Perhaps you should try some spelling variations:
hanh tai » thanh tai, hang tai, han tai
hieu va » lieu va, hieu qua
tai cua » thai cua, tai cuc, tri cua
va hanh » van hanh, va thanh, va danh
cham lo » cham o, cam lo, cham soc
cua tre » cua te, cuu tre, cua triet
sach ty » sach y, sach thu, xach tay
hieu vu » hieu ve, hieu su, dieu vu
nang ma » tang ma, sang ma, nang cao
sach tu » sach thu, cach tu, sach uu
lo va » lo van, lao va, ly va

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu ((sach ty) OR (sach tu)) nang ma hoa. ((hieu vu) or (hieu va)) cham lo va hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ty) OR (sach tu)) nang ma hoa. ((hieu vu) OR (hieu va)) cham lo va hanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ty) OR (sach tu)) nang ma hoa. ((hieu vu) or (hieu va)) cham lo va hanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ty) OR (sach tu)) nang ma hoa. ((hieu vu) or (hieu va)) cham lo va hanh tai cua tre*.