Perhaps you should try some spelling variations:
trinh luan » trinh luat, trinh quan, trinh han
hieu lang » chieu sang, hieu quang, nhieu tang
tinh cua » trinh cua, sinh cua, tinh chat
cong dan » cong tan, huong dan, cong dong
cong san » cong tac
toan cau » toan cao, toan ban, toan tap
ho hieu » ho chieu, hoi hieu, nho hieu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ho hieu lang - hanh ((trinh luan) or (tinh cua)) thong ((cong dan) or (cong san)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu lang - hanh ((trinh luan) OR (tinh cua)) thong ((cong dan) OR (cong san)) toan cau.
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - hanh ((trinh luan) or (tinh cua)) thong ((cong dan) or (cong san)) toan cau*.