全文获取类型
收费全文 | 145756篇 |
免费 | 6757篇 |
国内免费 | 3290篇 |
专业分类
电工技术 | 4325篇 |
技术理论 | 2篇 |
综合类 | 6297篇 |
化学工业 | 21896篇 |
金属工艺 | 8437篇 |
机械仪表 | 7024篇 |
建筑科学 | 6807篇 |
矿业工程 | 2690篇 |
能源动力 | 2788篇 |
轻工业 | 7516篇 |
水利工程 | 2335篇 |
石油天然气 | 4257篇 |
武器工业 | 526篇 |
无线电 | 16790篇 |
一般工业技术 | 23766篇 |
冶金工业 | 5658篇 |
原子能技术 | 890篇 |
自动化技术 | 33799篇 |
出版年
2024年 | 353篇 |
2023年 | 1131篇 |
2022年 | 1832篇 |
2021年 | 2576篇 |
2020年 | 1974篇 |
2019年 | 1770篇 |
2018年 | 16066篇 |
2017年 | 15260篇 |
2016年 | 11677篇 |
2015年 | 3060篇 |
2014年 | 3239篇 |
2013年 | 3802篇 |
2012年 | 7147篇 |
2011年 | 13707篇 |
2010年 | 11825篇 |
2009年 | 8981篇 |
2008年 | 10049篇 |
2007年 | 10981篇 |
2006年 | 3765篇 |
2005年 | 4225篇 |
2004年 | 3226篇 |
2003年 | 2949篇 |
2002年 | 2121篇 |
2001年 | 1541篇 |
2000年 | 1735篇 |
1999年 | 1772篇 |
1998年 | 1570篇 |
1997年 | 1302篇 |
1996年 | 1196篇 |
1995年 | 966篇 |
1994年 | 851篇 |
1993年 | 586篇 |
1992年 | 449篇 |
1991年 | 391篇 |
1990年 | 265篇 |
1989年 | 216篇 |
1988年 | 195篇 |
1987年 | 121篇 |
1986年 | 97篇 |
1985年 | 59篇 |
1968年 | 43篇 |
1967年 | 33篇 |
1966年 | 42篇 |
1965年 | 45篇 |
1959年 | 35篇 |
1958年 | 38篇 |
1957年 | 36篇 |
1956年 | 34篇 |
1955年 | 63篇 |
1954年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Jiaao Yan Gao Zhiming Tan Qingchao Yang Xian Hu Wenbin 《Protection of Metals and Physical Chemistry of Surfaces》2020,56(5):965-972
Protection of Metals and Physical Chemistry of Surfaces - The Al2O3 powder was added as a filler to polyurea and the effect of doping amount on Shore hardness and wetting property were... 相似文献
52.
In this paper, we consider the classical finite mixture model, which is an effective tool for modeling lifetime distributions for random samples from heterogeneous populations. We discuss new results on stochastic comparison for two finite mixtures when each of them is drawn from one of the following semiparametric families, i.e., proportional hazards, accelerated lifetime and proportional reversed hazards. 相似文献
53.
54.
55.
Variations of Incomplete Open Cubes is the major project by the twentieth-century conceptual artist Sol LeWitt. In this paper we interpret the enumerative component of the project as embeddings of graphs. This formulation permits use of an algorithm to check the completeness of the list of the structures produced by the artist. Our conclusion is that the artist found the correct number of structures (that is, 122), but that his list contains a mistake in the presentation of a pair of incomplete cubes, a discovery that appears not to have been noted before. 相似文献
56.
57.
58.
59.
Yanlong Shi Xiaojuan Feng Haiyu Guan Jiahua Zhang Zhongai Hu 《International Journal of Hydrogen Energy》2021,46(12):8557-8566
Constructing high-efficient and nonprecious electrocatalysts is of primary importance for improving the efficiency of water splitting. Herein, a novel sunflower plate-like NiFe2O4/CoNi–S nanosheet heterostructure was fabricated via facile hydrothermal and electrodeposition methods. The as-fabricated NiFe2O4/CoNi–S heterostructure array exhibits remarkable bifunctional catalytic activity and stability toward oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline media. It presents a small overpotential of 219 mV and 149 mV for OER and HER, respectively, to produce a current density of 10 mA cm?2. More significantly, when the obtained electrodes are used as both the cathode and anode in an electrolyzer, a voltage of 1.57 V is gained at 10 mA cm?2, with superior stability for 72 h. Such outstanding properties are ascribed to: the 3D porous network structure, which exposes more active sites and accelerates mass transfer and gas bubble emission; the high conductivity of CoNi–S, which provides faster charge transport and thus promotes the electrocatalytic reaction of the composites; and the effective interface engineering between NiFe2O4 (excellent performance for OER) and CoNi–S (high activity for HER), which leads to a shorter transport pathway and thus expedites electron transfer. This work provides a new strategy for designing efficient and inexpensive electrocatalysts for water splitting. 相似文献
60.