全文获取类型
收费全文 | 149619篇 |
免费 | 21104篇 |
国内免费 | 4160篇 |
专业分类
电工技术 | 5532篇 |
技术理论 | 1篇 |
综合类 | 6960篇 |
化学工业 | 36279篇 |
金属工艺 | 6177篇 |
机械仪表 | 8218篇 |
建筑科学 | 7522篇 |
矿业工程 | 1647篇 |
能源动力 | 4650篇 |
轻工业 | 16289篇 |
水利工程 | 1985篇 |
石油天然气 | 2913篇 |
武器工业 | 545篇 |
无线电 | 20944篇 |
一般工业技术 | 26800篇 |
冶金工业 | 7268篇 |
原子能技术 | 1599篇 |
自动化技术 | 19554篇 |
出版年
2024年 | 263篇 |
2023年 | 1286篇 |
2022年 | 2271篇 |
2021年 | 3614篇 |
2020年 | 3799篇 |
2019年 | 5171篇 |
2018年 | 5524篇 |
2017年 | 5971篇 |
2016年 | 6643篇 |
2015年 | 7008篇 |
2014年 | 8530篇 |
2013年 | 11256篇 |
2012年 | 10153篇 |
2011年 | 10832篇 |
2010年 | 9839篇 |
2009年 | 9774篇 |
2008年 | 9254篇 |
2007年 | 8367篇 |
2006年 | 7921篇 |
2005年 | 6637篇 |
2004年 | 5835篇 |
2003年 | 5442篇 |
2002年 | 5791篇 |
2001年 | 5006篇 |
2000年 | 3944篇 |
1999年 | 2733篇 |
1998年 | 2468篇 |
1997年 | 1776篇 |
1996年 | 1493篇 |
1995年 | 1169篇 |
1994年 | 908篇 |
1993年 | 739篇 |
1992年 | 557篇 |
1991年 | 484篇 |
1990年 | 431篇 |
1989年 | 350篇 |
1988年 | 312篇 |
1987年 | 250篇 |
1986年 | 157篇 |
1985年 | 170篇 |
1984年 | 132篇 |
1983年 | 94篇 |
1982年 | 56篇 |
1981年 | 58篇 |
1980年 | 49篇 |
1979年 | 45篇 |
1978年 | 40篇 |
1977年 | 50篇 |
1976年 | 76篇 |
1975年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Fan Deng-Ping Huang Ziling Zheng Peng Liu Hong Qin Xuebin Van Gool Luc 《国际自动化与计算杂志》2022,19(4):257-287
Machine Intelligence Research - This paper aims to conduct a comprehensive study on facial-sketch synthesis (FSS). However, due to the high cost of obtaining hand-drawn sketch datasets, there is a... 相似文献
4.
Hong Sae Jin Park Nam Il Hwang Dae Keun Yi Tae Gyu Eum Hyang Lan 《Food science and biotechnology》2022,31(6):669-679
Food Science and Biotechnology - Various hilling materials (rice hulls, pine sawdust, and perlite) were compared to produce sprout vegetables using beach silvertop (Glehnia littoralis Fr. Schm. ex... 相似文献
5.
International Journal of Information Security - Machine learning techniques have been widely used and shown remarkable performance in various fields. Along with the widespread utilization of... 相似文献
6.
Zhen Hong Mingshan Xue Yidan Luo Zuozhu Yin Chan Xie Junfei Ou Fajun Wang 《应用聚合物科学杂志》2021,138(2):49657
With the continuous development of bionics, such as, geckos and virginia creeper with both superhydrophobic and super-adhesive, the surface wetting and super-adhesive properties of various porous materials have attracted extensive attention of the scientific and medical communities. Here, the honeycomb polyurethane (PU) porous films with strong adhesion were successfully prepared by microphase separation method and the effects of growth parameters on their microstructure and adhesive strength to ice were investigated. It was found that a high relative humidity (e.g., 100%) and a low solution concentration (e.g., 2%) facilitated the formation of ordered honeycomb PU porous films, and as-prepared PU pores with average pore diameter as small as 5 μm are better ordered and more uniform than these in related documents. Although the contact angle of water droplets on the surface of PU porous films increased from the premodification value of 85–130° to more than 160° after surface modification with polydopamine (PDA), the corresponding rolling angle remained approximately constant (180°), indicating that the surface of PU porous films has strong adhesion similar to geckos and virginia creeper. Furthermore, at lower temperature, the PU porous films exhibited the high adhesive strength of 142.13 kPa on ice, which was strongly dependent on the porous microstructures and surface compositions. The improved adhesive behavior to ice of honeycomb PU porous films modified with PDA provides new strategies for surface modification of materials and potential applications in medical domain. 相似文献
7.
Jiajia Suo Bowen Yang Edoardo Mosconi Hyeon-Seo Choi YeonJu Kim Shaik M. Zakeeruddin Filippo De Angelis Michael Grätzel Hui-Seon Kim Anders Hagfeldt 《Advanced functional materials》2021,31(34):2102902
Surface passivation treatment is a widely used strategy to resolve trap-mediated nonradiative recombination toward high-efficiency metal-halide perovskite photovoltaics. However, a lack of passivation with mixture treatment has been investigated, as well as an in-depth understanding of its passivation mechanism. Here, a systematic study on a mixed-salt passivation strategy of formamidinium bromide (FABr) coupled with different F-substituted alkyl lengths of ammonium iodide is demonstrated. It is obtained better device performance with decreasing chain length of the F-substituted alkyl ammonium iodide in the presence of FABr. Moreover, they unraveled a synergistic passivation mechanism of the mixed-salt treatment through surface reconstruction engineering, where FABr dominates the reformation of the perovskite surface via reacting with the excess PbI2. Meanwhile, ammonium iodide passivates the perovskite grain boundaries both on the surface and top perovskite bulk through penetration. This synergistic passivation engineer results in a high-quality perovskite surface with fewer defects and suppressed ion migration, leading to a champion efficiency of 23.5% with mixed-salt treatment. In addition, the introduction of the moisture resisted F-substituted groups presents a more hydrophobic perovskite surface, thus enabling the decorated devices with excellent long-term stability under a high humid atmosphere as well as operational conditions. 相似文献
8.
Shuang Chen Chao Yu Zhanfang Cao Xiaoping Huang Shuai Wang Hong Zhong 《International Journal of Hydrogen Energy》2021,46(10):7037-7046
The development of efficient and stable oxygen evolution reaction (OER) catalysts is an ongoing challenge. In order to solve the problem of low oxygen evolution efficiency of the current OER catalysts, a novel material was synthesized by the incorporation of NiFeCr-LDH and MoS2, and its structural and electrochemical properties were also investigated. The introduction of MoS2 improves the electrochemical performance of NiFeCr-LDH. The polarization curve shows that the potential of composite material is only 1.50 V at a current density of 10 mA cm?2, which is far superior to commercial precious metal catalysts. In addition, the stability experiment shows that the composite material has excellent stability, and the current density has little change after 500 cycles. Furthermore, we found that some metal ions, such as Ni, Cr and Mo, exist in the form of high valence on the surface of NiFeCr-LDH@MoS2, which is also conducive to the occurrence of oxygen evolution reaction. 相似文献
9.
Bijan Nasri‐Nasrabadi Akif Kaynak Shayan Seyedin Zahra Komeily‐Nia Abbas Z Kouzani 《Polymer International》2019,68(5):922-928
Recent advances in three‐dimensional (3D) printing have enabled the fabrication of interesting structures which are not achievable using traditional fabrication approaches. The 3D printing of carbon microtube composite inks allows fabrication of conductive structures for practical applications in soft robotics and tissue engineering. However, it is challenging to achieve 3D printed structures from solution‐based composite inks, which requires an additional process to solidify the ink. Here, we introduce a wet 3D printing technique which uses a coagulation bath to fabricate carbon microtube composite structures. We show that through a facile nanogrooving approach which introduces cavitation and channels on carbon microtubes, enhanced interfacial interactions with a chitosan polymer matrix are achieved. Consequently, the mechanical properties of the 3D printed composites improve when nanogrooved carbon microtubes are used, compared to untreated microtubes. We show that by carefully controlling the coagulation bath, extrusion pressure, printing distance and printed line distance, we can 3D print composite lattices which are composed of well‐defined and separated printed lines. The conductive composite 3D structures with highly customised design presented in this work provide a suitable platform for applications ranging from soft robotics to smart tissue engineering scaffolds. © 2019 Society of Chemical Industry 相似文献
10.
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