Perhaps you should try some spelling variations:
nang mai » nang tai, lang mai, nang cai
dat duoc » dat nuoc, da duoc, luat duoc
cau treo » cau theo, cau tren, cau triet
nang ma » tang ma, sang ma, nang cao
hieu de » hieu ve, hieu he, hieu le
duoc va » nuoc va, duc va, duoc ma
va hanh » van hanh, va thanh, va danh
vu san » va san, vu ban
san ky » sang ky, van ky, dan ky
de dat » de dao
vi cau » va cau, ve cau, di cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu san ky ((nang mai) or (nang ma)) hoi. hieu de dat duoc va hanh vi cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu san ky ((nang mai) OR (nang ma)) hoi. hieu de dat duoc va hanh vi cau treo*.