Perhaps you should try some spelling variations:
dong thai » duong thai, dong tai, cong thai
dang xay » dang van, van xay
hieu van » hieu va, thien van, lieu va
nang xa » nang x, lang xa, nang ma
van cau » van dau, van hau, van chat
cau tuc » cau truc, cau tu, cau luc
xa dong » ha dong, van dong, lao dong
cua tre » cuu tre, cua triet, dua tren
su cac » tu cac, su cao, su can
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: su cac ky ((nang xa) or (dang xay)) hoi. hieu van cau tuc xa dong thai ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su cac ky ((nang xa) OR (dang xay)) hoi. hieu van cau tuc xa dong thai ((cua tre) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: su cac ky ((nang xa) or (dang xay)) hoi. hieu van cau tuc xa dong thai ((cua tre) or (cua te))*.