Perhaps you should try some spelling variations:
hanh dinh » thanh dinh, hinh dinh, hanh tinh
nang mai » nang ma, nang tai, lang mai
mai khoi » mai khoa, tai khoa, cac khoi
so sach » so sanh, bo sach, co sach
cam tuc » cam xuc, cam tu, nam thuc
va hanh » van hanh, va thanh, va danh
cu tren » tu tren, dua tren
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
hieu ve » hieu van
tuc va » thuc va, truc va, tuc xa
cu tre » cua tre, cuu tre, cu tri

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky nang mai khoi. ((hieu ve) or (hieu va)) cam tuc va hanh dinh ((cu tre) OR (cu tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang mai khoi. ((hieu ve) OR (hieu va)) cam tuc va hanh dinh ((cu tre) OR (cu tren))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky nang mai khoi. ((hieu ve) or (hieu va)) cam tuc va hanh dinh ((cu tre) OR (cu tren))*".