Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
tinh voi » trinh voi, tinh doi, binh voi
su sach » so sach, vu sach
voi cua » hoi cua, doi cua, moi cua
sach ty » sach y, sach tu, sach thu
van cau » van dau, van hau, van chat
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
xuc va » duc va, tuc va, xac va
luc va » duc va, tuc va, loc va

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 ty ((nang xa) or (nang cao)) hoi. hieu van cau ((xuc va) OR (luc va)) tinh voi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((nang xa) OR (nang cao)) hoi. hieu van cau ((xuc va) OR (luc va)) tinh voi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((nang xa) or (nang cao)) hoi. hieu van cau ((xuc va) OR (luc va)) tinh voi cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((nang xa) or (nang cao)) hoi. hieu van cau ((xuc va) OR (luc va)) tinh voi cua tre*.