Perhaps you should try some spelling variations:
dung doi » huong doi, dung tai, dung co
su sach » so sach, vu sach
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
qua cam » qua cham, qua cac, qua ca
doi cua » dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
xuc va » duc va, luc va, xac va
tuc va » thuc va, truc va, tuc xa

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 y ((nang xa) or (lang xa)) hoi. hieu qua cam ((xuc va) OR (tuc va)) dung doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang xa) OR (lang xa)) hoi. hieu qua cam ((xuc va) OR (tuc va)) dung doi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((nang xa) or (lang xa)) hoi. hieu qua cam ((xuc va) OR (tuc va)) dung doi cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang xa) or (lang xa)) hoi. hieu qua cam ((xuc va) OR (tuc va)) dung doi cua tre*.