Perhaps you should try some spelling variations:
nang cau » nang cao, hang cau, nang dau
tinh tai » trinh tai, tinh thai, tinh hai
cac toc » cac toi, cac nuoc, cac thoi
cua tre » cua te, cua triet, dua tren
va tinh » may tinh
cuu tre » cau tren, cau treo
sach ky » sac ky, sach y, sach kem
hieu ve » hieu va, hieu van
sach ty » sach y, sach tu, sach thu
toc va » hoc va, toc ta, tuc va
ve cac » va cac, vien 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 ((sach ky) or (sach ty)) nang cau hoi. hieu ve cac toc va tinh tai ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sach ty)) nang cau hoi. hieu ve cac toc va tinh tai ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) or (sach ty)) nang cau hoi. hieu ve cac toc va tinh tai ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sach ty)) nang cau hoi. hieu ve cac toc va tinh tai ((cua tre) OR (cuu tre))*.