Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
hanh vai » hanh vi, hanh va, hanh tai
nang xa » lang xa, nang ma, mang xa
nam duc » nam duoc, pham duc, nam thuc
duc van » duc va, duc tan, duc manh
vai cua » dai cua, hai cua, lai cua
sai ky » sac ky
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: thu ((sai ky) or (cac ky)) ((nang xa) OR (nang x)) hoi. hieu van nam duc van hanh vai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sai ky) OR (cac ky)) ((nang xa) OR (nang x)) hoi. hieu van nam duc van hanh vai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sai ky) or (cac ky)) ((nang xa) OR (nang x)) hoi. hieu van nam duc van hanh vai cua te".
• Adding a wildcard symbol may retrieve word variants: thu ((sai ky) or (cac ky)) ((nang xa) OR (nang x)) hoi. hieu van nam duc van hanh vai cua te*.