Perhaps you should try some spelling variations:
dung doi » huong doi, dung tai, dung co
vat dung » van dung, va dung, viet dung
hieu van » thien van, lieu va, hieu ve
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
doi cua » dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
cam tu » cam thu, nam tu, dam tu
tu vat » tu va, tu van, tu bat

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ky ((nang xa) or (nang ma)) hoi. ((hieu va) or (hieu van)) cam tu vat dung doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky ((nang xa) OR (nang ma)) hoi. ((hieu va) OR (hieu van)) cam tu vat dung doi cua tre.
• Adding a wildcard symbol may retrieve word variants: vu sach ky ((nang xa) or (nang ma)) hoi. ((hieu va) or (hieu van)) cam tu vat dung doi cua tre*.