全文获取类型
收费全文 | 9375篇 |
免费 | 917篇 |
国内免费 | 401篇 |
专业分类
电工技术 | 607篇 |
综合类 | 563篇 |
化学工业 | 1615篇 |
金属工艺 | 486篇 |
机械仪表 | 544篇 |
建筑科学 | 590篇 |
矿业工程 | 206篇 |
能源动力 | 367篇 |
轻工业 | 848篇 |
水利工程 | 164篇 |
石油天然气 | 427篇 |
武器工业 | 73篇 |
无线电 | 1224篇 |
一般工业技术 | 1325篇 |
冶金工业 | 382篇 |
原子能技术 | 124篇 |
自动化技术 | 1148篇 |
出版年
2024年 | 30篇 |
2023年 | 124篇 |
2022年 | 251篇 |
2021年 | 356篇 |
2020年 | 286篇 |
2019年 | 275篇 |
2018年 | 271篇 |
2017年 | 318篇 |
2016年 | 337篇 |
2015年 | 357篇 |
2014年 | 546篇 |
2013年 | 617篇 |
2012年 | 631篇 |
2011年 | 733篇 |
2010年 | 656篇 |
2009年 | 564篇 |
2008年 | 558篇 |
2007年 | 502篇 |
2006年 | 429篇 |
2005年 | 455篇 |
2004年 | 303篇 |
2003年 | 304篇 |
2002年 | 314篇 |
2001年 | 299篇 |
2000年 | 217篇 |
1999年 | 192篇 |
1998年 | 146篇 |
1997年 | 118篇 |
1996年 | 77篇 |
1995年 | 87篇 |
1994年 | 73篇 |
1993年 | 56篇 |
1992年 | 47篇 |
1991年 | 24篇 |
1990年 | 25篇 |
1989年 | 24篇 |
1988年 | 13篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 10篇 |
1983年 | 9篇 |
1982年 | 7篇 |
1981年 | 12篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1975年 | 3篇 |
1973年 | 3篇 |
1970年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
32.
In this paper, we propose a computational framework to incorporate regularization terms used in regularity based variational methods into least squares based methods. In the regularity based variational approach, the image is a result of the competition between the fidelity term and a regularity term, while in the least squares based approach the image is computed as a minimizer to a constrained least squares problem. The total variation minimizing denoising scheme is an exemplary scheme of the former approach with the total variation term as the regularity term, while the moving least squares method is an exemplary scheme of the latter approach. Both approaches have appeared in the literature of image processing independently. By putting schemes from both approaches into a single framework, the resulting scheme benefits from the advantageous properties of both parties. As an example, in this paper, we propose a new denoising scheme, where the total variation minimizing term is adopted by the moving least squares method. The proposed scheme is based on splitting methods, since they make it possible to express the minimization problem as a linear system. In this paper, we employed the split Bregman scheme for its simplicity. The resulting denoising scheme overcomes the drawbacks of both schemes, i.e., the staircase artifact in the total variation minimizing based denoising and the noisy artifact in the moving least squares based denoising method. The proposed computational framework can be utilized to put various combinations of both approaches with different properties together. 相似文献
33.
齐菊红 《自动化与仪器仪表》2014,(2):131-133
如何发挥现有网络设备的最佳功效,从而有效地提高现有网络的利用率,是校园网目前急需解决的问题。本文从探究如何建设高效安全的校园网,让校园网更好的为教育和科研服务为出发点,较好地阐述了目前校园网防御体系存在的问题,并提出了解决问题的措施。 相似文献
34.
A new characterization procedure for aqueous solutions with unknown composition was proposed based on the binomial distribution
of TOC (total organic carbon) fraction in terms of a characterizing variable, the Freundlich coefficient, k, so that the solution
in question can be described by a finite number of pseudo.species identified with a certain k value. The validity and computational
accuracy of this procedure has been demonstrated by characterizing three sets of experimental data chosen from different sources.
Predictions based on this procedure yielded acceptable results that agreed closely with experimental data. 相似文献
35.
We present an interactive method for mesh segmentation that is inspired by the classical live‐wire interaction for image segmentation. The core contribution of the work is the definition and computation of wires on surfaces that are likely to lie at segment boundaries. We define wires as geodesics in a new tensor‐based anisotropic metric, which improves upon previous metrics in stability and feature‐awareness. We further introduce a simple but effective mesh embedding approach that allows geodesic paths in an anisotropic path to be computed efficiently using existing algorithms designed for Euclidean geodesics. Our tool is particularly suited for delineating segmentation boundaries that are aligned with features or curvature directions, and we demonstrate its use in creating artist‐guided segmentations. 相似文献
36.
37.
Jakobi et al. for the first time proposed a novel and practical quantum private query (QPQ) protocol based on SARG04 (Scarani et al. in Phys Rev Lett 92:057901, 2004) quantum key distribution protocol (Jakobi et al. in Phys Rev A 83:022301, 2011). Gao et al. generalized Jakobi et al’s protocol and proposed a flexible QPQ protocol (Gao et al. in Opt Exp 20(16):17411–17420, 2012). When $\theta <\pi /4$ , Gao et al’s protocol exhibits better database security than Jakobi et al’s protocol, but has a higher probability with which Bob can correctly guess the address of Alice’s query. In this paper, we propose a flexible B92-based QPQ protocol. Although SARG04 protocol is a modification of B92 protocol and can be seen as a generalization of B92 protocol, our protocol shows different advantages from Gao et al’s protocol. It can simultaneously obtain better database security and a lower probability with which Bob can correctly guess the address of Alice’s query when $\theta <\pi /4$ . By introducing entanglement, the proposed QPQ protocol is robust against channel-loss attack, which also implies lower classical communication complexity. Similar to Gao et al’s protocol, it is flexible, practical, and robust against quantum memory attack. 相似文献
38.
赵红敏 《网络安全技术与应用》2014,(11):17-18
为了充分利用DTN中各节点资源,减少Epidemic Routing、spray and wait中不区分各节点资源不同,提出了一个基于节点密度、节点运动速度、生存期、节点缓存大小诸多因素,来进行消息转发的算法multi。通过仿真实验表明,multi算法较Epidemic Routing、spray and wait算法在消息成功传输率、平均延迟、网络开销、消息在缓存中滞留的时间上都有明显改善。 相似文献
39.
“CDIO”教学是将工程思维训练融合在教学各个环节当中,本文采用“CDIO”与“案例教学、启发教学”进行融合,组合成为一个新的“1+2”教学模式,以医学信息工程学院课程作为应用载体,将传统教学升华到工程思维教学、团队教学上,转变教师授课形式,激励和引导学生自主学习,为学生提供思维的空间和意境,帮助学生在学习时发现问题,发现、解决值得解决的问题,掌握计算在问题解决过程中发挥的作用,获得构建自身学科知识体系,终身自我学习的能力,滋生创新能力,达到学科知识与工程思维能力互相促进,共同提高的目的。 相似文献
40.
Particulate pollution has raised serious concerns regarding its potential impacts on human health in developing countries. However, much less attention has been paid to the threat of haze particles to machinery and industry. By employing a state-of-the-art in situ scanning electron microscope compression testing technique, we demonstrate that iron-rich and fly ash haze particles, which account for nearly 70% of the total micron-sized spherical haze particles, are strong enough to generate abrasive damage to most engineering alloys, and therefore can generate significant scratch damage to moving contacting surfaces in high precision machineries. Our finding calls for preventive measures to protect against haze related threat. 相似文献