全文获取类型
收费全文 | 6958篇 |
免费 | 947篇 |
国内免费 | 339篇 |
专业分类
电工技术 | 267篇 |
综合类 | 473篇 |
化学工业 | 611篇 |
金属工艺 | 138篇 |
机械仪表 | 231篇 |
建筑科学 | 29篇 |
矿业工程 | 14篇 |
能源动力 | 204篇 |
轻工业 | 51篇 |
水利工程 | 1篇 |
石油天然气 | 12篇 |
武器工业 | 37篇 |
无线电 | 2746篇 |
一般工业技术 | 486篇 |
冶金工业 | 42篇 |
原子能技术 | 22篇 |
自动化技术 | 2880篇 |
出版年
2024年 | 18篇 |
2023年 | 330篇 |
2022年 | 318篇 |
2021年 | 418篇 |
2020年 | 377篇 |
2019年 | 312篇 |
2018年 | 378篇 |
2017年 | 823篇 |
2016年 | 738篇 |
2015年 | 590篇 |
2014年 | 681篇 |
2013年 | 458篇 |
2012年 | 508篇 |
2011年 | 389篇 |
2010年 | 328篇 |
2009年 | 318篇 |
2008年 | 173篇 |
2007年 | 270篇 |
2006年 | 255篇 |
2005年 | 112篇 |
2004年 | 56篇 |
2003年 | 58篇 |
2002年 | 66篇 |
2001年 | 70篇 |
2000年 | 47篇 |
1999年 | 37篇 |
1998年 | 24篇 |
1997年 | 11篇 |
1996年 | 9篇 |
1995年 | 15篇 |
1994年 | 15篇 |
1993年 | 16篇 |
1992年 | 7篇 |
1991年 | 8篇 |
1990年 | 10篇 |
1986年 | 1篇 |
排序方式: 共有8244条查询结果,搜索用时 343 毫秒
101.
《Pattern recognition》2014,47(2):588-602
Fingerprint matching has emerged as an effective tool for human recognition due to the uniqueness, universality and invariability of fingerprints. Many different approaches have been proposed in the literature to determine faithfully if two fingerprint images belong to the same person. Among them, minutiae-based matchers highlight as the most relevant techniques because of their discriminative capabilities, providing precise results. However, performing a fingerprint identification over a large database can be an inefficient task due to the lack of scalability and high computing times of fingerprint matching algorithms.In this paper, we propose a distributed framework for fingerprint matching to tackle large databases in a reasonable time. It provides a general scheme for any kind of matcher, so that its precision is preserved and its time of response can be reduced.To test the proposed system, we conduct an extensive study that involves both synthetic and captured fingerprint databases, which have different characteristics, analyzing the performance of three well-known minutiae-based matchers within the designed framework. With the available hardware resources, our distributed model is able to address up to 400 000 fingerprints in approximately half a second. Additional details are provided at http://sci2s.ugr.es/ParallelMatching. 相似文献
102.
The aim of this study is to predict automatic trading decisions in stock markets. Comprehensive features (CF) for predicting future trend are very difficult to generate in a complex environment, especially in stock markets. According to related work, the relevant stock information can help investors formulate objects that may result in better profits. With this in mind, we present a framework of an intelligent stock trading system using comprehensive features (ISTSCF) to predict future stock trading decisions. The ISTSCF consists of stock information extraction, prediction model learning and stock trading decision. We apply three different methods to generate comprehensive features, including sentiment analysis (SA) that provides sensitive market events from stock news articles for sentiment indices (SI), technical analysis (TA) that yields effective trading rules based on trading information on the stock exchange for technical indices (TI), as well as the trend-based segmentation method (TBSM) that raises trading decisions from stock price for trading signals (TS). Experiments on the Taiwan stock market show that the results of employing comprehensive features are significantly better than traditional methods using numeric features alone (without textual sentiment features). 相似文献
103.
Web交互模型的形式化验证是对Web事件属性进行校验的十分可信的方法。通过一系列的系统模型建立、系统行为分析以及对于模型中关心属性的相关验证,能够让交互模型在设计阶段就能使形式化模型暴露出其所存在的缺陷,而不至于让缺陷保留到编码阶段或者更后面才能被真正地暴露出来,这样使系统模型的生存能力更加强大,同时避免了因后期缺陷暴露而出现的大代价修复。通过对Web系统的交互应用服务的过程模型化的体系进行研究,通过模型本身具有的属性进行相关正确性的校验,主要通过使用数学推理实现系统逻辑上的服务交互进程,从而进行过程的推演,并对系统服务的正确性进行过程的形式化验证,从而使系统服务模块的属性正确性可以通过逻辑上的演进来发现服务问题的存在,而不再是系统通过编码实现后才发现。对Web交互模型的形式化验证是基于IMWSC模型语义形成的IMWSC模型的验证机制。 相似文献
104.
105.
A low-power complementary metal oxide semiconductor(CMOS) operational amplifier (op-amp) for real-time signal processing of micro air vehicle (MAV) is designed in this paper. Traditional folded cascode architecture with positive channel metal oxide semiconductor(PMOS) differential input transistors and sub-threshold technology are applied under the low supply voltage. Simulation results show that this amplifier has significantly low power, while maintaining almost the same gain, bandwidth and other key performances. The power required is only 0.12mW, which is applicable to low-power and low-voltage real-time signal acquisition and processing system. 相似文献
106.
107.
将遗传算法与参数跟踪策略有效结合,跟踪过程中进行搜索域压缩与位移操作,形成了一种功能强大的新算法,可成功应用于电磁领域中各种各样复超越方程的高精度求解问题.在算法实现过程中,使用参数跟踪策略有效地缩小了搜索区域,保证了解的单一性,提高了运算速度;使用动态搜索域提高了解的精度;应用三阶差商公式预估新的搜索中心,使运算速度得以进一步提高.应用本文发展的算法详细求解了终端短路法测量材料的复介电常数时得到的复超越方程和部分填充矩形波导的特征方程,计算结果表明该算法能够轻松地解决复超越方程中的多值问题,解集完备性好,算法鲁棒性强. 相似文献
108.
A simple method using aided sliding rectangular windows for synchronization in e nergy detector (ED) receiver is proposed for impulse-based ultra wideband radio s (IR-UWB) under binary pulse position modulation (PPM), therefore grants an at tractive solution for gaining low complexity while the accompanying performance loss in terms of UWB signal reception is comparatively low. Also, a method is de veloped to suppress noise through accumulation of integrated results before sync hronization point is reached.... 相似文献
109.
The new features of H.264 video coding standard make the motion estimation module much more time consuming than before.Especially,the motion search is required for each of the 4 modes for inter prediction.In order to reduce the computational complexity,we analyze the statistics of results of motion estimation,such as the continuity of best modes of blocks in successive frames and the chance to give up a sub-partition mode(smaller than 16×16)after integer-pixel motion estimation,from which we suggest to make... 相似文献
110.
A new dual-mode transmission networks(DMTN)based on broad-storage architecture for digital television(DTV)is proposed,in which the primary TV network is superimposed by a complementary framework based on broad-storage TV(BSTV).The necessity of congregating hot TV resources is discussed via analyzing the scale-free properties in DMTN.The self-organized parallel broadcasting technology(SPBT)and the uniform content locator(UCL)are studied to utilize availably transmission channels and to help consumers to comm... 相似文献