Perhaps you should try some spelling variations:
tinh tai » trinh tai, tinh thai, tinh hai
nang cau » nang cao, hang cau, nang dau
tai cua » thai cua, tai cuc, tri cua
sach ky » sac ky, sach y, sach kem
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
sach ty » sach y, sach tu, sach thu
tu can » tu ban, tu cac, thu canh
ve cac » va cac, vien cac
tu ca » tu cac, tu cua, tu cay

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 ((tu ca) OR (tu can)) tinh tai cua 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 ((tu ca) OR (tu can)) tinh tai cua 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 ((tu ca) OR (tu can)) tinh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sach ty)) nang cau hoi. hieu ve cac ((tu ca) OR (tu can)) tinh tai cua tre*.