Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
hanh tai » thanh tai, hang tai, han tai
tai cua » thai cua, tai cuc, tri cua
va hanh » van hanh, va thanh, va danh
cac cop » cac hop, cac lop, cac cap
sach ky » sac ky, sach y, sach ty
su sach » so sach, vu sach
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
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 hien ((cac co) or (cac cop)) va hanh tai 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 hien ((cac co) OR (cac cop)) va hanh tai 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 hien ((cac co) or (cac cop)) va hanh tai cua te".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang xa) OR (nang ma)) hoi. hieu hien ((cac co) or (cac cop)) va hanh tai cua te*.