Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cua viet » ca viet, cua vat, cua dieu
thi hang » thi hanh, thi nang, thi hong
danh vi » hanh vi, dinh vi, danh di
ty hang » ly hang, ty xang, thu hang
hieu va » lieu va, hieu qua
cam tuc » cam xuc, cam tu, nam thuc
va danh » va dinh, va dan, va hanh
va cam » va cham, va cac, va cao
tuc va » thuc va, truc va, tuc xa

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 ((ty hang) or (thi hang)) xa hoi. hieu va cam tuc va danh vi ((cua viet) or (hoa viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ty hang) OR (thi hang)) xa hoi. hieu va cam tuc va danh vi ((cua viet) OR (hoa viet)).
• Adding a wildcard symbol may retrieve word variants: toc sach ((ty hang) or (thi hang)) xa hoi. hieu va cam tuc va danh vi ((cua viet) or (hoa viet))*.