全文获取类型
收费全文 | 19951篇 |
免费 | 3676篇 |
国内免费 | 2477篇 |
专业分类
电工技术 | 995篇 |
综合类 | 2041篇 |
化学工业 | 965篇 |
金属工艺 | 353篇 |
机械仪表 | 1184篇 |
建筑科学 | 205篇 |
矿业工程 | 210篇 |
能源动力 | 89篇 |
轻工业 | 333篇 |
水利工程 | 102篇 |
石油天然气 | 384篇 |
武器工业 | 282篇 |
无线电 | 4064篇 |
一般工业技术 | 1180篇 |
冶金工业 | 892篇 |
原子能技术 | 41篇 |
自动化技术 | 12784篇 |
出版年
2024年 | 97篇 |
2023年 | 400篇 |
2022年 | 858篇 |
2021年 | 985篇 |
2020年 | 970篇 |
2019年 | 695篇 |
2018年 | 582篇 |
2017年 | 716篇 |
2016年 | 816篇 |
2015年 | 876篇 |
2014年 | 1277篇 |
2013年 | 1142篇 |
2012年 | 1457篇 |
2011年 | 1581篇 |
2010年 | 1289篇 |
2009年 | 1327篇 |
2008年 | 1387篇 |
2007年 | 1516篇 |
2006年 | 1331篇 |
2005年 | 1135篇 |
2004年 | 933篇 |
2003年 | 862篇 |
2002年 | 707篇 |
2001年 | 481篇 |
2000年 | 411篇 |
1999年 | 377篇 |
1998年 | 309篇 |
1997年 | 241篇 |
1996年 | 184篇 |
1995年 | 173篇 |
1994年 | 135篇 |
1993年 | 134篇 |
1992年 | 109篇 |
1991年 | 52篇 |
1990年 | 48篇 |
1989年 | 67篇 |
1988年 | 42篇 |
1987年 | 25篇 |
1986年 | 23篇 |
1985年 | 33篇 |
1984年 | 33篇 |
1983年 | 43篇 |
1982年 | 38篇 |
1981年 | 33篇 |
1980年 | 27篇 |
1979年 | 22篇 |
1978年 | 23篇 |
1977年 | 26篇 |
1976年 | 23篇 |
1974年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
LU Jian-dong Science Technology Department Xi'an Institute of Posts Telecommunications Xi'an P.R. China 《中国邮电高校学报(英文版)》2004,11(3)
1 Introduction SinceZadeh[1] establishedfuzzysettheoryin 196 5 ,fuzzysetmakesgreatachievementintheoryandapplica tion[2~ 5] .Becausethereexistintrinsicfuzzinessinpat ternrecognition ,usingfuzzysettopatternrecognitionacquiregreatsuccess.Toexplainthedifferentandrela tionbetweenfuzzysetandprobabilitytheory ,Zadeh[6 ]introducedpossibilitytheoryin 1978.Possibilitytheoryhadbeenusedinfuzzyreason ,fuzzycontrolandexpertsystem[7~ 9] .Applingpossibilitytheoryto patternrecognitionisattemptedbyHalland… 相似文献
82.
83.
This paper presents an orientation-based representation for planar curves and shapes. The new representation can uniquely represent all types, of planar shapes, be it convex, nonconvex, polygonal, smoothly curved, or piecewise smooth shapes. It is based on a new parameterization, theabsolute integral orientation. This representation is invariant under translation and rotation. The absolute integral orientation is a parameter invariant under scaling. As a result, matching of similar shapes (i.e., determination of the relative orientation and the scaling factor) using the absolute integral orientation as the parameter is easier than using the arclength as the parameter. In addition, the new representation has the feature of adaptive sampling, making it more compact and efficient than arc-length-based representations. 相似文献
84.
85.
In many automatic face recognition systems,posture constraining is a key factor preventing them from application.In this paper a series of strategies will be described to achieve a system which enables face recognition under varying pose.These approaches include the multi-view face modeling,the threschold image based face feature detection,the affine transformation based face posture normalization and the template matching based face identification.Combining all of these strategies,a face recognition system with the pose invariance is designed successfully,Using a 75MHZ Pentium PC and with a database of 75 individuals,15 images for each person,and 225 test images with various postures,a very good recognition rate of 96.89% is obtained. 相似文献
86.
No authorship indicated 《Canadian Metallurgical Quarterly》1993,48(4):346
Recognizes Martha J. Farah for rigorous empirical and theoretical analysis of visual cognition, in which understanding of normal function and analysis of neurological deficits illuminate and strengthen one another. Applying diverse experimental techniques within an integrated approach to the study of mind and brain, she has sharpened and helped to answer fundamental questions about how humans generate and manipulate visual images, recognize objects, and attend to positions in space. Along with a citation, a biography is presented for Farah, as well as a bibliography of her works. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
87.
本文介绍了以一种比较两个句子的新的有效算法为基础而编制的连续语音识别系统性能评估软件,它通过比较连续语音识别系统输出的若干句子和相应的标准句子,得到系统性能的定量数据。该软件的可靠性得到大量实验验证。 相似文献
88.
基于极化不变量的飞机目标识别 总被引:5,自引:2,他引:3
基于宽带毫米波极化雷达体制背影,通过极化不变量之一的去极化系数,研究了飞机目标的极化散射特性,并提取了极化特征,设计了飞机目标的分类或识别器结构,它能对五种飞机目标进行有效的分类或识别。 相似文献
89.
90.
Reviews the book, Basic Processes in Reading Visual Word Recognition by Derek Besner and Glyn W. Humphreys (see record 1990-99017-000). While there has been an increase in the amount of work on many different aspects of reading, as Besner and Humphreys point out in the overview to their book, the vast majority of the research on the topic of reading in the past twenty years has been concerned with the processes involved in word recognition. For this reason, Besner and Humphreys have attempted to bring together studies on topics which are both relevant to current debates in the field of word recognition, and which are likely to be important for future developments in the field. They have compiled an edited volume consisting of their overview and eight additional chapters. The editors have attempted to span the continuum of processes involved in word recognition and thus have included chapters which cover topics ranging from the visual analysis of words, to those on the influence of semantic factors on word recognition. The authors of these chapters comprise an impressive list of researchers in the field of word recognition, with the majority of chapters being authored by leading researchers on the topic. Given the stature of the authors and the range of topics covered, in theory this volume should provide a very thorough overview of current theory and research on reading. There is no question that each of the chapters is interesting and important in its own right. However, in practice the volume as a whole fell somewhat short of my expectations. The different tacts taken by different authors has resulted in a very uneven coverage of the current debates in the field. Notwithstanding these criticisms, I am sure that the majority of researchers in this field will consider this volume to be an important contribution. The book would provide a very useful addition to graduate courses in cognitive sciences and as a supplemental text for an undergraduate course on the psychology of reading. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献