Perhaps you should try some spelling variations:
dua tren » dung tren
sach ly » sach y, sach lo, sach ty
va hanh » van hanh, va thanh, va danh
cac thu » cach thuc, cac thoi
hieu va » lieu va, hieu qua
su sach » so sach, vu sach
lang ha » long ha
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
thu va » thuc va, thue va, tu 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 ly ((nang xa) or (lang ha)) hoi. hieu va cac thu va hanh vi ((dua tren) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly ((nang xa) OR (lang ha)) hoi. hieu va cac thu va hanh vi ((dua tren) OR (cua tre)).
• Adding a wildcard symbol may retrieve word variants: su sach ly ((nang xa) or (lang ha)) hoi. hieu va cac thu va hanh vi ((dua tren) or (cua tre))*.