全文获取类型
收费全文 | 60577篇 |
免费 | 4289篇 |
国内免费 | 1705篇 |
专业分类
电工技术 | 3749篇 |
综合类 | 5810篇 |
化学工业 | 4078篇 |
金属工艺 | 1894篇 |
机械仪表 | 2252篇 |
建筑科学 | 11472篇 |
矿业工程 | 1554篇 |
能源动力 | 1166篇 |
轻工业 | 13612篇 |
水利工程 | 4717篇 |
石油天然气 | 1804篇 |
武器工业 | 222篇 |
无线电 | 3143篇 |
一般工业技术 | 2932篇 |
冶金工业 | 3293篇 |
原子能技术 | 185篇 |
自动化技术 | 4688篇 |
出版年
2024年 | 332篇 |
2023年 | 869篇 |
2022年 | 1419篇 |
2021年 | 1863篇 |
2020年 | 1892篇 |
2019年 | 1585篇 |
2018年 | 1437篇 |
2017年 | 1714篇 |
2016年 | 1798篇 |
2015年 | 2006篇 |
2014年 | 4326篇 |
2013年 | 3423篇 |
2012年 | 4311篇 |
2011年 | 4542篇 |
2010年 | 3534篇 |
2009年 | 3794篇 |
2008年 | 3423篇 |
2007年 | 4021篇 |
2006年 | 3634篇 |
2005年 | 2938篇 |
2004年 | 2564篇 |
2003年 | 2320篇 |
2002年 | 2030篇 |
2001年 | 1473篇 |
2000年 | 1202篇 |
1999年 | 945篇 |
1998年 | 624篇 |
1997年 | 492篇 |
1996年 | 422篇 |
1995年 | 356篇 |
1994年 | 276篇 |
1993年 | 208篇 |
1992年 | 185篇 |
1991年 | 120篇 |
1990年 | 86篇 |
1989年 | 85篇 |
1988年 | 65篇 |
1987年 | 56篇 |
1986年 | 32篇 |
1985年 | 35篇 |
1984年 | 26篇 |
1983年 | 18篇 |
1982年 | 17篇 |
1981年 | 9篇 |
1980年 | 20篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1975年 | 4篇 |
1964年 | 3篇 |
1959年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
本文介绍涟钢第一炼钢厂1号小方坯连铸机浇铸优质钢的生产实践,并探索连铸优质钢的途径。指出为保证质量,必须严格保证钢水质量,控制合适的浇铸温度,拉坯速度和冷却强度;钢水必须吹氩;采用大容量中间包和伸入式水口保护渣浇涛,确保连铸机的状况良好。 相似文献
72.
以当前的高职高专院校教育教学为平台,研究分析最小支持度关联规则挖掘技术与教学质量评价相结合的问题,针对教学质量评价结果中的盲目性、不易把握等问题,提出利用最小支持度来分析质量评价体系,获取以影响因素为条件,以评价分析为结论的关联规则来解决目前教学质量评价中的不合理性,使教学质量评价公平、公正、合理、高效,并给教学管理人员提供决策分析资料。 相似文献
73.
数据挖掘作为一种发现大量数据中潜在信息的数据分析技术,受到各界的密切关注。SAS数据挖掘技术是众多数据挖掘方法中的佼佼者,它在大型企业中得到很好的应用。本文介绍数据挖掘的背景知识,并利用SAS/EM工具,对该技术在冷轧酸洗卷质量缺陷原因分析作了初步尝试。 相似文献
74.
陈祖龙 《电脑编程技巧与维护》2012,(8):20-21,55
信息管理系统合理地借鉴国际领先的产品质量管理思想并结合国内企业产品质量管理现状,经过长期的现场调研,完全能满足国内一般企业的产品质量管理的需要。并通过对行业产品质量管理情况的长期研究探索,以灵活、通用为主要设计思想,开发了适合于企业产品质量管理的信息系统。 相似文献
75.
结合德州学院信息与计算科学专业教学团队建设的实际,阐述了教学团队的内涵与特征、教学团队的梯队建设、教学团队建设的策略,以及教学团队建设已取得的成果。 相似文献
76.
通过对智能建筑弱电技术中的电线/电缆导管的敷设、电气照明安装、工程中的冲突以及弱电系统的施工计划等问题的研究,总结了智能建筑弱电技术中的综合布线系统、计算机网络系统、子系统间接口方面、母线的安装、弱电设备功能以及配电装置等技术问题的解决要点。所述内容对智能建筑整体运行和安全管理以及电气施工安装的质量监控等具有较强的参考价值。 相似文献
77.
《Displays》2021
As the demand for high-quality stereo images has grown in recent years, stereoscopic image quality assessment (SIQA) has become an important research area in modern image processing technology.In this paper, we propose a no-reference stereoscopic image quality assessment (NR-SIQA) model using heterogeneous ensemble learning ‘quality-aware’ features from luminance image, chrominance image, disparity and cyclopean images via quaternion wavelet transform (QWT). Firstly, luminance image and chrominance image are generated by CIELAB color space as monocular perception, and the novel disparity and cyclopean images are utilized to complement with monocular information. Then, a number of ‘quality-aware’ features in the quaternion wavelet domain are discovered, including entropy, texture features, energy features, energy differences features and MSCN coefficients of high frequency sub-band. Finally, a heterogeneous ensemble model via support vector regression (SVR) & extreme learning machine (ELM) & random forest (RF) is proposed to predict quality score, and bootstrap sampling and rotated feature space are used to increase the diversity of data distribution. Comparing with the state-of-the-art NR-SIQA models, experimental results on four public databases prove the accuracy and robustness of the proposed model. 相似文献
78.
《Displays》2021
The image quality of three organic light-emitting diode (OLED) based smart-phone displays was assessed at three levels of ambient lighting conditions corresponding to the darkroom, indoor and outdoor environment, respectively. Seven perceptual attributes, i.e., naturalness, colorfulness, brightness, contrast, sharpness, preference, and overall image quality (IQ), were evaluated in both standard dynamic range (SDR) and high dynamic range (HDR) mode via psychophysical experiments by rank order method, while readability was assessed only in SDR mode and gradation was investigated only in HDR mode. The experimental results demonstrate that, besides the color gamut, the tone reproduction curve is also an important factor affecting the colorfulness of mobile display in the two modes. Higher peak luminance would not mean better performance on brightness and contrast for HDR images, which is opposite to SDR mode. Further analysis of variance (ANOVA) indicates that the ranking results of all perceptual attributes are not significantly affected by the ambient lighting levels in both SDR and HDR modes. 相似文献
79.
Emma P. Bullock Allison L. Roxburgh Patricia S. Moyer-Packenham Elif Bektas Joseph S. Webster Kathleen A. Bullock 《Journal of Computer Assisted Learning》2021,37(2):557-586
This study focused on an examination of how type, quality and children's awareness of design features in digital math games, along with an awareness of the mathematics goals of the game, were related to learning outcomes. We conducted a parallel conversion mixed methods study with 45 students in Grades 3 and 4 (ages 9–10). Students participated in clinical interviews using three digital math games. The results suggest a moderated mediation relationship in which the quality of the design features moderated the mediating impact of children's awareness of the game's design features, specifically when the child was aware of the mathematics content learning goal (MCLG) of the game. These findings show how important it is that design features are of high quality in a digital math game, and how this is intertwined with children's awareness of the features and the MCLG. When these variables intertwined in just the right way, the interactions between the children and the digital math game afforded mathematical learning growth. 相似文献
80.
A method capable of estimating the hydrograph from a prescribed storm for a practical mild slope upstream catchment is proposed. This method makes use of two new characteristic parameters, andS, in conjunction with the kinematic wave equation to compute lateral inflows of the main stream of the catchment. The depth profile of overland flow at any instant within the catchment and hydrograph at any location can be easily found. Lag times for individual lateral inflows are then considered and are linearly combined to obtain the hydrograph at the outlet of the catchment or depth profile of the main stream at any instant. The validity of the excess rainfall-surface runoff linear relationship in this study has also been verified with Tatsunokuchiyama catchment, and it shows good results for this computed runoff. 相似文献