全文获取类型
收费全文 | 185462篇 |
免费 | 10574篇 |
国内免费 | 5123篇 |
专业分类
电工技术 | 7028篇 |
技术理论 | 15篇 |
综合类 | 8949篇 |
化学工业 | 28710篇 |
金属工艺 | 10405篇 |
机械仪表 | 9299篇 |
建筑科学 | 9584篇 |
矿业工程 | 3602篇 |
能源动力 | 4336篇 |
轻工业 | 10035篇 |
水利工程 | 3102篇 |
石油天然气 | 6228篇 |
武器工业 | 1101篇 |
无线电 | 21670篇 |
一般工业技术 | 28771篇 |
冶金工业 | 7880篇 |
原子能技术 | 1593篇 |
自动化技术 | 38851篇 |
出版年
2024年 | 502篇 |
2023年 | 1793篇 |
2022年 | 3285篇 |
2021年 | 4554篇 |
2020年 | 3417篇 |
2019年 | 2828篇 |
2018年 | 17151篇 |
2017年 | 16516篇 |
2016年 | 12835篇 |
2015年 | 4845篇 |
2014年 | 5506篇 |
2013年 | 6709篇 |
2012年 | 9860篇 |
2011年 | 16440篇 |
2010年 | 14346篇 |
2009年 | 11425篇 |
2008年 | 12503篇 |
2007年 | 13168篇 |
2006年 | 5628篇 |
2005年 | 5821篇 |
2004年 | 4476篇 |
2003年 | 4090篇 |
2002年 | 3507篇 |
2001年 | 2772篇 |
2000年 | 2626篇 |
1999年 | 2517篇 |
1998年 | 2165篇 |
1997年 | 1815篇 |
1996年 | 1594篇 |
1995年 | 1249篇 |
1994年 | 994篇 |
1993年 | 759篇 |
1992年 | 606篇 |
1991年 | 485篇 |
1990年 | 353篇 |
1989年 | 314篇 |
1988年 | 263篇 |
1987年 | 145篇 |
1986年 | 149篇 |
1985年 | 111篇 |
1984年 | 61篇 |
1983年 | 54篇 |
1982年 | 61篇 |
1981年 | 48篇 |
1968年 | 46篇 |
1966年 | 48篇 |
1965年 | 49篇 |
1959年 | 40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
11.
Journal of Signal Processing Systems - With the latest development of automation technology, object detection technology has received more and more research attention. Automated object detection... 相似文献
12.
Zhang Qi Wang Yujing Zhang Xueling Song Jun Li Yinlei Wu Xuehong Yuan Kunjie 《Journal of Materials Science》2022,57(14):7208-7224
Journal of Materials Science - Form-stable composite phase change materials (C-PCMs) prepared by microencapsulation method and porous matrix adsorption method need for compression molding after... 相似文献
13.
14.
Wenlong Song Shoujun Wang Yang Lu Xuan Zhang Zixiang Xia Kai Sun Guangming Xin 《Ceramics International》2021,47(9):12631-12640
To enhance the tribological performance of Si3N4/TiC ceramics, MoS2/PTFE composite coatings were deposited on the ceramic substrate through spraying method. The micrographs and basic properties of the MoS2/PTFE coated samples were investigated. Dry sliding friction experiments against WC/Co ball were performed with the coated ceramics and traditional ones. These results showed that the composite coatings could significantly reduce the friction coefficient of ceramics, and protect the substrate from adhesion wear. The primary tribological mechanisms of the coated ceramics were abrasive wear, coating spalling and delamination, and the tribological property was transited from slight wear to serious wear with the increase of load because of the lower surface hardness and shear strength. The possible mechanisms for the effects of MoS2/PTFE composite coatings on the friction performance of ceramics were discussed. 相似文献
15.
Yuan-Xia Wang Ying Shi Chen-Chen Wang Jia-Hui Cheng Ying Wang Wen-Jun Shao Li-Zhi Liu 《应用聚合物科学杂志》2021,138(27):50651
Crosslinking of polyolefin elastomer (POE, ENGAGE™ 8480) with Dicumyl Peroxide (DCP) can have effects on its crystallization dynamics, crystal structure, and properties. The POE crosslinked uniformly has significantly lower crystalline ability than the one with only amorphous phase crosslinked, which, in turn, has weaker crystalline ability than neat POE. The crystallinity and melting point depend on how the POE is crosslinked. The neat POE and POE crosslinked in amorphous phase only, are investigated with DSC and in-situ tensile/synchrotron radiation (WAXD/SAXS). In situ tensile/synchrotron X-ray during a uniaxial stretching process indicates that severe crystal fragmentation is observed at a strain around 45%, and with further increase in strain. The stress in the crosslinked POE is significantly larger than neat POE. For both samples, crystal orientation increases sharply within the strain range up to 88% where orientation-induced new crystals aligned in stretching direction are observed. The long period increases more in stretching direction for the crosslinked POE, consistent with larger stress in this sample, and the stress difference is more pronounced at large strains (27.3 vs. 10.9 MPa at a strain 435%). Permanent set of the crosslinked POE is smaller, consistent with less oriented crystals observed after the test for permanent set. 相似文献
16.
With the emergence of large-scale knowledge base, how to use triple information to generate natural questions is a key technology in question answering systems. The traditional way of generating questions require a lot of manual intervention and produce lots of noise. To solve these problems, we propose a joint model based on semi-automated model and End-to-End neural network to automatically generate questions. The semi-automated model can generate question templates and real questions combining the knowledge base and center graph. The End-to-End neural network directly sends the knowledge base and real questions to BiLSTM network. Meanwhile, the attention mechanism is utilized in the decoding layer, which makes the triples and generated questions more relevant. Finally, the experimental results on SimpleQuestions demonstrate the effectiveness of the proposed approach. 相似文献
17.
18.
19.
介绍了电镀锡机组钝化污染缺陷的宏观形貌;从挤干设备、助熔工艺、钝化工艺、钝化设备等方面分析了钝化污染产生的原因。通过产线实践,发现助熔挤干辊位置,钝化段槽液中重铬酸钠浓度和p H值与钝化污染缺陷的产生无关,钝化极板的清洁程度、钝化液的老化程度以及助熔液的清洁程度才是导致钝化污染的主要原因。通过调整助熔槽液浓度,保证钝化极板清洁性,钝化污染缺陷得到有效控制。 相似文献
20.
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