全文获取类型
收费全文 | 128882篇 |
免费 | 21942篇 |
国内免费 | 4409篇 |
专业分类
电工技术 | 6271篇 |
技术理论 | 9篇 |
综合类 | 7378篇 |
化学工业 | 30940篇 |
金属工艺 | 6019篇 |
机械仪表 | 7027篇 |
建筑科学 | 8961篇 |
矿业工程 | 2756篇 |
能源动力 | 3457篇 |
轻工业 | 13751篇 |
水利工程 | 2224篇 |
石油天然气 | 5126篇 |
武器工业 | 848篇 |
无线电 | 16510篇 |
一般工业技术 | 21233篇 |
冶金工业 | 4671篇 |
原子能技术 | 1178篇 |
自动化技术 | 16874篇 |
出版年
2024年 | 261篇 |
2023年 | 1293篇 |
2022年 | 2538篇 |
2021年 | 3920篇 |
2020年 | 4164篇 |
2019年 | 5292篇 |
2018年 | 5445篇 |
2017年 | 6024篇 |
2016年 | 6323篇 |
2015年 | 7633篇 |
2014年 | 8556篇 |
2013年 | 10545篇 |
2012年 | 8976篇 |
2011年 | 9126篇 |
2010年 | 8847篇 |
2009年 | 8514篇 |
2008年 | 7886篇 |
2007年 | 7358篇 |
2006年 | 6980篇 |
2005年 | 5896篇 |
2004年 | 4637篇 |
2003年 | 4041篇 |
2002年 | 4030篇 |
2001年 | 3627篇 |
2000年 | 3022篇 |
1999年 | 2392篇 |
1998年 | 1517篇 |
1997年 | 1247篇 |
1996年 | 1092篇 |
1995年 | 869篇 |
1994年 | 768篇 |
1993年 | 531篇 |
1992年 | 408篇 |
1991年 | 340篇 |
1990年 | 238篇 |
1989年 | 214篇 |
1988年 | 149篇 |
1987年 | 104篇 |
1986年 | 104篇 |
1985年 | 49篇 |
1984年 | 45篇 |
1983年 | 45篇 |
1982年 | 30篇 |
1981年 | 35篇 |
1980年 | 22篇 |
1979年 | 16篇 |
1978年 | 7篇 |
1976年 | 17篇 |
1970年 | 6篇 |
1951年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
34.
SPEEK/cSMM membrane for simultaneous electricity generation and wastewater treatment in microbial fuel cell 下载免费PDF全文
35.
Efficacy of Crude and Purified Chitinases (SsChi50) Extracted from Offal Red Scorpion Fish in Biological Control of Chickpea Weevil (Callosobruchus maculatus L.) 下载免费PDF全文
36.
Quality enhancement of the abundant under‐valued crustacean,lobster krill (Munida spp.), during its chilled storage 下载免费PDF全文
Bibiana García‐Soto José M. Miranda Jorge Barros‐Velázquez Santiago P. Aubourg 《International Journal of Food Science & Technology》2015,50(3):708-716
Lobster krill (Munida genus) represents an under‐valued crustacean frequently caught on European fishing banks. In this work, its sensory, microbiological and biochemical qualities were evaluated during chilled storage. Additionally, the effects of a prestorage antimelanosic treatment consisting of soaking in sodium metabisulphite (SMB) solutions at two different concentrations (0.25% and 0.75%) were also studied. SMB prestorage treatment provided lobster specimens that still exhibited acceptable sensory quality after 10 days of storage, while control specimens were unacceptable at that time. SMB treatment also resulted in a significant (P < 0.05) inhibition of microbial growth, mainly of Enterobacteriaceae, psychrotrophes and proteolytic bacteria. Low lipid oxidation levels were observed for all batches; however, a significantly higher (P < 0.05) retention of polyunsaturated fatty acids was found in SMB‐treated lobster, especially in the 0.75% SMB batch. The results presented here open the way to the potential commercialisation of currently under‐utilised lobster krill as a chilled product. 相似文献
37.
Chenxu Liu Shuguang Zhang Ruonan Ji Peng Wang Jin Zhang Yu Tian Yonggang Meng Yedong He 《Ceramics International》2019,45(4):4747-4755
Semiconductor particles doped Al2O3 coatings were prepared by cathode plasma electrolytic deposition in Al(NO3)3 electrolyte dispersed with SiC micro- and nano-particles (average particle sizes of 0.5–1.7?µm and 40?nm respectively). The effects of the concentrations and particle sizes of the SiC on the microstructures and tribological performances of the composite coatings were studied. In comparison with the case of dispersing with SiC microparticles, the dispersion of SiC nanoparticles in the coatings was more uniform. When the concentration of SiC nanoparticles was 5?g/L, the surface roughness of the composite coating was reduced by 63%, compared with that of the unmodified coating. Friction results demonstrated that the addition of 5?g/L SiC nanoparticles reduced the friction coefficient from 0.60 to 0.38 and decreased the wear volume under dry friction. The current density and bath voltage were measured to analyze the effects of SiC particles on the deposition process. The results showed that the SiC particles could alter the electrical behavior of the coatings during the deposition process, weaken the bombardment of the plasma, and improve the structures of the coatings. 相似文献
38.
Magnetic Resonance Materials in Physics, Biology and Medicine - To investigate the value of using diffusion-weighted imaging (DWI) and intravoxel incoherent motion DWI (IVIM-DWI) to assess the... 相似文献
39.
40.
伏彩萍 《有色金属(冶炼部分)》2020,(6):66-69
针对现有柠檬酸铋制备工艺合成时间长、能耗高、产品纯度不高等不足,介绍了一种常温下制备柠檬酸铋的新工艺。新工艺制备时间短,制备的柠檬酸铋产品质量好,合成过程产生的废水可循环利用,废气经碱液循环吸收可生产硝酸钠副产品。 相似文献