Perhaps you should try some spelling variations:
"thin layer chromatography" » "thin liquid chromatography"
"than layer chromatography" » "than liquid chromatography", "than later chromatography", "than laser chromatography", "than larger chromatography"
"thin gas chromatography" » "thin glass chromatography", "thin base chromatography", "thin case chromatography"

Try widening your search to All Fields.

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: (((("thin layer chromatography") OR ("thin gas chromatography"))) OR ("than layer chromatography")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"thin layer chromatography\") OR (\"thin gas chromatography\"))) or (\"than layer chromatography\"))".
• Removing quotes may allow a broader search: (((( thin layer chromatography ) OR ( thin gas chromatography ))) or ( than layer chromatography )).
• Adding a wildcard symbol may retrieve word variants: (((("thin layer chromatography") OR ("thin gas chromatography"))) or ("than layer chromatography"))*.