全文获取类型
收费全文 | 223445篇 |
免费 | 32417篇 |
国内免费 | 10931篇 |
专业分类
电工技术 | 15357篇 |
技术理论 | 4篇 |
综合类 | 14750篇 |
化学工业 | 42897篇 |
金属工艺 | 11188篇 |
机械仪表 | 12849篇 |
建筑科学 | 16722篇 |
矿业工程 | 5836篇 |
能源动力 | 6401篇 |
轻工业 | 21740篇 |
水利工程 | 4745篇 |
石油天然气 | 8554篇 |
武器工业 | 2035篇 |
无线电 | 29214篇 |
一般工业技术 | 29877篇 |
冶金工业 | 10883篇 |
原子能技术 | 2099篇 |
自动化技术 | 31642篇 |
出版年
2024年 | 877篇 |
2023年 | 2874篇 |
2022年 | 5909篇 |
2021年 | 8266篇 |
2020年 | 7283篇 |
2019年 | 7596篇 |
2018年 | 8080篇 |
2017年 | 9352篇 |
2016年 | 9026篇 |
2015年 | 11630篇 |
2014年 | 13701篇 |
2013年 | 16932篇 |
2012年 | 16495篇 |
2011年 | 16861篇 |
2010年 | 15938篇 |
2009年 | 15140篇 |
2008年 | 14540篇 |
2007年 | 13825篇 |
2006年 | 12425篇 |
2005年 | 9860篇 |
2004年 | 7465篇 |
2003年 | 6816篇 |
2002年 | 6843篇 |
2001年 | 5992篇 |
2000年 | 4771篇 |
1999年 | 3457篇 |
1998年 | 2970篇 |
1997年 | 2200篇 |
1996年 | 1866篇 |
1995年 | 1480篇 |
1994年 | 1179篇 |
1993年 | 885篇 |
1992年 | 625篇 |
1991年 | 475篇 |
1990年 | 402篇 |
1989年 | 347篇 |
1988年 | 280篇 |
1987年 | 213篇 |
1986年 | 208篇 |
1985年 | 191篇 |
1984年 | 124篇 |
1983年 | 116篇 |
1982年 | 113篇 |
1981年 | 146篇 |
1980年 | 140篇 |
1979年 | 86篇 |
1978年 | 59篇 |
1977年 | 110篇 |
1976年 | 202篇 |
1975年 | 59篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
To overcome the drawbacks of solid microporous materials for CO2 capture, this proof‐of‐concept study demonstrates a low‐cost and rapid method for producing composites consisting of hypercrosslinked polymers (HCP) with a polyethyleneimine (PEI) binder. The resulting materials capture CO2 through physical and chemical absorption simultaneously. Compared with HCP, the composites exhibit higher CO2 uptake, higher volumetric density, and improved tolerance to water which is attributed to the PEI binder. 相似文献
42.
Malondialdehyde (MDA) was selected to represent a secondary by-product of lipid peroxidation during rice ageing. This study aimed to investigate the effects of MDA modification on the structural characteristics of rice protein. The results showed that as MDA concentration increased, rice protein carbonyl and disulphide groups increased, but sulphydryl content decreased. The blue shift of maximum fluorescence peak, the decrease of rice protein intrinsic fluorescence intensity and the reduction of surface hydrophobicity indicated the formation of protein aggregates caused by MDA oxidative modification. The results of molecular weight distribution and particle size distribution showed that MDA modification resulted in the formation of soluble protein aggregates, and the decrease of rice protein solubility indicated that insoluble protein aggregates were formed. Results of protein electrophoresis showed that MDA modification contributed to rice protein aggregation via non-disulphide covalent bonds. The results showed that rice protein gradually aggregated with increasing MDA concentration. 相似文献
43.
44.
45.
SPEEK/cSMM membrane for simultaneous electricity generation and wastewater treatment in microbial fuel cell 下载免费PDF全文
46.
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
47.
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
48.
49.
文章主要研究用水浸法提取落葵浆果天然染料及研究浸提液对羊毛织物的染色性能。以水为提取剂提取落葵浆果天然染料,探讨提取工艺中料液比、提取温度及时间等因素对落葵浆果天然染料提取效果的影响。研究结果表明,落葵浆果水浸提法优化工艺为:料液比1∶20、提取温度70℃、提取时间30 min。落葵浆果天然染料可以对羊毛织物进行染色,媒染染色与直接染色相比,染色深度深且会呈现不同的颜色。由于媒染剂的络合作用,媒染染色色牢度比直接染色普遍高1~2级。 相似文献
50.
Molecular structure and granule morphology of native and heat‐moisture‐treated pinhão starch 下载免费PDF全文
Vania Z. Pinto Khalid Moomand Nathan L. Vanier Rosana Colussi Franciene A. Villanova Elessandra R. Zavareze Loong‐Tak Lim Alvaro R. G. Dias 《International Journal of Food Science & Technology》2015,50(2):282-289
Pinhão seed is an unconventional source of starch and the pines grow up in native forests of southern Latin America. In this study, pinhão starch was adjusted at 15, 20 and 25% moisture content and heated to 100, 110 and 120 °C for 1 h. A decrease in λ max (starch/iodine complex) was observed as a result of increase in temperature and moisture content of HMT. The ratio of crystalline to amorphous phase in pinhão starch was determined via Fourier transform infra red by taking 1045/1022 band ratio. A decrease in crystallinity occurred as a result of HMT. Polarised light microscopy indicated a loss of birefringence of starch granules under 120 °C at 25% moisture content. Granule size distribution was further confirmed via scanning electron microscopy which showed the HMT effects. These results increased the understanding on molecular and structural properties of HMT pinhão starch and broadened its food and nonfood industrial applications. 相似文献