全文获取类型
收费全文 | 426385篇 |
免费 | 33716篇 |
国内免费 | 18193篇 |
专业分类
电工技术 | 24865篇 |
技术理论 | 50篇 |
综合类 | 29811篇 |
化学工业 | 70871篇 |
金属工艺 | 24676篇 |
机械仪表 | 27431篇 |
建筑科学 | 32907篇 |
矿业工程 | 13848篇 |
能源动力 | 11908篇 |
轻工业 | 28458篇 |
水利工程 | 7789篇 |
石油天然气 | 28161篇 |
武器工业 | 3293篇 |
无线电 | 46320篇 |
一般工业技术 | 47673篇 |
冶金工业 | 21849篇 |
原子能技术 | 4310篇 |
自动化技术 | 54074篇 |
出版年
2024年 | 1383篇 |
2023年 | 6159篇 |
2022年 | 10837篇 |
2021年 | 16122篇 |
2020年 | 12043篇 |
2019年 | 9910篇 |
2018年 | 11569篇 |
2017年 | 13058篇 |
2016年 | 11780篇 |
2015年 | 16258篇 |
2014年 | 20729篇 |
2013年 | 24998篇 |
2012年 | 27020篇 |
2011年 | 30065篇 |
2010年 | 26563篇 |
2009年 | 25070篇 |
2008年 | 24685篇 |
2007年 | 23568篇 |
2006年 | 24087篇 |
2005年 | 21308篇 |
2004年 | 14336篇 |
2003年 | 12893篇 |
2002年 | 11862篇 |
2001年 | 10600篇 |
2000年 | 10650篇 |
1999年 | 11549篇 |
1998年 | 9035篇 |
1997年 | 7622篇 |
1996年 | 7262篇 |
1995年 | 6000篇 |
1994年 | 4877篇 |
1993年 | 3364篇 |
1992年 | 2634篇 |
1991年 | 1996篇 |
1990年 | 1567篇 |
1989年 | 1251篇 |
1988年 | 1036篇 |
1987年 | 623篇 |
1986年 | 498篇 |
1985年 | 324篇 |
1984年 | 242篇 |
1983年 | 179篇 |
1982年 | 179篇 |
1981年 | 103篇 |
1980年 | 121篇 |
1979年 | 59篇 |
1978年 | 21篇 |
1977年 | 34篇 |
1976年 | 41篇 |
1975年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
101.
102.
Amino acid modified polyaspartic acids were evaluated as calcium-scale inhibitors. Feasibility of scale inhibition experiments was analyzed by molecular dynamics simulation and Gaussian optimization, and the scale inhibition mechanism was theoretically analyzed. Scale inhibition performance was studied by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, static scale inhibition experiments, and electrochemical performance testing, which provided an experimental basis for the molecular dynamics simulation. The experimental results showed that Arg-SA-PASP has better scale inhibition and corrosion inhibition performance than His-SA-PASP. The scale inhibition effect increased with increasing concentration. Electrochemical tests indicated that Arg-SA-PASP is an excellent scale and corrosion inhibitor. 相似文献
104.
Fluorescence‐Activated Cell Sorters: Standing Surface Acoustic Wave (SSAW)‐Based Fluorescence‐Activated Cell Sorter (Small 40/2018) 下载免费PDF全文
105.
106.
107.
108.
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
109.
Science China Technological Sciences - Accurate modelling of lithium ion batteries is crucial for battery management in electric vehicles. Recent studies have revealed the fractional order nature... 相似文献
110.
ABSTRACT In this study, effect of calcium and gypsum on scheelite and fluorite was investigated using sodium oleate as collector. Micro-flotation and contact angle results showed that the adsorption of calcium could inhibit the hydrophobicity of scheelite and fluorite. Moreover, sulfate could enhance the inhibition. FT-IR results showed that calcium could be priori precipitated into calcium oleate and adsorb on mineral surface. The adsorption of calcium could increase the scheelite potential to IEP, while it showed limited effect on fluorite potential. However, the interaction of calcium on scheelite and fluorite in gypsum solution was more complex than that in calcium solution. 相似文献