Perhaps you should try some spelling variations:
muong doong » muong duong, tuong duong, cuong duong
muong dong » muong duong, tuong dong, huong dong
hieu van » hieu va, thien van, lieu va
so sanh » do sanh
van cam » van nam, van lam, van cau
cam tuc » cam xuc, cam tu, nam thuc
sanh ky » hanh ky, sang ky, nganh ky
nang xa » lang xa, nang ma, mang xa
cuu tre » cua tre, cau tren, cau treo

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sanh ky ((nang xa) OR (nang x)) hoi. hieu van cam tuc xa ((muong dong) or (muong doong)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sanh ky ((nang xa) OR (nang x)) hoi. hieu van cam tuc xa ((muong dong) OR (muong doong)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sanh ky ((nang xa) OR (nang x)) hoi. hieu van cam tuc xa ((muong dong) or (muong doong)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: so sanh ky ((nang xa) OR (nang x)) hoi. hieu van cam tuc xa ((muong dong) or (muong doong)) cuu tre*.