Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu luc » hieu luat, hieu qua
van tuan » van quan, van ban, anh tuan
chat huu » pham huu
chat xuc » cam xuc, chao xu, chat cua
hieu cao » chieu cao, hieu cac, hieu ca
sach ty » sach y, sach tu, sach thu
hang ha » hang hoa, hang hai, hoang ha
ty hang » ly hang, ty xang, thi hang
tuan vi » quan vi, luan vi, quans vi
cua tre » cua te, cuu tre, cua triet
ha hoi » hoa hoi, ha noi, xa hoi
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: thu sach ty hang ha hoi. ((hieu cao) or (hieu luc)) ((chat xuc) OR (chat huu)) van tuan vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty hang ha hoi. ((hieu cao) OR (hieu luc)) ((chat xuc) OR (chat huu)) van tuan vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty hang ha hoi. ((hieu cao) or (hieu luc)) ((chat xuc) OR (chat huu)) van tuan vi cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ty hang ha hoi. ((hieu cao) or (hieu luc)) ((chat xuc) OR (chat huu)) van tuan vi cua tre*.