Perhaps you should try some spelling variations:
hang hai » hoang hai, hang tai, thanh hai
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
qua cac » cua cac
duc man » duc manh, duc tan, duc mau
duc van » duc va, duc tan, duc manh
hai cuu » hai cua, hai chu, hai cuc
cuu tre » cua tre, cau tren, cau treo

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 ky nang x ho. hieu qua cac ((duc man) or (duc van)) hang hai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang x ho. hieu qua cac ((duc man) OR (duc van)) hang hai cuu tre.
• Adding a wildcard symbol may retrieve word variants: so sach ky nang x ho. hieu qua cac ((duc man) or (duc van)) hang hai cuu tre*.