全文获取类型
收费全文 | 104788篇 |
免费 | 9454篇 |
国内免费 | 4734篇 |
专业分类
电工技术 | 5903篇 |
技术理论 | 4篇 |
综合类 | 6533篇 |
化学工业 | 17486篇 |
金属工艺 | 6169篇 |
机械仪表 | 6923篇 |
建筑科学 | 7575篇 |
矿业工程 | 3345篇 |
能源动力 | 2929篇 |
轻工业 | 6725篇 |
水利工程 | 1679篇 |
石油天然气 | 6227篇 |
武器工业 | 852篇 |
无线电 | 12751篇 |
一般工业技术 | 13338篇 |
冶金工业 | 5297篇 |
原子能技术 | 1097篇 |
自动化技术 | 14143篇 |
出版年
2024年 | 285篇 |
2023年 | 1857篇 |
2022年 | 2689篇 |
2021年 | 4486篇 |
2020年 | 3385篇 |
2019年 | 3063篇 |
2018年 | 3316篇 |
2017年 | 3535篇 |
2016年 | 3262篇 |
2015年 | 4282篇 |
2014年 | 5186篇 |
2013年 | 6228篇 |
2012年 | 6735篇 |
2011年 | 7521篇 |
2010年 | 6094篇 |
2009年 | 5903篇 |
2008年 | 5791篇 |
2007年 | 5435篇 |
2006年 | 5892篇 |
2005年 | 4831篇 |
2004年 | 3411篇 |
2003年 | 2959篇 |
2002年 | 2696篇 |
2001年 | 2405篇 |
2000年 | 2477篇 |
1999年 | 2667篇 |
1998年 | 2309篇 |
1997年 | 1949篇 |
1996年 | 1721篇 |
1995年 | 1454篇 |
1994年 | 1214篇 |
1993年 | 823篇 |
1992年 | 640篇 |
1991年 | 553篇 |
1990年 | 417篇 |
1989年 | 358篇 |
1988年 | 275篇 |
1987年 | 188篇 |
1986年 | 146篇 |
1985年 | 104篇 |
1984年 | 62篇 |
1983年 | 54篇 |
1982年 | 55篇 |
1981年 | 39篇 |
1980年 | 47篇 |
1979年 | 27篇 |
1978年 | 22篇 |
1976年 | 32篇 |
1975年 | 19篇 |
1973年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Zhao Jiandong Lei Wei Li Zijian Zhao Dongfeng Han Mingmin Hou Xiaoqing 《Multimedia Tools and Applications》2022,81(4):4753-4780
Multimedia Tools and Applications - The crowding in bus is an important factor affecting passenger satisfaction and bus dispatching level. However, how to use video images to detect crowding... 相似文献
2.
Xiao Zhu Chen Yanxun Jiang Hongbo Hu Zhenzhen Lui John C. S. Min Geyong Dustdar Schahram 《Wireless Networks》2022,28(7):3305-3322
Wireless Networks - Unmanned aerial vehicles (UAV) have been widely used in various fields because of their high mobility and portability. At the same time, due to the rapid development of... 相似文献
3.
Kelin Hu Feipeng Wang Yuyang Yan Hongcheng Liu Zijia Shen 《Ceramics International》2021,47(11):15228-15236
In this paper, a novel hybrid structure of Pd doped ZnO/SnO2 heterojunction nanofibers with hexagonal ZnO columns was one step synthesized from electrospun precursor nanofibers. Due to the synergistic effect of hexagonal ZnO, SnO2 and Pd, the structure exhibited excellent hydrogen (H2) gas sensing properties. At low-temperature of 120 °C, the response (Ra/Rg) to 100 ppm H2 gas exceeded 160, the response/recovery time was only 20 s and 6 s respectively and the limit of detection was only 0.5 ppm. Meanwhile, it also had good selectivity for H2 gas and excellent linearity. In addition, the materials were characterized by XRD, FESEM, HRTEM, XPS, and the synthesis mechanism and gas sensing mechanism were proposed. 相似文献
4.
5.
6.
8.
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
9.
Qian Wu Xiangmei Liu Bo Li Lei Tan Yong Han Zhaoyang Li Yanqin Liang Zhenduo Cui Shengli Zhu Shuilin Wu Yufeng Zheng 《材料科学技术学报》2021,67(8):70-79
Pathogens pose a serious challenge to environmental sanitation and a threat to public health.The frequent use of chemicals for sterilization in recent years has not only caused secondary damage to the environment but also increased pathogen resistance to drugs,which further threatens public health.To address this issue,the use of non-chemical antibacterial means has become a new trend for environmental disinfection.In this study,we developed red phosphorus nanoparticles(RPNPs),a safe and degradable photosensitive material with good photocatalytic and photothermal properties.The red phosphorus nanoparticles were prepared using a template method and ultrasonication.Under the irradiation of simulated sunlight for 20 min,the RPNPs exhibited an efficiency of 99.98%in killing Staphylococcus aureus due to their excellent photocatalytic and photothermal abilities.Transmission electron microscopy and ultraviolet–visible spectroscopy revealed that the RPNPs exhibited degradability within eight weeks.Both the RPNPs and their degradation products were nontoxic to fibroblast cells.Therefore,such RPNPs are expected to be used as a new type of low-cost,efficient,degradable,biocompatible,and eco-friendly photosensitive material for environmental disinfection. 相似文献
10.
盾构隧道施工物料无人运输有助于提升运输效率、降低运输成本、减少运输安全事故率。与公路汽车无人驾驶、港口车辆无人驾驶、轨道交通无人驾驶等逐步成熟的无人驾驶技术不同,在隧道场景下实施施工物料无人运输存在运输物料种类繁多、运输调度困难、地下定位信号拒止、狭窄车道频繁会车、行车路面工况复杂、地上地下联动响应慢等诸多挑战。从实现盾构隧道施工物料无人运输的关键问题分析入手,综述当前盾构隧道施工物料运输方式、运输需求、无人运输发展现状及存在的挑战,提出盾构隧道施工物料无人运输的五大关键技术:多种类物料智能货控能效管理技术,无人化垂直装卸门机控制技术,多传感器融合同步定位与地图构建技术,隧道复杂环境路径规划与自主避障技术,隧-地一体化联动响应的高可靠性无线通信技术。 相似文献