Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
sang mai » sang ma, sang tai, lang mai
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va thanh, va danh
cam tuc » cam xuc, nam thuc, dam thuc
su sach » so sach, vu sach
hieu ve » hieu van
mai hoi » mai khoi, dai hoi, lai hoi
ky sang » ky nang, ky dang, ky tang
hieu va » lieu va, hieu qua
cam tu » cam thu, nam tu, dam tu
vi cua » vai cua, di cua

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

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