Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
toc sach » hoc sach, doc sach, nuoc sach
cua viet » hoa viet, cua vat, cua dieu
danh vi » hanh vi, dinh vi, danh di
va danh » va dinh, va dan, va hanh
cam tuc » cam xuc, cam tu, nam thuc
ca viet » va viet, co viet, hoa viet
hieu va » lieu va, hieu qua
hang xa » hoang xa, hang va, hang ca
tu hang » thu hang, tu hanh, tu hung
tuc va » thuc va, truc va, tuc xa
va cam » va cham, va cac, va cao

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) or (thuoc sach)) tu hang xa hoi. hieu va cam tuc va danh vi ((cua viet) OR (ca viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (thuoc sach)) tu hang xa hoi. hieu va cam tuc va danh vi ((cua viet) OR (ca viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (thuoc sach)) tu hang xa hoi. hieu va cam tuc va danh vi ((cua viet) OR (ca viet))".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (thuoc sach)) tu hang xa hoi. hieu va cam tuc va danh vi ((cua viet) OR (ca viet))*.