Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
dua tren » dung tren
vu sach » vu bach, su sach, vu khach
sach ly » sach y, sach lo, sach ty
ly nang » ky nang, ly hang, ly vang
nang xa » nang x, lang xa, nang ma
van cac » van hac, van cau, van bac
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau tren, cau treo
cac tu » cac thu, cach tu, cac du

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 ly nang xa hoi. hieu van cac tu va hanh vi ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ly nang xa hoi. hieu van cac tu va hanh vi ((dua tren) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: vu sach ly nang xa hoi. hieu van cac tu va hanh vi ((dua tren) or (cuu tre))*.