Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
van hanh » van thanh, ban hanh, van anh
duc van » duc va, duc tan, duc manh
cac duc » cac du, cao duc, cac dac
qua cac » cua cac
ly hang » ly quang
ty hang » ty xang, thi hang, thu hang
tu sach » thu sach, su sach, te sach
vi cua » vai cua, di cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thuoc sach) or (tu sach)) ((ty hang) OR (ly hang)) cau hoi. hieu qua cac duc van hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuoc sach) OR (tu sach)) ((ty hang) OR (ly hang)) cau hoi. hieu qua cac duc van hanh vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thuoc sach) or (tu sach)) ((ty hang) OR (ly hang)) cau hoi. hieu qua cac duc van hanh vi cua te".
• Adding a wildcard symbol may retrieve word variants: ((thuoc sach) or (tu sach)) ((ty hang) OR (ly hang)) cau hoi. hieu qua cac duc van hanh vi cua te*.