Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc anh
danh di » danh du, xanh di, danh dien
danh vi » hanh vi, dinh vi, danh va
truc va » thuc va, thuc vat, trung va
ca tren » cau tren, cu tren, la tren
hieu ve » hieu va, hieu van
nang ma » tang ma, sang ma, nang cao
hoc cac » hoc cao
ma hoi » mai hoi, xa hoi, ma hoa
ve cau » ke cau, va cau, ve cac

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