Perhaps you should try some spelling variations:
thanh lai » thanh hai, thanh lap, thanh loi
nang mai » nang ma, nang tai, lang mai
hieu van » hieu va, thien van, lieu va
van chat » cao chat
dua tren » dung tren
mai hoi » mai khoi, dai hoi, lai hoi
cua tre » cua te, cuu tre, cua triet
te sac » te sach, te cac, te san
sac ky » cac ky, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sac ky nang mai hoi. hieu van chat ((quoc gia) or (duc gia)) thanh lai ((dua tren) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky nang mai hoi. hieu van chat ((quoc gia) OR (duc gia)) thanh lai ((dua tren) OR (cua tre)).
• Adding a wildcard symbol may retrieve word variants: te sac ky nang mai hoi. hieu van chat ((quoc gia) or (duc gia)) thanh lai ((dua tren) or (cua tre))*.