全文获取类型
收费全文 | 1089篇 |
免费 | 50篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 149篇 |
金属工艺 | 7篇 |
机械仪表 | 19篇 |
建筑科学 | 12篇 |
矿业工程 | 1篇 |
能源动力 | 22篇 |
轻工业 | 101篇 |
水利工程 | 9篇 |
石油天然气 | 4篇 |
无线电 | 53篇 |
一般工业技术 | 101篇 |
冶金工业 | 578篇 |
原子能技术 | 5篇 |
自动化技术 | 71篇 |
出版年
2024年 | 3篇 |
2023年 | 3篇 |
2022年 | 18篇 |
2021年 | 27篇 |
2020年 | 14篇 |
2019年 | 15篇 |
2018年 | 24篇 |
2017年 | 26篇 |
2016年 | 26篇 |
2015年 | 26篇 |
2014年 | 16篇 |
2013年 | 44篇 |
2012年 | 35篇 |
2011年 | 53篇 |
2010年 | 39篇 |
2009年 | 37篇 |
2008年 | 25篇 |
2007年 | 19篇 |
2006年 | 19篇 |
2005年 | 18篇 |
2004年 | 10篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 12篇 |
1998年 | 153篇 |
1997年 | 101篇 |
1996年 | 74篇 |
1995年 | 35篇 |
1994年 | 39篇 |
1993年 | 32篇 |
1992年 | 2篇 |
1991年 | 13篇 |
1990年 | 8篇 |
1989年 | 11篇 |
1988年 | 7篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1978年 | 2篇 |
1977年 | 29篇 |
1976年 | 55篇 |
1973年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有1139条查询结果,搜索用时 15 毫秒
1.
This article describes the different methods to design regular low density parity-check (LDPC) codes with large girth. In graph terms, this corresponds to designing bipartite undirected regular graphs with large girth. Large girth speeds the convergence of iterative decoding and improves the performance at least in the high SNR range, by slowing down the onsetting of the error floor. We reviewed several existing constructions from exhaustive search to highly structured designs based on Euclidean and projective finite geometries and combinatorial designs. We describe GB and TS LDPC codes and compared the BER performance with large girth to the BER performance of random codes. These studies confirm that in the high SNR regime these codes with high girth exhibit better BER performance. The regularity of the codes provides additional advantages that we did not explore in this article like the simplicity of their hardware implementation and fast encoding. 相似文献
2.
3.
The alarm lists presented to control center operators are usually difficult to interpret. The authors present an expert system that processes the alarm lists in Portuguese control centers. This system makes an intelligent synthesis of the available information and presents it in a flexible and structured way. It uses an original approach to deal with temporal reasoning and real-time constraints. The system incorporates an explanation module that enables its use as a tutor for novice operators 相似文献
4.
5.
We present a case where a Wiktor intracoronary stent was inserted for 'poor angiographic result' following balloon angioplasty. Despite appropriate positioning and repeated dilation of the stent a suboptimal result was achieved because of plaque herniation through the stent. The case emphasizes that the choice of stent used is important and will become more so as the number of choices available increases. 相似文献
6.
Infiltration systems are frequently used as an option to manage urban storm drainage. By reducing flows and volumes in downstream sewers or in surface waters, they decrease the overflows and make it possible to recharge groundwater. They come in various forms with different uses; therefore, their performance is diverse and integrates multiple aspects. Consequently, a multicriteria approach was developed in order to quantify the performance of these systems and to help in decision making problems. For that purpose, a list of performance indicators integrating technical, economical, environmental and social aspects was developed. The performances were defined with the help of a working group composed of engineers from different technical or strategic departments from Greater Lyon and researchers from different fields. The paper presents the last version of the performance indicators tested according to a set of quality requirements: availability of data, relevance, fidelity, precision, sensitivity/robustness. This critical review of the set of indicators has led us to redefine a certain number of indicators, identify numerous biases and allow putting forward general instructions for criterion or indicator construction. The last phase is to propose multicriteria decision aid methods; a procedure using ELECTRE methods should be used. 相似文献
7.
8.
9.
10.