Perhaps you should try some spelling variations:
trinh thiet » trinh viet, trinh thi
thiet luan » thien luan, thi luan, thien quan
doanh luan » doanh nhan
nguoi vien » nguoi viet, nguoi tien, nguoi chien
vien khoa » von khoa, lieu khoa, van khoa
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 luan ((doanh cua) OR (doanh luan)) nguoi vien khoa hoc ((dien han) or (vien than))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: giao trinh thiet luan ((doanh cua) OR (doanh luan)) nguoi vien khoa hoc ((dien han) OR (vien than)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "giao trinh thiet luan ((doanh cua) OR (doanh luan)) nguoi vien khoa hoc ((dien han) or (vien than))".
• Adding a wildcard symbol may retrieve word variants: giao trinh thiet luan ((doanh cua) OR (doanh luan)) nguoi vien khoa hoc ((dien han) or (vien than))*.