Perhaps you should try some spelling variations:
thien van » thi van
thuat san » thuat toan, thuat song, thuat lanh
hieu van » hieu va, lieu va, hieu ve
van hanh » van thanh, ban hanh, van anh
nang ma » sang ma, nang cao, mang may
tang ma » mang may, tang van
dat van » dao van, dat va, dam van
san ky » sang ky, van ky, dan ky
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuat san ky ((nang ma) or (tang ma)) hoi. ((hieu van) OR (thien van)) cai dat van hanh vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat san ky ((nang ma) OR (tang ma)) hoi. ((hieu van) OR (thien van)) cai dat van hanh vi cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat san ky ((nang ma) or (tang ma)) hoi. ((hieu van) OR (thien van)) cai dat van hanh vi cua vat".
• Adding a wildcard symbol may retrieve word variants: thuat san ky ((nang ma) or (tang ma)) hoi. ((hieu van) OR (thien van)) cai dat van hanh vi cua vat*.