Perhaps you should try some spelling variations:
doanh khoan » doanh khoa, doanh hoan, doanh nhan
thuat mach » thuat sach, thuat tach, thuyet mach
dai thuat » dai thua, giai thuat, ki thuat
mach khoa » bach khoa, anh khoa, may khoa
pho thong » he thong
thu doanh » thu oanh, tri doanh, thu hoach
khoan hoi » khoan nhoi, khoa hoi, khoa hoc
hoi khong » khoi khong, hoa khong, noi khong
sach dai » sach dao, sach bai, sach dat
khoa pho » khoa phu, khoa khoa, khoa phau
toc sach » hoc sach, doc sach, thuoc sach
sach tai » sach bai, sach tham, sach dao
su sach » so sach, vu sach
tai thu » thi thu, tai khu, tai thi

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 dai thuat mach khoa pho thong ) or ( toc sach tai thu doanh khoan hoi khong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( su sach dai thuat mach khoa pho thong ) OR ( toc sach tai thu doanh khoan hoi khong )).
• Adding a wildcard symbol may retrieve word variants: (( su sach dai thuat mach khoa pho thong ) or ( toc sach tai thu doanh khoan hoi khong ))*.