Perhaps you should try some spelling variations:
trinh thiet » trinh viet, trinh thi
vien thanh » viet thanh, tien thanh, dien thanh
thiet qua » thien quan, hieu qua, thien quy
qua doanh » cua doanh, qua danh, luat doanh
doanh cua » doanh luan
dien han » dien phan, dien than, dien dan
viet ha » viet nam
ha hoc » hoa hoc, nha hoc, va hoc

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: giao trinh thiet qua doanh cua nguoi viet ha hoc ((dien han) or (vien thanh))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: giao trinh thiet qua doanh cua nguoi viet ha hoc ((dien han) OR (vien thanh)).
• Adding a wildcard symbol may retrieve word variants: giao trinh thiet qua doanh cua nguoi viet ha hoc ((dien han) or (vien thanh))*.