全文获取类型
收费全文 | 194215篇 |
免费 | 20090篇 |
国内免费 | 11813篇 |
专业分类
电工技术 | 15872篇 |
技术理论 | 5篇 |
综合类 | 16332篇 |
化学工业 | 27882篇 |
金属工艺 | 12008篇 |
机械仪表 | 13222篇 |
建筑科学 | 16421篇 |
矿业工程 | 6278篇 |
能源动力 | 5804篇 |
轻工业 | 14436篇 |
水利工程 | 4774篇 |
石油天然气 | 9516篇 |
武器工业 | 2271篇 |
无线电 | 23283篇 |
一般工业技术 | 19802篇 |
冶金工业 | 7641篇 |
原子能技术 | 2165篇 |
自动化技术 | 28406篇 |
出版年
2024年 | 813篇 |
2023年 | 2930篇 |
2022年 | 5898篇 |
2021年 | 8437篇 |
2020年 | 6242篇 |
2019年 | 4932篇 |
2018年 | 5489篇 |
2017年 | 6362篇 |
2016年 | 5564篇 |
2015年 | 8481篇 |
2014年 | 10638篇 |
2013年 | 12667篇 |
2012年 | 14827篇 |
2011年 | 15465篇 |
2010年 | 14383篇 |
2009年 | 13692篇 |
2008年 | 13428篇 |
2007年 | 12742篇 |
2006年 | 11868篇 |
2005年 | 9331篇 |
2004年 | 6593篇 |
2003年 | 5825篇 |
2002年 | 5865篇 |
2001年 | 5139篇 |
2000年 | 3920篇 |
1999年 | 3278篇 |
1998年 | 2145篇 |
1997年 | 1740篇 |
1996年 | 1637篇 |
1995年 | 1413篇 |
1994年 | 1117篇 |
1993年 | 752篇 |
1992年 | 596篇 |
1991年 | 411篇 |
1990年 | 336篇 |
1989年 | 286篇 |
1988年 | 209篇 |
1987年 | 132篇 |
1986年 | 98篇 |
1985年 | 53篇 |
1984年 | 49篇 |
1983年 | 31篇 |
1982年 | 41篇 |
1981年 | 46篇 |
1980年 | 53篇 |
1979年 | 27篇 |
1978年 | 10篇 |
1976年 | 10篇 |
1959年 | 10篇 |
1951年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
131.
Li Wei Ren Yinghui Li Chenfang Li Zhipeng Li Maojun 《The International Journal of Advanced Manufacturing Technology》2020,106(3):921-935
The International Journal of Advanced Manufacturing Technology - The wear of micro-grinding tools less than 1 mm in diameter is crucial for achieving acceptable surface quality and accurate... 相似文献
132.
BDI模型能够很好地解决在特定环境下的Agent的推理和决策问题,但在动态和不确定环境下缺少决策和学习的能力。强化学习解决了Agent在未知环境下的决策问题,却缺少BDI模型中的规则描述和逻辑推理。针对BDI在未知和动态环境下的策略规划问题,提出基于强化学习Q-learning算法来实现BDI Agent学习和规划的方法,并针对BDI的实现模型ASL的决策机制做出了改进,最后在ASL的仿真平台Jason上建立了迷宫的仿真,仿真实验表明,在加入Q-learning学习机制后的新的ASL系统中,Agent在不确定环境下依然可以完成任务。 相似文献
133.
134.
Microsystem Technologies - Recently, nonlinear system identification has received increasingly more attention due to its promising applications in engineering fields. It has become a challenging... 相似文献
135.
Xiangrong Ma Rui Dang Ning Yang Xiao Li Ya zhang Ying Gong Zhipan Liu Wei Guo Yuanyuan Zhang Chunyan Li 《International Journal of Hydrogen Energy》2021,46(44):22842-22851
The high cost of noble metal catalysts has been a great bottleneck for the catalyst industry. Using the noble metal at a single-atom level for catalytic applications could dramatically decrease the cost. The impacts of single Pt atoms on the photocatalytic performance of Ag3VO4 have been investigated and reported. In this report, single Pt atoms were anchored on the surface of Ag3VO4 (AVO) as a cocatalyst, and the resultant composite photocatalyst has been studied for photocatalytic H2 production from water driven by visible light. The as-prepared AVO particles are hollow nanospheres in the monoclinic phase with a bandgap of 2.20 eV. The light absorption edge of AVO/Pt is slightly red-shifted compared to that of the pristine AVO, indicating more visible light absorption of AVO/Pt. The XPS peaks of Ag, V, and Pt exhibit a significant shift after AVO and Pt get into contact, suggesting the strong interaction between the surface Ag and V atoms, and single Pt atoms. After 3-h illumination, the photocatalytic H2 evolution amount from AVO/Pt is improved up to 1400 μmol, which is 2.8 times that on the bare AVO. Such efficient photocatalytic H2 evolution on AVO/Pt is still maintained after five reaction cycles. The better photocatalytic performance of AVO/Pt has been attributed to the more efficient visible light utilization and the lower interfacial charge transfer resistance, as demonstrated in the DRS and EIS spectra. The presence of the surface Pt atoms also leads to a higher amount of reactive radicals, which could efficiently promote the surface redox reactions. 相似文献
136.
137.
Xu Zhi-Zheng Jiang Feng Zhong Chong-Quan Gou Yong-Jie Teng Hong-Fei 《Structural and Multidisciplinary Optimization》2020,61(1):207-223
Structural and Multidisciplinary Optimization - The overall layout optimization design of an orbital propellant depot involves the optimization of shape, size, and positions of propellant tanks in... 相似文献
138.
建立了一种快速、高效的QuEChERS-高效液相色谱-质谱联用法(QuEChERS-HPLC-MS/MS)测定谷类杂粮制品中脱氧雪腐镰刀菌烯醇(DON)、3-乙酰脱氧雪腐镰刀菌烯醇(3-ADON)、15-乙酰脱氧雪腐镰刀菌烯醇(15-ADON)和玉米赤霉烯酮(ZON)共4种真菌毒素。样品前处理采用乙腈-水溶剂提取,经Florisil+C18+无水硫酸镁净化后检测。以0.10%甲酸-乙腈作为流动相,在质谱检测器的多反应监测模式下进行分析。结果表明,4种真菌毒素在各自的线性范围内线性关系良好,相关系数R2均大于0.999,回收率在85.1%~102.0%,相对标准偏差(RSD)为2.11%~6.22%。该方法具有前处理简单、净化效果好、灵敏度高和检测速度快的优点,适用于谷类杂粮制品中DON、3-ADON、15-ADON 和ZON的分析和定量检测。 相似文献
139.
140.
Dujuan Li Wei Yan Ronghui Qi Li-Zhi Zhang 《International Journal of Hydrogen Energy》2021,46(14):9267-9279
PEM-based electrolytic air dehumidification is innovative in dehumidification that requires high precision and small space due to its high efficiency, compactness, and cleanness. However, the system dehumidification performance and durability are limited by using commercial Anatase-IrO2 catalysts. In this study, two types of structurally modified OER catalyst materials, ATO-IrO2 and ND-MnO2-IrO2, are developed to improve the performance of the system. System experiments showed that, compared to the commercial catalysts, the use of ATO-IrO2 and ND-MnO2-IrO2 as the anode catalyst can improve the dehumidification performance by 45% and 20%, respectively. Furthermore, in 50-h accelerated aging tests, the attenuation rates of the ATO-IrO2 and ND-MnO2-IrO2 systems are 3% and 8% respectively, which are far lower than the 35% attenuation of commercial catalyst. The results indicate that, as catalysts with a classic core-shell structure, ATO-IrO2 and ND-MnO2-IrO2 still have a significant impact on improving the performance of the electrolytic dehumidification systems. 相似文献