全文获取类型
收费全文 | 40008篇 |
免费 | 14941篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 755篇 |
综合类 | 30篇 |
化学工业 | 17955篇 |
金属工艺 | 351篇 |
机械仪表 | 740篇 |
建筑科学 | 1790篇 |
矿业工程 | 9篇 |
能源动力 | 922篇 |
轻工业 | 7563篇 |
水利工程 | 329篇 |
石油天然气 | 52篇 |
无线电 | 6925篇 |
一般工业技术 | 11804篇 |
冶金工业 | 985篇 |
原子能技术 | 20篇 |
自动化技术 | 4720篇 |
出版年
2024年 | 15篇 |
2023年 | 30篇 |
2022年 | 150篇 |
2021年 | 396篇 |
2020年 | 1517篇 |
2019年 | 3250篇 |
2018年 | 3189篇 |
2017年 | 3510篇 |
2016年 | 3985篇 |
2015年 | 4030篇 |
2014年 | 3983篇 |
2013年 | 5149篇 |
2012年 | 2845篇 |
2011年 | 2549篇 |
2010年 | 2764篇 |
2009年 | 2643篇 |
2008年 | 2201篇 |
2007年 | 2008篇 |
2006年 | 1757篇 |
2005年 | 1431篇 |
2004年 | 1398篇 |
2003年 | 1378篇 |
2002年 | 1310篇 |
2001年 | 1129篇 |
2000年 | 1109篇 |
1999年 | 503篇 |
1998年 | 162篇 |
1997年 | 131篇 |
1996年 | 71篇 |
1995年 | 58篇 |
1994年 | 41篇 |
1993年 | 54篇 |
1992年 | 27篇 |
1991年 | 27篇 |
1990年 | 17篇 |
1989年 | 17篇 |
1988年 | 4篇 |
1987年 | 14篇 |
1986年 | 18篇 |
1985年 | 14篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 8篇 |
1975年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Optimization and Engineering - 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.
Claudia Paredes Francisco J. Martínez-Vázquez Hamada Elsayed Paolo Colombo Antonia Pajares Pedro Miranda 《Journal of the European Ceramic Society》2021,41(1):892-900
Bioactive ceramic scaffolds for bone regeneration consisting of a three-dimensional mesh of interpenetrating struts with square section were fabricated via Digital Light Processing (DLP). The ability of the technique to manufacture 3D porous structures from β-tricalcium phosphate (β-TCP) powders with different dimensions of struts and pores was evaluated, identifying the possibilities and limitations of the manufacturing process. Small pore sizes were found to seriously complicate the elimination of excess slurry from the scaffold’s innermost pores. The effect of the strut/pore size on the mechanical performance of the scaffolds under compressive stresses was also evaluated, but no significant influence was found. Under compressive stresses, the structures resulted weaker when tested perpendicularly to the printing plane due to interlayer shear failure. Interlayer superficial grooves are proposed as potential failure-controlling defects, which could also explain the lack of a Weibull size effect on the mechanical strength of the fabricated DLP scaffolds. 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.
Friederike Freiin von Hvel Ekaterini Kefalakes Claudia Grothe 《International journal of molecular sciences》2021,22(1)
Fibroblast growth factor 2 (FGF-2), ubiquitously expressed in humans and mice, is functionally involved in cell growth, migration and maturation in vitro and in vivo. Based on the same mRNA, an 18-kilo Dalton (kDa) FGF-2 isoform named FGF-2 low molecular weight (FGF-2LMW) isoform is translated in humans and rodents. Additionally, two larger isoforms weighing 21 and 22 kDa also exist, summarized as the FGF-2 high molecular weight (FGF-2HMW) isoform. Meanwhile, the human FGF-2HMW comprises a 22, 23, 24 and 34 kDa protein. Independent studies verified a specific intracellular localization, mode of action and tissue-specific spatiotemporal expression of the FGF-2 isoforms, increasing the complexity of their physiological and pathophysiological roles. In order to analyze their spectrum of effects, FGF-2LMW knock out (ko) and FGF-2HMWko mice have been generated, as well as mice specifically overexpressing either FGF-2LMW or FGF-2HMW. So far, the development and functionality of the cardiovascular system, bone formation and regeneration as well as their impact on the central nervous system including disease models of neurodegeneration, have been examined. This review provides a summary of the studies characterizing the in vivo effects modulated by the FGF-2 isoforms and, thus, offers a comprehensive overview of its actions in the aforementioned organ systems. 相似文献
7.
Fluorescence‐Activated Cell Sorters: Standing Surface Acoustic Wave (SSAW)‐Based Fluorescence‐Activated Cell Sorter (Small 40/2018) 下载免费PDF全文
8.
9.
SPEEK/cSMM membrane for simultaneous electricity generation and wastewater treatment in microbial fuel cell 下载免费PDF全文
10.
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