Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
thu nang » thi nang, thu hang, thu bang
dua tren » dung tren
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
hieu vu » hieu ve, hieu su, dieu vu
cua tre » cua te, cuu tre, cua triet
cham o » cham soc
o van » vo van, so van, do van

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