Perhaps you should try some spelling variations:
thuc xay » thuc day, tuc xay, thuat xay
hanh vai » hanh vi, hanh va, hanh tai
sach thu » sach thue, sach thieu, sach tham
hieu van » hieu va, thien van, lieu va
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
thuc xa » tuc xa, thuc va, thuc ha
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
van am » van nam, van lam, van dam

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) or (sach thu)) nang ma hoa. hieu van am ((thuc xa) OR (thuc xay)) hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach thu)) nang ma hoa. hieu van am ((thuc xa) OR (thuc xay)) hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sach thu)) nang ma hoa. hieu van am ((thuc xa) OR (thuc xay)) hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach thu)) nang ma hoa. hieu van am ((thuc xa) OR (thuc xay)) hanh vai cua tre*.