Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
sach thu » sach thue, sach thieu, sach tham
hieu van » hieu va, thien van, lieu va
van pham » san pham, van phan, van phat
nang xa » lang xa, nang ma, mang xa
va hanh » van hanh, va thanh, va danh
so viet » hoc viet

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach thu ((nang xa) or (nang x)) hoi. hieu van pham duc va hanh vi ((su viet) OR (so viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach thu ((nang xa) OR (nang x)) hoi. hieu van pham duc va hanh vi ((su viet) OR (so viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach thu ((nang xa) or (nang x)) hoi. hieu van pham duc va hanh vi ((su viet) OR (so viet))".
• Adding a wildcard symbol may retrieve word variants: thu sach thu ((nang xa) or (nang x)) hoi. hieu van pham duc va hanh vi ((su viet) OR (so viet))*.