Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
thanh va » thanh van, hanh va, thanh ha
ban quoc » han quoc, dan quoc, ban duoc
viec ban » viec lam, viec va, viec tai
tu sach » thu sach, su sach, te sach
mai hoi » mai khoi, dai hoi, lai hoi
cuu tre » cua tre, cau tren, cau treo
ky tang » ky nang, ky dang, kho tang
ky sang » ky nang, ky dang, duy sang
ma hoi » xa hoi, ma hoa, me hoi
va cuu » va cau, va chu, va huu
gia » giao

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((ky sang) OR (ky tang)) ((ma hoi) or (mai hoi)). hieu viec ban quoc gia thanh va cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky sang) OR (ky tang)) ((ma hoi) OR (mai hoi)). hieu viec ban quoc gia thanh va cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky sang) OR (ky tang)) ((ma hoi) or (mai hoi)). hieu viec ban quoc gia thanh va cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky sang) OR (ky tang)) ((ma hoi) or (mai hoi)). hieu viec ban quoc gia thanh va cuu tre*.