Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
van pham » san pham, van phan, van phat
van hanh » van thanh, ban hanh, van anh
va triet » va thiet, va trien, ve triet
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
va hanh » va thanh, va danh, ban hanh
vi va » vi van, vai va, vu va

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 y ((nang xa) or (nang ma)) hoi. hieu van pham duc ((va hanh) or (van hanh)) vi va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y ((nang xa) OR (nang ma)) hoi. hieu van pham duc ((va hanh) OR (van hanh)) vi va triet.
• Adding a wildcard symbol may retrieve word variants: thu sach y ((nang xa) or (nang ma)) hoi. hieu van pham duc ((va hanh) or (van hanh)) vi va triet*.