China 
Africa 
- 3D printing
- 3D printing speed
- 3D projection
- 3D radar
- 3D reconstruction
- 3D rendering
- 3D scanners
- 3D scanning
- 3D textiles
- 3D ultrasound
- 3G
- 3MF
- 3T3 cells
- 4+1 architectural view model
- 4+4 photocycloaddition
- 4-aminobenzoic acid
- 4-aminobiphenyl
- 4-aminophenol
- 4-aminopyridine
- 4-coumarate-coa ligase
- 4-dimethylaminopyridine
- 4-ethylphenol
- 4-hydroxybenzaldehyde
- 4-hydroxybenzoic acid
- 4-hydroxycoumarin
- 4-hydroxycoumarins
- 4-hydroxynonenal
- 4-methyl-1-pentene
- 4-methylbenzylidene camphor
- 4-methylpyridine
- 4-nitroaniline
- 4-nitrophenol
- 4-poster
- 4-tert-butylcatechol
- 4-tert-butylphenol
- 4130 steel
- 440c
- 45 nm
- 4G
- 4T1
- 4th dimension
- 5' UTR
- 5-HT receptor
- 5-HT1B
- 5-fluorouracil
- 5-hydroxyindoleacetic acid
- 5-hydroxymethylcytosine
- 5-hydroxytryptophan
- 5-lipoxygenase
- 5-methylcytosine
- 500 kHz
- 5052 aluminium alloy
- 5083 aluminium alloy
- 5CB
- 5G
- 5G NR
- 5G network slicing
- 5S rRNA
- 6-APA
- 6-hydroxydopamine
- 6-phosphogluconate
- 6-phosphogluconate dehydrogenase
- 6-thioguanine
- 600 nm
- 6061 aluminium alloy
- 6063 aluminium
- 6063 aluminium alloy
- 64-bit
- 64-bit computing
- 65 nm
- 6LoWPAN
- 6PPD
- 7-ACA
- 7-dehydrocholesterol
- 7075 aluminium alloy
- 8-aminoquinoline
- 8-bit
- 8-bit color
- 8-oxo-2'-deoxyguanosine
- 8-oxoguanine
- 80s
- 9-fluorenylmethyl chloroformate
- 90 nm
- A limit cycle
- A limit set
- A priori
- A priori and a posteriori
- A simplicial complex
- A* search algorithm
- A-DNA
- A-Train
- A-VSB
- A-frames
- A-scan
- A-site
- A-type granite
- A-weighting
- A2a
- A3
- A36 steel