Perhaps you should try some spelling variations:
thanh de » hanh de, thanh ve, thanh do
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, co sach
cua tre » cua te, cuu tre, cua triet
su viet » so viet
van cam » van nam, van lam, van cau
lang ha » long ha
xac va » tac va, ac va, bac va
y lang » o lang, _ lang, tay lang
tuc va » thuc va, truc va, tuc xa
ha hoi » hoa hoi, ha noi, xa hoi

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 lang ha hoi. hieu van cam ((xac va) or (tuc va)) thanh de ((cua tre) or (su viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y lang ha hoi. hieu van cam ((xac va) OR (tuc va)) thanh de ((cua tre) OR (su viet)).
• Adding a wildcard symbol may retrieve word variants: so sach y lang ha hoi. hieu van cam ((xac va) or (tuc va)) thanh de ((cua tre) or (su viet))*.