Perhaps you should try some spelling variations:
hinh thai » sinh thai, tinh thai, dinh thi
nhanh thi » nhanh thai, nhanh thuc, nhan tai
hanh thai » nhanh thai, hanh tai, anh thai
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
duc ban » duc tan, duc van, dua ban
cac duc » cac du, cao duc, cac dac
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
ve cac » va cac, vien cac
nang o » nang co, nang ho, nang ro
o hai » co hai, so hai, o lai

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang o hai. hieu ve cac duc ban ((((hanh thai) OR (hinh thai))) or (nhanh thi)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang o hai. hieu ve cac duc ban ((((hanh thai) OR (hinh thai))) OR (nhanh thi)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang o hai. hieu ve cac duc ban ((((hanh thai) OR (hinh thai))) or (nhanh thi)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang o hai. hieu ve cac duc ban ((((hanh thai) OR (hinh thai))) or (nhanh thi)) cua tre*.