Perhaps you should try some spelling variations:
thi nang » thi cong, ki nang, thi hanh
hang hai » hoang hai, hang tai, thanh hai
sach thi » sach thu, sach tai, sach thieu
so sach » so sanh, bo sach, co sach
ve phan » va phan, ke phan, ve phat
hai cua » thai cua, dai cua, hoi cua
va hang » van hang, va nang, va lang
chuc va » thuc va, thuc vat
ve pham » vi pham, v pham, ve phat
mai hoi » mai khoi, dai hoi, lai hoi
ma hoi » xa hoi, ma hoa, me hoi
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: so sach thi nang ((ma hoi) or (mai hoi)). hieu ((ve pham) OR (ve phan)) chuc va hang hai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach thi nang ((ma hoi) OR (mai hoi)). hieu ((ve pham) OR (ve phan)) chuc va hang hai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach thi nang ((ma hoi) or (mai hoi)). hieu ((ve pham) OR (ve phan)) chuc va hang hai cua te".
• Adding a wildcard symbol may retrieve word variants: so sach thi nang ((ma hoi) or (mai hoi)). hieu ((ve pham) OR (ve phan)) chuc va hang hai cua te*.