Perhaps you should try some spelling variations:
trinh thiet » trinh viet, trinh thi
xuan thanh » quan thanh, quang thanh, van thanh
ban thanh » ban hanh, ban hang
viet khoa » vien khoa, viec khoa, viet khoang
vien than » vien thanh, dien than, vien nhan
khoa hoc » hoa hoc
dien han » dien phan, dien than, dien dan

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 ((ban thanh) or (xuan thanh)) cua nguoi viet khoa hoc ((dien han) or (vien than))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: giao trinh thiet ((ban thanh) OR (xuan thanh)) cua nguoi viet khoa hoc ((dien han) OR (vien than)).
• Adding a wildcard symbol may retrieve word variants: giao trinh thiet ((ban thanh) or (xuan thanh)) cua nguoi viet khoa hoc ((dien han) or (vien than))*.