全文获取类型
收费全文 | 155274篇 |
免费 | 10721篇 |
国内免费 | 4071篇 |
专业分类
电工技术 | 5961篇 |
技术理论 | 6篇 |
综合类 | 5145篇 |
化学工业 | 27450篇 |
金属工艺 | 7547篇 |
机械仪表 | 9283篇 |
建筑科学 | 7208篇 |
矿业工程 | 2687篇 |
能源动力 | 5304篇 |
轻工业 | 10335篇 |
水利工程 | 1683篇 |
石油天然气 | 4613篇 |
武器工业 | 595篇 |
无线电 | 23279篇 |
一般工业技术 | 24979篇 |
冶金工业 | 12171篇 |
原子能技术 | 1667篇 |
自动化技术 | 20153篇 |
出版年
2024年 | 486篇 |
2023年 | 2180篇 |
2022年 | 3822篇 |
2021年 | 5635篇 |
2020年 | 4151篇 |
2019年 | 3802篇 |
2018年 | 4377篇 |
2017年 | 4434篇 |
2016年 | 4583篇 |
2015年 | 5008篇 |
2014年 | 6627篇 |
2013年 | 9505篇 |
2012年 | 9184篇 |
2011年 | 10766篇 |
2010年 | 8542篇 |
2009年 | 8670篇 |
2008年 | 8367篇 |
2007年 | 7325篇 |
2006年 | 6964篇 |
2005年 | 5820篇 |
2004年 | 4935篇 |
2003年 | 4679篇 |
2002年 | 4757篇 |
2001年 | 3948篇 |
2000年 | 3436篇 |
1999年 | 3353篇 |
1998年 | 4421篇 |
1997年 | 3192篇 |
1996年 | 2729篇 |
1995年 | 2218篇 |
1994年 | 1741篇 |
1993年 | 1436篇 |
1992年 | 1101篇 |
1991年 | 1008篇 |
1990年 | 901篇 |
1989年 | 841篇 |
1988年 | 646篇 |
1987年 | 557篇 |
1986年 | 468篇 |
1985年 | 443篇 |
1984年 | 363篇 |
1983年 | 261篇 |
1982年 | 259篇 |
1981年 | 232篇 |
1980年 | 244篇 |
1979年 | 172篇 |
1978年 | 170篇 |
1977年 | 195篇 |
1976年 | 263篇 |
1975年 | 127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.
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.
Ji Hye Yang Sae Kwang Ku IL Je Cho Je Hyeon Lee Chang-Su Na Sung Hwan Ki 《International journal of molecular sciences》2021,22(4)
Hepatic fibrosis occurs when liver tissue becomes scarred from repetitive liver injury and inflammatory responses; it can progress to cirrhosis and eventually to hepatocellular carcinoma. Previously, we reported that neoagarooligosaccharides (NAOs), produced by the hydrolysis of agar by β-agarases, have hepatoprotective effects against acetaminophen overdose-induced acute liver injury. However, the effect of NAOs on chronic liver injury, including hepatic fibrosis, has not yet been elucidated. Therefore, we examined whether NAOs protect against fibrogenesis in vitro and in vivo. NAOs ameliorated PAI-1, α-SMA, CTGF and fibronectin protein expression and decreased mRNA levels of fibrogenic genes in TGF-β-treated LX-2 cells. Furthermore, downstream of TGF-β, the Smad signaling pathway was inhibited by NAOs in LX-2 cells. Treatment with NAOs diminished the severity of hepatic injury, as evidenced by reduction in serum alanine aminotransferase and aspartate aminotransferase levels, in carbon tetrachloride (CCl4)-induced liver fibrosis mouse models. Moreover, NAOs markedly blocked histopathological changes and collagen accumulation, as shown by H&E and Sirius red staining, respectively. Finally, NAOs antagonized the CCl4-induced upregulation of the protein and mRNA levels of fibrogenic genes in the liver. In conclusion, our findings suggest that NAOs may be a promising candidate for the prevention and treatment of chronic liver injury via inhibition of the TGF-β/Smad signaling pathway. 相似文献
4.
6.
7.
Jincheng Yu Yabin Chang Ewa Jakubczyk Bing Wang Feridoon Azough Robert Dorey Robert Freer 《Journal of the European Ceramic Society》2021,41(9):4859-4869
Ca3Co4O9 is a promising p-type thermoelectric oxide material having intrinsically low thermal conductivity. With low cost and opportunities for automatic large scale production, thick film technologies offer considerable potential for a new generation of micro-sized thermoelectric coolers or generators. Here, based on the chemical composition optimized by traditional solid state reaction for bulk samples, we present a viable approach to modulating the electrical transport properties of screen-printed calcium cobaltite thick films through control of the microstructural evolution by optimized heat-treatment. XRD and TEM analysis confirmed the formation of high-quality calcium cobaltite grains. By creating 2.0 at% cobalt deficiency in Ca2.7Bi0.3Co4O9+δ, the pressureless sintered ceramics reached the highest power factor of 98.0 μWm?1 K-2 at 823 K, through enhancement of electrical conductivity by reduction of poorly conducting secondary phases. Subsequently, textured thick films of Ca2.7Bi0.3Co3.92O9+δ were efficiently tailored by controlling the sintering temperature and holding time. Optimized Ca2.7Bi0.3Co3.92O9+δ thick films sintered at 1203 K for 8 h exhibited the maximum power factor of 55.5 μWm?1 K-2 at 673 K through microstructure control. 相似文献
8.
Jing-jie Xie Xiao-Li Zou Yan-ping Li Zhuang-Li Kang Han-jun Ma 《International Journal of Food Science & Technology》2022,57(4):2459-2466
The effects of high-pressure-modified soy 11S globulin (0.1, 200, and 400 MPa) on the gel properties, water-holding capacity, and water mobility of pork batter were investigated. The high-pressure-modified soy 11S globulin significantly increased (P < 0.05) the emulsion stability, cooking yield, hardness, springiness, chewiness, resilience, cohesiveness, the a* and b* values, and the G′ and G′′ values of pork batter at 80 °C, compared with those of 0.1 MPa-modified globulin. In contrast, the centrifugal loss and initial relaxation time of T2b, T21, and T22 significantly decreased (P < 0.05). Meanwhile, the microstructure was denser, and the voids were smaller and more uniform compared with those of 0.1 MPa-modified globulin. In addition, the sample with 11S globulin modified at 400 MPa had the best water-holding capacity, gel structure, and gel properties among the samples. Overall, the use of high-pressure-modified soy 11S globulin improved the gel properties and water-holding capacity of pork batter, especially under 400 MPa. 相似文献
9.
10.