全文获取类型
收费全文 | 104072篇 |
免费 | 9920篇 |
国内免费 | 5651篇 |
学科分类
工业技术 | 119643篇 |
出版年
2024年 | 274篇 |
2023年 | 1674篇 |
2022年 | 3152篇 |
2021年 | 4437篇 |
2020年 | 3378篇 |
2019年 | 2662篇 |
2018年 | 2899篇 |
2017年 | 3370篇 |
2016年 | 2922篇 |
2015年 | 4372篇 |
2014年 | 5646篇 |
2013年 | 6508篇 |
2012年 | 7712篇 |
2011年 | 8422篇 |
2010年 | 7549篇 |
2009年 | 7133篇 |
2008年 | 7098篇 |
2007年 | 6640篇 |
2006年 | 6334篇 |
2005年 | 5025篇 |
2004年 | 3574篇 |
2003年 | 3022篇 |
2002年 | 3068篇 |
2001年 | 2582篇 |
2000年 | 2160篇 |
1999年 | 1856篇 |
1998年 | 1345篇 |
1997年 | 1024篇 |
1996年 | 901篇 |
1995年 | 686篇 |
1994年 | 555篇 |
1993年 | 389篇 |
1992年 | 327篇 |
1991年 | 246篇 |
1990年 | 165篇 |
1989年 | 145篇 |
1988年 | 92篇 |
1987年 | 72篇 |
1986年 | 54篇 |
1985年 | 26篇 |
1984年 | 15篇 |
1983年 | 22篇 |
1982年 | 23篇 |
1981年 | 22篇 |
1980年 | 32篇 |
1979年 | 9篇 |
1965年 | 2篇 |
1960年 | 2篇 |
1959年 | 8篇 |
1951年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 609 毫秒
11.
12.
随着全球卫星导航系统(Global Navigation Satellite System,GNSS)技术的迅速发展,定位精度持续优化,其应用范围越来越广.为了突破单基站载波相位差分(Real Time Kinematic,RTK)技术带来的局限性,网络RTK技术应运而生.网络RTK技术使设备在基准站网络覆盖范围内实现精准定位,因此在各个传统行业中的应用越来越广泛.广播电视的信号发射环节非常重要,由于广电发射塔一般地处高山地区,维护维修不便.基于此,设计一种基于网络RTK定位技术的高精度发射塔状态监测方法,可以在保证广电信号安全优质播出方面发挥重要作用. 相似文献
13.
Li Qian Chen Yan Sun Shikun Zhu Muyuan Xue Jing Gao Zihan Zhao Jinfeng Tang Yihe 《Water Resources Management》2022,36(12):4799-4817
Water Resources Management - Increasing water consumption in agriculture due to global climate change has posed considerable challenges to food security, thus improving the efficiency of water... 相似文献
14.
Virtual Reality - BRICKxAR is a novel augmented reality (AR) instruction method for construction toys such as LEGO®. With BRICKxAR, physical LEGO construction is guided by virtual bricks.... 相似文献
16.
Cuiping Yu Shuang Sun Sihui Li Huijia Yan Henan Zou 《International Journal of Food Science & Technology》2022,57(2):1173-1185
In this study, the effect of high-intensity ultrasound (HIUS) (200 and 400 W for 0, 5, 10 and 15 min respectively) on conformational changes, physicochemical, rheological and emulsifying properties of scallop (Patinopecten yessoensis) myofibrillar protein (SMP) was investigated. HIUS-treated SMP had lower α-helix content and higher β-sheet content compared with the native SMP. HIUS treatment induced the unfolding of SMP and increased the surface hydrophobicity. The particle size of SMP decreased and the absolute zeta-potential increased after ultrasonication, which in turn increased the solubility of SMP. The conformational changes and the improvement of physicochemical properties of SMP increased the ability for SMP to lower the interfacial tension at the oil–water interface and increased the percentage of adsorbed protein. As a result, the emulsifying properties, rheological properties of SMP and storage stability of emulsions were also improved. In conclusion, HIUS treatment has future potential for improving the emulsifying properties of SMP. 相似文献
17.
Yan He Kangren Kong Zhengxi Guo Weifeng Fang Zaiqiang Ma Haihua Pan Ruikang Tang Zhaoming Liu 《Advanced functional materials》2021,31(26):2101291
Sensitivity and multi-directional motivation are major two factors for developing optimized humidity-response materials, which are promising for sensing, energy production, etc. Organic functional groups are commonly used as the water sensitive units through hydrogen bond interactions with water molecules in actuators. The multi-coordination ability of inorganic ions implies that the inorganic ionic compounds are potentially superior water sensitive units. However, the particle forms of inorganic ionic compounds produced by classical nucleation limit the number of exposed ions to interact with water. Recent progress on the inorganic ionic oligomers has broken through the limitation of classical nucleation, and realized the molecular-scaled incorporation of inorganic ionic compounds into an organic matrix. Here, the incorporation of hydrophilic calcium carbonate ionic oligomers into hydrophobic poly(vinylidene fluoride) (PVDF) is demonstrated. The ultra-small calcium carbonate oligomers within a PVDF film endow it with an ultra-sensitive, reversible, and bidirectional response. The motivation ability is superior to other bidirectional humidity-actuators at present, which realizes self-motivation on an ice surface, converting the chemical potential energy of the humidity gradient from ice to kinetic energy. 相似文献
18.
利用蒸馏分离—气相色谱法技术,建立了同时测定煤焦油中苊、氧芴和芴的分析方法。通过对色谱条件的优化,以甲苯为溶剂,正十二烷为内标物,将煤焦油馏分采用DB-5毛细管柱,对煤焦油中苊、氧芴和芴定量分析。分析结果表明:3种主要成分线性关系良好,相关系数均大于0.9995,加标回收率为95.4%~102.4%,相对标准偏差为2.89%~7.14%。该方法分离效果好,检测结果准确、可靠。 相似文献
19.