Perhaps you should try some spelling variations:
van trieu » tan trieu, van tieu, van hieu
thanh vu » thanh va, thanh ve, thanh tu
truc va » thuc va, trung va
so sach » so sanh, bo sach, co sach
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
qua cam » qua cham, qua cac, qua ca
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 cam ((truc va) or (thuc vat)) thanh 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 cam ((truc va) OR (thuc vat)) thanh vu van trieu*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y ((nang ma) OR (tang ma)) hoi. hieu qua cam ((truc va) or (thuc vat)) thanh vu van trieu*".