全文获取类型
收费全文 | 1489篇 |
免费 | 70篇 |
国内免费 | 11篇 |
专业分类
电工技术 | 21篇 |
化学工业 | 403篇 |
金属工艺 | 33篇 |
机械仪表 | 42篇 |
建筑科学 | 29篇 |
矿业工程 | 5篇 |
能源动力 | 92篇 |
轻工业 | 126篇 |
水利工程 | 9篇 |
石油天然气 | 6篇 |
无线电 | 168篇 |
一般工业技术 | 367篇 |
冶金工业 | 77篇 |
原子能技术 | 11篇 |
自动化技术 | 181篇 |
出版年
2024年 | 7篇 |
2023年 | 55篇 |
2022年 | 74篇 |
2021年 | 108篇 |
2020年 | 73篇 |
2019年 | 82篇 |
2018年 | 104篇 |
2017年 | 72篇 |
2016年 | 88篇 |
2015年 | 47篇 |
2014年 | 79篇 |
2013年 | 114篇 |
2012年 | 79篇 |
2011年 | 78篇 |
2010年 | 66篇 |
2009年 | 49篇 |
2008年 | 57篇 |
2007年 | 44篇 |
2006年 | 18篇 |
2005年 | 12篇 |
2004年 | 20篇 |
2003年 | 18篇 |
2002年 | 13篇 |
2001年 | 17篇 |
2000年 | 17篇 |
1999年 | 5篇 |
1998年 | 22篇 |
1997年 | 23篇 |
1996年 | 11篇 |
1995年 | 11篇 |
1994年 | 5篇 |
1993年 | 10篇 |
1992年 | 9篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 7篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 11篇 |
1984年 | 5篇 |
1983年 | 9篇 |
1982年 | 5篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1976年 | 3篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有1570条查询结果,搜索用时 15 毫秒
1.
Wireless Personal Communications - Recently, the theory of effective rate has attracted much attention, since it can take the delay aspect into account when performing channel capacity analysis. In... 相似文献
2.
3.
Jain Amita Yadav Sudesh Vij Sonakshi Kumar Yogesh Tayal Devendra Kumar 《Wireless Personal Communications》2020,110(3):1303-1321
Wireless Personal Communications - Traffic network is basically a “network of networks” consisting of mainly two types of networks: road network and a travel network. Due to drastic... 相似文献
4.
D. Yadav 《Materials Science & Technology》2015,31(4):494-500
Copper particles were incorporated and retained in elemental state in an aluminium matrix by friction stir processing thereby producing a non-equilibrium particulate composite. The processed Al–Cup composite exhibited improved strength with significantly high ductility. The composite was stable up to a temperature of more than 300°C. Thermal exposure at 350°C for more than 10 min led to diffusion of Cu atoms into the Al matrix forming a core-shell type structure in the Cu particles and thus producing an Al–Cu core-shell composite. The shell consists of multiple layers, the thickness of which was controllable. 相似文献
5.
Chandel Narendra Singh Chakraborty Subir Kumar Rajwade Yogesh Anand Dubey Kumkum Tiwari Mukesh K. Jat Dilip 《Neural computing & applications》2021,33(10):5353-5367
Neural Computing and Applications - The identification of water stress is a major challenge for timely and effective irrigation to ensure global food security and sustainable agriculture. Several... 相似文献
6.
Multimedia Tools and Applications - In the way of communication, facial expression act as non-verbal communication and play an important role in social interaction by providing some contextual... 相似文献
7.
Conversion of acrylonitrile-based precursors to carbon fibres 总被引:1,自引:0,他引:1
Mukesh K. Jain M. Balasubramanian P. Desai A. S. Abhiraman 《Journal of Materials Science》1987,22(1):301-312
The progress of stabilization of two compositions of acrylic fibres with various orientations has been followed by a variety of techniques. The thermooxidative treatments for stabilization have been carried out in a continuous process and also in a batch process under free shrinkage, constant length and constant tension conditions. The morphological model of acrylic fibres consists of an alternating sequence of laterally ordered and laterally disordered regions along the fibre direction. This structure is consistent with the observations based on small-angle X-ray scattering of copper- impregnated precursor fibres and thermomechanical response, thermal stress development, calorimetry, wide- and small-angle X-ray scattering and sonic modu-lus measured at different extents of stabilization. Lateral as well as orientational order in these fibres can be increased markedly through a high-temperature deformation process prior to stabilization. An increase in perfection and extent of order is observed in the early stages of stabilization. There is also a simultaneous decrease in the orientation of the disordered phase at this stage and the extent of this decrease depends on the axial constraints imposed on the fibre. Little difference in the rate of stabilization is observed as measured by density or oxygen uptake for fibres with different extents of orientation, lateral order or restraint. Fibres containing itaconic add, a stabilization catalyst did show an increased rate of stabilization. Inferences have been drawn regarding additional research pertaining to achieving high order in precursor fibres, minimizing orientational relaxation during oxidative stabilization, and the techniques for monitoring the extents of the stabilization treatment and the changes in relevant morphological parameters. 相似文献
8.
Higher order elastic constants have been calculated in ZnS at 300 K and 500 K following the interaction potential model. Ultrasonic attenuation, velocity and other related parameters have been calculated using the higher order elastic constants for the different size of the material at 500 K. The size dependency of the ultrasonic properties is discussed in correlation with elastic, thermal and electrical properties. It has been found that the thermal conductivity is the main contributor to the behaviour of the ultrasonic attenuation as a function of the size and the responsible cause of attenuation is phonon-phonon interaction. The semiconducting nature of ZnS film has been achieved with the study of size variation of thermal relaxation time and ultrasonic attenuation. 相似文献
9.
N. K. Acharya P. K. Yadav S. Wate Y. K. Vijay F. Singh D. Kavasthi 《Bulletin of Materials Science》2004,27(5):417-420
Ion irradiation of Si8+ ion beam of 100 MeV was scattered by a gold foil on a Mylar membrane of 25 Μm thickness in the form of film roll (width,
12.5 cm and length, 400 cm) at the Nuclear Science Centre, New Delhi. The characterization of etched nuclear tracks was carried
out by gas permeation measurements. The samples cut from the film roll of required size for permeability measurements were
etched in a controlled manner in a constant temperature bath of 6N NaOH solution. The opening of the conical etched tracks
was characterized by hydrogen gas permeation. 相似文献
10.
An asymmetric line-axis compound parabolic concentrating single basin solar still of concentration 1.15, exit aperture 0.24 metres and length 0.48 metres, 30° inclination and 60° half acceptance angle has been designed fabricated and tested. 相似文献