全文获取类型
收费全文 | 478109篇 |
免费 | 39888篇 |
国内免费 | 23571篇 |
学科分类
工业技术 | 541568篇 |
出版年
2024年 | 712篇 |
2023年 | 4441篇 |
2022年 | 8870篇 |
2021年 | 11084篇 |
2020年 | 11867篇 |
2019年 | 9536篇 |
2018年 | 8879篇 |
2017年 | 11284篇 |
2016年 | 13528篇 |
2015年 | 15007篇 |
2014年 | 29074篇 |
2013年 | 26719篇 |
2012年 | 33776篇 |
2011年 | 35486篇 |
2010年 | 27662篇 |
2009年 | 28835篇 |
2008年 | 26648篇 |
2007年 | 34355篇 |
2006年 | 32607篇 |
2005年 | 28504篇 |
2004年 | 23867篇 |
2003年 | 21457篇 |
2002年 | 17683篇 |
2001年 | 14783篇 |
2000年 | 12154篇 |
1999年 | 9635篇 |
1998年 | 7129篇 |
1997年 | 5957篇 |
1996年 | 5429篇 |
1995年 | 4640篇 |
1994年 | 3958篇 |
1993年 | 2932篇 |
1992年 | 2514篇 |
1991年 | 1884篇 |
1990年 | 1573篇 |
1989年 | 1402篇 |
1988年 | 1088篇 |
1987年 | 772篇 |
1986年 | 594篇 |
1985年 | 518篇 |
1984年 | 504篇 |
1983年 | 368篇 |
1982年 | 280篇 |
1981年 | 220篇 |
1980年 | 194篇 |
1979年 | 156篇 |
1978年 | 86篇 |
1977年 | 104篇 |
1976年 | 69篇 |
1975年 | 73篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
针对目标估计过程需要大量人工参与、自动化程度低的问题,提出了基于数据质量评价的目标估计方法。利用目标数据质量评价方法,对不同传感器得到的目标数据质量进行科学、有效的测度和评价,并根据质量得分动态调整各数据源在目标估计过程中所占的权重,从而减少人工干预,提高目标估计效能。仿真试验结果证明了该方法的有效性。 相似文献
2.
3.
Recent generative adversarial networks (GANs) have yielded remarkable performance in face image synthesis. GAN inversion embeds an image into the latent space of a pretrained generator, enabling it to be used for real face manipulation. However, current inversion approaches for real faces suffer the dilemma of initialization collapse and identity loss. In this paper, we propose a hierarchical GAN inversion for real faces with identity preservation based on mutual information maximization. We first use a facial domain guaranteed initialization to avoid the initialization collapse. Furthermore, we prove that maximizing the mutual information between inverted faces and their identities is equivalent to minimizing the distance between identity features from inverted and original faces. Optimization for real face inversion with identity preservation is implemented on this mutual information-maximizing constraint. Extensive experimental results show that our approach outperforms state-of-the-art solutions for inverting and editing real faces, particularly in terms of face identity preservation. 相似文献
4.
5.
6.
7.
8.
《International Journal of Hydrogen Energy》2022,47(43):18587-18596
The development of cost-effective bifunctional catalysts with excellent performance and good stability is of great significance for overall water splitting. In this work, NiFe layered double hydroxides (LDHs) nanosheets are prepared on nickel foam by hydrothermal method, and then Ni2P(O)–Fe2P(O)/CeOx nanosheets are in situ synthesized by electrodeposition and phosphating on NiFe LDHs. The obtained self-supporting Ni2P(O)–Fe2P(O)/CeOx exhibit excellent catalytic performances in alkaline solution due to more active sites and fast electron transport. When the current density is 10 mA cm?2, the overpotential of hydrogen evolution reaction and oxygen evolution reaction are 75 mV and 268 mV, respectively. In addition, driven by two Ni2P(O)–Fe2P(O)/CeOx electrodes, the alkaline battery can reach 1.45 V at 10 mA cm?2. 相似文献
9.
《International Journal of Hydrogen Energy》2022,47(49):21231-21240
To explore the feasibility and related mechanism of MFC biosensor for wastewater detection under the action of combined heavy metals. Cyclic voltammetry (CV) and scanning electrochemical impedance spectroscopy (EIS) were used to explore the related bioelectrochemical process. The response of the reactor to single/combined heavy metals, low/high heavy metal concentrations, and the differences in ohmic resistance (Rs) and charge transfer resistance (Rct) were investigated using Ni as the core heavy metal and the combined action of Cd, Cu and Zn. The results indicated that there was a linear relationship between the concentration and output voltage of the MFC biosensor under the action of combined heavy metals (R2 = 0.8803–0.973). However, the internal resistance (Rint) of the MFC biosensor under the action of single heavy metal was far less than that of the combined heavy metal group, and the power density (19.849 W m?3) was 4 times that of the combined heavy metal group (3.109–4.589 W m?3). The Rs of the biosensors in the combined heavy metal group were 0.868Ω and 0.860, which were higher than 0.768Ω of the single heavy metal sensor. With the increase of the concentration of heavy metals in the influent, the increase of Rct was more obvious in the combined group, while the Rs in the single group significantly increased (P < 0.05). The results imply that it is possible for MFC biosensors to be used in the detection of actual water polluted by various heavy metals, but the biosensor performance is mainly limited by Rct, which needs to be further improved. 相似文献
10.
《International Journal of Hydrogen Energy》2022,47(66):28475-28485
Constructing efficient and stable bifunctional electrocatalysts for overall water splitting remains a challenge because of the sluggish reaction kinetics. Herein, the core-shell hybrids composed of Co(PO3)2 nanorod core and NiFe alloy shell in situ grown on nickel foam (NiFe/Co(PO3)2@NF) are synthesized. Owing to the hierarchical palm-leaf-like structures and strong adhesion between NiFe alloys, Co(PO3)2 and substrates, the catalyst provides a large surface area and rapid charge transfer, which facilitates active sites exposure and conductivity enhancement. The interfacial effect in the NiFe/Co(PO3)2 core-shell structure modulates the electronic structure of the active sites around the boundary, thereby boosting the intrinsic activity. Benefiting from the stable structure, the durability of the catalyst is not impaired by the inevitable surface reconfiguration. The NiFe/Co(PO3)2@NF electrode presents a low cell voltage of 1.63 V to achieve 10 mA cm?2 and manifests durability for up to 36 h at different current densities. 相似文献