Perhaps you should try some spelling variations:
chat trung » chat trong, ha trung, cua trung
thu sach » tu sach, thuat sach, thuoc sach
hieu cac » hieu luc, hieu va, hieu van
cac chat » cao chat, cac thuat, cac nha
va hanh » van hanh, va thanh, ban hanh
cua tre » cua te, cua triet, dua tren
va danh » va dinh, va dan, dia danh
sach ky » sac ky, sach y, sach ty
cuu tre » cau tren, cau treo
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky nang o hoi. hieu cac chat trung ((va danh) OR (va hanh)) dai ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang o hoi. hieu cac chat trung ((va danh) OR (va hanh)) dai ((cua tre) OR (cuu tre))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang o hoi. hieu cac chat trung ((va danh) OR (va hanh)) dai ((cua tre) or (cuu tre))*".