Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van tham » van thanh, van tuan, van chat
tham duc » pham duc, tham du, than duc
van hanh » van thanh, ban hanh, van anh
sach ty » sach y, sach tu, sach thu
nang xa » nang x, lang xa, nang ma
duc van » duc va, duc tan, duc manh
hanh ki » hanh vi, hanh ky, hanh kien
su viet » so viet
sac ky » cac ky, sai ky
ki su » ky su

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sac ky) or (sach ty)) nang xa hoi. hieu van tham duc van hanh ki su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sac ky) OR (sach ty)) nang xa hoi. hieu van tham duc van hanh ki su viet.
• Adding a wildcard symbol may retrieve word variants: tu ((sac ky) or (sach ty)) nang xa hoi. hieu van tham duc van hanh ki su viet*.