Perhaps you should try some spelling variations:
thuat sang » thuat song, thuat san, thuat bang
hieu van » thien van, lieu va, hieu ve
cap nuoc » dat nuoc
dang tai » dang thai, dung tai, hang tai
sang ky » sang kyo, dang ky, tang ky
nang ma » tang ma, sang ma, mang may
hieu va » lieu va, hieu qua
va dang » van dang, va nang, va lang
cuc te » cua te, cuc thue, cuc tieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuat sang ky ((nang ma) or (nang cao)) hoi. ((hieu van) OR (hieu va)) cap nuoc va dang tai cuc te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sang ky ((nang ma) OR (nang cao)) hoi. ((hieu van) OR (hieu va)) cap nuoc va dang tai cuc te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sang ky ((nang ma) or (nang cao)) hoi. ((hieu van) OR (hieu va)) cap nuoc va dang tai cuc te".
• Adding a wildcard symbol may retrieve word variants: thuat sang ky ((nang ma) or (nang cao)) hoi. ((hieu van) OR (hieu va)) cap nuoc va dang tai cuc te*.