Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
duc manh » suc manh, duc anh, duc minh
dang xay » dang van, van xay
van cam » van nam, van lam, van cau
duc van » duc va, duc tan, duc phan
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
can ky » van ky, dan ky, ban ky
anh vi » hanh vi, anh va, anh ve
vi cua » vai cua, di cua
tu can » tu ban, tu cac, thu canh

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu can ky ((nang ma) or (dang xay)) hoi. hieu van cam ((duc van) or (duc manh)) anh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu can ky ((nang ma) OR (dang xay)) hoi. hieu van cam ((duc van) OR (duc manh)) anh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu can ky ((nang ma) or (dang xay)) hoi. hieu van cam ((duc van) or (duc manh)) anh vi cua tre*.