Perhaps you should try some spelling variations:
sach thue » sach thu, sach thieu, sach tham
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
van pham » san pham, van phan, van phat
nang xa » lang xa, mang xa, ang xa
nang ma » tang ma, sang ma, nang cao
va hanh » van hanh, va thanh, va danh
hanh ki » hanh vi, hanh ky, hanh kien
su viet » so viet
ki su » ky su

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