Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, cau treo
so sach » so sanh, bo sach, co sach
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
ca tren » cu tren, la tren, co tren
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa
ve cam » ve cham, ve cac, va cam
xac va » tac va, ac va, bac va

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