Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
van pham » san pham, van phan, van tham
van phat » va phat, van chat, van phan
tu sach » thu sach, su sach, te sach
nang xa » lang xa, nang ma, mang xa
va hanh » van hanh, va thanh, va danh
su viet » so viet
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: tu sach thu ((nang xa) or (nang x)) hoi. hieu ((van pham) OR (van phat)) duc va hanh vi su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thu ((nang xa) OR (nang x)) hoi. hieu ((van pham) OR (van phat)) duc va hanh vi su viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach thu ((nang xa) or (nang x)) hoi. hieu ((van pham) OR (van phat)) duc va hanh vi su viet".
• Adding a wildcard symbol may retrieve word variants: tu sach thu ((nang xa) or (nang x)) hoi. hieu ((van pham) OR (van phat)) duc va hanh vi su viet*.