Perhaps you should try some spelling variations:
trinh thien » trinh thiet, trinh tien, trinh nghien
thien quan » trien quang, lien quan, thien van
nang quan » ban quan, nang suat
viet khoa » vien khoa, viec khoa, viet khoang
vien than » vien thanh, dien than, vien nhan
nang dua » nang du, nang suat, nang luc
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 thien quan ((nang dua) or (nang quan)) nguoi viet khoa hoc ((dien han) or (vien than))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: giao trinh thien quan ((nang dua) OR (nang quan)) nguoi viet khoa hoc ((dien han) OR (vien than)).
• Adding a wildcard symbol may retrieve word variants: giao trinh thien quan ((nang dua) or (nang quan)) nguoi viet khoa hoc ((dien han) or (vien than))*.