Perhaps you should try some spelling variations:
phuong tran » phuong trinh, phuong thao, hung tran
huong tran » huong dan, quang tran, chuong trinh
hieu lang » chieu sang, hieu quang, nhieu tang
tang luan » dung luan
hoc hieu » hoc thieu, hoc hien, doc hieu
tang cua » mang cua, hang cua, thong cua
tan cau » toan cau, van cau, tan ca

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hieu lang - hanh ((tang cua) or (tang luan)) cong ((phuong tran) OR (huong tran)) tan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - hanh ((tang cua) OR (tang luan)) cong ((phuong tran) OR (huong tran)) tan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu lang - hanh ((tang cua) or (tang luan)) cong ((phuong tran) OR (huong tran)) tan cau".
• Adding a wildcard symbol may retrieve word variants: hoc hieu lang - hanh ((tang cua) or (tang luan)) cong ((phuong tran) OR (huong tran)) tan cau*.