Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
dau truc » cau truc, dai truc, doan truc
va thanh » gia thanh, va tinh, le thanh
co viet » so viet, o viet, hoc viet
sach ly » sach lo, sach ty, sach hay
hieu va » lieu va, hieu qua
va dau » va dao
x hoi » xa hoi, o hoi, x ho
di co » doi co, de co, xi co

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach ly) or (sach y)) nang x hoi. hieu va dau truc ((va thanh) OR (ban thanh)) di co viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ly) OR (sach y)) nang x hoi. hieu va dau truc ((va thanh) OR (ban thanh)) di co viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ly) or (sach y)) nang x hoi. hieu va dau truc ((va thanh) OR (ban thanh)) di co viet".
• Adding a wildcard symbol may retrieve word variants: te ((sach ly) or (sach y)) nang x hoi. hieu va dau truc ((va thanh) OR (ban thanh)) di co viet*.