Perhaps you should try some spelling variations:
dang mam » dang nam, dang mau, dang mat
mam hoai » man hoai, pham hoai, nam hoi
hieu van » hieu va, thien van, lieu va
van cham » van chat, van tham, va cham
ky dang » ky nang, ky danh
cua tre » cuu tre, cua triet, dua tren
doan vi » doan va, don vi, doan thi
tu sac » tu sach, tu cac, tu san
tuc va » thuc va, truc va, duc va
sac ky » cac ky, sai ky
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky dang mam hoai. hieu van cham ((tuc va) or (tuc xa)) doan vi ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky dang mam hoai. hieu van cham ((tuc va) OR (tuc xa)) doan vi ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky dang mam hoai. hieu van cham ((tuc va) or (tuc xa)) doan vi ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: tu sac ky dang mam hoai. hieu van cham ((tuc va) or (tuc xa)) doan vi ((cua tre) OR (cua te))*.