Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hanh tai » thanh tai, hang tai, han tai
va triet » va thiet, va trien, ve triet
dan hoi » dan hoc, dai hoi, van hoi
dau hoi » cau hoi, dai hoi, dau noi
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
va tham » van tham, va cham, va thanh
lao va » tao va, cao va, bao va
tai va » thai va, mai va, tri va
lo va » lo van, ly va, le va

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 ky nang ((dau hoi) OR (dan hoi)). hieu va tham ((lo va) or (lao va)) hanh tai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ky nang ((dau hoi) OR (dan hoi)). hieu va tham ((lo va) OR (lao va)) hanh tai va triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ky nang ((dau hoi) OR (dan hoi)). hieu va tham ((lo va) or (lao va)) hanh tai va triet*".