全文获取类型
收费全文 | 217955篇 |
免费 | 24034篇 |
国内免费 | 15657篇 |
专业分类
电工技术 | 17756篇 |
技术理论 | 10篇 |
综合类 | 20089篇 |
化学工业 | 29685篇 |
金属工艺 | 14044篇 |
机械仪表 | 15077篇 |
建筑科学 | 17181篇 |
矿业工程 | 7841篇 |
能源动力 | 5966篇 |
轻工业 | 22166篇 |
水利工程 | 6584篇 |
石油天然气 | 8851篇 |
武器工业 | 2483篇 |
无线电 | 24313篇 |
一般工业技术 | 20854篇 |
冶金工业 | 9060篇 |
原子能技术 | 3766篇 |
自动化技术 | 31920篇 |
出版年
2024年 | 1075篇 |
2023年 | 3448篇 |
2022年 | 7765篇 |
2021年 | 9982篇 |
2020年 | 7457篇 |
2019年 | 5454篇 |
2018年 | 5880篇 |
2017年 | 6806篇 |
2016年 | 6083篇 |
2015年 | 9236篇 |
2014年 | 11707篇 |
2013年 | 13724篇 |
2012年 | 16531篇 |
2011年 | 17100篇 |
2010年 | 16529篇 |
2009年 | 15634篇 |
2008年 | 16157篇 |
2007年 | 15949篇 |
2006年 | 14103篇 |
2005年 | 11939篇 |
2004年 | 8588篇 |
2003年 | 6061篇 |
2002年 | 5766篇 |
2001年 | 5452篇 |
2000年 | 4658篇 |
1999年 | 3067篇 |
1998年 | 2103篇 |
1997年 | 1713篇 |
1996年 | 1587篇 |
1995年 | 1214篇 |
1994年 | 1115篇 |
1993年 | 843篇 |
1992年 | 630篇 |
1991年 | 498篇 |
1990年 | 380篇 |
1989年 | 332篇 |
1988年 | 279篇 |
1987年 | 176篇 |
1986年 | 136篇 |
1985年 | 92篇 |
1984年 | 46篇 |
1983年 | 49篇 |
1982年 | 53篇 |
1981年 | 49篇 |
1980年 | 65篇 |
1979年 | 30篇 |
1977年 | 6篇 |
1976年 | 8篇 |
1959年 | 27篇 |
1951年 | 30篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Deep Integration of Innovation and Entrepreneurship (InE) Education in Chinese University Classrooms
Recently, InE has been regarded as a popular education strategy in Chinese universities. However, problems have been exposed in the adoption of InE, for example, in InE courses and competitions. The purpose of this paper is to provide a possible solution to the problems, which is to organize effective InE courses by integrating InE with Inter-Course-level Problem-Based Learning (ICPBL). A detailed case is demonstrated by an ICPBL elective course design with deep integration of InE in the teaching, learning, and assessments. This paper contributes to a new curriculum design for promoting InE education in practically for Chinese universities. 相似文献
72.
The Journal of Supercomputing - Cyber physical system (CPS) is consisting of two interdependent networks, i.e., a cyber network embedding into a physical network. Although interdependence makes the... 相似文献
73.
“Smart firefighting” construction as a part of the “smart city” has been a concern of the public security and fire agencies at all levels. In this study, the status, problems, and reflections of “smart firefighting” construction in China are discussed. A recent survey indicates that China has launched its smart firefighting construction and initially created a new perspective on its regional smart firefighting work based on three main aspects: intelligent disaster perception by Internet of Things (IoT) construction, intelligent disaster prevention by big data construction, and intelligent disaster disposal by emergency rescue platform construction. However, the current smart firefighting construction in China still has some prominent problems such as the data interconnectivity and normalized management of various platforms, the extensibility of smart firefighting platforms, and the intelligent level of smart firefighting researches, which need to be solved urgently. Therefore, we argue that smart firefighting construction in China should establish data interconnectivity, industrial normalized management, 2D/3D geographic information interaction and extension, high-integration fire protection theory, and many other aspects in the near future and truly realize firefighting visualization and efficient data applications for 4D time space. This study could provide valuable reference for smart firefighting and smart city construction. 相似文献
74.
面对现代城市污染加剧的问题,做好城市规划对减少城市的碳排放具有决定性的作用。本文以低碳排放作为城市规划的出发点,从现代节能减排技术入手,构建城市空间规划立体网络,为低碳城市建设提供参考。 相似文献
75.
锦纶长丝的染色均匀度测试方法一直是采用人工判色方法,其判色结果会因人眼目光的不同导致经常会存在一定的误差,对企业节约成本和实际生产应用相当不利。本文提出了一种利用测试锦纶DTY长丝热收缩应力的方法,用热应力测试结果对锦纶染色性能进行预判,不需要进行织袜染色,为企业节约大量的人工成本。 相似文献
76.
77.
78.
Yong Pan Chen Zhu Wen Bin Zeng Pei Fu Chi Chen Bao Ming Xu Zhong Feng Gao 《Chembiochem : a European journal of chemical biology》2021,22(24):3431-3436
Rapid and sensitive point-of-care testing (POCT) is an extremely critical mission in practical applications, especially for rigorous military medicine, home health care, and in the third world. Here, we report a visual POCT method for adenosine triphosphate (ATP) detection based on Taylor rising in the corner of quadratic geometries between two rod surfaces. We discuss the principle of Taylor rising, demonstrating that it is significantly influenced by contact angle, surface tension, and density of the sample, which are controlled by ATP-dependent rolling circle amplification (RCA). In the presence of ATP, RCA reaction effectively suppresses Taylor-rising behavior, due to the increased contact angle, density, and decreased surface tension. Without addition of ATP, untriggered RCA reaction is favorable for Taylor rising, resulting in a significant height. With this proposed method, visual sensitive detection of ATP without the aid of other instruments is realized with only a 5 μL droplet, which has good selectivity and a low detection limit (17 nM). Importantly, this visual method provides a promising POCT tool for user-friendly molecular diagnostics. 相似文献
79.
Zhen Wu Jing Yao Pengfei Zhu Fusheng Yang Xiangyu Meng Sandra Kurko Zaoxiao Zhang 《International Journal of Hydrogen Energy》2021,46(19):11183-11198
Advanced biogas power generation technology has been attracting attentions, which contributes to the waste disposal and the mitigation of greenhouse gas emissions. This work proposes and models a novel biogas-fed hybrid power generation system consisting of solid oxide fuel cell, water gas shift reaction, thermal swing adsorption and proton exchange membrane fuel cell (SOFC-WGS-TSA-PEMFC). The thermodynamic, exergetic, and thermo-economic analyses of this hybrid system for power generation were conducted to comprehensively evaluate its performance. It was found that the novel biogas-fed hybrid system has a gross energy conversion efficiency of 68.63% and exergy efficiency of 65.36%, indicating high efficiency for this kind of hybrid power technology. The market sensitivity analysis showed that the hybrid system also has a low sensitivity to market price fluctuation. Under the current subsidy level for the distributed biogas power plant, the levelized cost of energy can be lowered to 0.02942 $/kWh for a 1 MW scale system. Accordingly, the payback period and annual return on investment can reach 1.4 year and about 20%, respectively. These results reveal that the proposed hybrid system is promising and economically feasible as a distributed power plant, especially for the small power scale (no more than 2 MW). 相似文献
80.
The support flux was first investigated as a separate influencing factor for its effect on performances of ceramic filtration membranes. Three pre-membranes were prepared by tape-casting and then transfer-coated to supports to form dual-layer ceramic membranes after sintering. Experiments demonstrated that membrane layers with almost the same properties were obtained despite the huge difference in support flux. When the support flux increases from 3.120 to 97.53 m3m?2h?1, the flux of these three membrane series have increased by 75%, 186% and 228%, respectively. Experimental rules can provide structural design and evaluation from the perspective of permeability. The limit membrane flux of a certain system was derived according to the resistance distribution law of internal membrane structure and the Darcy's theorem. On this basis, a method for designing support flux was proposed. Furthermore, we present a criterion to quickly and easily evaluate the match between the support and the top layer, which is the ratio of membrane resistance to total resistance. Finally, the filtration resistance of penetration caused by suction of membrane particles into the support was measured for the first time, taking the advantage of the transfer-coating method that inherently free of penetration. Our works are expected to deepen the understanding of the ceramic membrane structure and provided guidance for its rational design and optimization. 相似文献