Perhaps you should try some spelling variations:
vien sach » vien bach, dien sach, viet sach
sach duoc » sach nuoc, sach dao, sach dung
hieu vien » hieu hien, hieu viec, thieu nien
hanh tri » thanh tri, hanh tai, hanh trinh
nang doc » nang luc
van hanh » van thanh, ban hanh, van anh
duoc van » duoc va, duc van, duoc ban
cuu tre » cau tren, cau treo
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
nang co » nang cao, nang noi, nang hoc
cua tre » cua te, cua triet, dua tren

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky ((nang co) or (nang doc)) hoi. hieu vien sach duoc van hanh tri ((cuu tre) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky ((nang co) OR (nang doc)) hoi. hieu vien sach duoc van hanh tri ((cuu tre) OR (cua tre)).
• Adding a wildcard symbol may retrieve word variants: so sach ky ((nang co) or (nang doc)) hoi. hieu vien sach duoc van hanh tri ((cuu tre) or (cua tre))*.