Perhaps you should try some spelling variations:
thien quan » trien quang, lien quan, thien van
dien thanh » den thanh, tien thanh, dinh thanh
thiet qua » hieu qua, thien quy, khien qua
viet hoan » viet hoang, viet han, viet khoang
manh cua » doanh cua, ban cua
hoan hoc » hoa hoc, toan hoc, hoang hoa
dien dan » hien dai, vien dai, gian 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 qua) OR (thien quan)) manh cua nguoi viet hoan hoc ((dien dan) or (dien thanh))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: giao trinh ((thiet qua) OR (thien quan)) manh cua nguoi viet hoan hoc ((dien dan) OR (dien thanh)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "giao trinh ((thiet qua) OR (thien quan)) manh cua nguoi viet hoan hoc ((dien dan) or (dien thanh))".
• Adding a wildcard symbol may retrieve word variants: giao trinh ((thiet qua) OR (thien quan)) manh cua nguoi viet hoan hoc ((dien dan) or (dien thanh))*.