Perhaps you should try some spelling variations:
thuat mach » thuat sach, thuat tach, thuyet mach
doanh khoa » toan khoa
khoa khong » khoi khong, hoa khong, khon khong
dai thuat » dai thua, giai thuat, ki thuat
mach khoa » bach khoa, anh khoa, may khoa
phu thong » pho thong, phap thong, khau thong
thu doanh » thu oanh, tri doanh, thu hoach
khoa khoa » hoa khoa, khuan khoa, khoa hoc
sach dai » sach dao, sach bai, sach dat
khoa phu » khoa phau, khoa thu, hoa phu
sach tai » sach bai, sach tham, sach dao
so sach » so sanh, bo sach, co sach
te sach » toc 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: (( so sach dai thuat mach khoa phu thong ) or ( te sach tai thu doanh khoa khoa khong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( so sach dai thuat mach khoa phu thong ) OR ( te sach tai thu doanh khoa khoa khong )).
• Adding a wildcard symbol may retrieve word variants: (( so sach dai thuat mach khoa phu thong ) or ( te sach tai thu doanh khoa khoa khong ))*.