Perhaps you should try some spelling variations:
theo phap » thi phap
theo cap » pho cap, theo chu, theo ucp
te sach » toc sach
sach ky » sac ky, sach y, sach ty
doan vi » doan va, don vi, doan thi
hieu va » lieu va, hieu qua
dang ma » dang mau, dang mam, dang mat
hieu ve » hieu van
ky dang » ky nang, ky danh
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky dang ma hoi. ((hieu ve) or (hieu va)) cac ((theo cap) OR (theo phap)) doan vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky dang ma hoi. ((hieu ve) OR (hieu va)) cac ((theo cap) OR (theo phap)) doan vi cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky dang ma hoi. ((hieu ve) or (hieu va)) cac ((theo cap) OR (theo phap)) doan vi cua tre*".