Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hang cau » hang dau, hang ca, nhung cau
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
ty hang » ly hang, ty xang, thi hang
duc van » duc va, duc tan, duc manh
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 cau hoi. hieu ((qua cac) OR (cua 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 cau hoi. hieu ((qua cac) OR (cua 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 cau hoi. hieu ((qua cac) OR (cua cac)) duc van hanh vi cua te".
• Adding a wildcard symbol may retrieve word variants: ((thuoc sach) or (tu sach)) ty hang cau hoi. hieu ((qua cac) OR (cua cac)) duc van hanh vi cua te*.