全文获取类型
收费全文 | 210908篇 |
免费 | 16542篇 |
国内免费 | 8080篇 |
专业分类
电工技术 | 11579篇 |
技术理论 | 14篇 |
综合类 | 11565篇 |
化学工业 | 36765篇 |
金属工艺 | 10891篇 |
机械仪表 | 12301篇 |
建筑科学 | 16794篇 |
矿业工程 | 5081篇 |
能源动力 | 6006篇 |
轻工业 | 13511篇 |
水利工程 | 3363篇 |
石油天然气 | 11409篇 |
武器工业 | 1388篇 |
无线电 | 26017篇 |
一般工业技术 | 27363篇 |
冶金工业 | 11118篇 |
原子能技术 | 2227篇 |
自动化技术 | 28138篇 |
出版年
2024年 | 939篇 |
2023年 | 3420篇 |
2022年 | 6196篇 |
2021年 | 8292篇 |
2020年 | 6050篇 |
2019年 | 5247篇 |
2018年 | 5677篇 |
2017年 | 6472篇 |
2016年 | 5910篇 |
2015年 | 7637篇 |
2014年 | 9864篇 |
2013年 | 12670篇 |
2012年 | 12669篇 |
2011年 | 14344篇 |
2010年 | 12005篇 |
2009年 | 11834篇 |
2008年 | 11228篇 |
2007年 | 10733篇 |
2006年 | 11085篇 |
2005年 | 9800篇 |
2004年 | 6676篇 |
2003年 | 5856篇 |
2002年 | 5311篇 |
2001年 | 4764篇 |
2000年 | 4933篇 |
1999年 | 5694篇 |
1998年 | 5312篇 |
1997年 | 4393篇 |
1996年 | 3984篇 |
1995年 | 3337篇 |
1994年 | 2782篇 |
1993年 | 2201篇 |
1992年 | 1713篇 |
1991年 | 1287篇 |
1990年 | 1024篇 |
1989年 | 883篇 |
1988年 | 687篇 |
1987年 | 498篇 |
1986年 | 397篇 |
1985年 | 334篇 |
1984年 | 213篇 |
1983年 | 198篇 |
1982年 | 164篇 |
1981年 | 147篇 |
1980年 | 133篇 |
1979年 | 98篇 |
1978年 | 63篇 |
1977年 | 63篇 |
1976年 | 77篇 |
1975年 | 38篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
Qi Yang Qilong Wu Yang Liu Shuiping Luo Xiaotong Wu Xixia Zhao Haiyuan Zou Baihua Long Wen Chen Yujia Liao Lanxi Li Pei Kang Shen Lele Duan Zewei Quan 《Advanced materials (Deerfield Beach, Fla.)》2020,32(36):2002822
Engineering novel Sn-based bimetallic materials could provide intriguing catalytic properties to boost the electrochemical CO2 reduction. Herein, the first synthesis of homogeneous Sn1−xBix alloy nanoparticles (x up to 0.20) with native Bi-doped amorphous SnOx shells for efficient CO2 reduction is reported. The Bi-SnOx nanoshells boost the production of formate with high Faradaic efficiencies (>90%) over a wide potential window (−0.67 to −0.92 V vs RHE) with low overpotentials, outperforming current tin oxide catalysts. The state-of-the-art Bi-SnOx nanoshells derived from Sn0.80Bi0.20 alloy nanoparticles exhibit a great partial current density of 74.6 mA cm−2 and high Faradaic efficiency of 95.8%. The detailed electrocatalytic analyses and corresponding density functional theory calculations simultaneously reveal that the incorporation of Bi atoms into Sn species facilitates formate production by suppressing the formation of H2 and CO. 相似文献
12.
Wenshu Chen Jiajun Gu Yongping Du Fang Song Fanxing Bu Jinghan Li Yang Yuan Ruichun Luo Qinglei Liu Di Zhang 《Advanced functional materials》2020,30(25)
Large‐scale production of hydrogen from water‐alkali electrolyzers is impeded by the sluggish kinetics of hydrogen evolution reaction (HER) electrocatalysts. The hybridization of an acid‐active HER catalyst with a cocatalyst at the nanoscale helps boost HER kinetics in alkaline media. Here, it is demonstrated that 1T–MoS2 nanosheet edges (instead of basal planes) decorated by metal hydroxides form highly active / heterostructures, which significantly enhance HER performance in alkaline media. Featured with rich / sites, the fabricated 1T–MoS2 QS/Ni(OH)2 hybrid (quantum sized 1T–MoS2 sheets decorated with Ni(OH)2 via interface engineering) only requires overpotentials of 57 and 112 mV to drive HER current densities of 10 and 100 mA cm?2, respectively, and has a low Tafel slope of 30 mV dec?1 in 1 m KOH. So far, this is the best performance for MoS2‐based electrocatalysts and the 1T–MoS2 QS/Ni(OH)2 hybrid is among the best‐performing non‐Pt alkaline HER electrocatalysts known. The HER process is durable for 100 h at current densities up to 500 mA cm?2. This work not only provides an active, cost‐effective, and robust alkaline HER electrocatalyst, but also demonstrates a design strategy for preparing high‐performance catalysts based on edge‐rich 2D quantum sheets for other catalytic reactions. 相似文献
13.
Wireless Personal Communications - The traditional simultaneous wireless information and power transfer (SWIPT) system uses a part of signals to decode information, and the other part is used for... 相似文献
14.
Yuanyuan Zhang Haiyan Lu Bing Wang Zhuo Zhang Xiaorong Lin Zhongzheng Chen Bin Li 《International Journal of Food Science & Technology》2015,50(6):1397-1404
Removal of imidacloprid and acetamiprid in tea infusions by microfiltration membrane using dead‐end model was investigated in the present study. The results showed that microfiltration significantly promoted the removal of both pesticides (P < 0.05) in tea infusions. Furthermore, the extent of removal was strongly influenced by the pore size of membrane, operational pressure and the concentrations of tea infusions. The initial concentration of imidacloprid and acetamiprid showed no significant effect on their removal rates. The maximum removal rates were 79.7% for imidacloprid and 81.9% acetamiprid. The changes in major chemical components of tea infusions after microfiltration were evaluated. The results indicated that microfiltration caused no considerable changes in total polyphenols and total free amino acids, and small but statistically significant losses (6.3–18.0%) of eight catechins and three methylxanthines when filtration volume reached to 200 mL. The present study validated the application of microfiltration as a potentially feasible and promising method for the removal of imidacloprid and acetamiprid residues from tea infusions. 相似文献
15.
16.
17.
18.
19.
20.