Perhaps you should try some spelling variations:
xanh hanh » danh thanh, ban hanh, van hanh
duc xanh » duc anh, duc manh, duc hanh
dua tren » dung tren
hieu van » hieu va, thien van, lieu va
hanh tai » thanh tai, hang tai, han tai
tu sang » thu sang, tu san, tu lang
sang ky » sang kyo, dang ky, tang ky
cao duc » dao duc, cao suc, giao duc
van cao » van dao, van bao, van hao
nang ma » tang ma, sang ma, nang cao
ma hoi » mai hoi, xa hoi, ma hoa
cua te » cua tu
cua cu » cua chu, cua cau, cua su

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sang ky nang ma hoi. hieu van cao duc xanh hanh tai ((dua tren) or (((cua te) or (cua cu))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sang ky nang ma hoi. hieu van cao duc xanh hanh tai ((dua tren) OR (((cua te) OR (cua cu)))).
• Adding a wildcard symbol may retrieve word variants: tu sang ky nang ma hoi. hieu van cao duc xanh hanh tai ((dua tren) or (((cua te) or (cua cu))))*.