Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
so sach » so sanh, co sach, hoc sach
bo sach » co sach, hoc sach
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
hanh va » hang va, hanh vi
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa
ve cam » ve cham, ve cac, va cam
xuc va » tuc va, luc va, xac va
va dau » va dao

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