). An auxiliary design system is introduced to solve the problem of input saturation. The unknown nonlinear functions are approximated by the fuzzy logic systems (FLS), and the unmeasured states are estimated by a designed fuzzy observer. The novel controller can guarantee that all signals remain semiglobally uniformly ultimately bounded and satisfactory tracking performance is achieved. Finally, two simulation examples illustrate the effectiveness of the presented control methods. 相似文献
110.
The proliferating need for sustainability intervention in food grain transportation planning is anchoring the attention of researchers in the interests of stakeholders and environment at large. Uncertainty associated with food grain supply further intensifies the problem steering the need for designing robust, cost-efficient and sustainable models. In line with this, this paper aims to develop a robust and sustainable intermodal transportation model to facilitate single type of food grain commodity shipments while considering procurement uncertainty, greenhouse gas emissions, and intentional hub disruption. The problem is designed as a mixed integer non-linear robust optimisation model on a hub and spoke network for evaluating near optimal shipment quantity, route selection and hub location decisions. The robust optimisation approach considers minimisation of total relative regret associated with total cost subject to several real-time constraints. A version of Particle Swarm Optimisation with Differential Evolution is proposed to tackle the resulting NP-hard problem. The model is tested with two other state-of the art meta-heuristics for small, medium, and large datasets subject to different procurement scenarios inspired from real time food grain operations in Indian context. Finally, the solution is evaluated with respect to total cost, model and solution robustness for all instances. 相似文献