Perhaps you should try some spelling variations:
viec sach » viet sach, vien bach, dien sach
hieu viec » nhieu viec, hieu ve, sieu viet
nang mai » nang ma, nang tai, lang mai
luoc van » luoc can, luc van, luot van
mai hoi » mai khoi, dai hoi, lai hoi
luoc va » nuoc va, duoc va, loc va
tu bac » tu ban, tu cac, tu bat
bac ky » cac ky, ban ky, sac ky
vi cua » vai cua, di cua
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu bac ky nang mai hoi. hieu viec sach ((luoc van) or (luoc va)) hanh vi cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu bac ky nang mai hoi. hieu viec sach ((luoc van) OR (luoc va)) hanh vi cua tu.
• Adding a wildcard symbol may retrieve word variants: tu bac ky nang mai hoi. hieu viec sach ((luoc van) or (luoc va)) hanh vi cua tu*.