Perhaps you should try some spelling variations:
vat thanh » dat thanh, gat thanh, tat thanh
cua triet » cua viet, su triet, va triet
cac thuc » cach thuc, cac thu, can thuc
thanh ve » hanh ve, thanh va, thanh vien
su sach » so sach, vu sach
co sach » bo sach, cuon sach, hoc sach
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa
ve cac » va cac, vien cac
thiet » thieu

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 hoi. hieu ve cac thuc vat thanh ve ((cua triet) or (va thiet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (co sach)) y nang ma hoi. hieu ve cac thuc vat thanh ve ((cua triet) OR (va thiet)).
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (co sach)) y nang ma hoi. hieu ve cac thuc vat thanh ve ((cua triet) or (va thiet))*.