Perhaps you should try some spelling variations:
dinh thi » dinh tri
te sach » toc sach
thi cua » thai cua, thi cuc, tri cua
va dinh » van dinh, va kinh, va tinh
cac tac » cac toc, cac bac, cac dac
cac tuc » cac toc, cac tu, cac nuoc
hoa hoi » khoa hoi, hoa hoc, hoa doi
cua tre » cua te, cuu tre, cua triet
y lang » o lang, _ lang, tay lang
ha hoi » ha noi, xa hoi, va hoi

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 y lang ((ha hoi) OR (hoa hoi)). hieu qua ((cac tuc) or (cac tac)) va dinh thi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y lang ((ha hoi) OR (hoa hoi)). hieu qua ((cac tuc) OR (cac tac)) va dinh thi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y lang ((ha hoi) OR (hoa hoi)). hieu qua ((cac tuc) or (cac tac)) va dinh thi cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach y lang ((ha hoi) OR (hoa hoi)). hieu qua ((cac tuc) or (cac tac)) va dinh thi cua tre*.