全文获取类型
收费全文 | 7123篇 |
免费 | 945篇 |
国内免费 | 618篇 |
专业分类
电工技术 | 505篇 |
综合类 | 664篇 |
化学工业 | 121篇 |
金属工艺 | 95篇 |
机械仪表 | 350篇 |
建筑科学 | 368篇 |
矿业工程 | 84篇 |
能源动力 | 113篇 |
轻工业 | 90篇 |
水利工程 | 126篇 |
石油天然气 | 86篇 |
武器工业 | 63篇 |
无线电 | 1922篇 |
一般工业技术 | 549篇 |
冶金工业 | 140篇 |
原子能技术 | 247篇 |
自动化技术 | 3163篇 |
出版年
2024年 | 28篇 |
2023年 | 102篇 |
2022年 | 197篇 |
2021年 | 206篇 |
2020年 | 233篇 |
2019年 | 186篇 |
2018年 | 183篇 |
2017年 | 227篇 |
2016年 | 282篇 |
2015年 | 297篇 |
2014年 | 441篇 |
2013年 | 551篇 |
2012年 | 505篇 |
2011年 | 514篇 |
2010年 | 423篇 |
2009年 | 424篇 |
2008年 | 505篇 |
2007年 | 554篇 |
2006年 | 469篇 |
2005年 | 456篇 |
2004年 | 320篇 |
2003年 | 294篇 |
2002年 | 217篇 |
2001年 | 158篇 |
2000年 | 152篇 |
1999年 | 142篇 |
1998年 | 85篇 |
1997年 | 86篇 |
1996年 | 71篇 |
1995年 | 58篇 |
1994年 | 61篇 |
1993年 | 47篇 |
1992年 | 44篇 |
1991年 | 32篇 |
1990年 | 28篇 |
1989年 | 34篇 |
1988年 | 12篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 13篇 |
1984年 | 7篇 |
1983年 | 8篇 |
1982年 | 6篇 |
1981年 | 2篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1975年 | 2篇 |
1966年 | 2篇 |
1961年 | 2篇 |
1951年 | 1篇 |
排序方式: 共有8686条查询结果,搜索用时 296 毫秒
61.
M. Nicolaidis 《Journal of Electronic Testing》1991,1(4):257-273
It has been noted by several authors that the classical stuck-at logical fault model might not be an appropriate representation of certain real failures occurring in integrated circuits. Shorts are an important class of such faults. This article gives a detailed analysis of the effects of shorts in self-checking circuits and proposes techniques for dealing with them. More precisely, we show that, unlike other faults such as stuck-at, stuck-on, and stuck-open—which produce only single errors in the place they occur—shorts can produce double errors on the two shorted lines. In particular, feedback shorts can produce double errors on the two shorted lines. The double error is unidirectional for some feedback shorts and non-unidirectional for some others. Furthermore, in some technologies (e.g., CMOS), non-feedback shorts can also produce double non-unidirectional errors. We also show that unlike stuck-at, stuck-on, and stuck-open faults, redundant shorts can destroy the SFS property. Then we propose several techniques for coping with these problems and we illustrate the results by circuit implementation examples.The present study is given for NMOS and CMOS circuits but we show that it is valid for any other technology. 相似文献
62.
In this paper a methodology for the use of temporal logic as an executable imperative language is introduced. The approach, which provides a concrete framework, calledMetateM, for executing temporal formulae, is motivated and illustrated through examples. In addition, this introduction provides references to further, more detailed, work relating to theMetateM approach to executable logics. 相似文献
63.
Alessandra Lumini 《Pattern recognition》2007,40(3):1057-1065
Given the recent explosion of interest in human authentication, verification based on tokenized pseudo-random numbers and the user specific biometric feature (BioHashing) has received much attention. These methods have significant functional advantages over sole biometrics i.e. zero equal error rate. The main drawback of the base BioHashing method proposed in the literature relies in exhibiting low performance when an “impostor” B steals the pseudo-random numbers of A and he tries to authenticate as A. In this paper, we introduce some ideas to improve the base BioHashing approach in order to maintain a very low equal error rate when nobody steals the Hash key, and to reach good performance also when an “impostor” steals the Hash key. 相似文献
64.
Alessandra Lumini 《Pattern recognition》2006,39(4):714-716
We present a system for fingerprint verification that approaches the problem as a two-class pattern recognition problem. The features extracted by “FingerCode” are used to capture the ridge strength. This feature vector is then classified as genuine or impostor according to a novel approach to handle the fingerprint verification as a two-class problem. Moreover, we show that extracting the features from sub-images around the core permits to better represent the local information. 相似文献
65.
广义汉明重量下限函数Lr(j,d)的新证明 总被引:3,自引:0,他引:3
通过几个引理,对广义汉明重量下限函数Lr(j,d)的有限和表达式给出了一个思路简单的证明方法。给出了取整数函数[x],[x]的一些运算性质。 相似文献
66.
针对云存储中的可靠性产生的担忧,提出一种云存储系统完善的数据存储保障机制,以保证系统的高可靠性和数据的高可用性。在处理与数据持久存储的相关的数据分片、数据分发、完整性检查以及冗余数据的维护中,引入基于纠删码的数据冗余机制,与传统的复制冗余方案相比,能够在获得相同的数据可用性时降低存储空间和网络带宽的开销多达50%以上。采用基于缓冲区的分段读入编码对纠删码算法进行优化后,提高了对文件分片与合并的平均编码速率。 相似文献
67.
68.
郭崎 《计算机辅助设计与图形学学报》2012,24(5):690-698
如何生成高质量的验证激励是功能验证中的核心问题之一.随着功能验证的不断进行,验证激励的有效性也随之降低.为了提高验证激励的质量,提出一种在线筛选技术来处理验证激励.该技术采用单分类支持向量机来在线地构建分类器,以对新生成的验证激励是否冗余进行预测,如果是冗余的,则不进入仿真阶段进行仿真.在此基础上,进一步提出指令序列核函数来衡量不同指令序列的相似程度.实验结果表明,与约束随机生成技术相比,文中技术可以减少约83%的验证激励及79%的验证时间. 相似文献
69.
先进音频编码(AdvancedAudioCoding,AAC)以其多声道、多采样率、高压缩比、音质好等特点被广泛使用。文中首先介绍了MPEG-2/4AAC音频编码技术;接着基于MPEG-2/4AAC音频编码原理,开发了时钟复位、寄存器配置和音频数据收发的BFM模型,搭建了音频编码模块的RTL级虚拟验证平台,同时归纳了验证项;最后基于此验证平台和验证项,对设计进行了全面的仿真验证。实践证明该验证方法效率高、收敛快、覆盖率高,取得了较好的效果,为后续的FPGA平台验证和芯片应用提供了有力的保证。 相似文献
70.
"Mega"-analysis was developed by M. Carlson and N. Miller (see record 1987-31249-001) as an extension of traditional meta-analytic procedures for conducting integrative reviews of existing research literatures. One such mega-analysis was conducted by Carlson and Miller to synthesize the literature on the relation between negative mood states and helping. That analysis found no support for a theoretical account (negative state relief) that had been confirmed previously by using various experimental approaches. In an attempt to reconcile the discrepancy, the logic and methods used in Carlson and Miller's mega-analysis of the negative mood-helping literature were examined, and several serious problems were found. These problems are discussed, and data are presented to show that the results of that mega-analysis, and perhaps all mega-analyses, should not be viewed with confidence. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献