全文获取类型
收费全文 | 92705篇 |
免费 | 8132篇 |
国内免费 | 3944篇 |
专业分类
电工技术 | 3901篇 |
技术理论 | 13篇 |
综合类 | 8712篇 |
化学工业 | 15649篇 |
金属工艺 | 1630篇 |
机械仪表 | 2081篇 |
建筑科学 | 15968篇 |
矿业工程 | 5544篇 |
能源动力 | 5312篇 |
轻工业 | 5299篇 |
水利工程 | 19670篇 |
石油天然气 | 7703篇 |
武器工业 | 222篇 |
无线电 | 1373篇 |
一般工业技术 | 4246篇 |
冶金工业 | 3477篇 |
原子能技术 | 1145篇 |
自动化技术 | 2836篇 |
出版年
2024年 | 150篇 |
2023年 | 1045篇 |
2022年 | 2041篇 |
2021年 | 2549篇 |
2020年 | 2722篇 |
2019年 | 2252篇 |
2018年 | 2158篇 |
2017年 | 2649篇 |
2016年 | 2989篇 |
2015年 | 3006篇 |
2014年 | 5921篇 |
2013年 | 5753篇 |
2012年 | 7045篇 |
2011年 | 7159篇 |
2010年 | 5292篇 |
2009年 | 5547篇 |
2008年 | 4864篇 |
2007年 | 6402篇 |
2006年 | 5921篇 |
2005年 | 5373篇 |
2004年 | 4206篇 |
2003年 | 3836篇 |
2002年 | 3316篇 |
2001年 | 2658篇 |
2000年 | 2117篇 |
1999年 | 1618篇 |
1998年 | 1173篇 |
1997年 | 972篇 |
1996年 | 750篇 |
1995年 | 698篇 |
1994年 | 509篇 |
1993年 | 401篇 |
1992年 | 310篇 |
1991年 | 248篇 |
1990年 | 182篇 |
1989年 | 196篇 |
1988年 | 121篇 |
1987年 | 131篇 |
1986年 | 101篇 |
1985年 | 100篇 |
1984年 | 98篇 |
1983年 | 59篇 |
1982年 | 31篇 |
1981年 | 10篇 |
1980年 | 17篇 |
1979年 | 18篇 |
1977年 | 9篇 |
1976年 | 7篇 |
1956年 | 4篇 |
1951年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
《International Journal of Hydrogen Energy》2022,47(2):761-771
Exploring cost-effective, high-efficiency and stable electrocatalysts for overall water splitting is greatly desirable and challenging for sustainable energy. Herein, a novel designed Ni activated molybdenum carbide nanoparticle loaded on stereotaxically-constructed graphene (SCG) using two steps facile strategy (hydrothermal and carbonization) as a bifunctional electrocatalyst for overall water splitting. The optimized Ni/Mo2C(1:20)-SCG composites exhibit excellent performance with a low overpotential of 150 mV and 330 mV for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively to obtain a current density of 10 mA cm?2 in 1.0 M KOH solution. In addition, when the optimized Ni/Mo2C(1:20)-SCG composite is used as a bifunctional electrode for overall water splitting, the electrochemical cell required a low cell voltage of 1.68 V at a current density of 10 mA cm?2 and long-term stability of 24 h. More significantly, the synergetic effects between Ni-activated Mo2C nanoparticles and SCG are regarded as a significant contributor to accelerate charge transfer and promote electrocatalytic performance in hybrid electrocatalysts. Our works introduce a novel approach to design advanced bifunctional electrodes for overall water splitting. 相似文献
42.
Jihong Li Yipu Liu Hui Chen Zhankai Zhang Xiaoxin Zou 《Advanced functional materials》2021,31(27):2101820
The realization of seawater electrolysis requires high-performing anode materials that should possess good catalytic activity, stability, and specificity for the oxygen evolution reaction (OER) as well as high resistance toward chloride corrosion. Herein, the design of a multilayered oxygen-evolution electrode is reported to meet the multiple needs of anode material for saline water splitting. The multilayered electrode is synthesized through direct thermal boronization of commercially available NiFe alloy plate with boron powder, followed by electrochemical oxidation. And this electrode is composed of the surface oxidized NiFeBx alloy layer, the NiFeBx alloy interlayer, and the NiFe alloy substrate. The boron species are present in the form of metaborate in the outermost oxidized NiFeBx layer, and their existence is conductive to the generation and stabilization of the catalytic active phase γ-(Ni,Fe)OOH. The introduction of NiFeBx interlayer effectively prevents the excessive oxidative corrosion of the anode material in the electrolyte containing chloride ions. 相似文献
43.
44.
45.
Peng Li Haibin Jiang Ariel Barr Zhichu Ren Rui Gao Hua Wang Weiwei Fan Meifang Zhu Guiyin Xu Ju Li 《Advanced functional materials》2021,31(51):2105845
Mercury, lead, and cadmium are among the most toxic and carcinogenic heavy metal ions (HMIs), posing serious threats to the sustainability of aquatic ecosystems and public health. There is an urgent need to remove these ions from water by a cheap but green process. Traditional methods have insufficient removal efficiency and reusability. Structurally robust, large surface-area adsorbents functionalized with high-selectivity affinity to HMIs are attractive filter materials. Here, an adsorbent prepared by vulcanization of polyacrylonitrile (PAN), a nitrogen-rich polymer, is reported, giving rise to PAN-S nanoparticles with cyclic π-conjugated backbone and electronic conductivity. PAN-S can be coated on ultra-robust melamine (ML) foam by simple dipping and drying. In agreement with hard/soft acid/base theory, N- and S-containing soft Lewis bases have strong binding to Hg2+, Pb2+, Cu2+, and Cd2+, with extraordinary capture efficiency and performance stability. Furthermore, the used filters, when collected and electrochemically biased in a recycling bath, can release the HMIs into the bath and electrodeposit on the counter-electrode as metallic Hg0, Pb0, Cu0, and Cd0, and the PAN-S@ML filter can then be reused at least 6 times as new. The electronically conductive PAN-S@ML filter can be fabricated cheaply and holds promise for scale-up applications. 相似文献
46.
本文简述了酸水汽提工艺的发展概况和技术进展,详细介绍了煤化工酸水汽提装置实际运行中存在的几类主要问题,并提出切实可行的解决措施,具有一定的借鉴意义。 相似文献
47.
48.
邵啸 《皮革制作与环保科技》2021,(5):146-147
危险废物具有各种危害性,不仅对人体健康有着威胁,对于环境治理来说也有着极大的消极影响。就目前来说,虽然安全填埋技术已经较为成熟,但在实际实施过程中还是容易出现渗漏事故,渗漏液在地下容易穿透防渗层,从而影响地下水,所以这也是我们需要重视的问题之一。 相似文献
49.
John D. Rodney S. Deepapriya M. Cyril Robinson C. Justin Raj Suresh Perumal Byung Chul Kim S. Krishnan S. Jerome Das 《International Journal of Hydrogen Energy》2021,46(54):27585-27596
The production of hydrogen, a favourable alternative to an unsustainable fossil fuel remains as a significant hurdle with the pertaining challenge in the design of proficient, highly productive and sustainable electrocatalyst for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Herein, the dysprosium (Dy) doped copper oxide (Cu1-xDyxO) nanoparticles were synthesized via solution combustion technique and utilized as a non-noble metal based bi-functional electrocatalyst for overall water splitting. Due to the improved surface to volume ratio and conductivity, the optimized Cu1-xDyxO (x = 0.01, 0.02) electrocatalysts exhibited impressive HER and OER performance respectively in 1 M KOH delivering a current density of 10 mAcm?2 at a potential of ?0.18 V vs RHE for HER and 1.53 V vs RHE for OER. Moreover, the Dy doped CuO electrocatalyst used as a bi-functional catalyst for overall water splitting achieved a potential of 1.56 V at a current density 10 mAcm?2 and relatively high current density of 66 mAcm?2 at a peak potential of 2 V. A long term stability of 24 h was achieved for a cell voltage of 2.2 V at a constant current density of 30 mAcm?2 with only 10% of the initial current loss. This showcases the accumulative opportunity of dysprosium as a dopant in CuO nanoparticles for fabricating a highly effective and low-cost bi-functional electrocatalyst for overall water splitting. 相似文献
50.
Jun-Jie Xing Ju-Yuan Qiao Zhen Yang Xiao-Na Guo Ke-Xue Zhu 《International Journal of Food Science & Technology》2021,56(11):5609-5618
The effects of resting under ultrasonic treatment on the properties of whole wheat dough sheets and noodles were investigated. Compared with the control group, the resting time to reach the maximum breaking force and extensibility of whole wheat dough sheets treated with ultrasound was shortened by 20 min. The proportion of strongly bound water (T21) decreased, while the proportion of weakly bound water (T22) increased during resting, and the ultrasonic treatment could accelerate this moisture redistribution in the dough. The extent of the increase in gluten macropolymer and the decrease in –SH content of ultrasound-treated wheat dough was higher than that of the control one during the initial 5–15 min resting, which could be related to the improvement of whole wheat dough extensibility. Whole wheat noodles showed a better breaking distance for 10 min of ultrasonic-assisted resting. Ultrasonic treatment could be used to reduce the resting time of whole wheat dough sheets and improve the texture properties of noodles. 相似文献