全文获取类型
收费全文 | 516488篇 |
免费 | 62120篇 |
国内免费 | 43680篇 |
专业分类
电工技术 | 47696篇 |
综合类 | 58371篇 |
化学工业 | 62311篇 |
金属工艺 | 36674篇 |
机械仪表 | 37821篇 |
建筑科学 | 40080篇 |
矿业工程 | 23301篇 |
能源动力 | 13459篇 |
轻工业 | 55964篇 |
水利工程 | 18302篇 |
石油天然气 | 17956篇 |
武器工业 | 8826篇 |
无线电 | 53878篇 |
一般工业技术 | 41011篇 |
冶金工业 | 19940篇 |
原子能技术 | 8553篇 |
自动化技术 | 78145篇 |
出版年
2024年 | 2885篇 |
2023年 | 8073篇 |
2022年 | 20681篇 |
2021年 | 26522篇 |
2020年 | 18945篇 |
2019年 | 13042篇 |
2018年 | 13841篇 |
2017年 | 15764篇 |
2016年 | 14116篇 |
2015年 | 23067篇 |
2014年 | 29389篇 |
2013年 | 34150篇 |
2012年 | 44092篇 |
2011年 | 45904篇 |
2010年 | 43986篇 |
2009年 | 41662篇 |
2008年 | 43220篇 |
2007年 | 42261篇 |
2006年 | 35787篇 |
2005年 | 29131篇 |
2004年 | 20898篇 |
2003年 | 13507篇 |
2002年 | 12570篇 |
2001年 | 11530篇 |
2000年 | 8988篇 |
1999年 | 3169篇 |
1998年 | 835篇 |
1997年 | 624篇 |
1996年 | 487篇 |
1995年 | 427篇 |
1994年 | 281篇 |
1993年 | 331篇 |
1992年 | 295篇 |
1991年 | 178篇 |
1990年 | 194篇 |
1989年 | 230篇 |
1988年 | 139篇 |
1987年 | 93篇 |
1986年 | 97篇 |
1985年 | 49篇 |
1984年 | 67篇 |
1983年 | 58篇 |
1982年 | 47篇 |
1981年 | 88篇 |
1980年 | 170篇 |
1979年 | 110篇 |
1965年 | 16篇 |
1964年 | 10篇 |
1959年 | 106篇 |
1951年 | 112篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
21.
22.
Shuang Chen Chao Yu Zhanfang Cao Xiaoping Huang Shuai Wang Hong Zhong 《International Journal of Hydrogen Energy》2021,46(10):7037-7046
The development of efficient and stable oxygen evolution reaction (OER) catalysts is an ongoing challenge. In order to solve the problem of low oxygen evolution efficiency of the current OER catalysts, a novel material was synthesized by the incorporation of NiFeCr-LDH and MoS2, and its structural and electrochemical properties were also investigated. The introduction of MoS2 improves the electrochemical performance of NiFeCr-LDH. The polarization curve shows that the potential of composite material is only 1.50 V at a current density of 10 mA cm?2, which is far superior to commercial precious metal catalysts. In addition, the stability experiment shows that the composite material has excellent stability, and the current density has little change after 500 cycles. Furthermore, we found that some metal ions, such as Ni, Cr and Mo, exist in the form of high valence on the surface of NiFeCr-LDH@MoS2, which is also conducive to the occurrence of oxygen evolution reaction. 相似文献
23.
介绍装配式建筑电气设计中的管线分离SI体系、模块化机电设计、集成机电部品、装配式建筑防雷接地系统等关键技术,并进行简要分析. 相似文献
24.
本文通过对各项治理技术比选,提出了生态封场技术在非正规垃圾堆放场治理中的应用,并结合实际案例给出了详细治理方案. 相似文献
25.
26.
27.
全膜电容器边缘处的电场畸变是影响电容器元件击穿的重要因素之一.为研究浸渍情况和压紧系数对全膜电容器电场分布的影响,对电容器端部进行建模,通过改变浸渍情况和压紧系数,计算不同参数下电容器端部的电场分布情况,结果表明:未浸渍情况下电场最大值集中在折边处两侧,浸渍情况下场强在折边圆弧处分布较为均匀.同时发现,在浸渍情况下增大压紧系数K可以明显改善全膜电容器端部电场的分布情况. 相似文献
28.
29.
Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films are attracting famous applications in antistatic coating, energy storage and conversion, printed electronics, and biomedical fields due to their conductivity, optical transparency and flexibility. However, PEDOT:PSS has poor dispersion stability during long-term storage and transport. Moreover, the dried PEDOT:PSS films are insoluble in any solvent and cannot be redispersed again. In comparison to bake drying, here, a feasible strategy to achieve mechanically redispersed PEDOT:PSS with the help of freeze-drying process was reported. The redispersed PEDOT:PSS can recover not only the initial characters such as pH, chemical composition, viscosity, and particle size under similar solid contents, but also conductivity and surface morphology of treated films. In addition, the treated film exhibits self-healing properties similar to pristine film in terms of mechanical and electrical properties. This technology enables reuse and overcomes the technical problems of PEDOT:PSS dispersion, realizing real-time processing to meet variable applications. 相似文献
30.
Dr. Yibin Zhang Dr. Shuai Xia Shulin Wan Tessa E. Steenwinkel Tara Vohs Prof. Rudy L. Luck Prof. Thomas Werner Prof. Haiying Liu 《Chembiochem : a European journal of chemical biology》2021,22(13):2282-2291
Abnormal levels of glutathione, a cellular antioxidant, can lead to a variety of diseases. We have constructed a near-infrared ratiometric fluorescent probe to detect glutathione concentrations in biological samples. The probe consists of a coumarin donor, which is connected through a disulfide-tethered linker to a rhodamine acceptor. Under the excitation of the coumarin donor at 405 nm, the probe shows weak visible fluorescence of the coumarin donor at 470 nm and strong near-infrared fluorescence of the rhodamine acceptor at 652 nm due to efficient Forster resonance energy transfer (FRET) from the donor to the acceptor. Glutathione breaks the disulfide bond through reduction, which results in a dramatic increase in coumarin fluorescence and a corresponding decrease in rhodamine fluorescence. The probe possesses excellent cell permeability, biocompatibility, and good ratiometric fluorescence responses to glutathione and cysteine with a self-calibration capability. The probe was utilized to ratiometrically visualize glutathione concentration alterations in HeLa cells and Drosophila melanogaster larvae. 相似文献