Perhaps you should try some spelling variations:
su triet » su tien, ve triet
hanh vai » hanh vi, hanh va, hanh tai
truc va » thuc va, thuc vat, trung va
va hanh » van hanh, va thanh, va danh
su viet » so viet
sach ty » sach y, sach tu, sach thu
hieu va » lieu va, hieu qua
sai ky » sac ky
va cau » van cau, va cac, va dau
x hoi » xa hoi, o hoi, x ho

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) or (sai ky)) nang x hoi. hieu va cau truc va hanh vai ((su triet) OR (su viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sai ky)) nang x hoi. hieu va cau truc va hanh vai ((su triet) OR (su viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ty) or (sai ky)) nang x hoi. hieu va cau truc va hanh vai ((su triet) OR (su viet))".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ty) or (sai ky)) nang x hoi. hieu va cau truc va hanh vai ((su triet) OR (su viet))*.