全文获取类型
收费全文 | 38462篇 |
免费 | 4832篇 |
国内免费 | 2790篇 |
专业分类
电工技术 | 5698篇 |
技术理论 | 5篇 |
综合类 | 4924篇 |
化学工业 | 2570篇 |
金属工艺 | 1446篇 |
机械仪表 | 2852篇 |
建筑科学 | 4597篇 |
矿业工程 | 1120篇 |
能源动力 | 1421篇 |
轻工业 | 788篇 |
水利工程 | 1355篇 |
石油天然气 | 1341篇 |
武器工业 | 543篇 |
无线电 | 5250篇 |
一般工业技术 | 4351篇 |
冶金工业 | 930篇 |
原子能技术 | 577篇 |
自动化技术 | 6316篇 |
出版年
2024年 | 213篇 |
2023年 | 595篇 |
2022年 | 1076篇 |
2021年 | 1244篇 |
2020年 | 1551篇 |
2019年 | 1291篇 |
2018年 | 1079篇 |
2017年 | 1450篇 |
2016年 | 1595篇 |
2015年 | 1640篇 |
2014年 | 2693篇 |
2013年 | 2536篇 |
2012年 | 3024篇 |
2011年 | 3170篇 |
2010年 | 2334篇 |
2009年 | 2380篇 |
2008年 | 2251篇 |
2007年 | 2613篇 |
2006年 | 2220篇 |
2005年 | 1917篇 |
2004年 | 1561篇 |
2003年 | 1321篇 |
2002年 | 1078篇 |
2001年 | 950篇 |
2000年 | 772篇 |
1999年 | 656篇 |
1998年 | 489篇 |
1997年 | 410篇 |
1996年 | 349篇 |
1995年 | 335篇 |
1994年 | 260篇 |
1993年 | 193篇 |
1992年 | 184篇 |
1991年 | 136篇 |
1990年 | 109篇 |
1989年 | 98篇 |
1988年 | 79篇 |
1987年 | 47篇 |
1986年 | 29篇 |
1985年 | 33篇 |
1984年 | 18篇 |
1983年 | 12篇 |
1982年 | 22篇 |
1981年 | 8篇 |
1980年 | 9篇 |
1979年 | 18篇 |
1978年 | 4篇 |
1964年 | 2篇 |
1959年 | 12篇 |
1951年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
1.
吴敬东 《湖南工业职业技术学院学报》2015,(2):137-140
高校是培养人才的摇篮,肩负着科教兴国、人才强国两大历史性战略任务。由于社会环境的复杂化,人际关系的交错性,新时代的大学生行为状况给高校学生管理工作带来了新的挑战。针对新时期大学生行为特点,我们通过加强党建工作、强化学风建设、做好班级自主管理和深化社会服务四个方面工作进行分析,提出了全面引导、约束、规范和优化大学生的行为的建议和对策,从而有效解决新形势下普通高校学生管理工作的实际困难。 相似文献
2.
3.
The performance of surface ionic conduction single chamber fuel cell (SIC‐SCFC) prepared by the sol gel method was studied on electric characteristics due to the differences of the operating temperature and humidity, the electrode distance and electrolyte film depth, and multiple cells with the series and parallel connections. The SIC–SCFC was arranged the both anode of Pt and cathode of Au on the boehmite electrolyte. The open circuit voltage (OCV) of single cell achieved a maximum of 530mV in the dry gas mixtures of O2/H2=50% in room temperature operation, and but it became decrease as over 60%. The OCV was maintained the constant value between operating temperatures of 30°C to 80°C, and but it was decreased sharply at over 90°C because a humidity on the cell became lower as increasing operating temperature. Then, the cell property was improved to 120°C by adding to the humidity of 70% using a humidifier. The electrode distance and the electrolyte film depth of SIC‐SCFC found to be contributed to the reductions of the cell resistance and the surface roughness on the electrode, respectively. Moreover, the power property of SIC‐SCFC was significantly improved by cell stacks comprised of the series or parallel connection of a cell. 相似文献
4.
《International Journal of Hydrogen Energy》2019,44(2):587-593
A solid-state photoelectrochemical (SSPEC) cell is an attractive approach for solar water splitting, especially when it comes to monolithic device design. In a SSPEC cell the electrodes distance is minimized, while the use of polymer-based membranes alleviates the need for liquid electrolytes, and at the same time they can separate the anode from the cathode. In this work, we have made and tested, firstly, a SSPEC cell with a Pt/C electrocatalyst as the cathode electrode, under purely gaseous conditions. The anode was supplied with air of 80% relative humidity (RH) and the cathode with argon. Secondly, we replaced the Pt/C cathode with a photocathode consisting of 2D photocatalytic g-C3N4, which was placed in tandem with the photoanode (tandem-SSPEC). The tandem configuration showed a three-fold enhancement in the obtained photovoltage and a steady-state photocurrent density. The mechanism of operation is discussed in view of recent advances in surface proton conduction in absorbed water layers. The presented SSPEC cell is based on earth-abundant materials and provides a way towards systems of artificial photosynthesis, especially for areas where water sources are scarce and electrical grid infrastructure is limited or nonexistent. The only requirements to make hydrogen are humidity and sunlight. 相似文献
5.
为了减小传统的最差情况设计方法引入的电压裕量,提出了一种变化可知的自适应电压缩减(AVS)技术,通过调整电源电压来降低电路功耗.自适应电压缩减技术基于检测关键路径的延时变化,基于此设计了一款预错误原位延时检测电路,可以检测关键路径延时并输出预错误信号,进而控制单元可根据反馈回的预错误信号的个数调整系统电压.本芯片采用SMIC180 nm工艺设计验证,仿真分析表明,采用自适应电压缩减技术后,4个目标验证电路分别节省功耗12.4%,11.3%,10.4%和11.6%. 相似文献
6.
Baizhan Li Chenqiu Du Hong Liu Wei Yu Jie Zheng Meilan Tan Zhenxing Jin Wenjie Li Jing Wu Lu Chen Runming Yao 《Indoor air》2019,29(2):308-319
The extensive research interests in environmental temperature can be linked to human productivity / performance as well as comfort and health; while the mechanisms of physiological indices responding to temperature variations remain incompletely understood. This study adopted a physiological sensory nerve conduction velocity (SCV) as a temperature‐sensitive biomarker to explore the thermoregulatory mechanisms of human responding to annual temperatures. The measurements of subjects’ SCV (over 600 samples) were conducted in a naturally ventilated environment over all four seasons. The results showed a positive correlation between SCV and annual temperatures and a Boltzmann model was adopted to depict the S‐shaped trend of SCV with operative temperatures from 5°C to 40°C. The SCV increased linearly with operative temperatures from 14.28°C to 20.5°C and responded sensitively for 10.19°C‐24.59°C, while tended to be stable beyond that. The subjects’ thermal sensations were linearly related to SCV, elaborating the relation between human physiological regulations and subjective thermal perception variations. The findings reveal the body SCV regulatory characteristics in different operative temperature intervals, thereby giving a deeper insight into human autonomic thermoregulation and benefiting for built environment designs, meantime minimizing the temperature‐invoked risks to human health and well‐being. 相似文献
7.
8.
9.
10.
The microstructural aspects of compressive inelastic deformation in balsa wood are investigated with emphasis on the failure mode transition and its effects on energy dissipation characteristics. The architectural features as well as the composite character of cell wall ultrastructure are discussed in a framework to understand the complex interrelationship between microstructure and macroscopic behavior in this extremely lightweight cellular biocomposite. Based on this discussion and experimental results, it is concluded that the biomimetic approach may prove to be a viable strategy in designing composite structures with high specific energy absorption capacity. 相似文献