Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
ban hang » ngan hang
cau tren » cu tren, dau tren, ca tren
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
cac xuc » cam xuc, cac nuoc, chat xuc
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
tuan » quan, tran, luan

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 ky nang ma hoi. hieu vien cac xuc ((ban hang) or (tuan anh)) dai ((cau tren) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ma hoi. hieu vien cac xuc ((ban hang) OR (tuan anh)) dai ((cau tren) OR (cua tre)).
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ma hoi. hieu vien cac xuc ((ban hang) or (tuan anh)) dai ((cau tren) or (cua tre))*.