Perhaps you should try some spelling variations:
dinh thi » dinh tri
tu sach » thu sach, su sach, te sach
ty lang » tay lang, ty hang, tu lang
hieu va » hieu qua
cac loc » cac lop, cac toc, cac hoc
va dinh » van dinh, va kinh, va tinh
thi cua » thai cua, thi cuc, tri cua
loc va » hoc va, luc va
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((ty lang) OR (ty xang)) xa hoi. ((hieu va) or (lieu va)) cac loc va dinh thi cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty lang) OR (ty xang)) xa hoi. ((hieu va) OR (lieu va)) cac loc va dinh thi cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty lang) OR (ty xang)) xa hoi. ((hieu va) or (lieu va)) cac loc va dinh thi cua tu".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty lang) OR (ty xang)) xa hoi. ((hieu va) or (lieu va)) cac loc va dinh thi cua tu*.