Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
thuc van » thuc vat, thuc dan, thuc va
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va
tuc van » truc van, tuc va, duc van
y lang » o lang, _ lang, tay lang
vi cua » vai cua, di cua
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: toc sach y lang xa hoi. ((hieu ve) OR (hieu van)) cam ((tuc van) or (thuc van)) hanh vi cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y lang xa hoi. ((hieu ve) OR (hieu van)) cam ((tuc van) OR (thuc van)) hanh vi cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y lang xa hoi. ((hieu ve) OR (hieu van)) cam ((tuc van) or (thuc van)) hanh vi cua tu".
• Adding a wildcard symbol may retrieve word variants: toc sach y lang xa hoi. ((hieu ve) OR (hieu van)) cam ((tuc van) or (thuc van)) hanh vi cua tu*.