全文获取类型
收费全文 | 185991篇 |
免费 | 9751篇 |
国内免费 | 4875篇 |
专业分类
电工技术 | 6846篇 |
技术理论 | 5篇 |
综合类 | 8521篇 |
化学工业 | 28984篇 |
金属工艺 | 10567篇 |
机械仪表 | 9762篇 |
建筑科学 | 9628篇 |
矿业工程 | 3591篇 |
能源动力 | 4159篇 |
轻工业 | 10204篇 |
水利工程 | 2903篇 |
石油天然气 | 6556篇 |
武器工业 | 849篇 |
无线电 | 21206篇 |
一般工业技术 | 29263篇 |
冶金工业 | 7995篇 |
原子能技术 | 1329篇 |
自动化技术 | 38249篇 |
出版年
2024年 | 388篇 |
2023年 | 1794篇 |
2022年 | 3248篇 |
2021年 | 4533篇 |
2020年 | 3396篇 |
2019年 | 2964篇 |
2018年 | 17157篇 |
2017年 | 16383篇 |
2016年 | 12769篇 |
2015年 | 4753篇 |
2014年 | 5501篇 |
2013年 | 6453篇 |
2012年 | 9569篇 |
2011年 | 16548篇 |
2010年 | 14193篇 |
2009年 | 11274篇 |
2008年 | 12445篇 |
2007年 | 12964篇 |
2006年 | 5623篇 |
2005年 | 5724篇 |
2004年 | 4384篇 |
2003年 | 4087篇 |
2002年 | 3354篇 |
2001年 | 2559篇 |
2000年 | 2480篇 |
1999年 | 2630篇 |
1998年 | 2386篇 |
1997年 | 1982篇 |
1996年 | 1760篇 |
1995年 | 1411篇 |
1994年 | 1160篇 |
1993年 | 812篇 |
1992年 | 692篇 |
1991年 | 529篇 |
1990年 | 413篇 |
1989年 | 361篇 |
1988年 | 279篇 |
1987年 | 201篇 |
1986年 | 147篇 |
1985年 | 114篇 |
1984年 | 94篇 |
1983年 | 88篇 |
1982年 | 69篇 |
1981年 | 56篇 |
1980年 | 55篇 |
1976年 | 52篇 |
1968年 | 45篇 |
1965年 | 47篇 |
1955年 | 63篇 |
1954年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 156 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.
Chen Wen-Kuo Chang Jing-Rong Chen Long-Sheng Hsu Rui-Yang 《Multimedia Tools and Applications》2022,81(6):8317-8347
Multimedia Tools and Applications - With the advancement of technology and the spread of the COVID19 epidemic, learning can no longer only be done through face-to-face teaching. Numerous digital... 相似文献
3.
Peng Wang Yan Li Yujiao Qu Baowei Wang Jingxin Sun Chunwei Miao Ming Huang He Huang Congxiang Zhang 《International Journal of Food Science & Technology》2022,57(6):3428-3439
The effects of cellulose microfibres (CMFs, Average size: 100 ± 5 μm) and cellulose nanofibres (CNFs, Average size: 60 ± 3 nm) on the properties of myofibrillar protein (MP) gels from duck breast meat were studied. The results demonstrated that CMFs and CNFs were mostly connected to MP by non-covalent bonds, the diffusion and cross-linking of MP molecules was promoted, and a denser and more complete gel network was formed. With the increases of CMFs and CNFs concentration (0–10%), the hardness was increased by 13.15% and 19.78% for CMFs10% and CNFs10% gels, respectively, and the elasticity was increased by 40% and 80%, respectively. At the same concentration (0–10%), the increase in gel hardness, viscoelasticity and immobilised water content was greater in the CNFs-MP group than in the CMFs-MP group. The CNFs-MP group had a tighter gel network, and CNFs had a better potential to improve the gelation performance of MP. 相似文献
4.
Chenchen Zhou Jia Man Haibo Yu He Xia Luming Man Bin Qi Jianfeng Li 《Ceramics International》2021,47(8):10866-10872
Ceramic microparticles have great potentials in various fields such as materials engineering, biotechnology, microelectromechanical systems, etc. Morphology of the microparticle performs an important role on their application. To date, it remains difficult to find an effective and controllable way for fabricating nonspherical ceramic microparticles with 3D features. This work demonstrates a method that combines UV light lithography and single emulsion opaque-droplet-templated microfluidic molding to prepare the crescent-shaped ceramic microparticles. By tailoring the intensity of UV light and flow rate of fluid, the shapes of microparticles are accordingly tuned. Therefore, varieties of crescent-shaped microparticles and their variations have been fabricated. After sintering, the crescent-shaped alumina ceramic microparticles were obtained. Benefitting from the light absorption and scattering behavior of most ceramic nanoparticles, this system can serve as a general platform to produce crescent-shaped microparticles made from different materials, and hold great potentials for applications in microrobotics, structural materials in MEMS, and biotechnology. 相似文献
5.
6.
7.
9.
Wang Chen Bao Chun-Hui Wu Wan-Yu Hsu Chia-Hsun Zhao Ming-Jie Zhang Xiao-Ying Lien Shui-Yang Zhu Wen-Zhang 《Journal of Materials Science》2022,57(26):12341-12355
Journal of Materials Science - Molybdenum oxide (MoOx) films had been grown by using plasma-enhanced atomic layer deposition (PEALD) with Mo(CO)6 precursor and O2 plasma reactant in a substrate... 相似文献
10.
Ping-Chi Hsu Jia-Ying Jhong Li-Ping Huang Kuo-Hsin Lee Hsin-Pao Chen Yue-Leon Guo 《International journal of molecular sciences》2021,22(8)
Di(2-ethylhexyl) phthalate (DEHP) is widely used as a plasticizer in the manufacture of polyvinylchloride plastics and has been associated with concerns regarding male reproductive toxicity. In this study, we hypothesized that maternal exposure to DEHP induces transgenerational inheritance of adult-onset adverse reproductive outcomes through the male germline in the F1, F2, and F3 generations of male offspring. Pregnant rats were treated with 5 or 500 mg of DEHP/kg/day through gavage from gestation day 0 to birth. The offspring body weight, anogenital distance (AGD), anogenital index (AGI), sperm count, motility, and DNA fragmentation index (DFI) were measured for all generations. Methyl-CpG binding domain sequencing was performed to analyze sperm DNA methylation status in the F3. DEHP exposure at 500 mg/kg affected AGD, AGI, sperm count, mean DFI, and %DFI in the F1; AGD, sperm count, and mean DFI in the F2; and AGD, AGI, mean DFI, and %DFI in the F3. DEHP exposure at 5 mg/kg affected AGD, AGI, sperm count, and %DFI in the F1; sperm count in the F2; and AGD and AGI in F3. Compared with the control group, 15 and 45 differentially hypermethylated genes were identified in the groups administered 5 mg/kg and 500 mg/kg DEHP, respectively. Moreover, 130 and 6 differentially hypomethylated genes were observed in the groups administered 5 mg/kg and 500 mg/kg DEHP. Overall, these results demonstrated that prenatal exposure to DEHP caused transgenerational epigenetic effects, which may explain the observed phenotypic changes in the male reproductive system. 相似文献