Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
viec cac » vien cac, viec cua, viec lam
danh vai » danh sai, danh va, doanh van
cau tren » cu tren, dau tren, ca tren
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
vai cau » va cau, van cau, vai cac
ma hoi » mai hoi, xa hoi, ma hoa
lo van » le 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: tu sach ky nang ma hoi. hieu viec cac ((lo van) or (vo van)) danh vai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ma hoi. hieu viec cac ((lo van) OR (vo van)) danh vai cau tren*.