Perhaps you should try some spelling variations:
trinh thiet » trinh viet, trinh thi
trinh nhiet » trinh nghien, trinh viet, trinh triet
cho nguoi » cua nguoi
hoc tieng » hoc hien
tieng han » tieng anh
qua danh » qua dan, luan danh, luat danh
viet nma » viet nami, viet nhat, viet nam
viet nm » viet nam, viet nami, viet anh

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