全文获取类型
收费全文 | 81044篇 |
免费 | 18357篇 |
国内免费 | 2650篇 |
专业分类
电工技术 | 3529篇 |
技术理论 | 4篇 |
综合类 | 3566篇 |
化学工业 | 23646篇 |
金属工艺 | 2805篇 |
机械仪表 | 3431篇 |
建筑科学 | 5353篇 |
矿业工程 | 1252篇 |
能源动力 | 2297篇 |
轻工业 | 9528篇 |
水利工程 | 1116篇 |
石油天然气 | 2272篇 |
武器工业 | 347篇 |
无线电 | 12415篇 |
一般工业技术 | 16265篇 |
冶金工业 | 2620篇 |
原子能技术 | 620篇 |
自动化技术 | 10985篇 |
出版年
2024年 | 181篇 |
2023年 | 662篇 |
2022年 | 1197篇 |
2021年 | 1902篇 |
2020年 | 2637篇 |
2019年 | 4142篇 |
2018年 | 4206篇 |
2017年 | 4590篇 |
2016年 | 4950篇 |
2015年 | 5451篇 |
2014年 | 5829篇 |
2013年 | 7406篇 |
2012年 | 5306篇 |
2011年 | 5146篇 |
2010年 | 5169篇 |
2009年 | 4899篇 |
2008年 | 4454篇 |
2007年 | 4192篇 |
2006年 | 3864篇 |
2005年 | 3285篇 |
2004年 | 3101篇 |
2003年 | 3505篇 |
2002年 | 3896篇 |
2001年 | 3389篇 |
2000年 | 2444篇 |
1999年 | 1562篇 |
1998年 | 822篇 |
1997年 | 683篇 |
1996年 | 672篇 |
1995年 | 469篇 |
1994年 | 415篇 |
1993年 | 304篇 |
1992年 | 266篇 |
1991年 | 201篇 |
1990年 | 187篇 |
1989年 | 128篇 |
1988年 | 104篇 |
1987年 | 79篇 |
1986年 | 66篇 |
1985年 | 56篇 |
1984年 | 31篇 |
1983年 | 24篇 |
1982年 | 39篇 |
1981年 | 26篇 |
1980年 | 24篇 |
1979年 | 14篇 |
1978年 | 12篇 |
1977年 | 12篇 |
1976年 | 13篇 |
1959年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Da-Wang Tan Zhen-Yong Lao Zhan Zhang Wei-Ming Guo Shi-Kuan Sun Hua-Tay Lin 《Journal of the American Ceramic Society》2021,104(6):2860-2867
B4C-TiB2 ceramics (TiB2 ranging 5~70 vol%) with Mo-Co-WC as the sintering additive were prepared by spark plasma sintering. In comparison with B4C-TiB2 without additive, the enhanced densification was evident in the sintered specimen with Mo-Co-WC additive. Core-rim structured grain was observed around TiB2 grains. The interface of the rim between TiB2 and B4C phases demonstrated different feature: the inner borderline of the rim exhibited a smooth feature, whereas a sharp curved grain boundary was observed between the rim and the B4C grain. The formation mechanism is discussed: the epitaxial growth of (Ti,Mo,W)B2 rim around the TiB2 core may occur as a result of the solid solution and dissolution-precipitation between TiB2 phase and the sintering additive. It was revealed that the fracture toughness increased as the content of TiB2 content increased, alongside the decreased hardness. B4C-30 vol% TiB2 specimen demonstrated the optimal combination of mechanical properties, reaching Vickers hardness of 24.3 GPa and fracture toughness of 3.33 MPa·m1/2. 相似文献
3.
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
4.
5.
6.
7.
8.
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
9.
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)