全文获取类型
收费全文 | 28281篇 |
免费 | 1723篇 |
国内免费 | 1630篇 |
专业分类
电工技术 | 1576篇 |
技术理论 | 2篇 |
综合类 | 4684篇 |
化学工业 | 1300篇 |
金属工艺 | 824篇 |
机械仪表 | 2059篇 |
建筑科学 | 1239篇 |
矿业工程 | 755篇 |
能源动力 | 283篇 |
轻工业 | 732篇 |
水利工程 | 437篇 |
石油天然气 | 683篇 |
武器工业 | 312篇 |
无线电 | 2661篇 |
一般工业技术 | 2137篇 |
冶金工业 | 1300篇 |
原子能技术 | 304篇 |
自动化技术 | 10346篇 |
出版年
2024年 | 33篇 |
2023年 | 160篇 |
2022年 | 315篇 |
2021年 | 426篇 |
2020年 | 429篇 |
2019年 | 276篇 |
2018年 | 237篇 |
2017年 | 349篇 |
2016年 | 480篇 |
2015年 | 623篇 |
2014年 | 1293篇 |
2013年 | 1304篇 |
2012年 | 1477篇 |
2011年 | 1606篇 |
2010年 | 1671篇 |
2009年 | 1603篇 |
2008年 | 1615篇 |
2007年 | 2002篇 |
2006年 | 1871篇 |
2005年 | 1777篇 |
2004年 | 1496篇 |
2003年 | 1582篇 |
2002年 | 1296篇 |
2001年 | 1225篇 |
2000年 | 1108篇 |
1999年 | 882篇 |
1998年 | 734篇 |
1997年 | 670篇 |
1996年 | 576篇 |
1995年 | 496篇 |
1994年 | 414篇 |
1993年 | 278篇 |
1992年 | 226篇 |
1991年 | 183篇 |
1990年 | 135篇 |
1989年 | 127篇 |
1988年 | 91篇 |
1987年 | 80篇 |
1986年 | 62篇 |
1985年 | 65篇 |
1984年 | 85篇 |
1983年 | 60篇 |
1982年 | 63篇 |
1981年 | 28篇 |
1980年 | 21篇 |
1979年 | 20篇 |
1978年 | 11篇 |
1977年 | 17篇 |
1962年 | 5篇 |
1961年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
1.
2.
Besides entertainment, games have shown to have the potential to impact a broader variety of cognitive abilities. Research has consistently shown that several aspects in cognition such as visual short-memory, multitasking and spatial skills can be enhanced by game play. In a previous study, it was found that playing Monkey Tales, a game aimed at training arithmetic skills, helped second grade pupils to increase their accuracy in mental calculation as compared to paper exercises. In this follow up study we explore whether traditional methods and game training differ in terms of the cognitive processes that both are able to impact. We incorporated standardized measures of working memory and visuo-motor skills. Additionally, the mathematics game was modified and its contents extracted to allow precise comparison between the gaming and paper exercises condition. Thus each single math exercise, type of question (e.g., multiple choice), quantity and order was perfectly matched in the game training and the traditional training conditions. Gains in arithmetical performance, and self-reported measures of enjoyment were also investigated. We found some evidence suggesting that arithmetic performance enhancement induced by game play and paper exercises differ not only in terms of enjoyment but also of working memory capacity improvements. 相似文献
3.
Klaus Reinhardt Hans Georg Breunig Aisada Uchugonova Karsten K?nig 《Journal of the Royal Society Interface》2015,12(110)
We explore the possibility of characterizing sperm cells without the need to stain them using spectral and fluorescence lifetime analyses after multi-photon excitation in an insect model. The autofluorescence emission spectrum of sperm of the common bedbug, Cimex lectularius, was consistent with the presence of flavins and NAD(P)H. The mean fluorescence lifetimes showed smaller variation in sperm extracted from the male (tau m, τm = 1.54–1.84 ns) than in that extracted from the female sperm storage organ (tau m, τm = 1.26–2.00 ns). The fluorescence lifetime histograms revealed four peaks. These peaks (0.18, 0.92, 2.50 and 3.80 ns) suggest the presence of NAD(P)H and flavins and show that sperm metabolism can be characterized using fluorescence lifetime imaging. The difference in fluorescence lifetime variation between the sexes is consistent with the notion that female animals alter the metabolism of sperm cells during storage. It is not consistent, however, with the idea that sperm metabolism represents a sexually selected character that provides females with information about the male genotype. 相似文献
4.
5.
为了提升高校实验数据处理水平,高校实验室的相关建设工作已经步入正轨,但层出不穷的信息安全问题也向高校实验室计算机网络维护工作提出了新的挑战。文章从现阶段高校实验室计算机网络的相关建设工作出发,简要论述引发网络故障的具体原因,并对其诊断技术进行探讨。 相似文献
6.
Computer‐Interpretable Guidelines (CIGs) are the dominant medium for the delivery of clinical decision support, given the evidence‐based nature of their source material. Therefore, these machine‐readable versions have the ability to improve practitioner performance and conformance to standards, with availability at the point and time of care. The formalisation of Clinical Practice Guideline knowledge in a machine‐readable format is a crucial task to make it suitable for the integration in Clinical Decision Support Systems. However, the current tools for this purpose reveal shortcomings with respect to their ease of use and the support offered during CIG acquisition and editing. In this work, we characterise the current landscape of CIG acquisition tools based on the properties of guideline visualisation, organisation, simplicity, automation, manipulation of knowledge elements, and guideline storage and dissemination. Additionally, we describe the CompGuide Editor, a tool for the acquisition of CIGs in the CompGuide model for Clinical Practice Guidelines that also allows the editing of previously encoded guidelines. The Editor guides the users throughout the process of guideline encoding and does not require proficiency in any programming language. The features of the CIG encoding process are revealed through a comparison with already established tools for CIG acquisition. 相似文献
7.
全息术是一种三维成像技术,它已经被应用于多种实际场景。随着计算机科学与技术的迅猛发展,计算全息由于其方便和灵活的特性,已经成为一种广泛应用的全息成像方法。本文回顾了我们近期基于超表面的太赫兹计算全息研究进展。其中,作为全息板的超表面展示出了超越传统光学器件的独特性能。首先,利用超表面实现了对于全息板每个像素的相位振幅同时且独立的调控,进而实现了高质量全息成像。这种新的电磁波操控能力也带来了新的全息成像效果,如利用介质超表面实现了全息像沿传播方向上的连续变化。其次,对超表面在不同偏振态下的响应进行设计,分别实现了线偏振态与频率复用、圆偏振态复用、以及基于表面波的偏振复用超表面全息术。此外,本文提出了依赖于温度变化而主动可控的超表面全息术,为今后计算全息术的设计与实现提供了新的方案,也推动了超表面在实际应用方面的发展。 相似文献
8.
9.
Single image super resolution (SISR) is an important research content in the
field of computer vision and image processing. With the rapid development of deep
neural networks, different image super-resolution models have emerged. Compared to
some traditional SISR methods, deep learning-based methods can complete the superresolution tasks through a single image. In addition, compared with the SISR methods
using traditional convolutional neural networks, SISR based on generative adversarial
networks (GAN) has achieved the most advanced visual performance. In this review, we
first explore the challenges faced by SISR and introduce some common datasets and
evaluation metrics. Then, we review the improved network structures and loss functions
of GAN-based perceptual SISR. Subsequently, the advantages and disadvantages of
different networks are analyzed by multiple comparative experiments. Finally, we
summarize the paper and look forward to the future development trends of GAN-based
perceptual SISR. 相似文献
10.