Perhaps you should try some spelling variations:
dung tren » dung trong, dung trung
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
lang xa » lang ha, dang xay, lang van
van cam » van nam, van lam, van cau
cam duc » cam xuc, cao duc, pham duc
va hanh » van hanh, va thanh, va danh
y lang » o lang, _ lang, tay lang
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: tu sach y lang xa hoi. hieu van cam duc va hanh vi ((((dua tren) OR (dung tren))) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y lang xa hoi. hieu van cam duc va hanh vi ((((dua tren) OR (dung tren))) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y lang xa hoi. hieu van cam duc va hanh vi ((((dua tren) OR (dung tren))) or (cua te))".
• Adding a wildcard symbol may retrieve word variants: tu sach y lang xa hoi. hieu van cam duc va hanh vi ((((dua tren) OR (dung tren))) or (cua te))*.