Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
va tinh » may tinh
va hanh » van hanh, va thanh, va danh
hieu va » lieu va, hieu qua
cac tuc » cac toc, cac tu, cac tac
nang xa » nang x, lang xa, nang ma
sach ty » sach y, sach tu, sach thu
sai ky » sac ky
vi su » va su, ve su, ki su

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sai ky) or (sach ty)) nang xa hoi. hieu va cac tuc ((va hanh) or (va tinh)) vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sai ky) OR (sach ty)) nang xa hoi. hieu va cac tuc ((va hanh) OR (va tinh)) vi su triet.
• Adding a wildcard symbol may retrieve word variants: su ((sai ky) or (sach ty)) nang xa hoi. hieu va cac tuc ((va hanh) or (va tinh)) vi su triet*.