Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
nang ma » tang ma, sang ma, nang cao
hieu va » hieu qua
va dinh » van dinh, va tinh, vu dinh
va kinh » va tinh, qua kinh
su viet » so viet
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa
dam tu » nam tu, cam tu, tam tu

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 y nang ma hoi. ((hieu va) OR (lieu va)) dam tu ((va dinh) or (va kinh)) va su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach y nang ma hoi. ((hieu va) OR (lieu va)) dam tu ((va dinh) OR (va kinh)) va su viet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach y nang ma hoi. ((hieu va) OR (lieu va)) dam tu ((va dinh) or (va kinh)) va su viet*".