Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
hanh de » hanh ve, hanh kem
nang ma » tang ma, sang ma, nang cao
hieu va » hieu qua
hanh di » hanh vi, hang di, danh di
xuc va » duc va, tuc va, luc va
sach v » sach va, sach y, sach 2
ma hoi » mai hoi, xa hoi, ma hoa
v nang » va nang, vu nang, van nang
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach v nang ma hoi. ((hieu va) or (lieu va)) cam xuc va ((hanh di) OR (hanh de)) va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach v nang ma hoi. ((hieu va) OR (lieu va)) cam xuc va ((hanh di) OR (hanh de)) va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach v nang ma hoi. ((hieu va) or (lieu va)) cam xuc va ((hanh di) OR (hanh de)) va thiet".
• Adding a wildcard symbol may retrieve word variants: hoc sach v nang ma hoi. ((hieu va) or (lieu va)) cam xuc va ((hanh di) OR (hanh de)) va thiet*.