Perhaps you should try some spelling variations:
van trieu » tan trieu, van tieu, van hieu
so sach » so sanh, bo sach, co sach
nang ma » sang ma, nang cao, mang may
tang ma » mang may, tang van
qua cau » quan cau, qua cac, qua ca
truc va » thuc va, thuc vat, trung va
va hanh » van hanh, va thanh, va danh
hanh vu » hanh vi, hanh va, hanh tu
vu van » tu van

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach y ((nang ma) or (tang ma)) hoi. hieu qua cau truc va hanh vu van trieu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y ((nang ma) OR (tang ma)) hoi. hieu qua cau truc va hanh vu van trieu*.