Perhaps you should try some spelling variations:
manh tinh » man tinh, manh binh, canh tinh
tinh tai » trinh tai, tinh thai, tinh hai
duc manh » suc manh, duc anh, duc minh
tu sach » thu sach, su sach, te sach
tai cua » thai cua, tai cuc, tri cua
cam duc » cam xuc, cao duc, pham duc
qua cam » qua cham, qua cac, qua ca
lang xa » lang ha, dang xay, lang van
sach ty » sach y, sach tu, sach thu
tang ma » tang van
cua tre » cua te, cuu tre, cua triet

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 ty ((((tang ma) OR (mang may))) or (lang xa)) hoi. hieu qua cam duc manh tinh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((((tang ma) OR (mang may))) OR (lang xa)) hoi. hieu qua cam duc manh tinh tai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty ((((tang ma) OR (mang may))) or (lang xa)) hoi. hieu qua cam duc manh tinh tai cua tre*".