Perhaps you should try some spelling variations:
hieu thien » hieu hien, chieu chien, dieu khien
thien cac » hien cac, thien cau, thieu cac
ban hanh » ban hang
vai cua » dai cua, hai cua, lai cua
va hanh » van hanh, va thanh, va danh
sach ky » sac ky, sach y, sach ty
su sach » so sach, vu sach
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
cac co » cac cong
cua te » cua tu

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 (nang ma)) hoi. hieu thien cac co ((va hanh) or (ban hanh)) vai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang xa) OR (nang ma)) hoi. hieu thien cac co ((va hanh) OR (ban hanh)) vai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang xa) OR (nang ma)) hoi. hieu thien cac co ((va hanh) or (ban hanh)) vai cua te".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang xa) OR (nang ma)) hoi. hieu thien cac co ((va hanh) or (ban hanh)) vai cua te*.