Perhaps you should try some spelling variations:
xanh doi » xanh di, thanh doi, tinh doi
cham hoc » cham soc, chat hoc, cham hoi
hieu ve » hieu va, hieu van
doi cua » dai cua, hoi cua
va xanh » va danh, va hanh, va anh
cua tre » cua te, cuu tre, cua triet
hieu vu » hieu va, hieu su, dieu vu
sach v » sach va, sach 2, sach vay
x hoi » xa hoi, o hoi, x ho

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 v) or (sach y)) nang x hoi. ((hieu vu) OR (hieu ve)) cham hoc va xanh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach v) OR (sach y)) nang x hoi. ((hieu vu) OR (hieu ve)) cham hoc va xanh doi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach v) or (sach y)) nang x hoi. ((hieu vu) OR (hieu ve)) cham hoc va xanh doi cua tre".
• Adding a wildcard symbol may retrieve word variants: te ((sach v) or (sach y)) nang x hoi. ((hieu vu) OR (hieu ve)) cham hoc va xanh doi cua tre*.