Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
so sach » so sanh, bo sach, co sach
cam tuc » cam xuc, nam thuc, dam thuc
hieu ve » hieu van
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
ma hoi » mai hoi, xa hoi, ma hoa
sach v » sach va, sach y, sach 2
cam tu » cam thu, nam tu, dam tu
v nang » va nang, vu nang, van nang
vi cua » vai cua, di cua
cua te » cua tu

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 v nang ma hoi. ((hieu ve) OR (hieu va)) ((cam tuc) or (cam tu)) van hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach v nang ma hoi. ((hieu ve) OR (hieu va)) ((cam tuc) OR (cam tu)) van hanh vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach v nang ma hoi. ((hieu ve) OR (hieu va)) ((cam tuc) or (cam tu)) van hanh vi cua te".
• Adding a wildcard symbol may retrieve word variants: so sach v nang ma hoi. ((hieu ve) OR (hieu va)) ((cam tuc) or (cam tu)) van hanh vi cua te*.