全文获取类型
收费全文 | 1673673篇 |
免费 | 42137篇 |
国内免费 | 14082篇 |
学科分类
工业技术 | 1729892篇 |
出版年
2021年 | 21793篇 |
2020年 | 17105篇 |
2019年 | 19087篇 |
2018年 | 19711篇 |
2017年 | 19704篇 |
2016年 | 26140篇 |
2015年 | 24173篇 |
2014年 | 37582篇 |
2013年 | 98799篇 |
2012年 | 47654篇 |
2011年 | 61208篇 |
2010年 | 52932篇 |
2009年 | 60736篇 |
2008年 | 55290篇 |
2007年 | 52042篇 |
2006年 | 55518篇 |
2005年 | 48607篇 |
2004年 | 48071篇 |
2003年 | 47287篇 |
2002年 | 45414篇 |
2001年 | 39974篇 |
2000年 | 37831篇 |
1999年 | 37994篇 |
1998年 | 48805篇 |
1997年 | 42057篇 |
1996年 | 37148篇 |
1995年 | 33830篇 |
1994年 | 31367篇 |
1993年 | 30341篇 |
1992年 | 27348篇 |
1991年 | 24205篇 |
1990年 | 24273篇 |
1989年 | 23097篇 |
1988年 | 21485篇 |
1987年 | 19670篇 |
1986年 | 19122篇 |
1985年 | 22415篇 |
1984年 | 22471篇 |
1983年 | 20322篇 |
1982年 | 19223篇 |
1981年 | 19245篇 |
1980年 | 17885篇 |
1979年 | 18508篇 |
1978年 | 17700篇 |
1977年 | 17756篇 |
1976年 | 19314篇 |
1975年 | 15887篇 |
1974年 | 15452篇 |
1973年 | 15528篇 |
1972年 | 13087篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
Tribology Letters - The tribological behavior of a nickel-based single crystal superalloy treated by shot-peening has been investigated. Friction tests under three normal loads and three... 相似文献
52.
Russian Engineering Research - A mathematical model of a heat store based on melting of the working medium is verified by means of an experiment. The model describes a heat store containing a... 相似文献
53.
Gerasimov Sergey I. Ilyushin Mikhail A. Putis Sergey M. Dushenok Sergey A. Shugalei Irina V. Sudarikov Andrey M. 《含能材料》2022,30(4):370-378
In the present work it is found that the pyrotechnic composition VS-2 can be initiated with flash lamps IFC-500 and EVIS. VS-2 pyrotechnic composition contains 90% of mercury(Ⅱ) 5-hydrazinotetrazolate perchlorate and 10% of optically transparent copolymer of 2-methyl-5-vinyltetrazole and methacrylic acid (PVMT). We have found that the flash lamps make it possible to initiate combustion of VS-2 composition with its transition to detonation both in cylindrical charges placed in brass caps of 5 mm diameter and 2 mm high, and film charges with 10 mm×80 mm in size and surface weights of 60 mg·cm-2 and 90 mg·cm-2, showing ignition delay times 10 μs and 3 μs, respectively. We also measured detonation velocities for VS-2 composition film charges, which were 4375-4505 m·s-1 (of the charge being surface mass 60 mg·cm-2) and 4221-4281 m·s-1 (of the charge being surface mass 90 mg·cm-2) and their blasting action on the aluminum plate. The depths of the normal shock wave imprints at the charge-barrier interface were 0.6-0.7 mm (for surface mass of the film charges 60 mg·cm-2) and 1.2-1.3 mm (for surface mass of the film charges 90 mg·cm-2). 相似文献
54.
Uthayakumar J. Vengattaraman T. Arjunan Sariga 《Wireless Personal Communications》2022,122(4):2963-2994
Wireless Personal Communications - Image transmission from space borne equipment is a challenging task owing to its restrictions on bandwidth and memory requirement. Many of the state of art... 相似文献
55.
Wireless Personal Communications - Wireless sensor network is gaining popularity due to its large-scale deployment in Internet of Things. The constraints of resources influence the protocol design... 相似文献
56.
Potomkin M. M. Sedliar A. A. Sirchenko R. S. Ishchenko O. M. 《Cybernetics and Systems Analysis》2022,58(3):392-398
Cybernetics and Systems Analysis - It is noted that fuzzy methods are widely used to substantiate rational decisions in multi-criteria analysis of complex systems since the operating conditions of... 相似文献
57.
Wireless Personal Communications - Biometric authentications systems are being recognized as the better way of securing data or personal devices as they are unique. Face is considered the best way... 相似文献
58.
Kulikova M. V. Krylova A. Yu. Zhagfarov F. G. Krysanova K. O. 《Chemistry and Technology of Fuels and Oils》2022,58(2):327-332
Chemistry and Technology of Fuels and Oils - The review examines biomass of animal origin in terms of a potential renewable raw material for obtaining CO2-neutral fuel unaffecting the carbon... 相似文献
59.
随着工业互联网、车联网、元宇宙等新型互联网应用的兴起,网络的低时延、可靠性、安全性、确定性等方面的需求正面临严峻挑战。采用网络功能虚拟化技术在虚拟网络部署过程中,存在服务功能链映射效率低与部署资源开销大等问题,联合考虑节点激活成本、实例化开销,以最小化平均部署网络成本为优化目标建立了整数线性规划模型,提出基于改进灰狼优化算法的服务功能链映射(improved grey wolf optimization based service function chain mapping,IMGWO-SFCM)算法。该算法在标准灰狼优化算法基础上添加了基于无环K最短路径(K shortest path,KSP)问题算法的映射方案搜索、映射方案编码以及基于反向学习与非线性收敛改进三大策略,较好地平衡了其全局搜索及局部搜索能力,实现服务功能链映射方案的快速确定。仿真结果显示,该算法在保证更高的服务功能链请求接受率下,相较于对比算法降低了11.86%的平均部署网络成本。 相似文献
60.
Journal of Low Temperature Physics - The paper is devoted to the memory of Dmitry Diakonov. We discuss gravity emerging in the fermionic vacuum as suggested by Diakonov 10 years ago in his paper... 相似文献