Perhaps you should try some spelling variations:
duoc tren » nuoc tren, thuoc tren, dung tren
thien van » thi van
duc tre » duc tien
va hang » van hang, va nang, va lang
cam loc » cam lo
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
dang xa » dang xay, lang xa, dang ha
y dang » ky dang, 2 dang, _ dang
loc va » hoc va, luc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y dang xa hoi. ((hieu ve) or (thien van)) cam loc va hang va ((duc tre) OR (duoc tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y dang xa hoi. ((hieu ve) OR (thien van)) cam loc va hang va ((duc tre) OR (duoc tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y dang xa hoi. ((hieu ve) or (thien van)) cam loc va hang va ((duc tre) OR (duoc tren))".
• Adding a wildcard symbol may retrieve word variants: su sach y dang xa hoi. ((hieu ve) or (thien van)) cam loc va hang va ((duc tre) OR (duoc tren))*.