Perhaps you should try some spelling variations:
sach duoc » sach nuoc, sach dao, sach dung
viet sach » viet anh, dien sach, viet tech
lieu viet » sieu viet, lieu vien, tieu viet
tinh doi » trinh doc, trinh do, tinh hoc
cau tren » cu tren, dau tren, ca tren
lang xa » lang ha, dang xay, lang van
duoc va » nuoc va, duc va, duoc ma
nang xa » nang x, nang ma, mang xa
xanh di » danh di, vanh dai, xanh tai
xac ky » cac ky, sac ky, bac ky
su xac » pu xac, su cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: su xac ky ((nang xa) or (lang xa)) hoi. lieu viet sach duoc va ((tinh doi) or (xanh di)) cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su xac ky ((nang xa) OR (lang xa)) hoi. lieu viet sach duoc va ((tinh doi) OR (xanh di)) cau tren.
• Adding a wildcard symbol may retrieve word variants: su xac ky ((nang xa) or (lang xa)) hoi. lieu viet sach duoc va ((tinh doi) or (xanh di)) cau tren*.