全文获取类型
收费全文 | 101216篇 |
免费 | 9728篇 |
国内免费 | 5873篇 |
学科分类
工业技术 | 116817篇 |
出版年
2024年 | 372篇 |
2023年 | 1717篇 |
2022年 | 3123篇 |
2021年 | 4405篇 |
2020年 | 3500篇 |
2019年 | 2657篇 |
2018年 | 2924篇 |
2017年 | 3284篇 |
2016年 | 3001篇 |
2015年 | 4382篇 |
2014年 | 5699篇 |
2013年 | 6774篇 |
2012年 | 7614篇 |
2011年 | 8283篇 |
2010年 | 7410篇 |
2009年 | 6864篇 |
2008年 | 6762篇 |
2007年 | 6192篇 |
2006年 | 5653篇 |
2005年 | 4628篇 |
2004年 | 3330篇 |
2003年 | 2939篇 |
2002年 | 3013篇 |
2001年 | 2689篇 |
2000年 | 1881篇 |
1999年 | 1721篇 |
1998年 | 1171篇 |
1997年 | 935篇 |
1996年 | 855篇 |
1995年 | 646篇 |
1994年 | 543篇 |
1993年 | 403篇 |
1992年 | 340篇 |
1991年 | 238篇 |
1990年 | 176篇 |
1989年 | 150篇 |
1988年 | 101篇 |
1987年 | 71篇 |
1986年 | 72篇 |
1985年 | 29篇 |
1984年 | 37篇 |
1983年 | 34篇 |
1982年 | 34篇 |
1981年 | 29篇 |
1980年 | 28篇 |
1979年 | 23篇 |
1976年 | 13篇 |
1970年 | 6篇 |
1959年 | 8篇 |
1951年 | 16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
4.
5.
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
7.
Kai Liu Chenyang Zhou Jiaming Hu Song Zhang Qingqing Zhang Ce Sun Yusheng Shi Huajun Sun Changxia Yin Yuzhen Zhang Yu Fu 《Journal of the European Ceramic Society》2021,41(12):5909-5917
A digital light processing (DLP) technology has been developed for 3D printing lead-free barium titanate (BTO) piezoelectric ceramics. By comparing the curing and rheological properties of slurries with different photosensitive monomer, a high refractive index monomer acryloyl morpholine (ACMO) was chosen, and a design and preparation method of BTO slurry with high solid content, low viscosity and high curing ability was proposed. By further selecting the printing parameters, the single-layer exposure time was reduced and the forming efficiency has been greatly improved. Sintered specimens were obtained after a nitrogen-air double-step debinding and furnace sintering process, and the BTO ceramics fabricated with 80 wt% slurry shows the highest relative density (95.32 %) and piezoelectric constant (168.1 pC/N). Furthermore, complex-structured BTO ceramics were prepared, impregnated by epoxy resin and finally assembly made into hydrophones, which has significance for the future design and manufacture of piezoelectric ceramic-based composites that used in functional devices. 相似文献
8.
Hui Liu Yaohui Fu Jinhai Yuan Lei Yu Zhefei Wang Quan Liu Bo Wei Xuhong Wang 《Ceramics International》2021,47(12):16570-16578
To provide a basis for the high-temperature oxidation of ultra-high temperature ceramics (UHTCs), the oxidation behavior of Zr3[Al(Si)]4C6 and a novel Zr3[Al(Si)]4C6-ZrB2-SiC composite at 1500 °C were investigated for the first time. From the calculation results, the oxidation kinetics of the two specimens follow the oxidation dynamic parabolic law. Zr3[Al(Si)]4C6 exhibited a thinner oxide scale and lower oxidation rate than those of the composite under the same conditions. The oxide scale of Zr3[Al(Si)]4C6 exhibited a two-layer structure, while that of the composite exhibited a three-layer structure. Owing to the volatilization of B2O3 and the active oxidation of SiC, a porous oxide layer formed in the oxide scale of the composite, resulting in the degradation of its oxidation performance. Furthermore, the cracks and defects in the oxide scale of the composite indicate that the reliability of the oxide scale was poor. The results support the service temperature of the obtained ceramics. 相似文献
9.
Multimedia Tools and Applications - Since Noar and Shamir introduced visual cryptography scheme (VCS), the cheating problem of VCS has absorbed much attention of scholars. The current researches on... 相似文献
10.
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