全文获取类型
收费全文 | 8596篇 |
免费 | 415篇 |
国内免费 | 35篇 |
专业分类
电工技术 | 97篇 |
综合类 | 17篇 |
化学工业 | 1996篇 |
金属工艺 | 288篇 |
机械仪表 | 185篇 |
建筑科学 | 175篇 |
矿业工程 | 11篇 |
能源动力 | 623篇 |
轻工业 | 756篇 |
水利工程 | 70篇 |
石油天然气 | 25篇 |
无线电 | 833篇 |
一般工业技术 | 1915篇 |
冶金工业 | 1002篇 |
原子能技术 | 55篇 |
自动化技术 | 998篇 |
出版年
2023年 | 105篇 |
2022年 | 192篇 |
2021年 | 328篇 |
2020年 | 220篇 |
2019年 | 232篇 |
2018年 | 385篇 |
2017年 | 316篇 |
2016年 | 285篇 |
2015年 | 207篇 |
2014年 | 320篇 |
2013年 | 628篇 |
2012年 | 440篇 |
2011年 | 558篇 |
2010年 | 384篇 |
2009年 | 382篇 |
2008年 | 301篇 |
2007年 | 299篇 |
2006年 | 238篇 |
2005年 | 198篇 |
2004年 | 185篇 |
2003年 | 190篇 |
2002年 | 118篇 |
2001年 | 102篇 |
2000年 | 97篇 |
1999年 | 140篇 |
1998年 | 272篇 |
1997年 | 200篇 |
1996年 | 181篇 |
1995年 | 134篇 |
1994年 | 121篇 |
1993年 | 110篇 |
1992年 | 94篇 |
1991年 | 87篇 |
1990年 | 70篇 |
1989年 | 63篇 |
1988年 | 62篇 |
1987年 | 75篇 |
1986年 | 66篇 |
1985年 | 61篇 |
1984年 | 72篇 |
1983年 | 80篇 |
1982年 | 61篇 |
1981年 | 52篇 |
1980年 | 51篇 |
1979年 | 41篇 |
1978年 | 39篇 |
1977年 | 30篇 |
1976年 | 52篇 |
1974年 | 16篇 |
1973年 | 21篇 |
排序方式: 共有9046条查询结果,搜索用时 15 毫秒
1.
2.
Manik Chandra Biswas Samit Chakraborty Abhishek Bhattacharjee Zaheeruddin Mohammed 《Advanced functional materials》2021,31(19):2100257
Shape memory materials (SMMs) in 3D printing (3DP) technology garnered much attention due to their ability to respond to external stimuli, which direct this technology toward an emerging area of research, “4D printing (4DP) technology.” In contrast to classical 3D printed objects, the fourth dimension, time, allows printed objects to undergo significant changes in shape, size, or color when subjected to external stimuli. Highly precise and calibrated 4D materials, which can perform together to achieve robust 4D objects, are in great demand in various fields such as military applications, space suits, robotic systems, apparel, healthcare, sports, etc. This review, for the first time, to the best of the authors’ knowledge, focuses on recent advances in SMMs (e.g., polymers, metals, etc.) based wearable smart textiles and fashion goods. This review integrates the basic overview of 3DP technology, fabrication methods, the transition of 3DP to 4DP, the chemistry behind the fundamental working principles of 4D printed objects, materials selection for smart textiles and fashion goods. The central part summarizes the effect of major external stimuli on 4D textile materials followed by the major applications. Lastly, prospects and challenges are discussed, so that future researchers can continue the progress of this technology. 相似文献
3.
Prasad Ravi Kumar Madhu Santanoo Ramotra Prashant Edla Damodar Reddy 《Wireless Networks》2021,27(6):4111-4122
Wireless Networks - In Wireless Sensor Networks (WSNs), where power consumption is a huge concern, the improvement of the network’s lifetime is an area of constant study and innovation. The... 相似文献
4.
Mehmet Dorduncu Junuthula Narasimha Reddy 《Journal of Adhesion Science and Technology》2019,33(2):156-186
This study presents an improved mathematical model to analyse the stress wave propagation in adhesively bonded functionally graded (FG) circular cylinders (butt joint) under an axial impulsive load. The volume fractions of the material constituents in the upper and lower cylinders were functionally tailored through the thickness of each cylinder using a power-law. The effective material properties of both cylinders, which are made of aluminum (Al) and silicon carbide (SiC), at any point were predicted by using the Mori–Tanaka homogenization scheme. In this improved model, the governing equations of the wave propagation include the spatial derivatives of local mechanical properties and were discretized by means of the finite difference method. The influence of these spatial derivatives and the compositional gradient exponent on the displacement and stress distributions of the joint was investigated. The material composition variations of both cylinders affected the displacement and stress fields whereas the compositional gradient exponent had a minor effect. The stress concentrations were alleviated in time, the displacement and stress distributions/variations around/along the upper and lower cylinder-adhesive interfaces were significantly affected by the adhesive layer. The spatial derivatives also affected the temporal histories of the displacement and stress components evaluated at the selected critical points of the upper cylinder, adhesive layer and lower cylinder. The consideration of the spatial local material derivatives provided a more accurate mathematical model of wave propagations through the graded layered structures. 相似文献
5.
Kumar Kuila Saikat Kumbhakar Partha Sekhar Tiwary Chandra Kumar Kundu Tarun 《Journal of Materials Science》2022,57(19):8658-8675
Journal of Materials Science - Hybrid oxidation methodologies (HOMs) and active site enrichment of 2D nanocatalyst through defects induction are ubiquitously used for generating adequate reactive... 相似文献
6.
7.
8.
Madhu H. C. Edachery Vimal Lijesh K. P. Perugu Chandra Shekhar Kailas Satish V. 《Metallurgical and Materials Transactions A》2020,51(8):4086-4099
Metallurgical and Materials Transactions A - Hybrid nanocomposites have potential as wear-resistant materials. However, synthesizing these nanocomposites by conventional molten state methods result... 相似文献
9.
10.