全文获取类型
收费全文 | 477886篇 |
免费 | 36461篇 |
国内免费 | 20647篇 |
专业分类
电工技术 | 28568篇 |
技术理论 | 22篇 |
综合类 | 30969篇 |
化学工业 | 73012篇 |
金属工艺 | 27427篇 |
机械仪表 | 28553篇 |
建筑科学 | 34489篇 |
矿业工程 | 11984篇 |
能源动力 | 12644篇 |
轻工业 | 31707篇 |
水利工程 | 9561篇 |
石油天然气 | 20656篇 |
武器工业 | 3765篇 |
无线电 | 56517篇 |
一般工业技术 | 59783篇 |
冶金工业 | 21093篇 |
原子能技术 | 4666篇 |
自动化技术 | 79578篇 |
出版年
2024年 | 1457篇 |
2023年 | 5629篇 |
2022年 | 11170篇 |
2021年 | 15861篇 |
2020年 | 11577篇 |
2019年 | 9398篇 |
2018年 | 23624篇 |
2017年 | 24357篇 |
2016年 | 20037篇 |
2015年 | 16167篇 |
2014年 | 20404篇 |
2013年 | 25307篇 |
2012年 | 30626篇 |
2011年 | 38715篇 |
2010年 | 34594篇 |
2009年 | 31105篇 |
2008年 | 31836篇 |
2007年 | 31846篇 |
2006年 | 23716篇 |
2005年 | 20841篇 |
2004年 | 14813篇 |
2003年 | 12724篇 |
2002年 | 11370篇 |
2001年 | 9797篇 |
2000年 | 8970篇 |
1999年 | 8642篇 |
1998年 | 7197篇 |
1997年 | 5878篇 |
1996年 | 5393篇 |
1995年 | 4520篇 |
1994年 | 3793篇 |
1993年 | 2814篇 |
1992年 | 2208篇 |
1991年 | 1646篇 |
1990年 | 1281篇 |
1989年 | 1129篇 |
1988年 | 853篇 |
1987年 | 600篇 |
1986年 | 463篇 |
1985年 | 354篇 |
1984年 | 237篇 |
1983年 | 207篇 |
1982年 | 187篇 |
1981年 | 183篇 |
1980年 | 172篇 |
1979年 | 122篇 |
1978年 | 72篇 |
1977年 | 73篇 |
1976年 | 87篇 |
1954年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
全球炼化工程总承包市场呈现出垄断竞争型特征,欧美和日韩国际工程公司由于技术和报价竞争力较强,一直占据本行业高端市场,中国炼化工程企业尚有差距.文章综合考虑投标报价阶段竞争者分析路径,提出了随机型和不完全信息静态博弈综合集成分析的投标报价最优决策模型,并以中东海湾地区某炼化工程总承包项目为例,进行多维度的实证分析,提出模型的有效性和可行性,为中国炼化工程企业"走出去"高质量发展提供有益的决策支持和信息参考. 相似文献
92.
现代学徒制是一项深化产教融合、校企合作的育人机制,是创新技术技能人才的现代培养模式.山西铁道职业技术学院与山西安泰控股集团有限公司深度合作开展山西省现代学徒制试点项目,合作目的之一是培养企业煤化工专业人才.学校教师结合学生(员工)在企业车间岗位上的技能知识,系统地讲授煤化工专业课程"煤质分析及煤化工产品检验"理论知识,同时针对企业员工日常学习思想政治知识较少的实际,润物细无声地加入思政元素,实现专业知识与实践技能相结合,技能知识与思政教育相融合,真正培养知识型、技能型、创新型高素质技能人才,努力构建职业教育产业发展命运共同体. 相似文献
93.
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
94.
With the emergence of large-scale knowledge base, how to use triple information to generate natural questions is a key technology in question answering systems. The traditional way of generating questions require a lot of manual intervention and produce lots of noise. To solve these problems, we propose a joint model based on semi-automated model and End-to-End neural network to automatically generate questions. The semi-automated model can generate question templates and real questions combining the knowledge base and center graph. The End-to-End neural network directly sends the knowledge base and real questions to BiLSTM network. Meanwhile, the attention mechanism is utilized in the decoding layer, which makes the triples and generated questions more relevant. Finally, the experimental results on SimpleQuestions demonstrate the effectiveness of the proposed approach. 相似文献
95.
Amino acid modified polyaspartic acids were evaluated as calcium-scale inhibitors. Feasibility of scale inhibition experiments was analyzed by molecular dynamics simulation and Gaussian optimization, and the scale inhibition mechanism was theoretically analyzed. Scale inhibition performance was studied by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, static scale inhibition experiments, and electrochemical performance testing, which provided an experimental basis for the molecular dynamics simulation. The experimental results showed that Arg-SA-PASP has better scale inhibition and corrosion inhibition performance than His-SA-PASP. The scale inhibition effect increased with increasing concentration. Electrochemical tests indicated that Arg-SA-PASP is an excellent scale and corrosion inhibitor. 相似文献
96.
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)
97.
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
98.
99.
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
100.
Xueye Chen Yue Tian 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2020,95(3):806-812
Since the beginning of the 21st Century, the development of microfluidic chip technology has been very rapid and has attracted the attention of more and more scholars. As an important part of the microfluidic chip, the performance of the micromixer is critical. The fractal structure in the microchannels helps to improve the mixing performance of the micromixer and improve the mixing efficiency of the micromixer. The research results of other scholars are of great significance to the research of the present paper, which mainly studies the effect of changing the baffle state on the mixing efficiency of the micromixer based on the Koch fractal principle. Through simulation analysis, it was found that the mixing efficiency of the baffles distributed on both sides of the microchannel was higher than the mixing efficiency of the baffles distributed on the microchannel side. When the distance between adjacent baffles was divided into 0.15, 0.25 and 0.35 mm, simulated data suggested that the baffle distance of 0.15 mm was best. Increasing the number of baffles from six to eight groups increased the mixing path of the fluid in the microchannel and improved mixing efficiency. A comparison of mixing efficiencies of the 0°, 15° and 30° baffle angles revealed that very significant improvement in mixing efficiency was obtained at 30°. © 2019 Society of Chemical Industry 相似文献