全文获取类型
收费全文 | 46066篇 |
免费 | 15328篇 |
国内免费 | 226篇 |
专业分类
电工技术 | 1076篇 |
综合类 | 341篇 |
化学工业 | 18863篇 |
金属工艺 | 875篇 |
机械仪表 | 1382篇 |
建筑科学 | 2043篇 |
矿业工程 | 148篇 |
能源动力 | 1145篇 |
轻工业 | 7804篇 |
水利工程 | 387篇 |
石油天然气 | 197篇 |
武器工业 | 22篇 |
无线电 | 7871篇 |
一般工业技术 | 12862篇 |
冶金工业 | 1126篇 |
原子能技术 | 146篇 |
自动化技术 | 5332篇 |
出版年
2024年 | 31篇 |
2023年 | 167篇 |
2022年 | 317篇 |
2021年 | 604篇 |
2020年 | 1699篇 |
2019年 | 3371篇 |
2018年 | 3339篇 |
2017年 | 3670篇 |
2016年 | 4145篇 |
2015年 | 4240篇 |
2014年 | 4294篇 |
2013年 | 5550篇 |
2012年 | 3366篇 |
2011年 | 3059篇 |
2010年 | 3116篇 |
2009年 | 3041篇 |
2008年 | 2541篇 |
2007年 | 2293篇 |
2006年 | 2026篇 |
2005年 | 1678篇 |
2004年 | 1572篇 |
2003年 | 1576篇 |
2002年 | 1500篇 |
2001年 | 1280篇 |
2000年 | 1218篇 |
1999年 | 600篇 |
1998年 | 246篇 |
1997年 | 176篇 |
1996年 | 139篇 |
1995年 | 111篇 |
1994年 | 92篇 |
1993年 | 90篇 |
1992年 | 72篇 |
1991年 | 69篇 |
1990年 | 47篇 |
1989年 | 26篇 |
1988年 | 30篇 |
1987年 | 21篇 |
1986年 | 19篇 |
1985年 | 31篇 |
1984年 | 16篇 |
1983年 | 13篇 |
1982年 | 6篇 |
1981年 | 16篇 |
1980年 | 19篇 |
1979年 | 11篇 |
1977年 | 12篇 |
1976年 | 16篇 |
1975年 | 10篇 |
1974年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Chenchen Zhou Jia Man Haibo Yu He Xia Luming Man Bin Qi Jianfeng Li 《Ceramics International》2021,47(8):10866-10872
Ceramic microparticles have great potentials in various fields such as materials engineering, biotechnology, microelectromechanical systems, etc. Morphology of the microparticle performs an important role on their application. To date, it remains difficult to find an effective and controllable way for fabricating nonspherical ceramic microparticles with 3D features. This work demonstrates a method that combines UV light lithography and single emulsion opaque-droplet-templated microfluidic molding to prepare the crescent-shaped ceramic microparticles. By tailoring the intensity of UV light and flow rate of fluid, the shapes of microparticles are accordingly tuned. Therefore, varieties of crescent-shaped microparticles and their variations have been fabricated. After sintering, the crescent-shaped alumina ceramic microparticles were obtained. Benefitting from the light absorption and scattering behavior of most ceramic nanoparticles, this system can serve as a general platform to produce crescent-shaped microparticles made from different materials, and hold great potentials for applications in microrobotics, structural materials in MEMS, and biotechnology. 相似文献
3.
Zhang Nan Zhao Man Liu Guangfa Wang Jiaoyang Chen Yunzhi Zhang Zhengjian 《Journal of Materials Science》2022,57(19):8687-8700
Journal of Materials Science - A green modification method for effectively enhancing toughness of PLA was established. Herein, alkaline lignin (LG) was firstly alkylated with dodecane, and then... 相似文献
4.
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
5.
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
6.
Wireless Personal Communications - Random Access techniques are many, most of which are designed for a limited number of mobile nodes. However, in a 5G Internet of Things environment, the design of... 相似文献
7.
8.
Fluorescence‐Activated Cell Sorters: Standing Surface Acoustic Wave (SSAW)‐Based Fluorescence‐Activated Cell Sorter (Small 40/2018) 下载免费PDF全文
9.
Multimedia Systems - The preferences of Web information purchasers are changing. Cost-effectiveness (i.e., an emphasis on performance with respect to price) is becoming less regarded than... 相似文献