全文获取类型
收费全文 | 148635篇 |
免费 | 23974篇 |
国内免费 | 5856篇 |
学科分类
工业技术 | 178465篇 |
出版年
2024年 | 383篇 |
2023年 | 1701篇 |
2022年 | 3244篇 |
2021年 | 4773篇 |
2020年 | 5062篇 |
2019年 | 5886篇 |
2018年 | 6178篇 |
2017年 | 6895篇 |
2016年 | 6967篇 |
2015年 | 8438篇 |
2014年 | 9696篇 |
2013年 | 11834篇 |
2012年 | 10586篇 |
2011年 | 10711篇 |
2010年 | 10074篇 |
2009年 | 9346篇 |
2008年 | 8830篇 |
2007年 | 8241篇 |
2006年 | 7463篇 |
2005年 | 6146篇 |
2004年 | 4712篇 |
2003年 | 4247篇 |
2002年 | 4350篇 |
2001年 | 3800篇 |
2000年 | 2915篇 |
1999年 | 2087篇 |
1998年 | 1090篇 |
1997年 | 934篇 |
1996年 | 858篇 |
1995年 | 669篇 |
1994年 | 561篇 |
1993年 | 423篇 |
1992年 | 425篇 |
1991年 | 389篇 |
1990年 | 357篇 |
1989年 | 360篇 |
1988年 | 307篇 |
1986年 | 305篇 |
1984年 | 298篇 |
1983年 | 283篇 |
1979年 | 295篇 |
1978年 | 360篇 |
1977年 | 336篇 |
1976年 | 347篇 |
1975年 | 329篇 |
1974年 | 394篇 |
1973年 | 373篇 |
1972年 | 357篇 |
1971年 | 329篇 |
1970年 | 280篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
分析食品安全突发事件典型场景及产生的原因,利用虚拟现实技术基于Unity3D虚拟现实开发平台开发了食品安全应急演练系统,并优化系统运行的稳定性和流畅性。该系统实现了演练时沉浸式体验,人员通过仿真设备进入虚拟演练场景进行交互操作,进行实时演练有助于提升演练人员应急处置能力。 相似文献
2.
Mobile Networks and Applications - Inverse kinematics is an important basic theory in walking control of biped robot. This study focuses on the parameter setting using the improved algorithm in... 相似文献
3.
4.
Ya Gu Quanmin Zhu Hassan Nouri 《International Journal of Adaptive Control and Signal Processing》2022,36(1):138-154
This article presents a state-space model with time-delay to map the relationship between known input-output data for discrete systems. For the given input-output data, a model identification algorithm combining parameter estimation and state estimation is proposed in line with the causality constraints. Consequently, this article proposes a least squares parameter estimation algorithm, and analyzes its convergence for the studied systems to prove that the parameter estimation errors converge to zero under the persistent excitation conditions. In control system design, the U-model based control is introduced to provide a unilateral platform to improve the design efficiency and generality. A simulation portfolio from modeling to control is provided with computational experiments to validate the derived results. 相似文献
5.
6.
基于电信运营商数字化转型,系统性地提出了数据驱动的云网发展规划体系,以及六大关键数字化能力构建,设计和实现了一种云网规划数字化平台,该平台可用于实现目标网络精细规划、边缘计算精准预测等场景,并探讨了数字孪生在规划领域的应用前景,对运营商推进云网融合战略、推进高质量发展具有指导和参考意义。 相似文献
8.
Kravchenko V. F. Konovalov Ya. Yu. 《Journal of Communications Technology and Electronics》2022,67(8):952-964
Journal of Communications Technology and Electronics - A new design of wavelets based on the convolution of a compactly supported function with a rectangular pulse is proposed and theoretically... 相似文献
9.
Jia Dai Xiang Cheng Xiaofeng Li Zhisheng Wang Yufeng Wang Jing Zheng Jun Liu Jiawei Chen Changjin Wu Jinyao Tang 《Advanced functional materials》2021,31(48):2106204
Synthetic active matters are perfect model systems for non-equilibrium thermodynamics and of great potential for novel biomedical and environmental applications. However, most applications are limited by the complicated and low-yield preparation, while a scalable synthesis for highly functional microswimmers is highly desired. In this paper, an all-solution synthesis method is developed where the gold-loaded titania-silica nanotree can be produced as a multi-functional self-propulsion microswimmer. By applying light, heat, and electric field, the Janus nanotree demonstrated multi-mode self-propulsion, including photochemical self-electrophoresis by UV and visible light radiation, thermophoresis by near-infrared light radiation, and induced-charge electrophoresis under AC electric field. Due to the scalable synthesis, the Janus nanotree is further demonstrated as a high-efficiency, low-cost, active adsorbent for water decontamination, where the toxic mercury ions can be reclaimed with enhanced efficiency. 相似文献
10.
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