Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
tang van » dang van, hoang van, trong van
van hanh » van thanh, ban hanh, van anh
chat tuc » chat xuc, luat tuc, chat huu
cua tre » cuu tre, cua triet, dua tren
tuc van » thuc van, truc van, tuc va
hieu va » lieu va, hieu qua
hieu ve » hieu van
van hoc » van hoa
y tang » ky tang, 6 tang, 7 tang
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach y tang van hoc. ((hieu ve) or (hieu va)) chat tuc van hanh vi ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y tang van hoc. ((hieu ve) OR (hieu va)) chat tuc van hanh vi ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y tang van hoc. ((hieu ve) or (hieu va)) chat tuc van hanh vi ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: toc sach y tang van hoc. ((hieu ve) or (hieu va)) chat tuc van hanh vi ((cua tre) OR (cua te))*.