Perhaps you should try some spelling variations:
nang man » nang ma, nang ban, lang man
hang vai » hang tai, hang hai, hang vi
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
cuu tre » cua tre, cau tren, cau treo
cac duc » cao duc, cac dac, cac nuoc
hieu ve » hieu va, hieu van
man hoi » man hoai, dan hoi, van hoi

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang man hoi. hieu ve ((cac duc) OR (cac du)) va ((hang vai) OR (hang va)) cuu tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang man hoi. hieu ve ((cac duc) OR (cac du)) va ((hang vai) or (hang va)) cuu tre~".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang man hoi. hieu ve ((cac duc) OR (cac du)) va ((hang vai) or (hang va)) cuu tre*.