Perhaps you should try some spelling variations:
su sach » so sach, vu sach
sach tu » sach thu, cach tu, sach ty
tu nang » tru nang, tu nong, tu nano
cao hoa » cao hoat, cao khoa, cau hoa
qua cac » cua cac
doan vi » doan va, don vi, doan thi
vi cua » vai cua, di cua
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 tu nang cao hoa. hieu qua cac ((duc va) or (tuc xa)) doan vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach tu nang cao hoa. hieu qua cac ((duc va) OR (tuc xa)) doan vi cua te.
• Adding a wildcard symbol may retrieve word variants: su sach tu nang cao hoa. hieu qua cac ((duc va) or (tuc xa)) doan vi cua te*.