Perhaps you should try some spelling variations:
hoc thuoc » hoc thuc, hoc thuong, hoc nuoc
trinh va » trinh van, trinh vat, trinh ve
trong xa » trong xay, trong ca, trong xu
thuoc va » thuc va, thuoc ma, thuong va
su sach » so sach, vu sach
tinh vi » trinh vi, tinh voi, tinh va
cua tre » cua te, cuu tre, cua triet
sach tu » sach thu, cach tu, sach ty
hieu ve » hieu va, hieu van
tang ma » mang may, tang van
ve hoc » te hoc, va hoc, vi hoc

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 tu ((tang ma) or (trong xa)) hoi. hieu ve hoc thuoc va ((tinh vi) or (trinh va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach tu ((tang ma) OR (trong xa)) hoi. hieu ve hoc thuoc va ((tinh vi) OR (trinh va)) cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach tu ((tang ma) or (trong xa)) hoi. hieu ve hoc thuoc va ((tinh vi) or (trinh va)) cua tre*.