Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
hieu van » hieu va, thien van, lieu va
cac thuc » cach thuc, cac thu, can thuc
nang ma » tang ma, nang cao, mang may
sang ma » tang ma, sang tao, mang may
van cac » van hac, van cau, van bac
co sach » bo sach, cuon sach, hoc sach
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
hanh ve » hanh vi, hanh va, hanh kem
su sach » so sach, vu sach
ve su » va su

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (co sach)) y ((nang ma) or (sang ma)) hoi. hieu van cac thuc va hanh ve su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (co sach)) y ((nang ma) OR (sang ma)) hoi. hieu van cac thuc va hanh ve su triet.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (co sach)) y ((nang ma) or (sang ma)) hoi. hieu van cac thuc va hanh ve su triet*.