Perhaps you should try some spelling variations:
trinh thiet » trinh viet
trinh thi » trinh tai, dinh thi, trinh tu
cho nguoi » cua nguoi
hien huan » hien thuan, hien quan, tien huan
qua danh » qua dan, luan danh, luat danh
viet nha » viet nhat, viet ha, viec nha
hien han » hien hanh, dien han, hien thuan
nha hoc » nha thuoc, khoa hoc, nha nuoc

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) or (trinh thi)) qua danh cho nguoi viet nha hoc ((hien han) OR (hien huan))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: giao ((trinh thiet) OR (trinh thi)) qua danh cho nguoi viet nha hoc ((hien han) OR (hien huan)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "giao ((trinh thiet) or (trinh thi)) qua danh cho nguoi viet nha hoc ((hien han) OR (hien huan))".
• Adding a wildcard symbol may retrieve word variants: giao ((trinh thiet) or (trinh thi)) qua danh cho nguoi viet nha hoc ((hien han) OR (hien huan))*.