Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
ve cham » va cham, ve chat, vu cham
luc gia » luoc gia, duc gia, duc giao
cua tre » cua te, cuu tre, cua triet

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 ma)) hoi. hieu ve cham ((luc gia) OR (quoc gia)) thanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((nang xa) OR (nang ma)) hoi. hieu ve cham ((luc gia) OR (quoc gia)) thanh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((nang xa) or (nang ma)) hoi. hieu ve cham ((luc gia) OR (quoc gia)) thanh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((nang xa) or (nang ma)) hoi. hieu ve cham ((luc gia) OR (quoc gia)) thanh dai cua tre*.