Perhaps you should try some spelling variations:
cac nganh » hoc nganh
hanh gian » thanh gian, thanh giang, manh giang
gian cua » gian xu, ban cua
sach cac » sach cap, sach bac, sach dao
su sach » so sach, vu sach
xuc van » duc van, luc van, vuc van
dua ban » dia ban, cua ban, qua ban
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
ve cam » ve cham, ve cac, va cam
o hoi » co hoi, o hoc, o hai
y hoi » ky hoi, y hoc, 5 hoi

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 cac nganh ((y hoi) or (o hoi)). hieu ve cam ((xuc van) or (dua ban)) hanh gian cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach cac nganh ((y hoi) OR (o hoi)). hieu ve cam ((xuc van) OR (dua ban)) hanh gian cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach cac nganh ((y hoi) or (o hoi)). hieu ve cam ((xuc van) or (dua ban)) hanh gian cua tre*.