全文获取类型
收费全文 | 15579篇 |
免费 | 1899篇 |
国内免费 | 1472篇 |
专业分类
电工技术 | 690篇 |
技术理论 | 5篇 |
综合类 | 2135篇 |
化学工业 | 901篇 |
金属工艺 | 484篇 |
机械仪表 | 771篇 |
建筑科学 | 1525篇 |
矿业工程 | 403篇 |
能源动力 | 308篇 |
轻工业 | 937篇 |
水利工程 | 555篇 |
石油天然气 | 1365篇 |
武器工业 | 115篇 |
无线电 | 1858篇 |
一般工业技术 | 1032篇 |
冶金工业 | 317篇 |
原子能技术 | 156篇 |
自动化技术 | 5393篇 |
出版年
2024年 | 61篇 |
2023年 | 176篇 |
2022年 | 353篇 |
2021年 | 388篇 |
2020年 | 444篇 |
2019年 | 365篇 |
2018年 | 373篇 |
2017年 | 462篇 |
2016年 | 501篇 |
2015年 | 602篇 |
2014年 | 854篇 |
2013年 | 861篇 |
2012年 | 1027篇 |
2011年 | 1230篇 |
2010年 | 1005篇 |
2009年 | 1061篇 |
2008年 | 1114篇 |
2007年 | 1320篇 |
2006年 | 1153篇 |
2005年 | 941篇 |
2004年 | 843篇 |
2003年 | 667篇 |
2002年 | 551篇 |
2001年 | 413篇 |
2000年 | 342篇 |
1999年 | 304篇 |
1998年 | 254篇 |
1997年 | 186篇 |
1996年 | 176篇 |
1995年 | 168篇 |
1994年 | 165篇 |
1993年 | 106篇 |
1992年 | 88篇 |
1991年 | 58篇 |
1990年 | 50篇 |
1989年 | 52篇 |
1988年 | 23篇 |
1987年 | 21篇 |
1986年 | 17篇 |
1985年 | 32篇 |
1984年 | 24篇 |
1983年 | 19篇 |
1982年 | 17篇 |
1981年 | 14篇 |
1980年 | 11篇 |
1979年 | 11篇 |
1978年 | 8篇 |
1977年 | 10篇 |
1975年 | 5篇 |
1973年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 390 毫秒
81.
Failure analysis of hollow glasses The failure analysis is very important to clarify damages of hollow glasses. Damages of glass bottle through over pressure are very often linked with damages to persons. This is the reason why the causal research is from particular importance. Different surface characteristics of glass fragments as well as the fracture pattern give hints to the direction of the crack, the stress just before breakage and the reason of stress. A reconstruction of the bottle is a further helpful instrument for cause studies. The difference of the various characteristics of the surface will be explained. Further on there will be discussed different reasons and mechanism of fracture. 相似文献
82.
83.
化学模式识别法在钢铁工业中的若干应用 总被引:1,自引:0,他引:1
本文涉及一种崭新的非函数数据处理法及其在工业诊断和优化中的应用。并对其进行要因分析和优化决策的原理作了介绍。结合钢铁工业生产中的实例进行了分析。还探讨了该方法在钢铁工业中应用的意义。 相似文献
84.
Gerardo Gabriel Acosta Miguel Angel Mayosky José Maria Catalfo 《Applied Intelligence》1994,4(1):53-66
This article proposes a scheme for the on-line adjustment of three mode controller settings based on experimental measurements of closed-loop performance. It uses a recently developed heuristic tuning procedure to identify estimated process parameters. This method may give rise to conflicting estimates. Fuzzy Set theory is applied to manage the situation in terms of a fuzzy conjunction to combine the various estimates. PID control was chosen because of its wide use in the industrial environment due to driving simplicity and robustness. The article shows design, development, and computer simulation aspects. 相似文献
85.
针对针织服装结构设计的特点和现状,运用东华原型的结构原理和技术应用方法,通过试样着装实验,进行比较分析,建立了针织服装基型,并阐述了其应用的方法. 相似文献
86.
R. S. Fyath K. N. Darraj M. S. Alam M. N. Islam M. M. Alkhatib 《Optical Memory & Neural Networks》2007,16(3):125-135
A new joint transform correlation (JTC) technique, named two-channel JTC (TJTC), is proposed in this paper for optical pattern
recognition applications. The TJTC technique independently evaluates the autocorrelation and crosscorrelation values of the
reference and the target images and employs a modified decision algorithm. In addition, optical threshold operation and fringe-adjusted
filter are incorporated in the proposed technique to enhance the correlation output and to improve the discrimination performance.
The proposed technique shows better recognition performance compared to existing JTC techniques. Computer simulation are presented
to investigate the salient features of the proposed TJTC technique with noise-free as well as noisy input scenes.
The text was submitted by the authors in English. 相似文献
87.
医疗专家系统主要使用基于知识的技术,其中的决策规则和策略来自于人类的专家。把这些知识和各种推理方法结合,可以建立一个模拟专家决策过程的系统。建立这样一个系统,需要经常与专家磋商,以获取专家的知识,因而需要大量的时间和精力。为此,本文提出直接从数据中提取有效的信息,即用神经网络提取隐含在大量数据中对医疗诊断有效的信息,继之与基于规则的知识,各种推理方法相结合,建立一个神经网络专家系统。 相似文献
88.
我们研制了一种8毫米波变张角、半径突变的多模圆锥馈源。计算出其模比并推导出其辐射方向图公式;给出其在两个主平面——E平面与H平面上的辐射方向图和波束场分布特性的测试结果以及电压驻波比VSWR的测量结果;同时给出频带和旁瓣特性。分析与测试共同表明,在34.5GHz~37GHz频带里,该多模馈源的辐射图在大于24dB范围内获得幅度等化且不出现旁瓣,因此具有一定的应用价值。 相似文献
89.
Yoo‐Seong Kim Woong‐Sik Kim Hak‐Nyun Choi Tae‐Geum Koh Yong‐Seog Kim 《Journal of the Society for Information Display》2007,15(3):199-204
Abstract— Among various barrier‐rib manufacturing processes, the mold‐pattern‐transfer method has potential to reduce processing cost as well as the manufacture of high‐resolution pixels. In this study, the effects of major processing variables of the mold‐pattern‐transfer process on the formation of air‐trapped pores within barrier ribs were examined. The results indicated that with an optimum combination of the processing variables, barrier ribs without trapped defects can be produced, demonstrating the possibility of reducing the number of processing steps and costs of barrier ribs. 相似文献
90.
Target differentiation with simple infrared sensors using statistical pattern recognition techniques
Billur Barshan Author Vitae Tayfun Aytaç Author VitaeAuthor Vitae 《Pattern recognition》2007,40(10):2607-2620
This study compares the performances of various statistical pattern recognition techniques for the differentiation of commonly encountered features in indoor environments, possibly with different surface properties, using simple infrared (IR) sensors. The intensity measurements obtained from such sensors are highly dependent on the location, geometry, and surface properties of the reflecting feature in a way that cannot be represented by a simple analytical relationship, therefore complicating the differentiation process. We construct feature vectors based on the parameters of angular IR intensity scans from different targets to determine their geometry and/or surface type. Mixture of normals classifier with three components correctly differentiates three types of geometries with different surface properties, resulting in the best performance (100%) in geometry differentiation. Parametric differentiation correctly identifies six different surface types of the same planar geometry, resulting in the best surface differentiation rate (100%). However, this rate is not maintained with the inclusion of more surfaces. The results indicate that the geometrical properties of the targets are more distinctive than their surface properties, and surface recognition is the limiting factor in differentiation. The results demonstrate that simple IR sensors, when coupled with appropriate processing and recognition techniques, can be used to extract substantially more information than such devices are commonly employed for. 相似文献