全文获取类型
收费全文 | 419069篇 |
免费 | 4077篇 |
国内免费 | 979篇 |
专业分类
电工技术 | 7083篇 |
综合类 | 272篇 |
化学工业 | 65537篇 |
金属工艺 | 19227篇 |
机械仪表 | 13047篇 |
建筑科学 | 9346篇 |
矿业工程 | 3258篇 |
能源动力 | 8992篇 |
轻工业 | 32999篇 |
水利工程 | 5306篇 |
石油天然气 | 13190篇 |
武器工业 | 24篇 |
无线电 | 42851篇 |
一般工业技术 | 86929篇 |
冶金工业 | 73545篇 |
原子能技术 | 12298篇 |
自动化技术 | 30221篇 |
出版年
2021年 | 3370篇 |
2018年 | 5981篇 |
2017年 | 6039篇 |
2016年 | 6478篇 |
2015年 | 3826篇 |
2014年 | 6541篇 |
2013年 | 17132篇 |
2012年 | 10220篇 |
2011年 | 13458篇 |
2010年 | 11013篇 |
2009年 | 12471篇 |
2008年 | 12869篇 |
2007年 | 12723篇 |
2006年 | 11089篇 |
2005年 | 10303篇 |
2004年 | 9707篇 |
2003年 | 9384篇 |
2002年 | 9376篇 |
2001年 | 9237篇 |
2000年 | 8891篇 |
1999年 | 8825篇 |
1998年 | 20658篇 |
1997年 | 15270篇 |
1996年 | 11718篇 |
1995年 | 8908篇 |
1994年 | 7994篇 |
1993年 | 7961篇 |
1992年 | 6220篇 |
1991年 | 6211篇 |
1990年 | 6116篇 |
1989年 | 6055篇 |
1988年 | 5980篇 |
1987年 | 5208篇 |
1986年 | 5259篇 |
1985年 | 5900篇 |
1984年 | 5619篇 |
1983年 | 5247篇 |
1982年 | 4885篇 |
1981年 | 5196篇 |
1980年 | 4898篇 |
1979年 | 5066篇 |
1978年 | 5206篇 |
1977年 | 5752篇 |
1976年 | 7368篇 |
1975年 | 4781篇 |
1974年 | 4673篇 |
1973年 | 4711篇 |
1972年 | 4206篇 |
1971年 | 3833篇 |
1970年 | 3342篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
D. Trmouilles G. Bertrand M. Bafleur F. Beaudoin P. Perdu N. Guitard L. Lescouzres 《Microelectronics Reliability》2003,43(1):71-79
The number of circuit design iterations due to electrostatic discharge (ESD) failures increases with the complexity of VLSI technologies and their shrinking. In this paper, we show how TCAD and ESD SPICE modeling can be used to solve ESD protection issues in an analog CMOS technology. 相似文献
993.
I. S. Sheinin 《Power Technology and Engineering (formerly Hydrotechnical Construction)》1992,26(10):609-615
Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 10, pp. 1–6, October, 1992. 相似文献
994.
A comprehensive analysis of a 1-persistent carrier-sense multi-access (CSMA) system using a radio channel with imperfect carrier sensing is presented and discussed. It is shown that a careful optimization of the channel state detector parameters must be performed in order to get good system performance. If the threshold of the detector is too high, the system will tend to behave like an unslotted ALOHA; if the threshold is too low, the system throughput will be zero. It is also shown that for the larger average packet rate G the system throughput is decreased. This is because for the same probability of correct channel sensing, the probability of incorrect transmissions from the waiting mode is increased 相似文献
995.
V. S. Yamshchikov V. L. Shkuratnik K. G. Lykov V. M. Farafonov 《Journal of Mining Science》1991,27(2):100-103
Mining Institute, Moscow. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 2, pp. 26–29,
March–April, 1991. 相似文献
996.
997.
998.
On the capacity of a cellular CDMA system 总被引:37,自引:0,他引:37
Gilhousen K.S. Jacobs I.M. Padovani R. Viterbi A.J. Weaver L.A. Jr. Wheatley C.E. III 《Vehicular Technology, IEEE Transactions on》1991,40(2):303-312
It is shown that, particularly for terrestrial cellular telephony, the interference-suppression feature of CDMA (code division multiple access) can result in a many-fold increase in capacity over analog and even over competing digital techniques. A single-cell system, such as a hubbed satellite network, is addressed, and the basic expression for capacity is developed. The corresponding expressions for a multiple-cell system are derived. and the distribution on the number of users supportable per cell is determined. It is concluded that properly augmented and power-controlled multiple-cell CDMA promises a quantum increase in current cellular capacity 相似文献
999.
Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 10, pp. 30–34, October, 1991. 相似文献
1000.
Josef G. Krammer 《The Journal of VLSI Signal Processing》1991,3(1-2):93-103
This paper deals with the parallel execution of algorithms with global and/or irregular data dependencies on a regularly and locally connected processor array. The associated communication problems are solved by the use of a two-dimensional sorting algorithm. The proposed architecture, which is based on a two-dimensional sorting network, offers a high degree of flexibility and allows an efficient mapping of many irregularly structured algorithms. In this architecture a one-dimensional processor array performs all required control and arithmetic operations, whereas the sorter solves complex data transfer problems. The storage capability of the sorting network is also used as memory for data elements. The algorithms for sparse matrix computations, fast Fourier transformation and for the convex hull problem, which are mapped onto this architecture, as well as the simulation of a shared-memory computer show that the utilization of the most complex components, the processors, is O(1). 相似文献