Perhaps you should try some spelling variations:
trinh thiet » trinh viet, trinh thi
viet thang » viet thanh, viet thong, viet trang
thiet qua » thien quan, hieu qua, thien quy
qua tinh » qua trinh, quan tinh, qua kinh
tinh cua » trinh cua, sinh cua, tinh chat
hoc viet » hoc hien
viet va » viet van, viet ha, tiet va
va hoc » van 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 tinh cua nguoi viet va hoc viet thang~.
• Adding a wildcard symbol may retrieve word variants: giao trinh thiet qua tinh cua nguoi viet va hoc viet thang*.