全文获取类型
收费全文 | 3556篇 |
免费 | 93篇 |
国内免费 | 16篇 |
专业分类
电工技术 | 56篇 |
综合类 | 8篇 |
化学工业 | 708篇 |
金属工艺 | 128篇 |
机械仪表 | 109篇 |
建筑科学 | 47篇 |
矿业工程 | 15篇 |
能源动力 | 183篇 |
轻工业 | 215篇 |
水利工程 | 30篇 |
石油天然气 | 6篇 |
无线电 | 553篇 |
一般工业技术 | 873篇 |
冶金工业 | 352篇 |
原子能技术 | 37篇 |
自动化技术 | 345篇 |
出版年
2024年 | 13篇 |
2023年 | 44篇 |
2022年 | 79篇 |
2021年 | 162篇 |
2020年 | 87篇 |
2019年 | 89篇 |
2018年 | 131篇 |
2017年 | 90篇 |
2016年 | 108篇 |
2015年 | 78篇 |
2014年 | 112篇 |
2013年 | 218篇 |
2012年 | 139篇 |
2011年 | 199篇 |
2010年 | 153篇 |
2009年 | 167篇 |
2008年 | 144篇 |
2007年 | 115篇 |
2006年 | 111篇 |
2005年 | 90篇 |
2004年 | 67篇 |
2003年 | 70篇 |
2002年 | 58篇 |
2001年 | 63篇 |
2000年 | 67篇 |
1999年 | 53篇 |
1998年 | 110篇 |
1997年 | 60篇 |
1996年 | 56篇 |
1995年 | 51篇 |
1994年 | 65篇 |
1993年 | 61篇 |
1992年 | 57篇 |
1991年 | 58篇 |
1990年 | 46篇 |
1989年 | 36篇 |
1988年 | 30篇 |
1987年 | 35篇 |
1986年 | 32篇 |
1985年 | 23篇 |
1984年 | 32篇 |
1983年 | 22篇 |
1982年 | 29篇 |
1981年 | 14篇 |
1980年 | 24篇 |
1979年 | 21篇 |
1978年 | 12篇 |
1977年 | 18篇 |
1976年 | 23篇 |
1973年 | 8篇 |
排序方式: 共有3665条查询结果,搜索用时 31 毫秒
121.
122.
The role of nanotopography on the long‐term response of progenitor cells is explored using polycaprolactone (PCL) nanopillar and nanofiber surfaces seeded with plastic‐adherent rat multipotent mesenchymal stromal cells (MSCs). After 4 weeks in culture under normal expansion media conditions, MSCs cultured on nanofibers exhibit better adherence, increased proliferation, and maintain increasingly dense fibroblast‐like morphologies. In contrast, MSCs seeded on nanopillar surfaces display lowered adherence, reduced proliferation, and adopt highly elongated cellular morphologies. Immunofluorescent staining of MSCs on PCL nanopillars reveals the presence of two bone marker proteins, osteopontin and osteocalcin, providing evidence for surface induced differentiation into osteoblast‐like cells. Unlike the nanopillar topography, MSCs cultured on nanofiber and smooth PCL surfaces did not appear to undergo osteogenesis. Observed differences in cellular response to the PCL nanotopographies offer strategies to direct progenitor cell populations solely based upon submicron surface modifications. This study provides a foundation for future work exploring variations in PCL nanopillar topography with the goal of optimizing adherence and osteogenic response of MSCs. 相似文献
123.
Microsystem Technologies - In the current paper, a new temperature sensor with improved temperature inaccuracy and with very low power consumption has been designed for avionic industry. The... 相似文献
124.
Thermal analysis of randomly oriented carbon nanotube reinforced functionally graded timoshenko beam
Benedict Thomas Prasad K. Inamdar Tarapada Roy 《Journal of Mechanical Science and Technology》2014,28(5):1779-1788
The unique thermal properties of carbon nanotubes (CNT) are utilized to increase the use of functionally graded material (FGM) at higher temperatures which resulted in introduction of a new type of material called as functionally graded carbon nanotube-reinforced composites (FG-CNTRCs). To use the FG-CNTRCs at elevated temperatures, their thermal analysis is very important. In this context, this article presents the thermal analysis of a CNT based FG Timoshenko beam. Material properties distribution is assumed to vary along the thickness direction according to power law distribution and linear distributions. Finite difference method is implemented to find out the temperature distribution. Using first order shear deformation theory (FSDT), expressions for strains and stresses are obtained. The results are compared with temperature distribution according to power law. The effect of CNT distribution on strains and stresses is also observed. Based on these results important conclusions have been drawn. 相似文献
125.
Ajay Singh S. Samanta Arvind Kumar A.K. Debnath R. Prasad P. Veerender Vishal Balouria D.K. Aswal S.K. Gupta 《Organic Electronics》2012,13(11):2600-2604
Charge transport and gas sensing characteristics of cobalt phthalocyanine films deposited along (ATB) and perpendicular (PTB) to the natural twin boundaries of (0 0 1) LaAlO3 substrate have been investigated. The charge carrier mobility of ATB films (∼5 cm2 V−1 s−1) is five orders of magnitude higher compared to that of PTB films (∼7 × 10−5 cm2 V−1 s−1), suggesting that twin boundaries acts like a template for ordering of molecules. The ATB films on exposure to ammonia showed a reversible increase of resistance, with fast response and recovery. In contrast PTB films showed same sensitivity, but exhibits base resistance drift along with sluggish response. 相似文献
126.
Singh Chitranjan Prasad Agrawal Hemant Mishra Arvind Kumar 《Bulletin of Engineering Geology and the Environment》2021,80(10):8009-8019
Bulletin of Engineering Geology and the Environment - Vibrations induced due to blasting in mines may damage the nearby houses and disturb the habitants. The monitoring, prediction, and control of... 相似文献
127.
128.
Abhishek Mitra N. Siva Prasad G. D. Janaki Ram 《Journal of Materials Engineering and Performance》2016,25(4):1384-1393
Ferritic steel weldments are invariably post-weld heat treated for relieving the residual stresses. However, the long duration of post-weld heat treatment (PWHT) required for very thick weldments can adversely affect the mechanical properties and fracture toughness. Thus, there is a need to establish the relative importance of temperature and time of PWHT with respect to stress relief. Accordingly, in the present work, the phenomenon of stress relief (due to PWHT) in an 800-mm-thick steel weldment was investigated using finite element analysis and the results were validated against experimental measurements. An analytical study was also carried out to determine the relative influence of temperature and time of PWHT on stress relief. It was found that time of PWHT plays a more significant role in case of relatively lower PWHT temperatures. It was also found that, for a given value of Hollomon parameter, different combinations of PWHT temperature and time can be employed to achieve the same level of stress relief. A mathematical relationship has been established between Hollomon parameter and magnitude of residual stress after PWHT. It has been shown that residual stress is a monotonically decreasing function of the Hollomon parameter. 相似文献
129.
Debi Prasad Das Danielle J. Moreau Ben S. Cazzolato 《Control Engineering Practice》2013,21(4):544-555
In this paper, a feed-forward nonlinear active noise control algorithm is developed using the Filtered-S LMS (FSLMS) algorithm and virtual microphone control for an active headrest application. Virtual microphone control is implemented to attenuate noise at the ears of the headrest occupant using the physical microphones placed at remote locations. The proposed nonlinear virtual microphone control algorithm is verified in real-time in a headrest. Different nonlinear noise processes are studied and it is shown that in all cases, the FSLMS algorithm outperforms the FXLMS algorithm in controlling nonlinear primary noise at a virtual location. 相似文献
130.
eWALL framework, under development in the European eWALL project (project no. 610658: “eWALL for Active Long Living”) is meant for care of population with age related impairments, mild dementia and COPD. Expanded eWALL (e2WALL) is planned to be an integrated quality framework for long-term care services which will cover very different types of care: all healthcare (both preventive and rehabilitative), societal services, care for cognitive diseases, services delivered at home as well as support for caregivers as an integral part of the quality improvement process. Thus, we present e2WALL home system that would encompass installation (setup) of e2WALL in homes (flats, houses and aging homes) and their management and maintenance across Europe, starting from the partners involved in eWALL (Austria, Bulgaria, Croatia, Denmark, Former Yugoslav Republic of Macedonia, Germany, Greece, Italy, Montenegro, The Netherlands and Romania) and expanding the partnership to the most of Europe (e.g. United Kingdom, Poland, Czech Republic…). This would be a direct application of the developed e2WALL platform and should be done through a network of collaborating small-to-medium sized enterprises (SMEs), each of whom would lead the process of setting up e2WALL system and continuing to provide support services to homes in their respective country. In this way, the growth of high tech and innovative SMEs will be ensured at pan European level, which will enable growth over restricted national market and stimulate European investments in SMEs and startups. Actually, the bigger platform will enable e2WALL European Ecosystem (e4WALL), which can then expand into other non-European markets (e.g. Asia, USA) and means sustainability beyond the life of the project. e2WALL will lead to connected tech start-up hubs to the larger European business ecosystem and will contribute to increased access of country-specific and customized new product to the pan European market, which will lead to increase of employed qualified individuals. Another important focus would be creating an energy efficient environment for a new social network where registered users would provide on-demand services. 相似文献