Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
khau sach » hau sach, khoa sach, pham sach
tai thuoc » tri thuoc, bai thuoc, tac thuoc
khoa khap » khoa khac, kho khan, khoa than
khoa kham » kho khan, khoa than
thu sach » thuat sach, thu hoach, theo sach
tu sach » su sach, te sach, tu cach

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((((tu sach) or (thu sach))) or (khau sach)) tai thuoc sach ((khoa khap) OR (khoa kham)) thong~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((tu sach) OR (thu sach))) OR (khau sach)) tai thuoc sach ((khoa khap) OR (khoa kham)) thong.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((tu sach) or (thu sach))) or (khau sach)) tai thuoc sach ((khoa khap) OR (khoa kham)) thong".
• Adding a wildcard symbol may retrieve word variants: ((((tu sach) or (thu sach))) or (khau sach)) tai thuoc sach ((khoa khap) OR (khoa kham)) thong*.