Perhaps you should try some spelling variations:
van tham » van thanh, van tuan, van chat
van hanh » van thanh, ban hanh, van ban
tham duc » pham duc, tham du, than duc
hieu van » hieu va, thien van, lieu va
van anh » van thanh, tuan anh, van minh
su viet » so viet
nang xa » nang x, lang xa, nang ma
sach ty » sach y, sach tu, sach thu
sai ky » sac 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 ((sai ky) or (sach ty)) nang xa hoi. hieu van tham duc ((van hanh) OR (van anh)) ki su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sai ky) OR (sach ty)) nang xa hoi. hieu van tham duc ((van hanh) OR (van anh)) ki su viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sai ky) or (sach ty)) nang xa hoi. hieu van tham duc ((van hanh) OR (van anh)) ki su viet".
• Adding a wildcard symbol may retrieve word variants: tu ((sai ky) or (sach ty)) nang xa hoi. hieu van tham duc ((van hanh) OR (van anh)) ki su viet*.