Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
doanh van » doan van, doanh va, doanh ban
cau tren » cu tren, dau tren, ca tren
danh vai » danh sai, danh va, dang van
dua tren » dung tren
hien cac » thien cac, vien cac, hieu cac
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
sang ma » tang ma, nang ma, sang tao
ky sang » ky nang, ky dang, ky tang
cac lo » cac lop, cac co, cac bo
ma hoi » mai hoi, xa hoi, ma hoa
lo va » lo van, lao va, ly va

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 ma hoi. hieu hien cac lo va ((danh vai) or (doanh van)) ((dua tren) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky sang ma hoi. hieu hien cac lo va ((danh vai) OR (doanh van)) ((dua tren) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky sang ma hoi. hieu hien cac lo va ((danh vai) or (doanh van)) ((dua tren) or (cau tren))*.