全文获取类型
| 收费全文 | 318篇 |
| 免费 | 27篇 |
| 国内免费 | 13篇 |
专业分类
| 电工技术 | 10篇 |
| 综合类 | 19篇 |
| 化学工业 | 59篇 |
| 金属工艺 | 12篇 |
| 机械仪表 | 25篇 |
| 建筑科学 | 11篇 |
| 矿业工程 | 7篇 |
| 能源动力 | 10篇 |
| 轻工业 | 33篇 |
| 水利工程 | 3篇 |
| 石油天然气 | 13篇 |
| 武器工业 | 2篇 |
| 无线电 | 34篇 |
| 一般工业技术 | 36篇 |
| 冶金工业 | 22篇 |
| 原子能技术 | 6篇 |
| 自动化技术 | 56篇 |
出版年
| 2025年 | 1篇 |
| 2024年 | 11篇 |
| 2023年 | 8篇 |
| 2022年 | 19篇 |
| 2021年 | 14篇 |
| 2020年 | 26篇 |
| 2019年 | 17篇 |
| 2018年 | 13篇 |
| 2017年 | 8篇 |
| 2016年 | 6篇 |
| 2015年 | 17篇 |
| 2014年 | 15篇 |
| 2013年 | 29篇 |
| 2012年 | 17篇 |
| 2011年 | 18篇 |
| 2010年 | 12篇 |
| 2009年 | 26篇 |
| 2008年 | 20篇 |
| 2007年 | 6篇 |
| 2006年 | 6篇 |
| 2005年 | 5篇 |
| 2004年 | 13篇 |
| 2003年 | 5篇 |
| 2002年 | 6篇 |
| 2001年 | 4篇 |
| 2000年 | 5篇 |
| 1999年 | 4篇 |
| 1998年 | 6篇 |
| 1997年 | 2篇 |
| 1995年 | 2篇 |
| 1994年 | 1篇 |
| 1993年 | 5篇 |
| 1992年 | 2篇 |
| 1991年 | 1篇 |
| 1990年 | 2篇 |
| 1986年 | 1篇 |
| 1982年 | 1篇 |
| 1981年 | 1篇 |
| 1977年 | 1篇 |
| 1976年 | 1篇 |
| 1973年 | 1篇 |
排序方式： 共有358条查询结果，搜索用时 15 毫秒
11.
在卡尔曼滤波出现以前,已经建立了采用最小二乘法处理观测数据和采用维纳滤波方法处理平稳随机过程的滤波理论。卡尔曼滤波以其物理意义直观的时间域语言和有限时间内的数据观测及简单的递推方法对高速飞行体进行实时的预测和跟踪。本文提出了匀速和匀加速运动目标的运动模型,通过卡尔曼滤波算法进行预测跟踪并对其进行仿真。 相似文献
12.
Junhong Tan;Jin Zhang;Hao Sun;Kaixing Chen;Xing Gao;Ping Zhang;Cheng Zhong;Fei Wu;Zhong'an Li;Linna Zhu; 《Small (Weinheim an der Bergstrasse, Germany)》2024,20(52):2407027
Hole transport materials (HTMs) have a critical impact on the performance of perovskite solar cells (PSCs). Especially, the dopant-free HTMs could avoid the usage of hygroscopic dopants and reduce costs, which are important for device stability. Most of the current organic dopant-free HTMs are polycyclic aromatic hydrocarbons-based planar conjugated structures. Yet, the synthesis of conjugated fused heterocycles is often complicated. In this work, intramolecular non-covalent interaction is introduced to construct two organic HTMs (DCT and DTC), which can be facilely obtained through simple reactions. Compared to DTC with hexyl chain on the central benzene ring, DCT with hexyloxy chains shows better planarity in the core structure, as a result of the intramolecular non-covalent interactions between oxygen on hexyloxy and sulfur atom on the adjacent thiophene, as reflected from its single crystal structure. Moreover, DCT in a pristine state shows a decent hole mobility comparable to the doped Spiro-OMeTAD. Ultimately, conventional devices using dopant-free DCT as HTM show a high efficiency of 22.50%, with excellent long-term stability, and light and thermal stability. The results show that the noncovalent interaction is a useful and simple design strategy for dopant-free HTMs, that can effectively improve the efficiency and stability of PSCs. 相似文献
13.
This paper investigates the problems of controller design and stability analysis for singularly perturbed switched systems subject to actuator saturation. A set of well‐defined sufficient conditions for the existence of state feedback controllers is proposed, under which the closed‐loop system is locally asymptotically stable for arbitrary switching law as long as the singular perturbation parameter is sufficiently small. With the obtained controller, the estimation problem of stability bound and basin of attraction of the closed‐loop system is reduced to solving a convex optimization problem. A numerical example and a hydraulic servo position system are used to illustrate the obtained results. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
14.
15.
该研究将室温等离子（ARTP）诱变与微生物微滴培养（MMC）技术应用于几丁质脱乙酰基酶（CDA）高产菌株的诱变选育,构建高产CDA菌株的诱变及高通量筛选方法。结果表明,经过4轮的ARTP诱变及MMC筛选,从200个不同的液滴中共筛选出5个发酵产酶明显提升的液滴,并通过进一步的平板筛选、24-深孔板复筛,获得了17株产酶提高300%以上的诱变菌株。通过对比分析17株高产菌株产CDA的能力,确定了1株最佳CDA高产菌株B4,其CDA最大产量比出发菌株提高了3.15倍,发酵产酶总量达到419.11 U/mL,为原始菌种的3.90倍。该研究为CDA高产菌株的诱变选育及高通量筛选提供了借鉴。 相似文献
16.
王琳娜 《重庆科技学院学报(社会科学版)》2011,(3):53-55
在社会转型时期,土地不能满足农民家庭实现收支平衡的经济需求,农村家庭将经济生产空间转移到打工所在地区,农民工依赖出卖劳动力维持家庭的经济生产职能。工厂利用工人对工厂的这种依赖性和市场上劳动力过剩的形势,建立一系列与工人经济收入挂钩的管理体制,形成了工厂的专制主义体制。 相似文献
17.
18.
Lei?Zhang Feng?bao?YangEmail author Linna?Ji 《Automatic Control and Computer Sciences》2018,52(2):135-145
The features of infrared polarization and intensity images are not finely transferred to the fused image by using traditional fusion algorithms, which leads to a severe blur of the fused image. This study proposes a new infrared polarization and intensity image fusion algorithm based on the feature transfer. First, the contrast features of the infrared polarization image are extracted by the multiscale average filter decomposition with help of standard deviation constraint. The texture features of infrared polarization images are retrieved via non-subsample-shearlet transform at the same time. Second, the difference of the features is measured using the similarity index, which is used as the transfer weight for the infrared polarization feature images during the later phase of the image fusion. Finally, the fused image is obtained by the superimposition of the infrared intensity image and feature images, which are created from the infrared polarization image. The experimental results demonstrated that the proposed method is able to transfer the features of both the infrared intensity image and the polarization image into the fused images. It performs well on both subjective and objective image quality. 相似文献
19.
20.
对企业账面利润与现金流量关系的认识 总被引：3，自引：0，他引：3
本文阐述了企业账面利润与现金流量的关系 ,指出了企业账面利润与现金流量的四个不同点 ,并且提出了一个现代企业应如何在四个方面做好工作 ,正确处理好这两者的关系。 相似文献