全文获取类型
收费全文 | 53605篇 |
免费 | 15531篇 |
国内免费 | 546篇 |
专业分类
电工技术 | 1333篇 |
综合类 | 575篇 |
化学工业 | 19445篇 |
金属工艺 | 999篇 |
机械仪表 | 1636篇 |
建筑科学 | 2439篇 |
矿业工程 | 178篇 |
能源动力 | 1475篇 |
轻工业 | 8042篇 |
水利工程 | 558篇 |
石油天然气 | 406篇 |
武器工业 | 80篇 |
无线电 | 9516篇 |
一般工业技术 | 13638篇 |
冶金工业 | 1927篇 |
原子能技术 | 262篇 |
自动化技术 | 7173篇 |
出版年
2024年 | 36篇 |
2023年 | 176篇 |
2022年 | 380篇 |
2021年 | 779篇 |
2020年 | 1738篇 |
2019年 | 3448篇 |
2018年 | 3481篇 |
2017年 | 3781篇 |
2016年 | 4273篇 |
2015年 | 4410篇 |
2014年 | 4568篇 |
2013年 | 5991篇 |
2012年 | 3657篇 |
2011年 | 3472篇 |
2010年 | 3513篇 |
2009年 | 3489篇 |
2008年 | 2899篇 |
2007年 | 2684篇 |
2006年 | 2345篇 |
2005年 | 1987篇 |
2004年 | 1867篇 |
2003年 | 1878篇 |
2002年 | 1856篇 |
2001年 | 1634篇 |
2000年 | 1418篇 |
1999年 | 773篇 |
1998年 | 648篇 |
1997年 | 414篇 |
1996年 | 316篇 |
1995年 | 241篇 |
1994年 | 230篇 |
1993年 | 223篇 |
1992年 | 126篇 |
1991年 | 120篇 |
1990年 | 105篇 |
1989年 | 98篇 |
1988年 | 79篇 |
1987年 | 68篇 |
1986年 | 65篇 |
1985年 | 51篇 |
1984年 | 46篇 |
1983年 | 32篇 |
1982年 | 32篇 |
1981年 | 29篇 |
1980年 | 28篇 |
1979年 | 32篇 |
1978年 | 28篇 |
1977年 | 26篇 |
1976年 | 32篇 |
1973年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Bijan Nasri‐Nasrabadi Akif Kaynak Shayan Seyedin Zahra Komeily‐Nia Abbas Z Kouzani 《Polymer International》2019,68(5):922-928
Recent advances in three‐dimensional (3D) printing have enabled the fabrication of interesting structures which are not achievable using traditional fabrication approaches. The 3D printing of carbon microtube composite inks allows fabrication of conductive structures for practical applications in soft robotics and tissue engineering. However, it is challenging to achieve 3D printed structures from solution‐based composite inks, which requires an additional process to solidify the ink. Here, we introduce a wet 3D printing technique which uses a coagulation bath to fabricate carbon microtube composite structures. We show that through a facile nanogrooving approach which introduces cavitation and channels on carbon microtubes, enhanced interfacial interactions with a chitosan polymer matrix are achieved. Consequently, the mechanical properties of the 3D printed composites improve when nanogrooved carbon microtubes are used, compared to untreated microtubes. We show that by carefully controlling the coagulation bath, extrusion pressure, printing distance and printed line distance, we can 3D print composite lattices which are composed of well‐defined and separated printed lines. The conductive composite 3D structures with highly customised design presented in this work provide a suitable platform for applications ranging from soft robotics to smart tissue engineering scaffolds. © 2019 Society of Chemical Industry 相似文献
2.
Karolina Storesund Francine Amon Anne Steen‐Hansen Shayesteh Haghighatpanah Ida Larsson 《火与材料》2021,45(1):181-190
The aim of this exploratory study has been to investigate the fire properties and environmental aspects of different upholstery material combinations, mainly for domestic applications. An analysis of the sustainability and circularity of selected textiles, along with lifecycle assessment, is used to qualitatively evaluate materials from an environmental perspective. The cone calorimeter was the primary tool used to screen 20 different material combinations from a fire performance perspective. It was found that textile covers of conventional fibres such as wool, cotton and polyester, can be improved by blending them with fire resistant speciality fibres. A new three‐dimensional web structure has been examined as an alternative padding material, showing preliminary promising fire properties with regard to ignition time, heat release rates and smoke production. 相似文献
3.
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)
4.
目的研究蛋类礼盒包装结构的缓冲性能。方法以蛋类尺寸为基础,建立可发性聚乙烯(expandable polyethylene. EPE)缓冲单元结构和组合结构,进行静态仿真分析和实验验证,比较结构在形状、叠合层数、组合形式等参数变化时的载荷与位移。结果结构层数变化相同时,单元结构的极限载荷从143N增加到236 N,组合结构的极限载荷从224 N增加到476 N,均呈近线性增长。结论蛋类礼盒包装中,组合结构的承载能力优于单元结构,通过单元结构的组合,可满足不同蛋类的包装要求。 相似文献
5.
6.
7.
SPEEK/cSMM membrane for simultaneous electricity generation and wastewater treatment in microbial fuel cell
下载免费PDF全文
![点击此处可从《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
8.
Efficacy of Crude and Purified Chitinases (SsChi50) Extracted from Offal Red Scorpion Fish in Biological Control of Chickpea Weevil (Callosobruchus maculatus L.)
下载免费PDF全文
![点击此处可从《Journal of Food Processing and Preservation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
9.
Quality enhancement of the abundant under‐valued crustacean,lobster krill (Munida spp.), during its chilled storage
下载免费PDF全文
![点击此处可从《International Journal of Food Science & Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Bibiana García‐Soto José M. Miranda Jorge Barros‐Velázquez Santiago P. Aubourg 《International Journal of Food Science & Technology》2015,50(3):708-716
Lobster krill (Munida genus) represents an under‐valued crustacean frequently caught on European fishing banks. In this work, its sensory, microbiological and biochemical qualities were evaluated during chilled storage. Additionally, the effects of a prestorage antimelanosic treatment consisting of soaking in sodium metabisulphite (SMB) solutions at two different concentrations (0.25% and 0.75%) were also studied. SMB prestorage treatment provided lobster specimens that still exhibited acceptable sensory quality after 10 days of storage, while control specimens were unacceptable at that time. SMB treatment also resulted in a significant (P < 0.05) inhibition of microbial growth, mainly of Enterobacteriaceae, psychrotrophes and proteolytic bacteria. Low lipid oxidation levels were observed for all batches; however, a significantly higher (P < 0.05) retention of polyunsaturated fatty acids was found in SMB‐treated lobster, especially in the 0.75% SMB batch. The results presented here open the way to the potential commercialisation of currently under‐utilised lobster krill as a chilled product. 相似文献
10.
Eui Dae Jung Amit Kumar Harit Do Hui Kim Chung Hyeon Jang Jong Hyun Park Shinuk Cho Myoung Hoon Song Han Young Woo 《Advanced materials (Deerfield Beach, Fla.)》2020,32(30):2002333
A series of anionic conjugated polyelectrolytes (CPEs) is synthesized based on poly(fluorene-co-phenylene) by varying the side-chain ionic density from two to six per repeat units (MPS2-TMA, MPS4-TMA, and MPS6-TMA). The effect of MPS2, 4, 6-TMA as interlayers on top of a hole-extraction layer of poly(bis(4-phenyl)-2,4,6-trimethylphenylamine (PTAA) is investigated in inverted perovskite solar cells (PeSCs). Owing to the improved wettability of perovskites on hydrophobic PTAA with the CPEs, the PeSCs with CPE interlayers demonstrate a significantly enhanced device performance, with negligible device-to-device dependence relative to the reference PeSC without CPEs. By increasing the ionic density in the MPS-TMA interlayers, the wetting, interfacial defect passivation, and crystal growth of the perovskites are significantly improved without increasing the series resistance of the PeSCs. In particular, the open-circuit voltage increases from 1.06 V for the PeSC with MPS2-TMA to 1.11 V for the PeSC with MPS6-TMA. The trap densities of the PeSCs with MPS2,4,6-TMA are further analyzed using frequency-dependent capacitance measurements. Finally, a large-area (1 cm2) PeSC is successfully fabricated with MPS6-TMA, showing a power conversion efficiency of 18.38% with negligible hysteresis and a stable power output under light soaking for 60 s. 相似文献