全文获取类型
收费全文 | 4160篇 |
免费 | 535篇 |
国内免费 | 274篇 |
专业分类
电工技术 | 437篇 |
综合类 | 166篇 |
化学工业 | 897篇 |
金属工艺 | 785篇 |
机械仪表 | 48篇 |
建筑科学 | 62篇 |
矿业工程 | 192篇 |
能源动力 | 422篇 |
轻工业 | 17篇 |
水利工程 | 7篇 |
石油天然气 | 96篇 |
武器工业 | 12篇 |
无线电 | 342篇 |
一般工业技术 | 677篇 |
冶金工业 | 727篇 |
原子能技术 | 43篇 |
自动化技术 | 39篇 |
出版年
2024年 | 12篇 |
2023年 | 70篇 |
2022年 | 138篇 |
2021年 | 184篇 |
2020年 | 221篇 |
2019年 | 164篇 |
2018年 | 141篇 |
2017年 | 169篇 |
2016年 | 168篇 |
2015年 | 147篇 |
2014年 | 230篇 |
2013年 | 204篇 |
2012年 | 287篇 |
2011年 | 350篇 |
2010年 | 228篇 |
2009年 | 213篇 |
2008年 | 207篇 |
2007年 | 325篇 |
2006年 | 276篇 |
2005年 | 230篇 |
2004年 | 202篇 |
2003年 | 168篇 |
2002年 | 142篇 |
2001年 | 107篇 |
2000年 | 106篇 |
1999年 | 80篇 |
1998年 | 40篇 |
1997年 | 38篇 |
1996年 | 34篇 |
1995年 | 23篇 |
1994年 | 20篇 |
1993年 | 8篇 |
1992年 | 10篇 |
1991年 | 6篇 |
1990年 | 9篇 |
1989年 | 1篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1951年 | 4篇 |
排序方式: 共有4969条查询结果,搜索用时 31 毫秒
81.
82.
83.
K. Hashimoto M. YamasakiS. Meguro T. SasakiH. Katagiri K. IzumiyaN. Kumagai H. HabazakiE. Akiyama K. Asami 《Corrosion Science》2002,44(2):371-386
CO2 emissions, which induce global warming, increase with the development of economic activity. It is impossible to decrease the CO2 emissions by suppression of the economic activity. Global CO2 recycling can solve this problem. The global CO2 recycling consists of three district: The electricity is generated by solar cells on deserts. At desert coasts, the electricity is used for H2 production by seawater electrolysis and H2 is used for CH4 production by the reaction with CO2. CH4 which is the main component of liquefied natural gas is liquefied and transported to energy consuming districts where CO2 is recovered, liquefied and transported to the desert coasts. A CO2 recycling plant for substantiation of our idea has been built on the roof of the Institute for Materials Research in 1996. Key materials necessary for the global CO2 recycling are the anode and cathode for seawater electrolysis and the catalyst for CO2 conversion. All of them have been tailored by us. They have very high activity and selectivity for necessary reactions in addition to excellent durability. A pilot plant consisting of minimum units in an industrial scale is going to be built in three years. 相似文献
84.
利用X-射线衍射和扫描电镜技术研究了纯Zn和Zn-Fe合金(含Fe0.2~0.7wt%)镀层的结构,发现Zn-Fe合金镀层的晶粒较纯Zn镀层细小,晶体排布更为致密;利用电化学综合测试仪研究了纯Zn和Zn-Fe合金镀层的极化电阻和腐蚀电流,结果表明Zn-Fe合金镀层的极化电阻更高而腐蚀电流较纯Zn镀层显著减小。 相似文献
85.
86.
87.
网状阳极已在储罐罐底的阴极保护系统中大量使用,保护效果明显,并得到很多应用单位的认可。本文主要结合巴基斯坦国家重点工程——成品油管线工程(White Oil Pipeline Project)具体情况,对该项目储罐罐底外壁阴极保护的设计、计算、实施情况等进行了详细介绍,并对实际保护效果和存在问题进行了分析讨论。 相似文献
88.
通过溶胶凝胶 (Sol gel)法经涂刷、烧结、退火等工艺制备了添加不同含量SnO2 的RuO2 SnO2 TiO2 /Ti三元涂层钛阳极。并通过X射线衍射 (XRD)、差热分析 (DTA)、透射电子显微 (TEM )分析了SnO2 组元对RuO2 TiO2 SnO2 /Ti阳极涂层组织、晶粒尺寸和外观形貌的影响。结果表明 ,所获三元涂层颗粒尺寸细小 ,均为纳米结构 ,且添加SnO2 组元后有显著细化涂层晶粒的效果。在不同退火温度下 ,随SnO2 含量的增加 ,涂层晶粒均能发生一定程度的细化。所获三元阳极涂层主要组成物相为金红石 (Ru ,Sn ,Ti)O2 固溶体 ,SnO2 组元含量较高的涂层出现不同成分金红石相共存的现象 ;当涂层退火温度由 45 0℃升高至 6 0 0℃后 ,SnO2 组元不能阻止 (Ru ,Sn ,Ti)O2 固溶体脱溶分解 ,并析出六方晶系Ru单质 ;添加SnO2 组元的RuO2 SnO2 TiO2 涂层晶粒外观呈较理想等轴状特征 相似文献
89.
Mei Yang Kean Chen Hui Li Yuliang Cao Hanxi Yang Xinping Ai 《Advanced functional materials》2023,33(47):2306828
Many organic solvents have excellent solution properties, but fail to serve as lithium-ion batteries (LIBs) electrolyte solvents, due to their electrochemical incompatibility with graphite anodes. Herein, a new strategy is proposed to address this issue by introducing a surface-adsorbed molecular layer to regulate the interfacial solvation structure without the alteration of electrolyte composition and properties. As a proof-of-concept study, it is demonstrated for the first time that the intrinsically incompatible propylene carbonate (PC)-based electrolyte becomes completely compatible with graphite anodes by introducing a layer of adsorbed hexafluorobenzene (HFB) molecules to weaken the Li+-PC coordination strength and facilitate the interfacial desolvation process. As a consequence, the graphite/ NCM811 pouch cells using the PC-based electrolyte containing only 1 vol.% HFB demonstrate excellent long-term cycling stabilities over 1150 cycles. This strategy is also proved to be applicable to other ethylene carbonate (EC)–free electrolytes, thus providing a new avenue for developing advanced LIB electrolytes. 相似文献
90.
Ziquan Li Jinquan Wen Yuqing Cai Fengting Lv Xu Zeng Qian Liu Titus Masese Chuanxiang Zhang Xusheng Yang Yanwen Ma Haijiao Zhang Zhen-Dong Huang 《Advanced functional materials》2023,33(22):2300582
Potassium-ion batteries have emerged not only as low-cost alternatives to lithium-ion batteries, but also as high-voltage energy storage systems. However, their development is still encumbered by the scarcity of high-performance electrode materials that can endure successive potassium-ion uptake. Herein, a hydrated Bi-Ti bimetallic ethylene glycol (H-Bi-Ti-EG) compound is reported as a new high-capacity and stable anode material for potassium storage. H-Bi-Ti-EG possesses a long-range disordered layered framework, which helps to facilitate electrolyte ingress into the entire Bi nanoparticles. A suite of spectroscopic analyses reveals the in situ formation Bi nanoparticles within the organic polymer matrix, which can alleviate stresses caused by the huge volume expansion/contraction during deep cycles, thereby maintaining the superior structural integrity of H-Bi-Ti-EG organic anode. As expected, H-Bi-Ti-EG anode exhibits a high capacity and superior long-term cycling stability. Importantly for potassium storage, it can be cycled at current densities of 0.1, 0.5, 1, and 2 Ag−1 for 800, 700, 1000, and even 6000 cycles, retaining charging capacities of 361, 206, 185, and 85.8 mAh g−1, respectively. The scalable synthetic method along with the outstanding electrochemical performance of hydrated Bi-Ti-EG, which is superior to other reported Bi-based anode materials, places it as a promising anode material for high-performance potassium storage. 相似文献