Perhaps you should try some spelling variations:
van thang » van thanh, van khang, van than
su triet » su viet, su tien, ve triet
van hang » van khang, van hoang, ban hang
cac truc » cau truc, cac tru, cac trung
su sach » so sach, vu sach
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
qua cac » cua cac
sach v » sach va, sach y, sach 2
don su » dong su, down su, dan su

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 v ((nang xa) OR (nang ma)) hoi. hieu qua cac truc ((van hang) or (van thang)) don su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach v ((nang xa) OR (nang ma)) hoi. hieu qua cac truc ((van hang) OR (van thang)) don su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach v ((nang xa) OR (nang ma)) hoi. hieu qua cac truc ((van hang) or (van thang)) don su triet".
• Adding a wildcard symbol may retrieve word variants: su sach v ((nang xa) OR (nang ma)) hoi. hieu qua cac truc ((van hang) or (van thang)) don su triet*.