Perhaps you should try some spelling variations:
pair chromatography » paper chromatography, planar chromatography, layer chromatography
think liquid » thin liquid, tank liquid, third liquid
think pair » thin pair, think fair, things pair

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (( think pair chromatography ) OR ( think liquid chromatography )).
• Adding a wildcard symbol may retrieve word variants: (( think pair chromatography ) or ( think liquid chromatography ))*.