Perhaps you should try some spelling variations:
vanh dai » vanh tai, lanh dao, van dao
su sach » so sach, vu sach
ky lang » ky nang, ky dang, tay lang
ky tang » ky nang, ky dang, kho tang
qua hai » qua hoat
hai xuc » hai cuc, hai xu, chat xuc
van dai » van dao, van hai, can dai
xuc va » duc va, tuc va, luc va
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: su sach ((ky lang) or (ky tang)) xa hoi. hieu qua hai xuc va ((vanh dai) OR (van dai)) cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ky lang) OR (ky tang)) xa hoi. hieu qua hai xuc va ((vanh dai) OR (van dai)) cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ky lang) or (ky tang)) xa hoi. hieu qua hai xuc va ((vanh dai) OR (van dai)) cua te".
• Adding a wildcard symbol may retrieve word variants: su sach ((ky lang) or (ky tang)) xa hoi. hieu qua hai xuc va ((vanh dai) OR (van dai)) cua te*.