Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
cau tren » cu tren, dau tren, ca tren
sang ma » tang ma, nang ma, sang tao
ky sang » ky nang, ky dang, ky tang
sach ky » sac ky, sach y, sach ty
va danh » va dinh, va dan, va hanh
danh vi » hanh vi, dinh vi, danh di
ma hoi » mai hoi, xa hoi, ma hoa
ve cau » ve cac, le cau, ve cai
ke cau » ket cau
va cau » van cau, va cac, va dau
luc va » duc va, tuc va, loc va
vi cau » di cau, viet cau

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 ky sang ma hoi. hieu ((((ve cau) OR (ke cau))) or (va cau)) luc va danh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ky sang ma hoi. hieu ((((ve cau) OR (ke cau))) OR (va cau)) luc va danh vi cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ky sang ma hoi. hieu ((((ve cau) OR (ke cau))) or (va cau)) luc va danh vi cau tren".
• Adding a wildcard symbol may retrieve word variants: hoc sach ky sang ma hoi. hieu ((((ve cau) OR (ke cau))) or (va cau)) luc va danh vi cau tren*.