Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
thai cua » than cua, tai cuc, tri cua
su sach » so sach, vu sach
va hanh » van hanh, va thanh, va danh
cau duc » cao duc, cau luc, chu duc
van cau » van dau, van hau, van chat
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
va han » va phan, van han, va hang
cua su » qua 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 sach ky ((nang xa) or (lang xa)) hoi. hieu van cau duc ((va han) OR (va hanh)) thai cua su~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang xa) OR (lang xa)) hoi. hieu van cau duc ((va han) OR (va hanh)) thai cua su.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang xa) or (lang xa)) hoi. hieu van cau duc ((va han) OR (va hanh)) thai cua su".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang xa) or (lang xa)) hoi. hieu van cau duc ((va han) OR (va hanh)) thai cua su*.