Perhaps you should try some spelling variations:
cham truc » cau truc, nham thuc, pham thuc
cuu tre » cua tre, cau tren, cau treo
doan vi » doan va, don vi, doan thi
truc va » thuc va, thuc vat, trung va
hieu ve » hieu va, hieu van
ve cham » va cham, ve chat, vu cham
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
sac ky » cac ky, sai ky
dan vi » don vi, dan va, gan vi
tu sac » tu sach, tu cac, tu san

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 ((nang ma) or (tang ma)) hoi. hieu ve cham truc va ((dan vi) or (doan vi)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky ((nang ma) OR (tang ma)) hoi. hieu ve cham truc va ((dan vi) OR (doan vi)) cuu tre.
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((nang ma) or (tang ma)) hoi. hieu ve cham truc va ((dan vi) or (doan vi)) cuu tre*.